CN118194775B - Method and device for determining icing thickness of rotary negative pressure fan - Google Patents

Abstract

The present application discloses a method and device for determining the ice thickness of a rotary negative pressure fan. The method includes: determining the temperature and wind speed at the head of the fan, and obtaining the first speed of the airflow; determining the air pressure difference between the windward side and the leeward side of the fan blade, determining the second speed of the airflow when it flows to the blade, and determining the solution function of the freezing coefficient of the fan icing; determining the freezing coefficient of the fan icing; determining the freezing rain ice weight of the fan at a future predicted time point in a freezing rain environment, and the freezing fog ice weight at a future predicted time point in a freezing fog environment; predicting the ice weight of the fan at a future predicted time point, and determining the ice thickness of the fan at a future predicted time point based on the ice weight and the side length of the blade, so as to realize the prediction of the ice thickness of the fan in the freezing rain environment and/or the freezing fog environment, and improve the accuracy of the prediction of the ice thickness of the fan, so that the obtained ice thickness of the fan is more real and more in line with the actual icing situation.

Description

Method and device for determining ice thickness of a rotary negative pressure fan

Technical Field

The present application relates to the technical field of fan ice coating treatment, and in particular to a method, device and storage medium for determining ice coating thickness of a rotary negative pressure fan.

Background Art

Most wind turbine units are located in high-altitude areas. In winter, cold waves and cold air cause wind turbines to be iced and shut down in a concentrated manner, resulting in large-scale grid disconnection, which has a great impact on the safe, reliable and stable supply of electricity. Among them, wind turbine units include rotary negative pressure fans, which are fans that operate on the cooling principle of air convection and negative pressure ventilation. In order to ensure power safety, it is necessary to accurately predict the future icing conditions of wind turbines. However, since the icing of wind turbine blades in wind farms is affected by the coupling of multiple factors such as terrain factors and environmental factors, the icing conditions of wind turbines are complicated, and the prediction of icing thickness is more difficult. In addition, during freezing fog and freezing rain, the environment of the wind farm is more difficult to grasp, and the condition of the wind turbine is more difficult to understand, making it difficult to predict the icing of the wind turbine, and the accuracy of the predicted icing results is low.

Summary of the invention

The purpose of the embodiments of the present application is to provide a method, device and storage medium for determining the ice thickness of a rotary negative pressure fan, so as to solve the problem in the prior art that it is impossible to accurately determine the ice thickness of the fan in a freezing fog and freezing rain environment.

In order to achieve the above-mentioned object, the first aspect of the present application provides a method for determining the ice thickness of a rotary negative pressure fan, the method comprising:

Determine the temperature and wind speed at the head of the fan, and obtain the first speed of the airflow, wherein the airflow refers to the airflow that is at a preset distance from the fan and currently flows toward the fan, determine the pressure difference between the windward side and the leeward side of the blades of the fan according to the first speed, determine the second speed of the airflow when it flows to the blades according to the first function and the pressure difference, and determine the solution function of the freezing coefficient of the icing of the fan according to the second speed, the second function and the third function, wherein the first function represents the functional relationship between the first speed and the acceleration distance, the acceleration distance refers to the distance between the acceleration point of the airflow and the fan, the second function represents the functional relationship between the amount of ice per unit surface area of the fan per unit time and the first speed, and the third function represents the functional relationship between the amount of ice per unit surface area of the fan per unit time, the second speed and the freezing coefficient;

Determine the freezing coefficient of the fan according to the wind speed at the head of the fan and the solution function of the freezing coefficient, and determine whether the fan is in a freezing rain environment and/or a freezing fog environment according to the temperature at the head of the fan;

When it is determined that the fan is in a freezing rain environment and/or a freezing fog environment, the freezing rain ice weight of the fan at a future predicted time point in the freezing rain environment is determined according to the final falling speed of the freezing rain drops and the speed of the supercooled water droplets on the blades, and the freezing fog ice weight of the fan at a future predicted time point in the freezing fog environment is determined according to the freezing coefficient, the speed of the supercooled water droplets and the supercooled water content in the air;

The ice weight of the wind turbine at a predicted future time point is predicted based on the ice weight of freezing rain and the ice weight of freezing fog, and the ice thickness of the wind turbine at a predicted future time point is determined based on the ice weight and the side length of the blades.

In the embodiment of the present application, the solution function for determining the freezing coefficient of the fan icing according to the second speed, the second function and the third function includes the solution function as shown in formula (1):

(1)

in, is the freezing coefficient, is the first speed, i is a constant, is the density of ice, is the density of water, is a constant, is the pressure difference, is the density of moist air.

In an embodiment of the present application, determining the temperature and wind speed at the head of the wind turbine includes: constructing a multi-layer nested grid of the micro-topography area where the wind turbine is located, and determining the meteorological data of each grid in the micro-topography area through an ice cover numerical model, wherein the meteorological data includes temperature and wind speed; obtaining the altitude of the head; determining the average temperature and average altitude of all grids in the micro-topography area; determining the temperature of the head according to the altitude, average temperature and average altitude of the head; obtaining the altitude curve of the micro-topography area, and selecting any two adjacent peak points from the altitude curve as target peak points; obtaining each target peak point the altitude of the wind turbine and the altitude of the trough point between the two target crest points; determine the first area of the micro-topography area according to the altitude of each target crest point and the horizontal distance between the two target crest points; determine the second area of the micro-topography area according to the altitude of each target crest point and the altitude of the trough point; determine the valley line at the wind turbine position in the digital elevation data of the micro-topography area; determine the angle between the valley line and the wind direction at the wind turbine position; determine the wind speed of the micro-topography area according to the angle and the wind speed of the grid corresponding to the head; determine the wind speed at the head according to the first area, the second area and the wind speed of the micro-topography area.

In the embodiment of the present application, determining the second speed of the airflow when it flows to the blade according to the first function and the pressure difference includes determining the second speed according to formula (2):

(2)

in, is the second speed, is the first speed, is the pressure difference, is a constant, is the density of moist air.

In the embodiment of the present application, determining the freezing rain ice weight of the fan at a future predicted time point in a freezing rain environment according to the final falling speed of freezing rain drops and the speed of supercooled water droplets on the blades includes determining the freezing rain ice weight according to formula (3):

(3)

in, The weight of ice covered by freezing rain, is the total ice weight in the freezing rain environment for a period of time t, V is the velocity of supercooled water droplets, is the final falling velocity of freezing raindrops, is the precipitation in the freezing rain environment within a period of time t, is the density of water.

In the embodiment of the present application, determining the freezing fog ice weight of the fan at a future predicted time point in the freezing fog environment according to the freezing coefficient, the speed of the supercooled water droplets, and the supercooled water content in the air includes determining the freezing fog ice weight according to formula (4):

(4)

in, The weight of the ice covered by the freezing fog, is the total ice weight in the freezing fog environment within a period of t, is the freezing coefficient, V is the velocity of supercooled water droplets, W is the supercooled water content in the air, is the density of moist air.

In the embodiment of the present application, predicting the ice weight of the wind turbine at a future prediction time point according to the ice weight of freezing rain and the ice weight of freezing fog includes determining the ice weight according to formula (5):

(5)

in, is the weight of ice, t and T are both durations, is the total ice weight in the freezing rain environment for a period of time t, is the total ice weight within t time in freezing fog environment.

In the embodiment of the present application, determining the ice thickness of the wind turbine at a predicted future time point according to the ice weight and the side length of the blade includes determining the ice thickness according to formula (6):

(6)

in, is the ice thickness, is the ice weight, is the density of ice, Is the side length.

A second aspect of the present application provides a device for determining ice thickness of a rotary negative pressure fan, comprising:

A first processing module is used to determine the temperature and wind speed at the head of the fan, and obtain a first speed of the airflow, wherein the airflow refers to the airflow that is at a preset distance from the fan and currently flows toward the fan, determine the pressure difference between the windward side and the leeward side of the blades of the fan according to the first speed, determine the second speed of the airflow when it flows to the blades according to the first function and the pressure difference, and determine a solution function for the freezing coefficient of the icing of the fan according to the second speed, the second function and the third function, wherein the first function represents a functional relationship between the first speed and the acceleration distance, the acceleration distance refers to the distance between the acceleration point of the airflow and the fan, the second function represents a functional relationship between the amount of ice per unit surface area of the fan per unit time and the first speed, and the third function represents a functional relationship between the amount of ice per unit surface area of the fan per unit time, the second speed and the freezing coefficient;

The second processing module is used to determine the freezing coefficient of the fan according to the wind speed at the head of the fan and the solution function of the freezing coefficient, and determine whether the fan is in a freezing rain environment and/or a freezing fog environment according to the temperature at the head;

The third processing module is used to determine the freezing rain ice weight of the fan at a future predicted time point in the freezing rain environment according to the final falling speed of the freezing rain raindrops and the speed of the supercooled water droplets on the blades when it is determined that the fan is in a freezing rain environment and/or a freezing fog environment, and to determine the freezing fog ice weight of the fan at a future predicted time point in the freezing fog environment according to the freezing coefficient, the speed of the supercooled water droplets and the supercooled water content in the air;

The fourth processing module is used to predict the ice weight of the wind turbine at a future predicted time point based on the ice weight of freezing rain and the ice weight of freezing fog, and determine the ice thickness of the wind turbine at a future predicted time point based on the ice weight and the side length of the blades.

In the embodiment of the present application, the first processing module determines the solution function of the freezing coefficient of the fan icing according to the second speed, the second function and the third function, including the solution function as shown in formula (1):

(1)

in, is the freezing coefficient, is the first speed, i is a constant, is the density of ice, is the density of water, is a constant, is the pressure difference, is the density of moist air.

In an embodiment of the present application, the first processing module determines the temperature and wind speed at the head of the wind turbine, including: constructing a multi-layer nested grid in the micro-topography area where the wind turbine is located, and determining the meteorological data of each grid in the micro-topography area through an ice cover numerical model, wherein the meteorological data includes temperature and wind speed; obtaining the altitude of the head; determining the average temperature and average altitude of all grids in the micro-topography area; determining the temperature of the head according to the altitude, average temperature and average altitude of the head; obtaining the altitude curve of the micro-topography area, and selecting any two adjacent peak points from the altitude curve as target peak points; obtaining each target The altitude of the crest point and the altitude of the trough point between two target crest points; determine the first area of the micro-topography area according to the altitude of each target crest point and the horizontal distance between the two target crest points; determine the second area of the micro-topography area according to the altitude of each target crest point and the altitude of the trough point; determine the valley line at the wind turbine position in the digital elevation data of the micro-topography area; determine the angle between the valley line and the wind direction at the wind turbine position; determine the wind speed of the micro-topography area according to the angle and the wind speed of the grid corresponding to the head; determine the wind speed at the head according to the first area, the second area and the wind speed of the micro-topography area.

In the embodiment of the present application, the first processing module determines the second speed of the airflow when it flows to the blade according to the first function and the pressure difference, including determining the second speed according to formula (2):

(2)

in, is the second speed, is the first speed, is the pressure difference, is a constant, is the density of moist air.

In the embodiment of the present application, the third processing module determines the freezing rain ice weight of the fan at a future predicted time point in the freezing rain environment according to the final falling speed of the freezing rain droplets and the speed of the supercooled water droplets on the blades, including determining the freezing rain ice weight according to formula (3):

(3)

in, The weight of ice covered by freezing rain, is the total ice weight in the freezing rain environment for a period of time t, V is the velocity of supercooled water droplets, is the final falling velocity of freezing raindrops, is the precipitation in the freezing rain environment within a period of time t, is the density of water.

In the embodiment of the present application, the third processing module determines the freezing fog ice weight of the fan at a future predicted time point in the freezing fog environment according to the freezing coefficient, the speed of the supercooled water droplets, and the supercooled water content in the air, including determining the freezing fog ice weight according to formula (4):

(4)

in, The weight of the ice covered by the freezing fog, is the total ice weight in the freezing fog environment within a period of t, is the freezing coefficient, V is the velocity of supercooled water droplets, W is the supercooled water content in the air, is the density of moist air.

In the embodiment of the present application, the fourth processing module predicts the ice weight of the wind turbine at a future prediction time point according to the freezing rain ice weight and the freezing fog ice weight, including determining the ice weight according to formula (5):

(5)

in, is the weight of ice, t and T are both durations, is the total ice weight in the freezing rain environment for a period of time t, is the total ice weight within t time in freezing fog environment.

In the embodiment of the present application, the fourth processing module determines the ice thickness of the wind turbine at a future predicted time point according to the ice weight and the side length of the blade, including determining the ice thickness according to formula (6):

(6)

in, is the ice thickness, is the ice weight, is the density of ice, Is the side length.

A third aspect of the present application provides a machine-readable storage medium having instructions stored thereon, the instructions being used to enable a machine to execute the above-mentioned method for determining the ice thickness of a rotary negative pressure fan.

Through the above technical scheme, the solution function of the freezing coefficient of the fan can be determined according to the second speed, the second function and the third function, and the freezing coefficient of the fan can be determined according to the wind speed at the fan head and the solution function, so that the freezing coefficient is determined with more comprehensive factors and the freezing coefficient is calculated in a more rigorous and accurate way, so that the obtained freezing coefficient has higher precision and is more accurate; whether the fan is in a freezing rain environment and/or a freezing fog environment can be determined according to the temperature at the fan head; when it is determined that the fan is in a freezing rain environment and/or a freezing fog environment, it can be determined that the fan is in a freezing rain environment according to the final falling speed of the freezing raindrops and the speed of the supercooled water droplets on the fan blades. The freezing rain ice cover weight at a future prediction time point is determined, and the freezing fog ice cover weight of the fan at a future prediction time point is determined according to the freezing coefficient, the speed of supercooled water droplets and the supercooled water content in the air; and the ice cover weight of the fan at a future prediction time point is predicted according to the freezing rain ice cover weight and the freezing fog ice cover weight, and the ice cover thickness of the fan at a future prediction time point is determined according to the ice cover weight and the side length of the blade, so as to realize the prediction of the ice cover thickness of the fan in the freezing rain environment and/or freezing fog environment, and the ice cover thickness is predicted based on a more accurate freezing coefficient, which improves the accuracy of the prediction of the ice cover thickness of the fan, so that the obtained ice cover thickness of the fan is more realistic and more in line with the actual icing conditions.

Other features and advantages of the embodiments of the present application will be described in detail in the subsequent specific implementation section.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present application, but do not constitute a limitation on the embodiments of the present application. In the accompanying drawings:

FIG1 schematically shows a flow chart of a method for determining ice thickness of a rotary negative pressure fan according to an embodiment of the present application;

FIG2 schematically shows a schematic diagram of an altitude curve according to an embodiment of the present application;

FIG3 schematically shows an internal structure diagram of a computer device according to an embodiment of the present application.

DETAILED DESCRIPTION

In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the specific implementation methods described herein are only used to illustrate and explain the embodiments of the present application, and are not used to limit the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back...), such directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

Fig. 1 schematically shows a flow chart of a method for determining ice thickness of a rotary negative pressure fan according to an embodiment of the present application. As shown in Fig. 1, an embodiment of the present application provides a method for determining ice thickness of a rotary negative pressure fan, which may include the following steps.

Step 101: Determine the temperature and wind speed at the head of the fan, and obtain the first speed of the airflow, wherein the airflow refers to the airflow that is at a preset distance from the fan and currently flows toward the fan, determine the pressure difference between the windward side and the leeward side of the fan blade according to the first speed, determine the second speed of the airflow when it flows to the blade according to the first function and the pressure difference, and determine the solution function of the freezing coefficient of the fan icing according to the second speed, the second function and the third function, wherein the first function represents the functional relationship between the first speed and the acceleration distance, the acceleration distance refers to the distance between the acceleration point of the airflow and the fan, the second function represents the functional relationship between the amount of ice per unit surface area of the fan per unit time and the first speed, and the third function represents the functional relationship between the amount of ice per unit surface area of the fan per unit time, the second speed and the freezing coefficient.

The processor can determine the temperature and wind speed at the head of the fan, and obtain the first speed of the airflow, wherein the airflow refers to the airflow that is at a preset distance from the fan and currently flows toward the fan. After obtaining the first speed, the processor can determine the pressure difference between the windward side and the leeward side of the blade of the fan according to the first speed. After obtaining the pressure difference, the processor can determine the second speed of the airflow when it flows to the blade according to the first function and the pressure difference. After obtaining the second speed, the processor can determine the solution function of the freezing coefficient of the fan icing according to the second speed, the second function and the third function, wherein the first function represents the functional relationship between the first speed and the acceleration distance, the acceleration distance refers to the distance between the acceleration point of the airflow and the fan, the second function represents the functional relationship between the amount of ice per unit surface area of the fan per unit time and the first speed, and the third function represents the functional relationship between the amount of ice per unit surface area of the fan per unit time, the second speed and the freezing coefficient.

In an embodiment of the present application, the processor can obtain a first speed of the airflow, wherein the airflow refers to an airflow whose distance from the fan is a preset distance and currently flows toward the fan, determine the pressure difference between the windward side and the leeward side of the fan blade according to the first speed, determine the second speed of the airflow when it flows to the blade according to the first function and the pressure difference, and determine the solution function of the freezing coefficient of the fan icing according to the second speed, the second function and the third function, wherein the first function represents the functional relationship between the first speed and the acceleration distance, the acceleration distance refers to the distance between the acceleration point of the airflow and the fan, the second function represents the functional relationship between the amount of ice per unit surface area of the fan per unit time and the first speed, and the third function represents the functional relationship between the amount of ice per unit surface area of the fan per unit time, the second speed and the freezing coefficient. After determining the solution function of the freezing coefficient of the fan icing, the processor can determine the temperature and wind speed at the head of the fan.

Alternatively, the processor may determine the temperature and wind speed at the head of the fan. After determining the temperature and wind speed at the head, the processor may obtain a first speed of the airflow, wherein the airflow refers to an airflow that is at a preset distance from the fan and currently flows toward the fan, determine the pressure difference between the windward side and the leeward side of the fan blades according to the first speed, determine the second speed of the airflow when it flows to the blades according to the first function and the pressure difference, and determine a solution function for the freezing coefficient of the icing of the fan according to the second speed, the second function, and the third function, wherein the first function represents the functional relationship between the first speed and the acceleration distance, the acceleration distance refers to the distance between the acceleration point of the airflow and the fan, the second function represents the functional relationship between the amount of ice per unit surface area of the fan per unit time and the first speed, and the third function represents the functional relationship between the amount of ice per unit surface area of the fan per unit time, the second speed, and the freezing coefficient.

In an embodiment of the present application, determining the temperature and wind speed at the head of the wind turbine includes: constructing a multi-layer nested grid of the micro-topography area where the wind turbine is located, and determining the meteorological data of each grid in the micro-topography area through an ice cover numerical model, wherein the meteorological data includes temperature and wind speed; obtaining the altitude of the head; determining the average temperature and average altitude of all grids in the micro-topography area; determining the temperature of the head according to the altitude, average temperature and average altitude of the head; obtaining the altitude curve of the micro-topography area, and selecting any two adjacent peak points from the altitude curve as target peak points; obtaining each target peak point the altitude of the wind turbine and the altitude of the trough point between the two target crest points; determine the first area of the micro-topography area according to the altitude of each target crest point and the horizontal distance between the two target crest points; determine the second area of the micro-topography area according to the altitude of each target crest point and the altitude of the trough point; determine the valley line at the wind turbine position in the digital elevation data of the micro-topography area; determine the angle between the valley line and the wind direction at the wind turbine position; determine the wind speed of the micro-topography area according to the angle and the wind speed of the grid corresponding to the head; determine the wind speed at the head according to the first area, the second area and the wind speed of the micro-topography area.

The processor can determine the temperature and wind speed at the head of the wind turbine. Specifically, the processor can construct a multi-layer nested grid of the micro-topography area where the wind turbine is located. After establishing the multi-layer nested grid of the micro-topography area, the processor can determine the meteorological data of each grid in the micro-topography area through the ice cover numerical model. Among them, the meteorological data may include temperature and wind speed. After determining the meteorological data of each grid in the micro-topography area, the processor can obtain the altitude at the head. The processor can also obtain the altitude of each grid, and determine the average altitude of all grids in the micro-topography area based on the altitude of each grid. The processor can determine the average temperature of all grids in the micro-topography area based on the temperature of each grid. After the average altitude and average temperature of all grids, the processor can determine the temperature at the head based on the altitude of the head, the average temperature of all grids and the average altitude. For example, the processor determines the average temperature of all grids in the micro-topography area based on the temperature of each grid. , determine the average altitude of all grids in the micro-topography area based on the altitude of each grid The processor can also obtain the altitude of the nose . After getting the average temperature of all grids , average altitude and the altitude at the nose of the aircraft After that, the processor can , average altitude and altitude Determine the temperature at the head ,Right now ,in, is the wet adiabatic lapse rate, and its value is 0.6℃/100m.

The processor can obtain an altitude curve of the micro-topography area. After obtaining the altitude curve, the processor can select any two adjacent peak points from the altitude curve as target peak points. After obtaining two target peak points, the processor can obtain the altitude of each target peak point and the altitude of the trough point between the two target peak points. The processor can also determine the horizontal distance between the two target peak points. After determining the horizontal distance between the two target peak points, the processor can determine the first area of the micro-topography area according to the altitude of each target peak point and the horizontal distance between the two target peak points. The processor can also determine the second area of the micro-topography area according to the altitude of each target peak point and the altitude of the trough point. The processor can also determine the valley line at the location of the fan in the digital elevation data (DEM) of the micro-topography area. For example, the valley line can be a line connecting the two lowest altitude points at the location of the fan. After determining the valley line, the processor can determine the angle between the valley line and the wind direction at the location of the fan. After determining the angle between the valley line and the wind direction at the wind turbine position, the processor can determine the wind speed of the micro-topography area according to the angle and the wind speed of the grid corresponding to the head. For example, when the micro-topography area is a valley, the wind speed of the micro-topography area can be the wind speed at the entrance of the valley. After determining the wind speed of the micro-topography area, the processor can determine the wind speed at the head according to the first area, the second area and the wind speed of the micro-topography area.

For example, the micro-topography area is a valley, a pass or a canyon, and the processor can obtain the altitude curve of the micro-topography area. As shown in Figure 2, two adjacent peak points in the altitude curve are both the highest points of the peak, where the highest point of the peak can include the height of the head of the wind turbine on the peak. The trough point between two adjacent peak points is the lowest point of the valley. The processor can obtain the altitude of the highest point of each peak and the altitude of the lowest point of the valley. The processor can also obtain the horizontal distance between the highest points of the two peaks. In Figure 2, the altitudes of the highest points of the two peaks and the horizontal distance between the highest points of the two peaks form a rectangle. The processor can determine the area of the rectangle based on the altitudes of the highest points of the two peaks and the horizontal distance between the highest points of the two peaks. The altitude of the highest point of the two peaks and the altitude of the lowest point of the valley form a triangle. The processor can determine the area of the triangle based on the altitude of the highest point of the two peaks and the altitude of the lowest point of the valley. .

The processor can determine the line between the two lowest altitude points at the wind turbine location from the digital elevation data and use the line as the valley line. The processor can also obtain the wind direction at the wind turbine location and determine the angle between the valley line and the wind direction. The processor can also obtain the wind speed of the grid corresponding to the head of the fan , and according to the angle and wind speed Determine wind speed in micro-topographic areas, i.e., the entrance wind speed to the valley After determining the area of the rectangle , triangle area And the inlet wind speed The processor can then calculate the area of the rectangle. , triangle area And the inlet wind speed Determine the wind speed at the fan head , .

Step 102: Determine the freezing coefficient of the fan according to the wind speed at the head of the fan and the solution function of the freezing coefficient, and determine whether the fan is in a freezing rain environment and/or a freezing fog environment according to the temperature at the head.

The processor can determine the freezing coefficient of the fan according to the wind speed at the head of the fan and the solution function of the freezing coefficient, and determine whether the fan is in a freezing rain environment and/or a freezing fog environment according to the temperature at the head.

In an embodiment of the present application, the processor can determine the freezing coefficient of the fan according to the wind speed at the head of the fan and the solution function of the freezing coefficient. After determining the freezing coefficient of the fan, the processor can determine whether the fan is in a freezing rain environment and/or a freezing fog environment according to the temperature at the head. Alternatively, the processor can determine whether the fan is in a freezing rain environment and/or a freezing fog environment according to the temperature at the head. After determining whether the fan is in a freezing rain environment and/or a freezing fog environment, the processor can determine the freezing coefficient of the fan according to the wind speed at the head of the fan and the solution function of the freezing coefficient.

In an embodiment of the present application, after determining the temperature and wind speed at the head, the processor can obtain the first speed of the airflow, wherein the airflow refers to the airflow whose distance from the fan is a preset distance and currently flows toward the fan. After obtaining the first speed, the processor can determine the pressure difference between the windward side and the leeward side of the fan blade according to the first speed. For example, the processor can obtain the speed U of the airflow whose distance from the fan is a preset distance and currently flows toward the fan from the rotation plane of the blade perpendicular to the fan. When the airflow flows into the rotation plane of the blade at the speed U, the cross-sectional area of the flow tube on the windward side and the leeward side of the blade will change. Specifically, the cross-sectional area on the windward side becomes smaller, and the cross-sectional area on the leeward side becomes larger after being blocked by the blade. Based on the conservation of air mass when the airflow flows into the front end of the rotation plane of the blade and flows out of the rear end of the rotation plane of the blade, the processor can determine that there will be a pressure difference between the windward side and the leeward side of the blade. After determining that there will be a pressure difference between the windward side and the leeward side, the processor can determine the pressure difference between the windward side and the leeward side based on the speed U and the conservation of air mass. On the windward side of the blade there is , the leeward side of the blade has ,in, is the air pressure on the windward side of the blade, is the air density, is the air pressure at a preset distance, is the wind speed at the blade, is the wind speed at the blade wake, is the air pressure on the leeward side of the blade. The processor can determine the , and determined from the Betz limit (Lancaster-Betz limit) , finally determined . After determining the pressure difference between the windward side and the leeward side of the blade, the processor can determine the second speed of the airflow when it flows to the blade based on the first function and the pressure difference, wherein the first function represents the functional relationship between the first speed and the acceleration distance, and the acceleration distance refers to the distance between the acceleration point of the airflow and the fan. For example, in a specific test environment, the processor can obtain multiple different values of the wind speed U of the airflow, and determine the acceleration points of the airflow when it flows toward the fan at different values of wind speed U when the fan is not covered with ice. The acceleration points are due to the influence of the nearby negative pressure when the airflow approaches the fan, and it will accelerate to flow toward the fan. After determining the acceleration point corresponding to each value of the wind speed U, the processor can obtain the distance between each acceleration point and the fan as the acceleration distance L, so as to construct a functional relationship between the wind speed U and the acceleration distance, that is, the first function is , where T is the time it takes for the airflow to flow from the acceleration point to the fan, After constructing the first function, the processor can and pressure difference Determine the second velocity of the airflow to the blade For example, the processor can obtain a function curve of the first function based on a plurality of wind speeds U of different values and an acceleration distance L corresponding to each wind speed U. The processor can also determine a numerical curve of the air pressure difference corresponding to a plurality of wind speeds U of different values, and process the two curves to obtain a second speed curve for determining the airflow to the blade. The calculation formula is as follows, wherein the processor can perform simulation processing, derivation processing, differential processing, and integration processing on the two curves. In the embodiment of the present application, determining the second speed of the airflow when it flows to the blade according to the first function and the pressure difference includes determining the second speed according to formula (2):

(2)

in, is the second speed, is the first speed, is the pressure difference, is a constant, For example, as shown in Table 1, a number of different values of wind speed U and air pressure difference are provided. The corresponding second speed .

Table 1 Wind speed U and air pressure difference for different values The corresponding second speed

After determining the second speed, the processor can determine the solution function of the freezing coefficient of the fan according to the second speed, the second function and the third function. Among them, the second function represents the functional relationship between the amount of ice per unit surface area of the fan per unit time and the first speed, and the third function represents the functional relationship between the amount of ice per unit surface area of the fan per unit time, the second speed and the freezing coefficient. For example, in a specific test environment, the processor can obtain multiple different values of the wind speed U of the airflow, set the water vapor content in the air, and then determine the amount of ice N per unit surface area of the fan per unit time corresponding to each wind speed value through CFD (computational fluid dynamics) to construct the functional relationship between the amount of ice N per unit surface area of the fan per unit time and the wind speed U, that is, the second function. , where i is a constant, is the density of ice. The amount of ice N per unit surface area of the fan per unit time, the second speed And the freezing coefficient of the fan The functional relationship between them can be expressed as ,in, is the density of water, that is, the third function is After constructing the second function and the third function, the processor can determine the freezing coefficient of the fan according to the second speed, the second function and the third function. In the embodiment of the present application, the solution function for determining the freezing coefficient of the fan according to the second speed, the second function and the third function includes the solution function as shown in formula (1):

(1)

in, is the freezing coefficient, is the first speed, i is a constant, is the density of ice, is the density of water, is a constant, is the pressure difference, is the density of moist air.

After determining the solution function of the freezing coefficient of the fan icing, the processor can determine the freezing coefficient of the fan icing according to the wind speed at the head of the fan and the solution function of the freezing coefficient. Substitute into formula (1) to replace U in formula (1) to obtain the freezing coefficient , that is, the processor can set U in formula (1) to be the wind speed at the head of the wind turbine , that is, in When , the freezing coefficient is calculated The processor can also obtain the linear velocity of the fan blade tip. . The linear velocity at the blade tip is The processor can then calculate the linear velocity at the blade tip. and wind speed at the nose Determine the fan tip speed ratio , . In determining the tip speed ratio of the fan The processor can then calculate the tip speed ratio of the fan. and wind speed at the nose Determining the velocity of supercooled water droplets on fan blades , The speed of the supercooled water droplets is the speed of the horizontally moving supercooled water droplets moving toward the rotating fan blades with the blades as the reference system, also called the supercooled water collection speed.

Step 103: When it is determined that the wind turbine is in a freezing rain environment and/or a freezing fog environment, the freezing rain ice cover weight of the wind turbine at a predicted future time point in the freezing rain environment is determined based on the final falling velocity of the freezing rain droplets and the velocity of the supercooled water droplets on the blades, and the freezing fog ice cover weight of the wind turbine at a predicted future time point in the freezing fog environment is determined based on the freezing coefficient, the velocity of the supercooled water droplets and the supercooled water content in the air.

Step 104: predicting the ice weight of the wind turbine at a future prediction time point according to the ice weight of freezing rain and the ice weight of freezing fog, and determining the ice thickness of the wind turbine at a future prediction time point according to the ice weight and the side length of the blades.

After determining the solution function of the freezing coefficient of the fan icing, the processor can determine whether the fan is in a freezing rain environment and/or a freezing fog environment based on the temperature at the head. In the case where it is determined that the fan is in a freezing rain environment and/or a freezing fog environment, the processor can determine the freezing rain ice weight of the fan at a future predicted time point in the freezing rain environment based on the final falling velocity of the freezing rain raindrops and the speed of the supercooled water droplets on the blades. Among them, the final falling velocity of the freezing rain raindrops can be measured by a rain measuring radar. In an embodiment of the present application, determining the freezing rain ice weight of the fan at a future predicted time point in the freezing rain environment based on the final falling velocity of the freezing rain raindrops and the speed of the supercooled water droplets on the blades includes determining the freezing rain ice weight according to formula (3):

(3)

in, The weight of ice covered by freezing rain, is the total ice weight in the freezing rain environment for a period of time t, V is the velocity of supercooled water droplets, is the final falling velocity of freezing raindrops, is the precipitation in the freezing rain environment within a period of time t, is the density of water.

The processor may also determine the weight of the frozen fog ice at a future predicted time point in the freezing fog environment of the fan according to the freezing coefficient, the speed of the supercooled water droplets, and the supercooled water content in the air. In an embodiment of the present application, determining the weight of the frozen fog ice at a future predicted time point in the freezing fog environment of the fan according to the freezing coefficient, the speed of the supercooled water droplets, and the supercooled water content in the air includes determining the weight of the frozen fog ice according to formula (4):

(4)

in, The weight of the ice covered by the freezing fog, is the total ice weight in the freezing fog environment within a period of t, is the freezing coefficient, V is the velocity of supercooled water droplets, W is the supercooled water content in the air, is the density of moist air.

After determining the weight of ice covering by freezing rain and the weight of ice covering by freezing fog, the processor may predict the weight of ice covering by the wind turbine at a future prediction time point according to the weight of ice covering by freezing rain and the weight of ice covering by freezing fog. In the embodiment of the present application, predicting the weight of ice covering by the wind turbine at a future prediction time point according to the weight of ice covering by freezing rain and the weight of ice covering by freezing fog includes determining the weight of ice covering according to formula (5):

(5)

in, is the weight of ice, t and T are both durations, is the total ice weight in the freezing rain environment for a period of time t, is the total ice weight within t time in freezing fog environment.

After determining the ice weight of the fan at a predicted future time point, the processor can obtain the side length of the blade, and determine the ice thickness of the fan at the predicted future time point according to the ice weight and the side length of the blade. In an embodiment of the present application, determining the ice thickness of the fan at the predicted future time point according to the ice weight and the side length of the blade includes determining the ice thickness according to formula (6):

(6)

in, is the ice thickness, is the ice weight, is the density of ice, Is the side length.

Through the above technical scheme, the ice thickness of the wind turbine in a freezing rain environment and/or freezing fog environment is predicted, and the accuracy of the prediction of the ice thickness of the wind turbine is improved, so that the obtained ice thickness of the wind turbine is more realistic and more in line with the actual icing conditions.

FIG1 is a flow chart of a method for determining the ice thickness of a rotary negative pressure fan in one embodiment. It should be understood that although the various steps in the flow chart of FIG1 are displayed in sequence as indicated by the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise clearly stated herein, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, at least a portion of the steps in FIG1 may include multiple sub-steps or multiple stages, and these sub-steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternating with other steps or at least a portion of the sub-steps or stages of other steps.

The embodiment of the present application also provides a device for determining the ice thickness of a rotary negative pressure fan, comprising:

A first processing module is used to determine the temperature and wind speed at the head of the fan, and obtain a first speed of the airflow, wherein the airflow refers to the airflow that is at a preset distance from the fan and currently flows toward the fan, determine the pressure difference between the windward side and the leeward side of the blades of the fan according to the first speed, determine the second speed of the airflow when it flows to the blades according to the first function and the pressure difference, and determine a solution function for the freezing coefficient of the icing of the fan according to the second speed, the second function and the third function, wherein the first function represents a functional relationship between the first speed and the acceleration distance, the acceleration distance refers to the distance between the acceleration point of the airflow and the fan, the second function represents a functional relationship between the amount of ice per unit surface area of the fan per unit time and the first speed, and the third function represents a functional relationship between the amount of ice per unit surface area of the fan per unit time, the second speed and the freezing coefficient;

The second processing module is used to determine the freezing coefficient of the fan according to the wind speed at the head of the fan and the solution function of the freezing coefficient, and determine whether the fan is in a freezing rain environment and/or a freezing fog environment according to the temperature at the head;

The third processing module is used to determine the freezing rain ice weight of the fan at a future predicted time point in the freezing rain environment according to the final falling speed of the freezing rain raindrops and the speed of the supercooled water droplets on the blades when it is determined that the fan is in a freezing rain environment and/or a freezing fog environment, and to determine the freezing fog ice weight of the fan at a future predicted time point in the freezing fog environment according to the freezing coefficient, the speed of the supercooled water droplets and the supercooled water content in the air;

The fourth processing module is used to predict the ice weight of the wind turbine at a future predicted time point based on the ice weight of freezing rain and the ice weight of freezing fog, and determine the ice thickness of the wind turbine at a future predicted time point based on the ice weight and the side length of the blades.

In the embodiment of the present application, the first processing module determines the solution function of the freezing coefficient of the fan icing according to the second speed, the second function and the third function, including the solution function as shown in formula (1):

(1)

in, is the freezing coefficient, is the first speed, i is a constant, is the density of ice, is the density of water, is a constant, is the pressure difference, is the density of moist air.

In an embodiment of the present application, the first processing module determines the temperature and wind speed at the head of the wind turbine, including: constructing a multi-layer nested grid in the micro-topography area where the wind turbine is located, and determining the meteorological data of each grid in the micro-topography area through an ice cover numerical model, wherein the meteorological data includes temperature and wind speed; obtaining the altitude of the head; determining the average temperature and average altitude of all grids in the micro-topography area; determining the temperature of the head according to the altitude, average temperature and average altitude of the head; obtaining the altitude curve of the micro-topography area, and selecting any two adjacent peak points from the altitude curve as target peak points; obtaining each target The altitude of the crest point and the altitude of the trough point between two target crest points; determine the first area of the micro-topography area according to the altitude of each target crest point and the horizontal distance between the two target crest points; determine the second area of the micro-topography area according to the altitude of each target crest point and the altitude of the trough point; determine the valley line at the wind turbine position in the digital elevation data of the micro-topography area; determine the angle between the valley line and the wind direction at the wind turbine position; determine the wind speed of the micro-topography area according to the angle and the wind speed of the grid corresponding to the head; determine the wind speed at the head according to the first area, the second area and the wind speed of the micro-topography area.

In the embodiment of the present application, the first processing module determines the second speed of the airflow when it flows to the blade according to the first function and the pressure difference, including determining the second speed according to formula (2):

(2)

in, is the second speed, is the first speed, is the pressure difference, is a constant, is the density of moist air.

In the embodiment of the present application, the third processing module determines the freezing rain ice weight of the fan at a future predicted time point in the freezing rain environment according to the final falling speed of the freezing rain droplets and the speed of the supercooled water droplets on the blades, including determining the freezing rain ice weight according to formula (3):

(3)

in, The weight of ice covered by freezing rain, is the total ice weight in the freezing rain environment for a period of time t, V is the velocity of supercooled water droplets, is the final falling velocity of freezing raindrops, is the precipitation in the freezing rain environment within a period of time t, is the density of water.

In the embodiment of the present application, the third processing module determines the freezing fog ice weight of the fan at a future predicted time point in the freezing fog environment according to the freezing coefficient, the speed of the supercooled water droplets, and the supercooled water content in the air, including determining the freezing fog ice weight according to formula (4):

(4)

in, The weight of the ice covered by the freezing fog, is the total ice weight in the freezing fog environment within a period of t, is the freezing coefficient, V is the velocity of supercooled water droplets, W is the supercooled water content in the air, is the density of moist air.

In the embodiment of the present application, the fourth processing module predicts the ice weight of the wind turbine at a future prediction time point according to the freezing rain ice weight and the freezing fog ice weight, including determining the ice weight according to formula (5):

(5)

in, is the weight of ice, t and T are both durations, is the total ice weight in the freezing rain environment for a period of time t, is the total ice weight within t time in freezing fog environment.

In the embodiment of the present application, the fourth processing module determines the ice thickness of the wind turbine at a future predicted time point according to the ice weight and the side length of the blade, including determining the ice thickness according to formula (6):

(6)

in, is the ice thickness, is the ice weight, is the density of ice, Is the side length.

An embodiment of the present application also provides a machine-readable storage medium having instructions stored thereon, the instructions being used to enable a machine to execute the above-mentioned method for determining the ice thickness of a rotary negative pressure fan.

In one embodiment, a computer device is provided, which may be a server, and its internal structure diagram may be shown in FIG3. The computer device includes a processor A01, a network interface A02, a memory (not shown in the figure), and a database (not shown in the figure) connected through a system bus. Among them, the processor A01 of the computer device is used to provide computing and control capabilities. The memory of the computer device includes an internal memory A03 and a non-volatile storage medium A04. The non-volatile storage medium A04 stores an operating system B01, a computer program B02, and a database (not shown in the figure). The internal memory A03 provides an environment for the operation of the operating system B01 and the computer program B02 in the non-volatile storage medium A04. The database of the computer device is used to store temperature, wind speed, first speed, air pressure difference, second speed, freezing coefficient, ice weight, and ice thickness data. The network interface A02 of the computer device is used to communicate with an external terminal through a network connection. When the computer program B02 is executed by the processor A01, a method for determining the ice thickness of a rotary negative pressure fan is implemented.

Those skilled in the art will understand that the structure shown in FIG. 3 is merely a block diagram of a partial structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different arrangement of components.

An embodiment of the present application provides a device, which includes a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, the following steps are implemented: determining the temperature and wind speed at the head of the fan, and obtaining a first speed of the airflow, wherein the airflow refers to the airflow that is a preset distance away from the fan and currently flows toward the fan; determining the pressure difference between the windward side and the leeward side of the blades of the fan according to the first speed; determining the second speed of the airflow when it flows to the blades according to the first function and the pressure difference; determining a solution function for the freezing coefficient of the fan according to the second speed, the second function, and the third function, wherein the first function represents a functional relationship between the first speed and the acceleration distance, and the acceleration distance refers to the distance between the acceleration point of the airflow and the fan; the second function represents a functional relationship between the amount of ice formed per unit surface area of the fan per unit time and the first speed; and the third function represents a functional relationship between the amount of ice formed per unit surface area of the fan per unit time and the first speed. The three functions represent the functional relationship between the amount of ice formed per unit surface area of the fan per unit time, the second speed and the freezing coefficient; the freezing coefficient of the fan is determined based on the wind speed at the head of the fan and the solution function of the freezing coefficient, and whether the fan is in a freezing rain environment and/or a freezing fog environment is determined based on the temperature at the head; when it is determined that the fan is in a freezing rain environment and/or a freezing fog environment, the freezing rain ice cover weight of the fan at a future predicted time point in the freezing rain environment is determined based on the final falling speed of the freezing rain droplets and the speed of the supercooled water droplets on the blades, and the freezing fog ice cover weight of the fan at a future predicted time point in the freezing fog environment is determined based on the freezing coefficient, the speed of the supercooled water droplets and the supercooled water content in the air; the ice cover weight of the fan at a future predicted time point is predicted based on the freezing rain ice cover weight and the freezing fog ice cover weight, and the ice cover thickness of the fan at a future predicted time point is determined based on the ice cover weight and the side length of the blades.

In one embodiment, the solution function for determining the freezing coefficient of the fan icing according to the second speed, the second function and the third function includes a solution function as shown in formula (1):

(1)

in, is the freezing coefficient, is the first speed, i is a constant, is the density of ice, is the density of water, is a constant, is the pressure difference, is the density of moist air.

In one embodiment, determining the temperature and wind speed at the head of the wind turbine includes: constructing a multi-layer nested grid in the micro-topography area where the wind turbine is located, and determining the meteorological data of each grid in the micro-topography area through an ice cover numerical model, wherein the meteorological data includes temperature and wind speed; obtaining the altitude of the head; determining the average temperature and average altitude of all grids in the micro-topography area; determining the temperature of the head according to the altitude, average temperature and average altitude of the head; obtaining the altitude curve of the micro-topography area, and selecting any two adjacent peak points from the altitude curve as target peak points; obtaining each target peak point the altitude of the wind turbine and the altitude of the trough point between the two target crest points; determine the first area of the micro-topography area according to the altitude of each target crest point and the horizontal distance between the two target crest points; determine the second area of the micro-topography area according to the altitude of each target crest point and the altitude of the trough point; determine the valley line at the wind turbine position in the digital elevation data of the micro-topography area; determine the angle between the valley line and the wind direction at the wind turbine position; determine the wind speed of the micro-topography area according to the angle and the wind speed of the grid corresponding to the head; determine the wind speed at the head according to the first area, the second area and the wind speed of the micro-topography area.

In one embodiment, determining the second speed of the airflow when it flows to the blade according to the first function and the pressure difference includes determining the second speed according to formula (2):

(2)

in, is the second speed, is the first speed, is the pressure difference, is a constant, is the density of moist air.

In one embodiment, determining the freezing rain ice weight of the wind turbine at a future predicted time point in a freezing rain environment according to the final falling velocity of freezing rain drops and the velocity of supercooled water droplets on the blades includes determining the freezing rain ice weight according to formula (3):

(3)

in, The weight of ice covered by freezing rain, is the total ice weight in the freezing rain environment for a period of time t, V is the velocity of supercooled water droplets, is the final falling velocity of freezing raindrops, is the precipitation in the freezing rain environment within a period of time t, is the density of water.

In one embodiment, determining the freezing fog ice weight of the fan at a future predicted time point in the freezing fog environment according to the freezing coefficient, the speed of the supercooled water droplets, and the supercooled water content in the air includes determining the freezing fog ice weight according to formula (4):

(4)

in, The weight of the ice covered by the freezing fog, is the total ice weight in the freezing fog environment within a period of t, is the freezing coefficient, V is the velocity of supercooled water droplets, W is the supercooled water content in the air, is the density of moist air.

In one embodiment, predicting the ice weight of the wind turbine at a future prediction time point according to the freezing rain ice weight and the freezing fog ice weight includes determining the ice weight according to formula (5):

(5)

in, is the weight of ice, t and T are both durations, is the total ice weight in the freezing rain environment for a period of time t, is the total ice weight within t time in freezing fog environment.

In one embodiment, determining the ice thickness of the wind turbine at a predicted future time point according to the ice weight and the side length of the blade includes determining the ice thickness according to formula (6):

(6)

in, is the ice thickness, is the ice weight, is the density of ice, Is the side length.

The present application also provides a computer program product, which, when executed on a data processing device, is suitable for executing a program that initializes the method steps for determining the ice thickness of a rotary negative pressure fan.

Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems or computer program products. Therefore, the present application may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

The present application is described with reference to the flowchart and/or block diagram of the method, device (system), and computer program product according to the embodiment of the present application. It should be understood that each process and/or box in the flowchart and/or block diagram, as well as the combination of the process and/or box in the flowchart and/or block diagram can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate a device for implementing the functions specified in one process or multiple processes in the flowchart and/or one box or multiple boxes in the block diagram.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including an instruction device that implements the functions specified in one or more processes in the flowchart and/or one or more boxes in the block diagram.

These computer program instructions may also be loaded onto a computer or other programmable data processing device so that a series of operational steps are executed on the computer or other programmable device to produce a computer-implemented process, whereby the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more processes in the flowchart and/or one or more boxes in the block diagram.

In a typical configuration, a computing device includes one or more processors (CPU), input/output interfaces, network interfaces, and memory.

The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and/or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims (15)

1. A method for determining the icing thickness of a rotary negative pressure fan, the method comprising:

Determining the temperature and the wind speed at a machine head of a fan, and obtaining a first speed of air flow, wherein the air flow is the air flow which is a preset distance from the fan and flows to the fan currently, the air pressure difference between the windward side and the leeward side of a blade of the fan is determined according to the first speed, the second speed when the air flow flows to the blade is determined according to a first function and the air pressure difference, the solution function of the freezing coefficient of the fan is determined according to the second speed, a second function and a third function, the first function represents the functional relation between the first speed and the acceleration distance, the acceleration distance is the distance between the acceleration point of the air flow and the fan, the second function represents the functional relation between the freezing amount of the unit surface area of the fan in unit time and the first speed, and the third function represents the functional relation between the freezing amount of the unit surface area of the fan in unit time and the second speed and the freezing coefficient;

determining the freezing coefficient of the fan according to the wind speed at the machine head of the fan and the solving function of the freezing coefficient, and determining whether the fan is in a freezing rain environment and/or a freezing fog environment according to the temperature at the machine head;

Determining the frost-rain ice-covering weight of the fan at a future predicted time point in the frost-rain environment according to the falling end speed of the frost-rain drops and the speed of supercooled water drops of the blades under the condition that the fan is determined to be in the frost-rain environment and/or the frost-fog environment, and determining the frost-fog ice-covering weight of the fan at the future predicted time point in the frost-fog environment according to the freezing coefficient, the speed of supercooled water drops and the supercooled water content in air;

predicting the ice coating weight of the fan at the future predicted time point according to the ice coating weight of the freezing rain and the ice coating weight of the freezing fog, and determining the ice coating thickness of the fan at the future predicted time point according to the ice coating weight and the side length of the blade;

Wherein the first function is The second function isThe third function is，For the first speed of the machine in question,Is constant, L is the acceleration distance, T is the time taken for the airflow to flow from the acceleration point to the fan, N is the icing amount of the fan per unit surface area in unit time, i is constant,In order to achieve a density of ice,In order to achieve the density of water,For the second speed of the machine in question,Is the freezing coefficient;

wherein determining a solution function for a freezing coefficient of the fan icing according to the second speed, the second function and the third function includes the solution function as shown in formula (1):

（1）

Wherein, For the said freezing coefficient(s),For said first speed, i is a constant,In order to achieve a density of ice,In order to achieve the density of water,Is a constant value, and is used for the treatment of the skin,For the difference in the air pressure value of the air pressure,Is the wet air density.

2. The method for determining the icing thickness of a rotary negative pressure fan of claim 1 wherein determining the temperature and wind speed at the handpiece of the fan comprises:

constructing a multi-layer nested grid of a micro-terrain area where a fan is located, and determining meteorological data of each grid in the micro-terrain area through an icing numerical mode, wherein the meteorological data comprise temperature and wind speed;

acquiring the altitude of the machine head;

determining an average temperature and an average altitude of all grids within the micro-terrain area;

Determining the temperature of the handpiece according to the altitude of the handpiece, the average temperature and the average altitude;

Acquiring an altitude curve of the micro-topography area, and selecting any two adjacent peak points from the altitude curve to serve as target peak points;

Acquiring the altitude of each target peak point and the altitude of a trough point between two target peak points;

determining a first area of the micro-terrain area according to the altitude of each target peak point and the horizontal distance between two target peak points;

Determining a second area of the micro-terrain area according to the altitude of each target peak point and the altitude of each trough point;

determining a valley line at the fan position in the digital elevation data of the micro-topography area;

Determining an angle between the valley line and a wind direction at a location of the fan;

Determining the wind speed of the micro-terrain area according to the included angle and the wind speed of the grid corresponding to the machine head;

and determining the wind speed at the machine head according to the first area, the second area and the wind speed of the micro-terrain area.

3. The method for determining the icing thickness of a rotary negative pressure fan of claim 1 wherein determining a second speed of said airflow as it flows to said blade based on a first function and said air pressure differential comprises determining said second speed according to equation (2):

（2）

Wherein, For the second speed of the machine in question,For the first speed of the machine in question,For the difference in the air pressure value of the air pressure,Is a constant value, and is used for the treatment of the skin,Is the wet air density.

4. The method for determining the icing thickness of a rotary negative pressure fan of claim 1 wherein determining the ice-on-ice weight of the fan at a future predicted point in time in the ice-rain environment from the falling end velocity of ice-rain drops and the velocity of supercooled water drops of the blades comprises determining the ice-on-ice weight according to equation (3):

（3）

Wherein, For the weight of the ice-covered by the frozen rain,For the total ice coating weight during the period t in the freezing rain environment, V is the velocity of the supercooled water droplets,For the falling end speed of the freezing rain drops,For precipitation during a period t in said freezing rain environment,Is the density of water.

5. The method for determining the icing thickness of a rotary negative pressure fan of claim 1 wherein determining the frost fog ice weight of the fan at a future predicted point in time in the frost fog environment based on the freezing coefficient, the velocity of the supercooled water droplets, and the supercooled water content in the air comprises determining the frost fog ice weight according to equation (4):

（4）

Wherein, For the weight of the frozen mist ice coating,For the total ice coating weight during the time period t in the frost fog environment,For the freezing coefficient, V is the velocity of the supercooled water droplets, W is the supercooled water content in the air,Is the wet air density.

6. The method for determining the icing thickness of a rotary negative pressure fan of claim 1 wherein predicting the icing weight of the fan at the future predicted point in time from the frost rain icing weight and the frost fog icing weight comprises determining the icing weight according to equation (5):

（5）

Wherein, For the weight of the ice coating, T and T are both time length,For the total ice-over weight during the period t in the freezing rain environment,Is the total ice coating weight in the period t in the frost fog environment.

7. The method for determining the icing thickness of a rotary negative pressure fan of claim 1 wherein determining the icing thickness of the fan at the future predicted point in time based on the icing weight and the side length of the blade comprises determining the icing thickness according to equation (6):

（6）

Wherein, For the thickness of the ice coating to be described,For the weight of the ice coating to be the same,In order to achieve a density of ice,For the side length.

8. An apparatus for determining the icing thickness of a rotary negative pressure fan comprising:

The first processing module is used for determining the temperature and the wind speed at the machine head of the fan and obtaining the first speed of the air flow, wherein the air flow is the air flow which is at a preset distance from the fan and flows to the fan currently, the air pressure difference between the windward side and the leeward side of the blade of the fan is determined according to the first speed, the second speed when the air flow flows to the blade is determined according to a first function and the air pressure difference, the solution function of the freezing coefficient of the fan is determined according to the second speed, a second function and a third function, the first function represents the functional relation between the first speed and the acceleration distance, the acceleration distance is the distance between the acceleration point of the air flow and the fan, the second function represents the functional relation between the freezing amount of the unit surface area of the fan in unit time and the first speed, and the third function represents the functional relation between the freezing coefficient and the freezing amount of the unit surface area of the fan in unit time;

The second processing module is used for determining the freezing coefficient of the fan according to the wind speed at the machine head of the fan and the solving function of the freezing coefficient, and determining whether the fan is in a freezing rain environment and/or a freezing fog environment according to the temperature at the machine head;

the third processing module is used for determining the frost-rain icing weight of the fan at a future predicted time point in the frost-rain environment according to the falling end speed of the frost-rain drops and the speed of supercooled water drops of the blades under the condition that the fan is determined to be in the frost-rain environment and/or the frost-fog environment, and determining the frost-fog icing weight of the fan at the future predicted time point in the frost-fog environment according to the freezing coefficient, the speed of supercooled water drops and the supercooled water content in air;

The fourth processing module is used for predicting the ice coating weight of the fan at the future prediction time point according to the ice coating weight of the freezing rain and the ice coating weight of the freezing fog, and determining the ice coating thickness of the fan at the future prediction time point according to the ice coating weight and the side length of the blade;

Wherein the first function is The second function isThe third function is，For the first speed of the machine in question,Is constant, L is the acceleration distance, T is the time taken for the airflow to flow from the acceleration point to the fan, N is the icing amount of the fan per unit surface area in unit time, i is constant,In order to achieve a density of ice,In order to achieve the density of water,For the second speed of the machine in question,Is the freezing coefficient;

The first processing module determines a solving function of a freezing coefficient of the fan icing according to the second speed, the second function and the third function, wherein the solving function is shown in a formula (1):

（1）

Wherein, For the said freezing coefficient(s),For said first speed, i is a constant,In order to achieve a density of ice,In order to achieve the density of water,Is a constant value, and is used for the treatment of the skin,For the difference in the air pressure value of the air pressure,Is the wet air density.

9. The apparatus for determining ice coating thickness of a rotary negative pressure fan of claim 8, wherein the first processing module determining temperature and wind speed at a handpiece of the fan comprises:

constructing a multi-layer nested grid of a micro-terrain area where a fan is located, and determining meteorological data of each grid in the micro-terrain area through an icing numerical mode, wherein the meteorological data comprise temperature and wind speed;

acquiring the altitude of the machine head;

determining an average temperature and an average altitude of all grids within the micro-terrain area;

Determining the temperature of the handpiece according to the altitude of the handpiece, the average temperature and the average altitude;

Acquiring an altitude curve of the micro-topography area, and selecting any two adjacent peak points from the altitude curve to serve as target peak points;

Acquiring the altitude of each target peak point and the altitude of a trough point between two target peak points;

determining a first area of the micro-terrain area according to the altitude of each target peak point and the horizontal distance between two target peak points;

Determining a second area of the micro-terrain area according to the altitude of each target peak point and the altitude of each trough point;

determining a valley line at the fan position in the digital elevation data of the micro-topography area;

Determining an angle between the valley line and a wind direction at a location of the fan;

Determining the wind speed of the micro-terrain area according to the included angle and the wind speed of the grid corresponding to the machine head;

and determining the wind speed at the machine head according to the first area, the second area and the wind speed of the micro-terrain area.

10. The apparatus for determining the icing thickness of a rotary negative-pressure fan of claim 8 wherein said first processing module determining a second speed of said airflow as it flows to said blade based on a first function and said air pressure differential comprises determining said second speed according to equation (2):

（2）

Wherein, For the second speed of the machine in question,For the first speed of the machine in question,For the difference in the air pressure value of the air pressure,Is a constant value, and is used for the treatment of the skin,Is the wet air density.

11. The apparatus for determining the icing thickness of a rotary negative pressure fan of claim 8 wherein said third processing module determining the ice-on-ice weight of said fan at a future predicted point in time in said ice-rain environment based on the falling end velocity of ice-on-rain drops and the velocity of supercooled water drops of said blades comprises determining said ice-on-ice weight according to equation (3):

（3）

Wherein, For the weight of the ice-covered by the frozen rain,For the total ice coating weight during the period t in the freezing rain environment, V is the velocity of the supercooled water droplets,For the falling end speed of the freezing rain drops,For precipitation during a period t in said freezing rain environment,Is the density of water.

12. The apparatus for determining the icing thickness of a rotary negative pressure fan of claim 8 wherein said third processing module determining a frost fog ice weight of said fan at a future predicted point in time in said frost fog environment based on said freezing coefficient, a velocity of said supercooled water droplets, and a supercooled water content in air comprises determining said frost fog ice weight according to equation (4):

（4）

Wherein, For the weight of the frozen mist ice coating,For the total ice coating weight during the time period t in the frost fog environment,For the freezing coefficient, V is the velocity of the supercooled water droplets, W is the supercooled water content in the air,Is the wet air density.

13. The apparatus for determining the icing thickness of a rotary negative pressure fan of claim 8 wherein said fourth processing module predicting the icing weight of said fan at said future predicted point in time based on said frost rain icing weight and said frost fog icing weight comprises determining said icing weight according to equation (5):

（5）

Wherein, For the weight of the ice coating, T and T are both time length,For the total ice-over weight during the period t in the freezing rain environment,Is the total ice coating weight in the period t in the frost fog environment.

14. The apparatus for determining a icing thickness of a rotary negative pressure fan of claim 8 wherein said fourth processing module determining a icing thickness of said fan at said future predicted point in time based on said icing weight and a side length of said blade comprises determining said icing thickness according to equation (6):

（6）

Wherein, For the thickness of the ice coating to be described,For the weight of the ice coating to be the same,In order to achieve a density of ice,For the side length.

15. A machine-readable storage medium having instructions stored thereon for causing a machine to perform the method for determining icing thickness of a rotary negative pressure fan according to any of claims 1 to 7.