CN113177951B - Device and method for non-contact measurement of content of incompatible gas-liquid two-phase mixed gas - Google Patents

Abstract

The invention discloses a device and a method for non-contact measurement of the content of incompatible gas-liquid two-phase mixed gas, wherein the method comprises the following steps: collecting video data in an incompatible gas-liquid two-phase mixing process, carrying out image segmentation on the video data to obtain a binary pattern of the incompatible gas-liquid two-phase mixing process, and calculating the gas content of a gas-liquid mixture at the position close to the wall based on the binary pattern; closing the air inlet valve, simultaneously acquiring the overflow amount of gas in the liquid working medium in the gas-liquid mixing stirrer through the gas flow measuring meter, and calculating the gas content coefficient in the gas-liquid mixing stirrer based on the overflow amount; and solving the real gas content of the gas-liquid two-phase mixture in the gas-liquid mixing stirrer based on the gas content coefficient and the gas content of the gas-liquid mixture at the position close to the wall. The method has strong practicability, can intuitively and accurately calculate the gas content in the incompatible-gas-liquid two-phase mixing process, and can be applied to various fields such as chemical industry, wet metallurgy and the like.

Description

Device and method for non-contact measurement of incompatible gas-liquid two-phase mixture gas content

technical field

The invention relates to the technical fields of biological, chemical and hydrometallurgical engineering, in particular to a non-contact device and method for measuring the gas content of an incompatible gas-liquid two-phase mixture.

Background technique

The percentage of the gas phase in the volume of the gas-liquid mixture is called the gas holdup. The gas holdup is one of the evaluation methods of the multiphase flow stirring and mixing effect. At present, the measurement methods of gas holdup mainly include: differential pressure method, volume expansion method, double conductivity probe method, and γ-ray projection method. The differential pressure method is mainly used to measure the local gas holdup; the volume expansion method is inconvenient to operate during the actual test; the double conductance probe method can measure the size of the bubble, but the intrusion of the probe disturbs the gas-liquid mixing flow field; γ rays The projection method can calculate the local gas holdup in the field according to the ray attenuation intensity of the empty field and full field of the gas-liquid mixing experimental device, as well as the ray attenuation intensity of the gas-liquid mixed state.

Over the past few years, with the improvement of image processing technology and the need for non-invasive measurement, the method of filming the gas-liquid mixing process through high-speed cameras, and then obtaining the gas holdup through image analysis and processing has gradually entered people's field of vision. However, the gas holdup obtained by this method is only the gas holdup near the wall, that is, the local gas holdup. Therefore, it is particularly necessary to provide a non-contact device and method for measuring the gas content of an incompatible gas-liquid two-phase mixture.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a non-contact device and method for measuring the gas content of an incompatible gas-liquid two-phase mixture, which has strong practicability and can intuitively and accurately obtain the incompatibility-gas-liquid two-phase mixing process. It can be used in many fields such as chemical industry and hydrometallurgy.

In order to achieve the above object, the present invention provides the following solutions: the present invention provides a non-contact device for measuring the gas content of incompatible gas-liquid two-phase mixture, including: an air pump, an air inlet pipe, and a gas-liquid mixing agitator; Wherein, the air pump is connected to the bottom of the gas-liquid mixing agitator through the air inlet pipe, an air inlet valve is provided on the air inlet pipe, and one end of the air inlet pipe is connected to the gas-liquid mixing agitator A nozzle is provided, and the nozzle is arranged inside the gas-liquid mixing agitator; an air outlet is arranged on the upper end of the gas-liquid mixing agitator; a gas flow meter is arranged at the air outlet; One side of the mixer is provided with an image acquisition device.

The gas-liquid mixing agitator is provided with liquid, and the gas pump feeds gas to the gas-liquid mixing agitator through the air inlet pipe, and the gas is incompatible with the liquid; the gas-liquid mixing The mixing mixer is used for mixing the liquid and gas; the image acquisition device is used for collecting video data during the mixing process of incompatible gas-liquid two-phase; the gas outlet is used for the gas-liquid mixing mixer The overflow of gas in the gas-liquid mixing agitator; the gas flow meter is used to measure the overflow amount of the gas inside the liquid working medium in the gas-liquid mixing agitator.

Preferably, a whiteboard is further provided on one side of the gas-liquid mixing agitator, and the whiteboard and the image acquisition device are arranged on opposite sides of the gas-liquid mixing agitator and are arranged correspondingly.

Preferably, the image acquisition device includes but is not limited to a high-speed camera.

The present invention also provides a non-contact method for measuring the gas content of an incompatible gas-liquid two-phase mixture, comprising the following steps:

S1, collecting video data in the incompatible gas-liquid two-phase mixing process by the image acquisition device, and performing image segmentation on the video data to obtain a binary pattern of the incompatible gas-liquid two-phase mixing process;

S2. Calculate the gas holdup of the gas-liquid mixture near the wall based on the binary pattern of the incompatible gas-liquid two-phase mixing process;

S3. Close the intake valve, and at the same time, obtain the overflow amount of the gas inside the liquid working medium in the gas-liquid mixing agitator through the gas flow meter, and calculate the gas-liquid mixing and stirring based on the overflow amount gas holdup coefficient in the device;

S4, based on the gas holdup coefficient and the gas holdup of the gas-liquid mixture near the wall, calculate the true gas holdup of the gas-liquid two-phase mixing in the gas-liquid mixing agitator.

Preferably, in the step S1, the mixture obtained by mixing incompatible gas-liquid two phases is a transparent or translucent liquid.

Preferably, in the step S2, the calculation of the gas holdup q of the gas-liquid mixture _{near the wall near the wall} is shown in the following formula:

In the formula, Ri is the radius of the _i -th bubble, n is the number of bubbles in the binary pattern, and V is the volume of the pure liquid phase in the gas-liquid mixing agitator.

Preferably, in the step S3, the calculation of the gas holdup coefficient a in the gas-liquid mixing agitator is shown in the following formula:

In the formula, v is the overflow amount of gas inside the liquid working medium in the gas-liquid mixing agitator; q is the _measured gas content of the gas-liquid mixture in the gas-liquid mixing agitator.

Preferably, in the step S4, the _{comprehensive} calculation of the true gas holdup q of the gas-liquid two-phase mixing in the gas-liquid mixing agitator is shown in the following formula:

q _synthesis = a × q _{near the wall} .

The present invention discloses the following technical effects:

The present invention collects video data in the process of incompatible gas-liquid two-phase mixing through an image acquisition device, and performs image segmentation to obtain a binary pattern of the incompatible gas-liquid two-phase mixing process. That is, the gas holdup of the local gas-liquid mixture, the gas holdup coefficient is measured by the experimental method, and the true gas holdup is obtained through the relationship between the true gas holdup, the gas holdup coefficient and the local gas holdup, and the gas holdup is realized. The global comprehensive measurement of holdup has strong practicability and can intuitively and accurately obtain the gas holdup in the process of incompatibility-gas-liquid two-phase mixing. Non-invasive measurement of gas holdup; the gas holdup measurement method of the present invention can be applied to many fields such as chemical industry and hydrometallurgy, for example, gas-liquid direct contact heat exchange process, and can also be used to study water model research of pyrometallurgy .

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings required in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some of the present invention. In the embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without any creative effort.

Fig. 1 is the device structure schematic diagram of the present invention for non-contact measurement of incompatible gas-liquid two-phase mixing process gas holdup;

Fig. 2 is the flow chart of the method for non-contact measurement of gas holdup in incompatible gas-liquid two-phase mixing process of the present invention;

Fig. 3 is the binary pattern of incompatible gas-liquid two-phase mixing process in the embodiment of the present invention;

In the figure, 1 is an air pump, 2 is a white board, 3 is an air inlet pipe, 4 is a nozzle, 5 is a gas-liquid mixing mixer, 6 is an air outlet, and 7 is an image acquisition device.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

In order to make the above objects, features and advantages of the present invention more clearly understood, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

1, the present embodiment provides a non-contact device for measuring the gas content of incompatible gas-liquid two-phase mixture, including:

Air pump 1, whiteboard 2, air inlet pipe 3, gas-liquid mixing mixer 5, image acquisition device 7; wherein, the air pump 1 is connected to the bottom of the gas-liquid mixing mixer 5 through the air inlet pipe 3, so The air inlet pipe 3 is provided with an air inlet valve, and the end of the air inlet pipe 3 connected with the gas-liquid mixing agitator 5 is provided with a nozzle 4, and the nozzle 4 is arranged inside the gas-liquid mixing agitator 5. The upper end of the gas-liquid mixing mixer 5 is provided with an air outlet 6; the air outlet 6 is provided with a gas flow meter; the whiteboard 2 and the image acquisition device 7 are correspondingly arranged on the gas-liquid mixing mixer 5 sides.

The gas-liquid mixing agitator 5 is provided with liquid, and the gas pump 1 feeds gas into the gas-liquid mixing agitator 5 through the air inlet pipe 3, and the gas is incompatible with the liquid; The gas-liquid mixing mixer 5 is used to mix the liquid and gas; the image acquisition device 7 is used to collect video data during the mixing process of incompatible gas-liquid two-phase; the whiteboard 2 is used to The background is provided in the video data collection process to ensure the clarity of video data shooting; the gas outlet 6 is used for the overflow of gas in the gas-liquid mixing mixer 5; the gas flow meter is used to measure the gas-liquid The overflow amount of the gas inside the liquid working medium in the liquid mixing agitator 5 .

To further optimize the solution, the image acquisition device 7 includes but is not limited to a high-speed camera. In this embodiment, the high-speed camera adopts an ACS series camera with a full-frame 1280×800 pixels and a collection speed of 100,000 frames per second, which can adapt to various harsh conditions. condition.

To further optimize the solution, the container of the gas-liquid mixing agitator 5 is made of transparent material.

Referring to FIG. 2 , the present embodiment provides a non-contact method for measuring the gas content of an incompatible gas-liquid two-phase mixture, which specifically includes the following steps:

S1. Collect the video data in the incompatible gas-liquid two-phase mixing process by the image acquisition device 7, and perform image segmentation on the video data to obtain a binary pattern of the incompatible gas-liquid two-phase mixing process ;

In the present embodiment, the method of dividing the video data by frame or dividing by time is adopted for image segmentation, specifically, the KMPlayer software is used to perform image segmentation on the video data, or the matlab software is used, and the encoded code is used to perform image segmentation on the video data, The segmented image is obtained; and the segmented image is binarized by the big law, and the binary pattern of the incompatible gas-liquid two-phase mixing process is obtained. The mixture obtained by mixing incompatible gas-liquid two-phase is a transparent or translucent liquid, which is convenient for the shooting of video data during the mixing process of incompatible gas-liquid two-phase, otherwise bubbles cannot be photographed; the binary value obtained in this example is The pattern is shown in Figure 3. In Figure 3, the white is the gas phase (bubble), and the black is the liquid phase.

S2. Calculate the gas holdup of the gas-liquid mixture near the wall based on the binary pattern of the incompatible gas-liquid two-phase mixing process; in this embodiment, it is assumed that the shape of the bubble is spherical, and the gas-liquid mixture near the wall The calculation of the gas holdup q _{near the wall} is as follows:

In the formula, Ri is the radius of the _i -th bubble, n is the number of bubbles in the binary pattern, and V is the volume of the pure liquid phase in the gas-liquid mixing agitator 5 .

S3, close the intake valve, and at the same time, obtain the overflow amount v of the gas inside the liquid working medium in the gas-liquid mixing agitator 5 through the gas flow meter, and calculate the gas-liquid based on the overflow amount v The gas holdup coefficient a in the liquid mixing agitator 5.

The calculation of the gas holdup coefficient a is as follows:

S4. Based on the gas holdup coefficient a and the gas holdup q of the gas-liquid mixture _{near the wall} , _{comprehensively} solve the real gas holdup q of the gas-liquid two-phase mixing in the gas-liquid mixing mixer 5 , as shown in the following formula:

q _synthesis = a × q _{near the wall} .

The present invention has the following technical effects:

The present invention collects video data in the process of incompatible gas-liquid two-phase mixing through an image acquisition device, and performs image segmentation to obtain a binary pattern of the incompatible gas-liquid two-phase mixing process. That is, the gas holdup of the local gas-liquid mixture, the gas holdup coefficient is measured by the experimental method, and the true gas holdup is obtained through the relationship between the true gas holdup, the gas holdup coefficient and the local gas holdup, and the gas holdup is realized. The global comprehensive measurement of holdup has strong practicability and can intuitively and accurately obtain the gas holdup in the process of incompatibility-gas-liquid two-phase mixing. Non-invasive measurement of gas holdup; the gas holdup measurement method of the present invention can be applied to many fields such as chemical industry and hydrometallurgy, for example, gas-liquid direct contact heat exchange process, and can also be used to study water model research of pyrometallurgy .

The above-mentioned embodiments are only to describe the preferred mode of the present invention, and do not limit the scope of the present invention. Without departing from the design spirit of the present invention, those of ordinary skill in the art can make various Variations and improvements should fall within the protection scope determined by the claims of the present invention.

Claims (8)

1. the device for non-contact measurement of incompatible gas-liquid two-phase mixed gas content rate, is characterized in that, comprises: air pump (1), air inlet pipe (3), gas-liquid mixing agitator (5); Wherein, The air pump (1) is connected to the bottom of the gas-liquid mixing agitator (5) through the air inlet pipe (3), the air inlet pipe (3) is provided with an air inlet valve, and the air inlet pipe (3) ) is provided with a nozzle (4) at one end connected to the gas-liquid mixing agitator (5), and the nozzle (4) is arranged inside the gas-liquid mixing agitator (5); the gas-liquid mixing An air outlet (6) is arranged at the upper end of the agitator (5); a gas flow measuring meter is arranged at the air outlet (6); an image acquisition device (7) is arranged on one side of the gas-liquid mixing agitator (5). ); The gas-liquid mixing agitator (5) is provided with a liquid, and the gas pump (1) feeds gas to the gas-liquid mixing agitator (5) through the air inlet pipe (3), and the gas is mixed with the gas. The liquid is incompatible; the gas-liquid mixing agitator (5) is used for mixing the liquid and gas; the image acquisition device (7) is used for collecting the incompatible gas-liquid two-phase mixing process The video data in; the gas outlet (6) is used for the overflow of gas in the gas-liquid mixing mixer (5); the gas flow meter is used to measure the gas-liquid mixing mixer (5) The amount of overflow of the gas inside the liquid working medium. 2. The device for non-contact measurement of incompatible gas-liquid two-phase mixed gas content according to claim 1, characterized in that, one side of the gas-liquid mixing agitator (5) is also provided with a whiteboard (2), the whiteboard (2) and the image acquisition device (7) are arranged on opposite sides of the gas-liquid mixing agitator (5), and are arranged correspondingly. 3. The device for non-contact measurement of incompatible gas-liquid two-phase mixture gas content according to claim 1, wherein the image acquisition device (7) includes but is not limited to a high-speed camera. 4. The method for using the device for non-contact measurement of incompatible gas-liquid two-phase mixed gas content according to any one of claims 1 to 3, characterized in that, comprising the following steps: S1, collect the video data in the incompatible gas-liquid two-phase mixing process by the image acquisition device (7), and perform image segmentation on the video data to obtain the two-phase mixing process of the incompatible gas-liquid two-phase mixing process. value pattern; S2. Calculate the gas holdup of the gas-liquid mixture near the wall based on the binary pattern of the incompatible gas-liquid two-phase mixing process; S3. Close the intake valve, and at the same time, obtain the overflow amount of the gas inside the liquid working medium in the gas-liquid mixing agitator (5) through the gas flow meter, and calculate the gas-liquid based on the overflow amount. The gas holdup coefficient in the liquid mixing agitator (5); S4. Based on the gas holdup coefficient and the gas holdup of the gas-liquid mixture near the wall, the true gas holdup of the gas-liquid two-phase mixing in the gas-liquid mixing agitator (5) is calculated. 5. The method for using the device for non-contact measurement of incompatible gas-liquid two-phase mixed gas content according to claim 4, characterized in that, in the S1, incompatible gas-liquid two-phase mixing obtains The mixture is a transparent or translucent liquid. 6. The method used by the device for non-contact measurement of incompatible gas-liquid two-phase mixture gas content according to claim 4, characterized in that, in the S2, the gas content of the gas-liquid mixture near the wall The calculation of the rate q _{near the wall} is as follows:

In the formula, Ri is the radius of the _ith bubble, n is the number of bubbles in the binary pattern, and V is the volume of the pure liquid phase in the gas-liquid mixing agitator (5). 7. The method for using the device for non-contact measurement of incompatible gas-liquid two-phase mixed gas content according to claim 6, characterized in that, in the S3, the gas-liquid mixing agitator (5 ) in the gas holdup coefficient a is calculated as follows:

In the formula, v is the overflow amount of the gas inside the liquid working medium in the gas-liquid mixing agitator (5); q is the _measured gas content of the gas-liquid mixture in the gas-liquid mixing agitator (5). . 8. The method for using the device for non-contact measurement of incompatible gas-liquid two-phase mixed gas content according to claim 7, characterized in that, in the S4, the gas-liquid mixing agitator (5 ), the _{comprehensive} calculation of the true gas holdup q of gas-liquid two-phase mixing is shown in the following formula: q _synthesis = a × q _{near the wall} .

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