CN110716065B - Flow velocity measurement system and method based on optical fiber vector hydrophone - Google Patents
Flow velocity measurement system and method based on optical fiber vector hydrophone Download PDFInfo
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- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P5/00—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft
- G01P5/18—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring the time taken to traverse a fixed distance
- G01P5/22—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring the time taken to traverse a fixed distance using auto-correlation or cross-correlation detection means
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- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P5/00—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft
- G01P5/26—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring the direct influence of the streaming fluid on the properties of a detecting optical wave
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Abstract
The invention discloses a flow velocity measurement system and a flow velocity measurement method based on a fiber vector hydrophone, wherein the system comprises the following components: the light emitting module is used for acquiring a light source signal, modulating and converting the light source signal into a pulse light signal, and transmitting the pulse light signal to the vector sensing module through the light transmission module; an optical transmission module for transmitting an optical signal; the vector sensing module comprises a plurality of groups of measuring units, each group of measuring units comprises 2 optical fiber vector hydrophones with the position interval of d, and each optical fiber vector hydrophone is used for detecting weak three-phase flow noise signals; and the signal processing module is used for demodulating the interference optical signal to obtain a three-phase flow noise signal, calculating time delay on the 2 three-phase flow noise signals from the same group of measuring units by adopting a correlation method, calculating the fluid speed by utilizing the time delay and the position interval, and finally integrating the fluid speeds obtained by all the measuring units to obtain the fluid speed of the fluid to be measured. The flow velocity measuring device has high flow velocity measuring sensitivity and precision.
Description
Technical Field
The invention relates to the technical field of fluid measurement, in particular to a flow velocity measurement system and a flow velocity measurement method based on an optical fiber vector hydrophone.
Background
Before oil exploitation, the first work includes well logging, and various oil geology and engineering technical data including the position and direction of an oil source, the flow characteristics of an oil-gas-water mixed phase and the component content of each phase are obtained through well logging, so that the yield of oil is accurately obtained. Therefore, the measurement of the flow rate of the oil-gas-water mixed phase becomes one of the important tasks in oil production.
In the multiphase measurement technology in the prior art, the following methods are mainly used for gas-liquid two phases:
1. separation methods, including complete separation and partial separation. The complete separation means that the gas-liquid two-phase flow is split phase by a separator and then respectively measured by a single-phase flow meter, and the complete separation method has a complex measurement process and is not economical and practical; the liquid and gas-liquid ratios of the fluids separated by the partial separation method cannot be determined.
2. Direct measurement methods, including differential pressure, velocity, volumetric, and mass measurement methods, are disadvantageous for measuring weak three-phase flow noise, resulting in low accuracy in measuring the fluid flow rate.
Therefore, it is necessary to provide a new flow rate measurement system and a new flow rate measurement method.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a flow velocity measurement system and a flow velocity measurement method based on an optical fiber vector hydrophone, so that the accuracy and the sensitivity of flow velocity measurement are improved.
In order to achieve the technical purpose, the invention adopts the following technical scheme:
a fiber-optic vector hydrophone based flow velocity measurement system, comprising: the device comprises a light emitting module, a light transmission module, a vector sensing module and a signal processing module;
the light emitting module is used for acquiring a light source signal, modulating the light source signal, converting an optical signal obtained by modulation into a pulse optical signal, and transmitting the pulse optical signal to the vector sensing module through the optical transmission module;
the vector sensing module comprises at least one group of measuring units, and each group of measuring units comprises 2 optical fiber vector hydrophones with the position interval of d; each fiber vector hydrophone is used for sensing a three-phase flow noise signal and transmitting a pulse light signal loaded with the three-phase flow noise signal to the signal processing module through the light transmission module;
the signal processing module is used for demodulating the pulse light signals loaded with the three-phase flow noise signals to obtain three-phase flow noise signals, calculating time delay t of the three-phase flow noise signals for the 2 three-phase flow noise signals from the same group of measuring units by adopting a correlation method, calculating fluid speed of the measuring units in the direction by utilizing the time delay t of the three-phase flow noise signals and the position interval d, and finally integrating the fluid speeds of all the measuring units in the direction as the fluid speed of the position of the vector sensing module.
Further, the vector sensing module comprises 8 optical fiber vector hydrophones, the 8 optical fiber vector hydrophones are respectively arranged at the vertex of a cube with the side length of d, 2 optical fiber vector hydrophones arranged at two ends of each edge of the cube form a group of measuring units, and 12 groups of measuring units are obtained.
Furthermore, 3 coordinate axes of each fiber vector hydrophone in the vector sensing module are consistent with the directions of three edges passing through the vertex of the cube respectively;
the method for calculating the fluid speed of the position of the vector sensing module comprises the following steps:
calculating the average value of the fluid speeds of 4 measuring units in each coordinate axis direction to obtain the fluid speeds of the fluid in 3 coordinate axis directions; and then solving the vector sum of the fluid velocities in the directions of 3 coordinate axes to obtain the fluid velocity of the position of the vector sensing module.
Furthermore, the data processing module adopts an FPGA chip and is realized by an FPGA programming technology.
The terminal module is provided with a mathematical model matched with the fluid to be measured in flow rate, and the terminal module is used for representing the flow rate of the fluid at the positions of all the measuring units on the mathematical model for display.
Furthermore, the optical transmission module and the signal processing module are integrated into a same optical signal preprocessor, and the optical signal preprocessor is connected with the optical transmission module by adopting optical navigation plug; the vector sensing module and the light transmission module are connected in a fusion mode.
The invention also provides a flow velocity measuring method based on the optical fiber vector hydrophone, which comprises the following steps:
step 1, a light emitting module acquires and modulates a light source signal, converts the modulated light signal into a pulse light signal, and transmits the pulse light signal to a vector sensing module through a light transmission module;
the vector sensing module comprises at least one group of measuring units, and each group of measuring units comprises 2 optical fiber vector hydrophones with the position interval of d;
and 3, demodulating the received pulse light signals loaded with the three-phase flow noise signals by the signal processing module to obtain three-phase flow noise signals, calculating time delay t of the three-phase flow noise signals for 2 three-phase flow noise signals from the same group of measuring units by adopting a correlation method, calculating the fluid speed of the measuring units in the direction by utilizing the time delay t of the three-phase flow noise signals and the position interval d, and finally integrating the fluid speeds of all the measuring units in the direction as the fluid speed of the position of the vector sensing module.
Further, the vector sensing module comprises 8 optical fiber vector hydrophones, the 8 optical fiber vector hydrophones are respectively arranged at the vertex of a cube with the side length of d, 2 optical fiber vector hydrophones arranged at two ends of each edge of the cube form a group of measuring units, and 12 groups of measuring units are obtained.
Furthermore, 3 coordinate axes of each fiber vector hydrophone in the vector sensing module are consistent with the directions of three edges passing through the vertex of the cube respectively;
the method for calculating the fluid speed of the position of the vector sensing module comprises the following steps:
calculating the average value of the fluid speeds of 4 measuring units in each coordinate axis direction to obtain the fluid speeds of the fluid in 3 coordinate axis directions; and then solving the vector sum of the fluid velocities in the directions of 3 coordinate axes to obtain the fluid velocity of the position of the vector sensing module.
Further, the method further comprises: the terminal module establishes a mathematical model of the fluid to be measured in flow velocity; and after step 3 further comprising:
and 4, the terminal module represents the fluid flow rates of the positions of all the measuring units on the mathematical model for displaying.
Advantageous effects
The invention has the technical effects that:
1. the photoacoustic field signals are measured by adopting the optical fiber vector hydrophones, the time delay between the two optical fiber vector hydrophones is solved by adopting a cross-correlation technology and the photoacoustic field signals obtained by utilizing a group of 2 optical fiber vector hydrophones, and the fluid flow velocity can be calculated by utilizing the time delay and the interval, so that the sensitivity and the precision of the flow velocity measurement system and the flow velocity measurement method are improved;
2. 8 optical fiber vector hydrophones are arranged in a cubic mode to form 12 groups of measuring units, and the flow velocity of fluid obtained through integration is more accurate;
3. and the fluid flow speed representations of the positions of all the measuring units are displayed on the mathematical model, so that the spatial distribution condition of the fluid flow speed can be displayed more intuitively and stereoscopically through a terminal interface.
Drawings
FIG. 1 is a block diagram of a system according to an embodiment of the invention;
fig. 2 is a layout diagram of vector hydrophones of the system according to the embodiment of the present invention.
Detailed Description
The following describes embodiments of the present invention in detail, which are developed based on the technical solutions of the present invention, and give detailed implementation manners and specific operation procedures to further explain the technical solutions of the present invention.
The present embodiment provides a flow velocity measurement system based on a fiber-optic vector hydrophone, as shown in fig. 1, including: the system comprises a light emitting module, a light transmission module, a vector sensing module, a signal processing module and a terminal module; the optical transmission module is connected with the optical transmission module through optical navigation plug; the vector sensing module and the light transmission module are connected in a fusion mode.
The light emitting module is used for acquiring a light source signal, modulating the light source signal, converting the modulated light signal into a pulse light signal, and transmitting the pulse light signal to the vector sensing module through the light transmission module.
The light emitting module acquires a light source signal from a light source, then modulates the light source signal by using a carrier signal, forms a periodic pulse light signal by using an acousto-optic modulator so as to achieve the effect of time division multiplexing, and then divides the pulse light into a plurality of beams by using a beam splitter so as to achieve the effect of space division multiplexing. The light source signals are required to be subjected to time division multiplexing and space division multiplexing processing, and the number of the time division multiplexing and the space division multiplexing is set according to the number of the optical fiber vector hydrophones in the vector sensing module and the number of paths of each optical fiber vector hydrophone. In the present embodiment, there are 8 fiber vector hydrophones, each of which has 3 channels, so that each measurement requires the optical transmitting module to send out 24 channels of pulsed optical signals.
The vector sensing module comprises 8 optical fiber vector hydrophones, the 8 optical fiber vector hydrophones are respectively arranged at the vertex of a cube with the side length of d, as shown in fig. 2, and 3 coordinate axes are respectively consistent with the directions of three edges passing through the vertex of the cube, namely the directions of the x axis, the y axis and the z axis of the 8 vector hydrophones are consistent. Wherein 2 vector hydrophones arranged at two ends of each edge of the cube form a group of measuring units, and 12 groups of measuring units are obtained. Each fiber vector hydrophone is used for sensing weak three-phase flow noise signals and then transmitting the weak three-phase flow noise signals to the signal processing module through the optical transmission module.
In this embodiment, michelson in the optical fiber vector hydrophone generates an optical interference signal, and an optical fiber of the interferometer is subjected to a change in length by a three-phase flow noise signal, so that the optical interference signal changes, which is equivalent to that the optical fiber vector hydrophone loads the three-phase flow noise signal into a received pulsed light signal and sends the pulsed light signal loaded with the three-phase flow noise signal to the signal processing module, so as to demodulate and extract the three-phase flow noise signal.
The signal processing module is used for demodulating the pulse light signal loaded with the three-phase flow noise signal to obtain a three-phase flow noise signal, calculating the time delay t of the three-phase flow noise signal for 2 three-phase flow noise signals from the same group of measuring units by adopting a correlation method, and calculating the fluid speed of the position of the measuring unit by utilizing the time delay t of the three-phase flow noise signal and the position interval d.
In this embodiment, the method for calculating the time delay of the 2 three-phase flow noise signals from the same group of measurement units by using the correlation method specifically includes: firstly, carrying out equal-length processing on the obtained 2 three-phase flow noise signals x '(n) and y' (n), namely taking sampling data with the same length, wherein the sampling data is insufficient and can be filled with zero; then, fast Fourier transform FFT is respectively carried out on 2 signals x (n) and y (n) obtained by equivalent length processing to obtain corresponding frequency spectrums x (k) and y (k); and then, performing product operation on the two obtained frequency spectrums: gxy ═ x (k) y (k); and finally, performing Inverse Fast Fourier Transform (IFFT) on the signal obtained by the product to obtain the time delay t to be solved.
The embodiment specifically uses the PGC demodulation technique to demodulate and obtain a three-phase flow noise signal. The PGC demodulation method includes the steps of mixing, low-pass, differentiation, cross multiplication, integration, high-pass, and the like, and is a mature technology in the prior art, and thus, the details are not repeated here.
The directivity of the vector hydrophone shows that when the propagation direction of the three-phase flow noise is parallel to the direction of the axis of the vector hydrophone, the axis has the maximum response, and the characteristic is favorable for improving the precision of the flow velocity and the flow direction.
Since 8 fiber-vector hydrophones are arranged in a cube, 12 groups of measuring units can be formed, and each coordinate axis direction has 4 measuring units. Therefore, for each coordinate axis direction, the fluid velocity average value of 4 measurement units in the direction can be calculated, and the fluid velocity of the fluid in 3 coordinate axis directions can be obtained; and then, the vector sum of the fluid velocities in the directions of 3 coordinate axes is obtained, so that the fluid velocity at the position of the vector sensing module is obtained, and the measurement precision of the flow velocity measurement system can be improved.
In this embodiment, the data processing module is implemented by using an FPGA chip and using an FPGA programming technology.
The position interval d can be actually set according to the type and the measurement accuracy of the fluid to be measured, the fluid speed can be obtained through solving the interval, if the interval is too small, the flow speed calculation condition cannot be met, and if the interval is too large, the noise of flow speed calculation is increased, so that the calculation accuracy of the flow speed is reduced.
The terminal module is provided with a mathematical model matched with the fluid to be measured, and the terminal module is used for representing the fluid flow rates of all the positions of the measuring units on the mathematical model to be displayed. Therefore, the spatial distribution condition of the fluid flow velocity can be displayed more intuitively and stereoscopically through the terminal interface.
In addition, the invention also provides an embodiment of a flow velocity measurement method corresponding to the flow velocity measurement system based on the fiber vector hydrophone, and the flow velocity measurement method comprises the following steps:
step 1, a light emitting module acquires and modulates a light source signal, converts the modulated light signal into a pulse light signal, and transmits the pulse light signal to a vector sensing module through a light transmission module;
the vector sensing module comprises at least one group of measuring units, and each group of measuring units comprises 2 optical fiber vector hydrophones with the position interval of d;
step 4, the terminal module represents the fluid flow rates of the positions of all the measuring units on a mathematical model to display; the mathematical model is a virtual model matched with the fluid to be measured in flow speed.
The above embodiments are preferred embodiments of the present application, and those skilled in the art can make various changes or modifications without departing from the general concept of the present application, and such changes or modifications should fall within the scope of the claims of the present application.
Claims (6)
1. A flow velocity measurement system based on a fiber-optic vector hydrophone, comprising: the device comprises a light emitting module, a light transmission module, a vector sensing module and a signal processing module;
the light emitting module is used for acquiring a light source signal, modulating the light source signal, converting an optical signal obtained by modulation into a pulse optical signal, and transmitting the pulse optical signal to the vector sensing module through the optical transmission module;
the vector sensing module comprises at least one group of measuring units, and each group of measuring units comprises 2 optical fiber vector hydrophones with the position interval of d; each fiber vector hydrophone is used for sensing a three-phase flow noise signal and transmitting a pulse light signal loaded with the three-phase flow noise signal to the signal processing module through the light transmission module;
the vector sensing module comprises 8 optical fiber vector hydrophones, the 8 optical fiber vector hydrophones are respectively arranged at the vertex of a cube with the side length of d, 2 optical fiber vector hydrophones arranged at two ends of each edge of the cube form a group of measuring units, and 12 groups of measuring units are obtained;
3 coordinate axes of each fiber vector hydrophone in the vector sensing module are respectively consistent with the directions of three edges passing through the vertex of the cube;
the method for calculating the fluid speed of the position of the vector sensing module comprises the following steps:
calculating the average value of the fluid speeds of 4 measuring units in each coordinate axis direction to obtain the fluid speeds of the fluid in 3 coordinate axis directions; then, the vector sum of the fluid velocities in the 3 coordinate axis directions is obtained, and the fluid velocity of the position where the vector sensing module is located is obtained;
the signal processing module is used for demodulating the pulse light signals loaded with the three-phase flow noise signals to obtain three-phase flow noise signals, calculating time delay t of the three-phase flow noise signals for the 2 three-phase flow noise signals from the same group of measuring units by adopting a correlation method, calculating fluid speed of the measuring units in the direction by utilizing the time delay t of the three-phase flow noise signals and the position interval d, and finally integrating the fluid speeds of all the measuring units in the direction as the fluid speed of the position of the vector sensing module.
2. The system of claim 1, wherein the signal processing module is implemented by using an FPGA chip and using an FPGA programming technology.
3. The system of claim 1, further comprising a terminal module, wherein the terminal module is provided with a mathematical model matched with the fluid to be measured, and the terminal module is used for representing the fluid flow rate of the positions of all the measuring units on the mathematical model for displaying.
4. The system of claim 1, wherein the optical transmitter module and the signal processor module are integrated into a single optical signal pre-processor, and the optical signal pre-processor is connected to the optical transmitter module by optical fiber; the vector sensing module and the light transmission module are connected in a fusion mode.
5. A flow velocity measurement method based on a fiber vector hydrophone is characterized by comprising the following steps:
step 1, a light emitting module acquires and modulates a light source signal, converts the modulated light signal into a pulse light signal, and transmits the pulse light signal to a vector sensing module through a light transmission module;
the vector sensing module comprises at least one group of measuring units, and each group of measuring units comprises 2 optical fiber vector hydrophones with the position interval of d;
the vector sensing module comprises 8 optical fiber vector hydrophones, the 8 optical fiber vector hydrophones are respectively arranged at the vertex of a cube with the side length of d, 2 optical fiber vector hydrophones arranged at two ends of each edge of the cube form a group of measuring units, and 12 groups of measuring units are obtained;
3 coordinate axes of each fiber vector hydrophone in the vector sensing module are respectively consistent with the directions of three edges passing through the vertex of the cube;
the method for calculating the fluid speed of the position of the vector sensing module comprises the following steps:
calculating the average value of the fluid speeds of 4 measuring units in each coordinate axis direction to obtain the fluid speeds of the fluid in 3 coordinate axis directions; then, the vector sum of the fluid velocities in the 3 coordinate axis directions is obtained, and the fluid velocity of the position where the vector sensing module is located is obtained;
step 2, each fiber vector hydrophone senses a three-phase flow noise signal at the position, namely, the three-phase flow noise signal is loaded into a pulse light signal, and then the pulse light signal loaded with the three-phase flow noise signal is transmitted to a signal processing module through an optical transmission module;
and 3, demodulating the received pulse light signals loaded with the three-phase flow noise signals by the signal processing module to obtain three-phase flow noise signals, calculating time delay t of the three-phase flow noise signals for 2 three-phase flow noise signals from the same group of measuring units by adopting a correlation method, calculating the fluid speed of the measuring units in the direction by utilizing the time delay t of the three-phase flow noise signals and the position interval d, and finally integrating the fluid speeds of all the measuring units in the direction as the fluid speed of the position of the vector sensing module.
6. The method of claim 5, further comprising: the terminal module establishes a mathematical model of the fluid to be measured in flow velocity; after the step 3, the method also comprises the following steps:
and 4, the terminal module represents the fluid flow rates of the positions of all the measuring units on the mathematical model for displaying.
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| CN112485465A (en) * | 2020-12-08 | 2021-03-12 | 吉林大学 | Device and method for measuring flow velocity of ice river based on correlation method |
| CN112710380A (en) * | 2020-12-17 | 2021-04-27 | 湖南长城海盾光纤科技有限公司 | Deep and far sea optical fiber hydrophone shore-based detection system digital repeater and manufacturing method thereof |
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| US5600073A (en) * | 1994-11-02 | 1997-02-04 | Foster-Miller, Inc. | Method and system for analyzing a two phase flow |
| GB2327761A (en) * | 1997-07-28 | 1999-02-03 | Pcme Limited | Velocity measurement |
| CN1737579A (en) * | 2005-04-01 | 2006-02-22 | 辽宁工程技术大学 | Two-phase flow velocity multi-sensor real-time measuring instrument and testing method |
| US8130592B2 (en) * | 2009-03-07 | 2012-03-06 | Lockheed Martin Corporation | Correlation method for SONAR or RADAR |
| CN102445307B (en) * | 2011-07-20 | 2014-01-15 | 南京帝坝工程科技有限公司 | Method for measuring flow rate and flow direction of single-well underground water and leaking point of reservoir, and measuring device thereof |
| CN103148992B (en) * | 2013-03-11 | 2015-07-08 | 南京帝坝工程科技有限公司 | Three-dimensional flow velocity vector energy and mass measurement device |
| CN107014478B (en) * | 2017-04-10 | 2019-03-05 | 中国人民解放军国防科学技术大学 | Modulation-demodulation device for optical fiber vector hydrophone |
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