Multi-channel ultrasonic flowmeter measuring method based on pressure correction and application

Abstract

The invention relates to a multichannel ultrasonic flowmeter measuring method and application based on pressure correction, and the measuring method comprises the steps: uniformly and annularly arranging a plurality of ultrasonic transducers on the same circumferential section, and collecting signal data of a plurality of groups of sound channels; two pressure sensors are arranged at the front position and the rear position of the circumferential section respectively, and the pressure difference and the average pressure are calculated; correcting the instantaneous flow velocity of each group of sound channels based on the average pressure; determining a flow field model according to the pressure difference, and calculating the weighted average flow velocity of the plurality of groups of sound channels according to the instantaneous flow velocity; correcting a cross-sectional area of the circumferential cross-section based on the average pressure; and calculating the medium flow according to the corrected sectional area of the circumferential section and the weighted average flow velocity. The defect that an ultrasonic flowmeter is not high in measurement precision during measurement of a large-pipe-diameter and high-pressure pipeline is overcome, the measurement accuracy can be remarkably improved, the influence of errors of a single sensor or local flow field abnormity on the overall result is reduced, and stability is good.

Description

Technical Field

[0001] This application relates to the field of flow meter technology, and in particular to a pressure-corrected multi-channel ultrasonic flow meter measurement method and its application. Background Technology

[0002] In industrial settings, when ultrasonic flow meters are used to measure the flow rate of large-diameter pipelines carrying high-pressure media, measurement accuracy deviations due to physical deformation of the pipeline become a concern. Large-diameter pipelines are often made of metals such as carbon steel, alloy steel, or stainless steel. While these materials possess high compressive strength, under the continuous action of high-pressure media, the pipe body undergoes slight expansion due to the elastic deformation characteristics of the material. The internal pressure causes circumferential stress in the pipe wall, resulting in a slight increase in the radial dimension of the pipe diameter. For example, a DN1000 carbon steel pipeline under 20MPa pressure can experience a radial expansion of 0.3mm-0.5mm. Although this expansion is much smaller than the pipe diameter itself, it can still affect the signal transmission system of the ultrasonic transducer. The core measurement function of an ultrasonic flow meter relies on the transmission and reception of ultrasonic signals between one or more pairs of transducers. A fixed "straight-line signal path" is formed between the transducer transmitter and receiver, and the signal propagation distance and angle are within the preset calibration parameter range. However, when the pipeline expands radially due to high pressure, it will cause two key deformations: First, the radius of the arc surface of the pipeline outer wall changes, causing the transducer support fixed on the pipeline wall to make a slight displacement, causing the installation angle of the transducer to deviate from the initial calibration value, and the original straight signal path will produce an "angle offset"; Second, the radial expansion of the pipe diameter directly increases the signal propagation distance between transducers, breaking the preset "distance-flow velocity" calculation model inside the flow meter. Therefore, the deviation of the signal propagation angle will cause the ultrasonic wave to deviate from the optimal propagation path in the medium, increasing the signal reflection and refraction loss in the pipe wall and medium, resulting in a decrease in signal strength and signal-to-noise ratio at the receiving end. This, in turn, causes the flow meter to detect the "passage time difference" (the time difference between the downstream and upstream propagation of ultrasonic waves, which is the core parameter for calculating flow velocity), with an error range typically reaching 1%-3%. Furthermore, the increase in signal propagation distance will directly lead to an overestimation of the "flow velocity value" calculated by the flow meter. If not calibrated in time, this will cause a positive deviation in the final flow measurement result. Under high flow conditions, this deviation will lead to a significant increase in the gap between the actual delivery volume and the measured value, posing risks to production scheduling, cost accounting, and trade settlement. Summary of the Invention

[0003] Therefore, the purpose of this invention is to overcome the shortcomings of measurement accuracy in large-diameter and high-pressure pipelines, where the slight expansion of the pipe diameter under high pressure causes deformation of the signal path of the ultrasonic transducer in the ultrasonic flowmeter, thus affecting measurement accuracy. This invention provides a pressure-corrected multi-channel ultrasonic flowmeter measurement method and application. This invention significantly improves measurement accuracy by fusing ultrasonic and pressure signals from multiple sources, reducing the impact of single sensor errors or local flow field anomalies on the overall results, and resulting in better stability.

[0004] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: A pressure-corrected multi-channel ultrasonic flow meter measurement method specifically includes the following steps: Several ultrasonic transducers are evenly arranged in a ring on the same circumferential cross section to collect signal data from several channels. Two pressure sensors are installed at the front and rear positions of the circumferential cross-section to collect pressure data and calculate the pressure difference. P and mean pressure ; Based on average pressure Correct the instantaneous flow rate of each audio channel; Based on pressure difference P determines the flow field model and calculates the weighted average flow velocity of several sound channels based on the instantaneous flow velocity; Based on average pressure Correct the cross-sectional area of ​​the circular section; Calculate the medium flow rate based on the corrected cross-sectional area and weighted average velocity of the circular section. .

[0005] This application uniformly arranges multiple sets of transducers on the same circumferential cross section to collect flow velocity signals from different channels (i.e., different propagation paths), covering the flow field at different locations within the pipe. This avoids the problem that a single channel cannot reflect the non-uniformity of the flow field. Pressure sensors are set before and after this cross section to simultaneously collect pressure at two points, calculating the pressure difference and average pressure. Since pressure affects medium density, sound velocity, and pipe deformation, the average pressure can compensate for the influence of changes in the ultrasonic propagation path under high pressure on flow velocity measurement. Therefore, the average pressure is used to correct the instantaneous flow velocity of each channel. High pressure causes pipe expansion, and the average pressure can quantify this expansion, thus obtaining a more accurate flow cross-sectional area. Therefore, the actual surface of the pipe's circumferential cross section is corrected based on the average pressure. The flow field model is determined by the pressure difference, such as laminar flow, turbulent flow, or local eddies. Under different flow fields, the flow velocity weights at different locations in the pipe are different. The instantaneous flow velocities of multiple channels are weighted and averaged to obtain a cross-sectional average flow velocity that is closer to reality. Finally, the medium flow rate is calculated by multiplying the corrected cross-sectional area by the weighted average flow velocity, achieving dynamic compensation throughout the entire process.

[0006] This application can adapt to complex flow fields, with multi-channel annular layout and pressure difference flow field modeling, covering velocity differences at different locations within the pipeline and solving measurement deviations caused by non-uniform flow fields in large-diameter pipes. Simultaneously, this application can correct both velocity and cross-sectional area through average pressure, specifically addressing the impact of pipeline expansion and changes in medium properties under high pressure on measurements. It is particularly suitable for high-pressure pipeline scenarios. The dynamic correction mechanism runs through the entire process of "velocity-area-flow field," and compared to traditional fixed-parameter measurements, it can compensate for fluctuations in operating conditions (such as pressure changes) in real time, significantly improving measurement accuracy. The fusion of ultrasonic and pressure signals from multiple sources reduces the impact of single sensor errors or local flow field anomalies on the overall results, resulting in better stability.

[0007] Furthermore, the method for correcting the instantaneous flow velocity is as follows: Liquid sound velocity is not very sensitive to pressure, but it can cause pipe deformation (pipe wall expansion), so the sound channel path L needs to be modified. (1) Correct the pipe diameter of the circumferential cross section using the average pressure value; ; ; in, For the corrected pipe diameter, The initial pipe diameter, For the pipe diameter deformation, For average pressure, The pipe deformation coefficient (determined based on different pipe materials, such as carbon steel). ≈2.3×10 -6 MPa -1 ); ; in, This refers to the pressure at the front end of the circumferential cross-section. This refers to the pressure at the rear end of the circumferential cross-section; (2) Obtain the corrected channel path based on the corrected pipe diameter; ; in, For the corrected vocal tract path. The angle between the channel path and the tube axis (a fixed value, determined by the installation position). (3) Correct the sound velocity according to the corrected sound channel path to eliminate sound velocity drift error: ; in, For the speed of sound, To bridge the time difference; (4) Calculate the instantaneous velocity of each channel using the transit time difference method based on the corrected sound velocity; ; in, For the first Instantaneous flow velocity of each channel (i=1-8, corresponding to 8 measurement points at 45° intervals in the circumferential direction); / For the first The sound velocity of the group of channels in the forward / backward direction (the core is affected by the fluid temperature and pressure).

[0008] Furthermore, the weighted average flow velocity is calculated as follows: (1) Determine the flow field model based on the pressure difference; (2) Determine the weights of the weighted average velocity based on the flow field model; (3) Calculate the weighted average velocity of several vocal channels based on the weights and instantaneous velocity; Weighted average flow rate It is the core intermediate quantity, weight It is directly determined by the flow field model corresponding to ΔP, realizing the correlation between "pressure parameters → weight allocation → velocity fusion": ; in, For weighted average flow velocity, The weight is determined by the flow field model corresponding to the pressure difference. For the first The instantaneous flow rate of a group of audio channels.

[0009] Furthermore, the method for determining the weights is as follows: ΔP reflects the uniformity of the circumferential flow field: the smaller ΔP is, the more stable the flow field (circumferential velocity deviation <5%); the larger ΔP is, the more turbulent the flow field (e.g., after a bend, an increase in ΔP can lead to a circumferential velocity deviation of up to 15%). It is necessary to establish a mapping relationship between ΔP and the flow field model. ; (1) When When P≤0.1MPa, it is a uniform flow field model, and the weights of each group of sound channels are the same. ; (2) When 0.1MPa≤ For P≤0.5MPa, a weakly turbulent flow field model is used, where the weights are inversely proportional to the velocity deviation. The first calculation is performed... Flow velocity deviation of the group: ; ; Recalculate the weights: ; (3) When P > 0.5 MPa indicates a strongly turbulent flow field model, with weights allocated according to the high-velocity and low-velocity regions. The high-velocity region contributes 60% of the flow rate; the high-velocity region is defined as... , for The standard deviation, quantity The number of low-velocity regions is The weights are: .

[0010] Furthermore, the method for correcting the cross-sectional area is as follows: Pipeline pressure This can cause pipe deformation (especially with liquid media), requiring correction of the cross-sectional area to eliminate systemic errors.

[0011] in, To correct the cross-sectional area of ​​the circumferential section, The larger the cross-sectional area, the more pronounced the expansion of the pipe wall, and the more significant the change in cross-sectional area. Larger than the initial cross-sectional area, which can be obtained from the pipe specifications. .

[0012] Furthermore, the method for calculating the medium flow rate is as follows: .

[0013] Furthermore, the number of ultrasonic transducers is at least six, installed in a Z-shaped path with simultaneous transmission and reception on the same side, and the sound channel path... The coverage area should cover more than half of the radial direction of the pipe section. Sufficient signal coverage is necessary to ensure the completeness of the multi-channel data coverage area during detection; therefore, at least six sets of ultrasonic transducers are required to guarantee detection accuracy.

[0014] Furthermore, the distance between the pressure sensor and the circumferential cross-section does not exceed 2-5 times the pipe diameter to avoid pressure measurement lag.

[0015] The present invention also provides an ultrasonic flow meter that applies the pressure-corrected multi-channel ultrasonic flow meter measurement method described above, comprising a measuring pipe section, a plurality of ultrasonic transducers uniformly and annularly arranged on the same circumferential cross section of the measuring pipe section, two pressure sensors respectively disposed on the inlet side and the outlet side of the measuring pipe section, and a processor respectively connected to the plurality of ultrasonic transducers and the two pressure sensors.

[0016] Furthermore, the number of ultrasonic transducers is 8 sets, which are evenly distributed along the inner circumference of the measuring tube section.

[0017] Compared with the prior art, the beneficial effects of the present invention are: (1) This application uniformly sets multiple transducers on the same circumferential cross section to collect flow velocity signals from different channels (i.e., different propagation paths) to cover the flow field at different locations in the pipe, avoiding the problem that a single channel cannot reflect the non-uniformity of the flow field. Pressure sensors are set before and after the cross section to collect the pressure at two points simultaneously and calculate the pressure difference and average pressure. Since pressure affects the medium density, sound velocity and pipe deformation, the average pressure can compensate for the influence of the change in ultrasonic propagation path under high pressure on the flow velocity measurement. Therefore, the average pressure is used to correct the instantaneous flow velocity of each channel. High pressure will cause the pipe to expand. The average pressure can quantify this expansion and obtain a more accurate flow cross-sectional area. Therefore, the actual surface of the pipe circumferential cross section is corrected based on the average pressure. The flow field model is judged by the pressure difference, such as laminar flow, turbulent flow or local eddy. Under different flow fields, the flow velocity weights at different locations in the pipe are different. The instantaneous flow velocities of multiple channels are weighted and averaged to obtain a cross-sectional average flow velocity that is closer to the actual value. Finally, the medium flow rate is calculated by multiplying the corrected cross-sectional area with the weighted average flow velocity to achieve dynamic compensation throughout the entire process.

[0018] (2) This application can adapt to complex flow fields, multi-channel annular layout and pressure difference flow field modeling, and can cover the velocity difference at different locations in the pipeline, and solve the measurement deviation caused by the non-uniform flow field in large-diameter pipes; at the same time, this application can correct the velocity and cross-sectional area by means of average pressure, and specifically solve the influence of pipeline expansion and medium property changes on measurement under high pressure, especially suitable for high-pressure pipeline scenarios. The dynamic correction mechanism runs through the entire process of "velocity-area-flow field". Compared with traditional fixed parameter measurement, it can compensate for operating condition fluctuations (such as pressure changes) in real time, significantly improve measurement accuracy, and realize multi-source data fusion of ultrasonic signals and pressure signals, reducing the influence of single sensor error or local flow field anomaly on the overall results, and has better stability. Attached Figure Description

[0019] Figure 1 This is a flowchart of the steps of a pressure-corrected multi-channel ultrasonic flow meter measurement method in one embodiment. Figure 2 This is a flowchart illustrating the steps for correcting instantaneous flow velocity in one embodiment; Figure 3 This is a schematic diagram of the steps for weighted average flow rate in one embodiment. Detailed Implementation

[0020] The present invention will be further described below with reference to specific embodiments. The accompanying drawings are for illustrative purposes only, representing schematic diagrams rather than actual physical objects, and should not be construed as limiting the scope of this application. To better illustrate the embodiments of the present invention, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0021] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0022] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present application. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0023] Example 1 like Figure 1 As shown, this embodiment discloses a pressure-corrected multi-channel ultrasonic flow meter measurement method, which specifically includes the following steps: Several ultrasonic transducers are evenly arranged in a ring on the same circumferential cross section to collect signal data from several channels. Two pressure sensors are installed at the front and rear positions of the circumferential cross section to collect pressure data and calculate the pressure difference and average pressure. The instantaneous flow rate of each channel is corrected based on the average pressure. The flow field model is determined based on the pressure difference, and the weighted average velocity of several sound channels is calculated based on the instantaneous flow velocity. The cross-sectional area of ​​the circumferential section is corrected based on the average pressure. The flow rate of the medium is calculated based on the corrected cross-sectional area and weighted average velocity of the circumferential section.

[0024] This application uniformly arranges multiple sets of transducers on the same circumferential cross section to collect flow velocity signals from different channels (i.e., different propagation paths), covering the flow field at different locations within the pipe. This avoids the problem that a single channel cannot reflect the non-uniformity of the flow field. Pressure sensors are set before and after this cross section to simultaneously collect pressure at two points, calculating the pressure difference and average pressure. Since pressure affects medium density, sound velocity, and pipe deformation, the average pressure can compensate for the influence of changes in the ultrasonic propagation path under high pressure on flow velocity measurement. Therefore, the average pressure is used to correct the instantaneous flow velocity of each channel. High pressure causes pipe expansion, and the average pressure can quantify this expansion, thus obtaining a more accurate flow cross-sectional area. Therefore, the actual surface of the pipe's circumferential cross section is corrected based on the average pressure. The flow field model is determined by the pressure difference, such as laminar flow, turbulent flow, or local eddies. Under different flow fields, the flow velocity weights at different locations in the pipe are different. The instantaneous flow velocities of multiple channels are weighted and averaged to obtain a cross-sectional average flow velocity that is closer to reality. Finally, the medium flow rate is calculated by multiplying the corrected cross-sectional area by the weighted average flow velocity, achieving dynamic compensation throughout the entire process.

[0025] like Figure 2 As shown, the method for correcting instantaneous flow velocity is as follows: Liquid sound velocity is not very sensitive to pressure, but it can cause pipe deformation (pipe wall expansion), so the sound channel path L needs to be modified. (1) Correct the pipe diameter of the circumferential cross section using the average pressure value; ; ; in, For the corrected pipe diameter, The initial pipe diameter, For the pipe diameter deformation, For average pressure, The pipe deformation coefficient (determined based on different pipe materials, such as carbon steel). ≈2.3×10 -6 MPa -1 ); ; in, This refers to the pressure at the front end of the circumferential cross-section. This refers to the pressure at the rear end of the circumferential cross-section; (2) Obtain the corrected channel path based on the corrected pipe diameter; ; in, For the corrected vocal tract path. The angle between the channel path and the tube axis (a fixed value, determined by the installation position). (3) Correct the sound velocity according to the corrected sound channel path to eliminate sound velocity drift error: ; in, For the speed of sound, To bridge the time difference; (4) Calculate the instantaneous velocity of each channel using the transit time difference method based on the corrected sound velocity; ; in, For the first Instantaneous flow velocity of each channel (i=1-8, corresponding to 8 measurement points at 45° intervals in the circumferential direction); / For the first The sound velocity of the group of channels in the forward / backward direction (the core is affected by the fluid temperature and pressure).

[0026] like Figure 3 As shown, the method for calculating the weighted average flow velocity is as follows: (1) Determine the flow field model based on the pressure difference; (2) Determine the weights of the weighted average velocity based on the flow field model; (3) Calculate the weighted average velocity of several vocal channels based on the weights and instantaneous velocity; Weighted average flow rate It is the core intermediate quantity, weight It is directly determined by the flow field model corresponding to ΔP, realizing the correlation between "pressure parameters → weight allocation → velocity fusion": ; in, For weighted average flow velocity, The weight is determined by the flow field model corresponding to the pressure difference. for For the first The instantaneous flow rate of a group of audio channels.

[0027] In this embodiment, the method for determining the weights is as follows: ΔP reflects the uniformity of the circumferential flow field: the smaller ΔP is, the more stable the flow field (circumferential velocity deviation <5%); the larger ΔP is, the more turbulent the flow field (e.g., after a bend, an increase in ΔP can lead to a circumferential velocity deviation of up to 15%). It is necessary to establish a mapping relationship between ΔP and the flow field model. ; (1) When When P≤0.1MPa, it is a uniform flow field model, and the weights of each group of sound channels are the same. ; (2) When 0.1MPa≤ For P≤0.5MPa, a weakly turbulent flow field model is used, where the weights are inversely proportional to the velocity deviation. The first calculation is performed... Flow velocity deviation of the group: ; ; Recalculate the weights: ; (3) When P > 0.5 MPa indicates a strongly turbulent flow field model, with weights allocated according to the high-velocity and low-velocity regions. The high-velocity region contributes 60% of the flow rate; the high-velocity region is defined as... , for The standard deviation, quantity The number of low-velocity regions is The weights are: .

[0028] In this embodiment, the method for correcting the cross-sectional area is as follows: Pipeline pressure This can cause pipe deformation (especially with liquid media), requiring correction of the cross-sectional area to eliminate systemic errors.

[0029] in, To correct the cross-sectional area of ​​the circumferential section, The larger the cross-sectional area, the more pronounced the expansion of the pipe wall, and the more significant the change in cross-sectional area. Larger than the initial cross-sectional area, which can be obtained from the pipe specifications. .

[0030] In this embodiment, the method for calculating the medium flow rate is as follows: .

[0031] The advantages of this application are as follows: It can adapt to complex flow fields, with multi-channel annular layout and pressure difference flow field modeling, covering the velocity differences at different locations within the pipeline, and solving the measurement deviation caused by the non-uniform flow field in large-diameter pipes; at the same time, it can simultaneously correct the velocity and cross-sectional area through average pressure, specifically addressing the impact of pipeline expansion and changes in medium properties under high pressure on the measurement, making it particularly suitable for high-pressure pipeline scenarios. The dynamic correction mechanism runs through the entire process of "velocity-area-flow field", which, compared with traditional fixed parameter measurement, can compensate for fluctuations in operating conditions (such as pressure changes) in real time, significantly improving measurement accuracy. The fusion of ultrasonic and pressure signals from multiple sources reduces the impact of single sensor errors or local flow field anomalies on the overall results, resulting in better stability.

[0032] Example 2 This embodiment is similar to Embodiment 1, except that: In this embodiment, the number of ultrasonic transducers is eight, evenly distributed along the circumference of the inner wall of the pipe, with adjacent ultrasonic transducers at a 45° angle, and installed using a Z-shaped path for transmitting and receiving on the same side. The acoustic channel path... The coverage area extends to more than half of the radial direction of the pipe section. Sufficient signal coverage is necessary to ensure the completeness of the multi-channel data coverage area during detection; therefore, this embodiment uses eight sets of ultrasonic transducers to guarantee detection accuracy.

[0033] In this embodiment, the distance between the pressure sensor and the circumferential cross-section does not exceed 5 times the pipe diameter to avoid pressure measurement lag.

[0034] All other principles in this embodiment are the same as in Embodiment 1.

[0035] Example 3 The present invention also provides an ultrasonic flow meter, including a measuring pipe section, and a plurality of ultrasonic transducers uniformly and annularly arranged on the same circumferential cross section of the measuring pipe section. In this embodiment, the number of ultrasonic transducers is 8 sets, which are uniformly distributed along the inner circumference of the measuring pipe section. It also includes two pressure sensors respectively located on the inlet and outlet sides of the measuring pipe section; It also includes a processor that is connected to the plurality of ultrasonic transducers and the two pressure sensors respectively. The processor runs the pressure-corrected multi-channel ultrasonic flow meter measurement method described in the above embodiment to process the data and obtain the medium flow data.

[0036] This application can adapt to complex flow fields, with multi-channel annular layout and pressure difference flow field modeling, covering velocity differences at different locations within the pipeline and solving measurement deviations caused by non-uniform flow fields in large-diameter pipes. Simultaneously, this application can correct both velocity and cross-sectional area through average pressure, specifically addressing the impact of pipeline expansion and changes in medium properties under high pressure on measurements. It is particularly suitable for high-pressure pipeline scenarios. The dynamic correction mechanism runs through the entire process of "velocity-area-flow field," and compared to traditional fixed-parameter measurements, it can compensate for fluctuations in operating conditions (such as pressure changes) in real time, significantly improving measurement accuracy. The fusion of ultrasonic and pressure signals from multiple sources reduces the impact of single sensor errors or local flow field anomalies on the overall results, resulting in better stability.

[0037] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for measuring multi-channel ultrasonic flowmeters based on pressure correction, characterized in that, Specifically, the following steps are included: Several ultrasonic transducers are evenly arranged in a ring on the same circumferential cross section to collect signal data from several channels. Two pressure sensors are installed at the front and rear positions of the circumferential cross-section to collect pressure data and calculate the pressure difference. P and mean pressure ; Based on average pressure Correct the instantaneous flow rate of each audio channel; Based on pressure difference P determines the flow field model and calculates the weighted average flow velocity of several sound channels based on the instantaneous flow velocity; Based on average pressure Correct the cross-sectional area of ​​the circular section; Calculate the medium flow rate based on the corrected cross-sectional area and weighted average velocity of the circular section. .

2. The method for measuring multi-channel ultrasonic flowmeters based on pressure correction according to claim 1, characterized in that, The method for correcting the instantaneous flow velocity is as follows: The pipe diameter of the circumferential cross-section is corrected using the average pressure value; The corrected channel path is obtained based on the corrected pipe diameter; The sound velocity is corrected based on the corrected duct path to eliminate sound velocity drift error; Based on the corrected sound velocity, the instantaneous flow velocity of each channel is calculated using the transit time difference method.

3. The method for measuring multi-channel ultrasonic flowmeters based on pressure correction according to claim 1, characterized in that, The weighted average flow velocity is calculated as follows: The flow field model is determined based on the pressure difference; The weights of the weighted average velocity are determined based on the flow field model; Calculate the weighted average flow rate of several audio channels based on weights and instantaneous flow rates; in, For weighted average flow velocity, As weight, For the first The instantaneous flow rate of a group of audio channels.

4. The method for measuring multi-channel ultrasonic flowmeters based on pressure correction according to claim 3, characterized in that, The method for determining the weights is as follows: when When P≤0.1MPa, it is a uniform flow field model, and the weights of each group of sound channels are the same; When 0.1MPa≤ For P≤0.5MPa, it is a weakly turbulent flow field model, and the weight is inversely proportional to the velocity deviation; when P > 0.5 MPa indicates a strongly turbulent flow field model, with weights allocated according to the high-velocity and low-velocity regions.

5. The method for measuring multi-channel ultrasonic flowmeters based on pressure correction according to claim 1, characterized in that, The method for correcting the cross-sectional area is as follows: ； in, To correct the cross-sectional area of ​​the circumferential section, For average pressure, The initial pipe diameter, This is the pipe deformation coefficient.

6. The method for measuring multi-channel ultrasonic flowmeters based on pressure correction according to claim 1, characterized in that, The medium flow rate The calculation method is as follows: 。 7. The method for measuring multi-channel ultrasonic flowmeters based on pressure correction according to claim 2, characterized in that, The number of ultrasonic transducers is at least six, and they are installed in a Z-shaped path with transmission and reception on the same side. The sound channel path covers more than 1 / 2 of the radial area of ​​the pipe section.

8. The method for measuring multi-channel ultrasonic flowmeters based on pressure correction according to claim 1, characterized in that, The distance between the pressure sensor and the circumferential cross-section shall not exceed 2-5 times the pipe diameter to avoid pressure measurement lag.

9. An ultrasonic flow meter employing the pressure-corrected multi-channel ultrasonic flow meter measurement method as described in any one of claims 1-8, characterized in that, The device includes a measuring pipe section, a plurality of ultrasonic transducers uniformly arranged in a ring on the same circumferential cross section of the measuring pipe section, two pressure sensors respectively located on the inlet side and the outlet side of the measuring pipe section, and a processor respectively connected to the plurality of ultrasonic transducers and the two pressure sensors.

10. The ultrasonic flow meter according to claim 9, characterized in that, The ultrasonic transducers consist of 8 sets, which are evenly distributed along the inner circumference of the measuring pipe section.

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