Method and system for measuring axial flow velocity or flow by adopting sonic sensor

Abstract

The invention provides a method and a system for measuring axial flow velocity or flow by adopting a sonic sensor, and the system comprises a first sonic sensor which is used for transmitting and receiving sound waves; a second acoustic wave sensor for receiving acoustic waves; the first sound wave sensor completes a transceiving function and forms a first effective sound wave propagation path; the first sound wave sensor and the second sound wave sensor are matched to form a second effective sound wave propagation path; combining the sound wave propagation time data of the two effective sound wave propagation paths and a basic formula for measuring the axial flow velocity by a sound ray bending method, constructing a reconstruction model algorithm, obtaining the axial flow velocity of the fluid to be measured, and further calculating the flow. The method and the system do not need to know parameters such as temperature and pressure of the to-be-measured medium to determine the static sound velocity; in addition, compared with a time difference method which is widely adopted at present, the method is high in accuracy, the larger the flow velocity is, the more uniform the medium temperature distribution is, the more reliable the measurement result is, and the more prominent advantages are.

Description

Technical Field

[0001] The present invention relates to the technical field of fluid measurement, and in particular to a method and system for measuring axial flow velocity or flow rate by using an acoustic wave sensor. Background Art

[0002] Flow velocity and flow rate in pipes, jets or containers are important or critical technical parameters for a large number of industrial and scientific research applications, requiring effective and reliable measurement methods. The acoustic wave method is an applicable and advanced measurement method.

[0003] The time difference method is a velocity and flow measurement method currently widely used internationally. This method uses a pair of acoustic wave sensors, which are arranged along the upstream and downstream of the pipeline to be measured. By measuring the propagation time between the two acoustic wave sensors in two directions, the pipeline flow can be effectively measured. However, it has a corresponding system approximation error, and the greater the flow velocity in the pipe, the greater the system error of this traditional method. The principle of the traditional time difference method is as follows: Figure 1 , the calculation formula is as shown in formula (7)~(10).

[0004]

[0005]

[0006] in is the direction vector of the sound propagation path, and the top line of the variable represents the average value. From the above time difference method, it can be seen that on the one hand, the sound path bending caused by the axial flow velocity of the medium is ignored and produces corresponding errors, and there is also a problem in the derivation process. The error caused by ignoring the term, where the larger the flow velocity u, the larger the error of this term. In contrast, the measurement reconstruction model (Formulas (1) to (6)) disclosed in the present invention does not have the corresponding error. It decomposes the static sound velocity c and flow velocity u in the field into radial components and axial components in the cross section, and performs linear integration along the sound path accordingly, so that the above-mentioned corresponding system error does not exist.

[0007] On the other hand, the inventors' previous work has achieved preliminary reconstruction of pipeline velocity and flow measurement based on acoustic path bending (i.e., sound line bending method), which can refer to the international patent application number PCT / CN2018 / 108837 (patents in the same group: USA 10739174 B2, ZL201880010719.X, Japan 7032842), named as a method and system for measuring axial flow velocity distribution and flow in a pipe by acoustic wave method, which discloses a method and system for arranging a certain number of multiple acoustic wave sensors on a single cross-section of the pipeline to be measured, calculating the axial flow velocity distribution in the cross-section through a certain reconstruction algorithm, and then reliably obtaining the pipeline flow. However, this method assumes that the temperature, pressure and other conditions of the medium to be measured are known, so the static sound velocity of the medium is known. In fact, the static sound velocity of the internal fluid medium of the pipeline to be measured is generally unknown and difficult to measure accurately and reliably. In addition, for the method published in the PCT / CN2018 / 108837 patent, in most cases in actual industrial applications, it is not necessary to know the axial flow velocity distribution on the cross section of the pipeline, and only the flow rate of the medium in the pipeline needs to be measured. Furthermore, in general, the axial flow velocity of the pipeline does not change significantly along the cross section, or even if there is a significant change, the average flow velocity along the diameter line segment is close enough to the average flow velocity on the entire cross section, which can effectively replace the latter, and further calculate the flow rate to be measured.

[0008] The axial velocity and flow rate are measured based on the sound ray bending method. The basic formula is (11):

[0009]

[0010] Wherein, L is the straight-line distance from the transmitting end to the receiving end of the acoustic wave signal, t is the propagation time of the acoustic wave from the transmitting end to the receiving end, and c is the acoustic wave propagation velocity under static conditions of the fluid medium in the pipeline to be measured. The acoustic wave sensor can be single, that is, it completes both transmission and reception, and forms the acoustic wave propagation path through reflection of the opposite side walls of the pipeline; the acoustic wave sensor can also be two, which are respectively installed on the two side walls of the pipeline symmetrical about the axis, to complete the transmission and reception of the acoustic wave signal.

[0011] The static sound velocity of the medium in formula (11) is determined by parameters such as the fluid medium temperature and pressure, so when these parameters are unknown, the static sound velocity c is also unknown, that is, there are two unknown variables u and c in formula (11), and more than two measurement data are required to solve it. The method disclosed in the present invention forms two effective sound paths, and there are two corresponding measurement time data, so that when the parameters such as the temperature and pressure of the medium to be measured are unknown, the static sound velocity and axial flow velocity of the medium to be measured can be effectively measured at the same time, and the flow rate can be further calculated.

[0012] Compared with the traditional time difference method, the latter requires two measuring acoustic wave sensors to emit sound waves relative to each other and receive sound wave signals respectively; in the aforementioned single-section axial flow velocity distribution acoustic wave method measurement (PCT patent number: PCT / CN2018 / 108837), each sound path also requires an acoustic wave sensor to emit sound waves, and the acoustic wave sensor at the other end receives the sound signal; relatedly, the applicant has applied for a patent (US18 / 663,117; CN 202410444670.6) to publish a system that uses a single acoustic sensor to measure the average flow velocity and flow rate of a pipeline. Under known conditions such as the temperature and pressure of the medium in the pipeline, the static sound velocity c of the medium can be determined, and then the average axial flow velocity can be calculated based on the aforementioned formula (11), and the flow rate can be finally calculated.

[0013] In summary, the sound ray bending method is relatively more accurate, the system is relatively simple, and it is more in line with actual needs. Therefore, how to effectively measure the flow velocity or flow rate in the pipe under the premise that the parameters such as the temperature and pressure of the fluid medium are unknown is a technical problem that needs to be solved urgently.

[0014] In order to solve the above problems, people have been seeking an ideal technical solution. Summary of the invention

[0015] The purpose of the present invention is to address the deficiencies of the prior art and thus provide a method and system for measuring axial flow velocity or flow using an acoustic wave sensor without knowing parameters such as temperature and pressure of the medium to be measured, with more accurate measurement results and more obvious advantages as the flow rate increases.

[0016] In order to achieve the above object, the technical solution adopted by the present invention is:

[0017] The method disclosed in the present invention measures and reconstructs the flow velocity and flow rate of a pipeline or a jet based on the principle of sound ray bending when the parameters such as the temperature and pressure of the medium to be measured are unknown. The theoretical model constructed has corresponding important innovations and solves the problems that the existing methods have not solved, making the axial flow velocity and flow rate measurement method based on the sound ray bending method more and truly applicable, so that its fundamental advantages can be directly and effectively reflected.

[0018] Specifically, in most cases, the axial velocity in the pipeline does not change significantly along the pipeline cross section, so the average axial velocity along a certain diameter line segment can approximately represent the average velocity on the entire cross section. Sometimes the particularity of the medium properties in the horizontal pipeline will cause the velocity value in the cross section to change along the vertical direction. At this time, the average velocity on the vertical diameter is generally closer to the average velocity of the cross section.

[0019] Therefore, take the above-mentioned effective pipe cross-section, take the opposite wall reflected sound wave path and a certain axially inclined sound wave path in the cross-section, and these two sound wave paths can be used based on the above-mentioned sound line bending method to effectively solve the average flow velocity on the cross-section of the measurement area under the condition of unknown parameters such as pipeline medium temperature and pressure, and then calculate the flow rate.

[0020] Specifically, the present invention provides a method for measuring axial flow velocity or flow rate using an acoustic wave sensor, comprising:

[0021] A first acoustic wave sensor, having the capability of transmitting and receiving acoustic waves, is disposed on one side of the cross section to be measured of the fluid flow channel, and is used to transmit acoustic waves to the fluid and receive echoes;

[0022] A second acoustic wave sensor, having an acoustic wave receiving capability, is disposed on the opposite side or the same side of the fluid flow channel relative to the first acoustic wave sensor, and is axially offset by a certain distance relative to the cross section where the first acoustic wave sensor is located, and is used to receive the acoustic wave emitted by the first acoustic wave sensor;

[0023] The sound wave emitted by the first sound wave sensor is reflected by the wall of the opposite fluid flow channel and then received by the first sound wave sensor, forming a first effective sound wave propagation path, which is a path along the cross section to be measured;

[0024] The sound waves emitted by the first sound wave sensor are received by the second sound wave sensor on the opposite side, or are reflected by the wall of the fluid flow channel on the opposite side and then received by the second sound wave sensor on the same side, forming a second effective sound wave propagation path, which is an inclined path; combining the sound wave propagation time of the first effective sound wave propagation path and the sound wave propagation time of the second effective sound wave propagation path, and based on the principle of sound line bending, a reconstruction model algorithm is constructed, and the static sound velocity and axial flow velocity of the medium are measured and reconstructed at the same time, and the flow rate can be further calculated in combination with the cross-sectional area of ​​the measurement area.

[0025] Based on the above, the formula for constructing the reconstruction model algorithm is expressed as follows:

[0026]

[0027] c(x,y) 2 =c i,xy (x,y) 2 +c i,z (x,y) 2 (3)

[0028]

[0029] c(x,y) 2 =c xy (x,y) 2 +c z (x,y)2 (6)

[0030] Among them, x and y represent the horizontal and vertical coordinates of the rectangular coordinate system in the cross section of the measurement area respectively;

[0031] t AC represents the time taken for the sound wave emitted by the first sound wave sensor to propagate to the second sound wave sensor;

[0032] ΔY represents the axial offset distance of the installation position of the second acoustic wave sensor relative to the cross section where the first acoustic wave sensor is located;

[0033] c(x,y) represents the acoustic wave propagation velocity under static conditions of the fluid medium to be measured in the fluid flow channel, c i,xy (x, y) is the radial component of the static sound velocity of the medium along the inclined curved sound path along the cross section, c i,z (x, y) is the axial component of the static sound velocity of the medium along the inclined curved sound path; c xy (x, y) is the radial component of the static sound velocity of the medium along the curved sound path in the cross-sectional direction, c z (x,y) the axial component of the static sound velocity of the medium along the curved sound path in the cross-sectional direction;

[0034] t AB represents the time taken for the sound wave emitted by the first sound wave sensor to propagate to the opposite side and reflect back to the first sound wave sensor;

[0035] l AB The straight line integral path representing the acoustic path in the cross-sectional direction or the projection corresponding to the inclined acoustic path along the cross-sectional surface;

[0036] u(x, y) represents the axial flow velocity of the fluid medium to be measured in the fluid flow channel under the flow state.

[0037] When there is only one first effective acoustic wave path and one second effective acoustic wave path, the static sound velocity and flow velocity of the medium obtained by measurement and reconstruction are both correspondingly average values ​​along the measurement section.

[0038] Based on the above, the fluid flow channel is a circular pipe or a rectangular pipe or a jet.

[0039] If it is a rectangular cross-section pipeline, and the axial flow velocity and other parameters are distributed uniformly along the cross-section, in addition to selecting the axial section located in the center, you can also choose to arrange the acoustic wave sensor on the axial section deviating from the center of the pipeline based on the above principles to measure the acoustic wave propagation time and reconstruct the flow velocity and flow rate.

[0040] Based on the above, the first acoustic wave sensor and the second acoustic wave sensor are installed on the inner wall or the outer wall of the fluid flow channel.

[0041] A system for measuring axial flow velocity or flow rate using an acoustic wave sensor, comprising an acoustic signal data processing module, a first acoustic wave sensor, and a second acoustic wave sensor;

[0042] The first acoustic wave sensor has the capability of transmitting and receiving acoustic waves, is disposed on one side of the cross section to be measured of the fluid flow channel, and is used to transmit acoustic waves to the fluid and receive echoes;

[0043] The second acoustic wave sensor has an acoustic wave receiving capability and is disposed on the opposite side or the same side of the fluid flow channel relative to the first acoustic wave sensor and is axially offset by a certain distance relative to the cross section where the first acoustic wave sensor is located, and is used to receive the acoustic waves emitted by the first acoustic wave sensor;

[0044] The sound wave emitted by the first sound wave sensor is reflected by the wall surface of the opposite fluid flow channel and then received by the first sound wave sensor, thereby forming a first effective sound wave propagation path;

[0045] The sound wave emitted by the first sound wave sensor is received by the second sound wave sensor on the opposite side, or is reflected by the wall of the fluid flow channel on the opposite side and then received by the second sound wave sensor on the same side, thereby forming a second effective sound wave propagation path;

[0046] The acoustic signal data processing module is used to collect signals from the first acoustic wave sensor and the second acoustic wave sensor.

[0047] Based on the above, the acoustic signal data processing module is provided with a reconstruction model algorithm program for processing the collected signals of the first acoustic wave sensor and the second acoustic wave sensor. The formula of the reconstruction model algorithm is expressed as follows:

[0048]

[0049] c(x,y) 2 =c i,xy (x,y) 2 +c i,z (x,y) 2 (3)

[0050]

[0051] c(x,y) 2 =c xy (x,y) 2 +c z (x,y) 2 (6)

[0052] Among them, x and y represent the horizontal and vertical coordinates of the rectangular coordinate system in the cross section of the measurement area respectively;

[0053] t ACrepresents the time taken for the sound wave emitted by the first sound wave sensor to propagate to the second sound wave sensor;

[0054] ΔY represents the axial offset distance of the installation position of the second acoustic wave sensor relative to the cross section where the first acoustic wave sensor is located;

[0055] c(x,y) represents the acoustic wave propagation velocity under static conditions of the fluid medium to be measured in the fluid flow channel, c i,xy (x, y) is the radial component of the static sound velocity of the medium along the inclined curved sound path along the cross section, c i,z (x, y) is the axial component of the static sound velocity of the medium along the inclined curved sound path; c xy (x, y) is the radial component of the static sound velocity of the medium along the curved sound path in the cross-sectional direction, c z (x,y) the axial component of the static sound velocity of the medium along the curved sound path in the cross-sectional direction;

[0056] t AB represents the time taken for the sound wave emitted by the first sound wave sensor to propagate to the opposite side and reflect back to the first sound wave sensor;

[0057] l AB The straight line integral path representing the acoustic path in the cross-sectional direction or the projection corresponding to the inclined acoustic path along the cross-sectional surface;

[0058] u(x, y) represents the axial flow velocity of the fluid medium to be measured in the fluid flow channel under the flow state.

[0059] Based on the above, the fluid flow channel is a circular pipe or a rectangular pipe or a jet.

[0060] When the fluid flow channel is a jet and is used to measure the jet velocity or flow rate, it further includes a third acoustic wave sensor, which is arranged on the opposite side of the cross section where the first acoustic wave sensor is located.

[0061] Based on the above, the first acoustic wave sensor and the second acoustic wave sensor are installed on the inner wall or the outer wall of the fluid flow channel.

[0062] The present invention has outstanding substantive features and significant progress compared to the prior art. Specifically, the present invention utilizes the transmitting and receiving capabilities of the first acoustic wave sensor to synchronously complete the transmitting and receiving of the first acoustic wave, and utilizes the second acoustic wave sensor in cooperation with the first acoustic wave sensor to complete the transmitting and receiving of the second acoustic wave. The path lengths and times of the two acoustic wave signals are different, and a certain geometric position relationship is formed based on the structure of the fluid flow channel. Then, the reconstruction model algorithm is constructed in combination with the sound line bending method and the geometric relationship formula, so that under the condition that the parameters such as the temperature and pressure of the fluid medium in the fluid flow channel are unknown, the average flow velocity on the cross section of the measurement area can be effectively solved, and the flow rate can be further calculated in combination with the cross-sectional area.

[0063] Compared with the traditional method, the present invention has higher accuracy, especially in the case of high flow rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 This is the schematic diagram of the traditional time difference flow measurement for comparison.

[0065] Figure 2 It is a schematic diagram of a system for simultaneously measuring and reconstructing static sound velocity and flow velocity based on the sound ray bending method in the present invention.

[0066] Figure 3 It is a schematic diagram of a same-side installation system of an acoustic sensor for simultaneously measuring static sound velocity and flow velocity based on the sound ray bending method in the present invention.

[0067] Figure 4 It is a comparison chart of the results of the new method in the present invention and the traditional time difference method for working condition 1.

[0068] Figure 5 It is a comparison chart of the results of the new method in the present invention and the traditional time difference method for working condition 2.

[0069] Figure 6 It is a comparison chart of the results of the new method in the present invention and the traditional time difference method for working condition 3. DETAILED DESCRIPTION

[0070] The technical solution of the present invention is further described in detail below through specific implementation methods.

[0071] like Figure 2 and Figure 3 As shown, a circular tube is taken as an example, in which the vertical direction is elongated 50 times to fully demonstrate the distribution characteristics of curved sound lines in the flow field.

[0072] Specifically, in the figure, A is the installation position of the first acoustic wave sensor, B is the other side of the cross section to be measured, and C is the installation position of the second acoustic wave sensor.

[0073] The first acoustic wave sensor transmits the acoustic wave from point A, which is reflected by the inner wall of the pipe at point B and then returns to point A to be received by the first acoustic wave sensor, thus forming a first effective acoustic wave propagation path.

[0074] like Figure 2 In the figure, the first acoustic wave sensor transmits the acoustic wave from point A, which is directly received by the second acoustic wave sensor at point C, forming a second effective acoustic wave propagation path.

[0075] like Figure 3 In another embodiment, the first acoustic wave sensor transmits the acoustic wave from A, which is reflected by the inner wall of the opposite pipe and received by the second acoustic wave sensor at C, forming a second effective acoustic wave propagation path. In this case, the acoustic sensor offset along the axial direction must also be reflected by the opposite wall surface, which has the advantage of reducing the measurement error of the axial offset path accordingly, making the measurement reconstruction result of the new method more accurate and reliable.

[0076] At the same time, since the second effective sound wave propagation path is a path with a certain axial deviation, in terms of plane geometric relationship, the positions of A, B and C can form a geometric relationship based on a right triangle.

[0077] The second effective sound wave propagation path is combined with the first effective sound wave path, and based on the sound line bending method, the average flow velocity at the cross section to be measured can be effectively solved under the condition that the parameters such as the temperature and pressure of the pipeline medium are unknown, and the flow rate can be further calculated.

[0078] The formula of the reconstruction model algorithm is as follows:

[0079]

[0080] c(x,y) 2 =c i,xy (x,y) 2 +c i,z (x,y) 2 (3)

[0081]

[0082] c(x,y) 2 =c xy (x,y) 2 +c z (x,y) 2 (6)

[0083] Among them, x and y represent the horizontal and vertical coordinates of the rectangular coordinate system in the cross section of the measurement area respectively;

[0084] t AC represents the time taken for the sound wave emitted by the first sound wave sensor to propagate to the second sound wave sensor;

[0085] ΔY represents the axial offset distance of the installation position of the second acoustic wave sensor relative to the cross section where the first acoustic wave sensor is located;

[0086] c(x,y) represents the acoustic wave propagation velocity under static conditions of the fluid medium to be measured in the fluid flow channel, c i,xy (x, y) is the radial component of the static sound velocity of the medium along the inclined curved sound path along the cross section, c i,z (x, y) is the axial component of the static sound velocity of the medium along the inclined curved sound path; c xy (x, y) is the radial component of the static sound velocity of the medium along the curved sound path in the cross-sectional direction, c z (x,y) the axial component of the static sound velocity of the medium along the curved sound path in the cross-sectional direction;

[0087] t AB represents the time taken for the sound wave emitted by the first sound wave sensor to propagate to the opposite side and reflect back to the first sound wave sensor;

[0088] l AB The straight line integral path representing the acoustic path in the cross-sectional direction or the projection corresponding to the inclined acoustic path along the cross-sectional surface;

[0089] u(x, y) represents the axial flow velocity of the fluid medium to be measured in the fluid flow channel under the flow state.

[0090] The six unknown quantities and six equations can solve the problem effectively, and the static sound velocity c and flow velocity u of the medium can be reconstructed at the same time, and finally the pipeline flow rate can be calculated from the flow velocity u and the cross-sectional area of ​​the pipeline to be measured.

[0091] This embodiment takes the flow velocity and flow measurement of a gas pipeline as an example, and takes three typical working conditions to illustrate the feasibility and reliability of the method, which are specifically given in Table 1. The coordinates are as follows: Figure 2 The results of direct measurement and reconstruction based on the above-mentioned reconstruction model equations (1) to (6) through two acoustic paths are the static flow velocity c and the axial flow velocity u of the medium; in contrast, the model equations of the traditional time difference method are equations (7) to (10).

[0092] In this embodiment, the fluid medium in the tube is air, which is an ideal gas under the specified working conditions. After the static sound velocity c of the medium is reconstructed by the above model, the formula T(x,y)=c(x,y) 2 / (γR) can be used to calculate the medium temperature T, where γ is the specific heat ratio of the medium gas and R is the medium gas constant.

[0093] In the following description, the method performed by this embodiment is referred to as a “new method”.

[0094] Table 1 Basic numerical experimental model parameters

[0095]

[0096] (1) Results and analysis of working condition 1

[0097] In this condition, the acoustic wave propagation time data along the inclined path AC with different axial offset distances ΔY are shown in Table 2. At the same time, the one-way propagation time of the horizontal path: A→B is 0.00223579288s. The corresponding reconstruction results are compared. Figure 4 . Figure 4 In the figure, the left figure is (a) temperature comparison, and the right figure is (b) flow rate comparison.

[0098] Table 2 Propagation time data of two paths for condition 1

[0099]

[0100]

[0101] The results show that the error of the temperature measured by the new method is negligible, while the temperature reconstructed by the traditional time difference method is too low. The error of the flow velocity reconstructed by the new method is smaller than that of the traditional time difference method, especially the average value of the measurement results in the forward and reverse directions, and the error is small enough when the axial offset of the two sensors is appropriately small.

[0102] On the other hand, the measurement results of the new method are relatively more stable, especially for temperature. The overall error of the new method is ~0.0001%. The measurement reconstruction of the time difference method is relatively small and stable when the axial deviation of the two sensors is small. For example, when the axial deviation is 0.02D, its reconstruction error is ~0.43%.

[0103] (2) Results and analysis of working condition 2

[0104] Compared with working condition 1, the flow velocity of working condition 2 is significantly increased when the medium temperature remains unchanged. The acoustic wave propagation time data along the inclined path AC with different axial offset distances ΔY are shown in Table 3. At the same time, the one-way propagation time of the horizontal path: A→B is 0.0022656067s. The corresponding reconstruction results of the two methods for this working condition are compared. Figure 5 . Figure 5 In the figure, the left figure is (a) temperature comparison, and the right figure is (b) flow rate comparison.

[0105] Table 3 Propagation time data of two paths for condition 2

[0106]

[0107] The results show that when the flow velocity is relatively large, the new method is more accurate and stable in measuring and reconstructing temperature and flow velocity than when the flow velocity is relatively small in condition 1, and the errors in the forward and reverse directions of the inclined path are small enough, and the corresponding averages of the two are also small enough; at the same time, compared with the traditional time difference method, the error it produces is small enough to be ignored, while the latter has relatively poor accuracy and stability when the flow velocity is relatively large. Among them, when the axial deviation of the two sensors is small enough, the measured and reconstructed flow velocity of the latter is also relatively ideal.

[0108] Temperature reconstruction error: new method, ~0.000085%; time difference method (0.01D), ~3.12%.

[0109] (3) Results and analysis of working condition 3

[0110] Compared with the first two conditions, the temperature of the pipe cross section in this condition varies along the space, and the model is set up in three dimensions, that is, the temperature and flow rate vary along the cross-sectional spatial coordinates. The acoustic wave propagation time data along the inclined path AC with different axial offset distances ΔY are shown in Table 4. At the same time, the one-way propagation time of the horizontal path: A→B is 0.00224269s. The corresponding reconstruction results are compared with Figure 6 . Figure 6 In the figure, the left figure is (a) temperature comparison, and the right figure is (b) flow rate comparison.

[0111] Table 4 Propagation time data of two paths for condition 3

[0112]

[0113] It can be seen from the measurement and reconstruction results of working condition 3 that when the temperature of the pipeline section has a certain spatial variation along the radial direction, the reconstruction results of the new method disclosed in the present invention do not show an advantage over the traditional time difference method. On the contrary, the error of the temperature reconstruction result is relatively larger. According to analysis, the reason is that when the sound wave propagates, its path is affected by the axial medium flow rate and causes axial bending. At the same time, it is also affected by the radial temperature change and causes corresponding radial bending in the section, so the measurement results of the new method produce additional errors. But overall, the measurement and reconstruction error of the new method is still small, and in most applications, the temperature in the pipeline does not change significantly along the section. At this time, the new method will be able to give significantly more accurate and reliable measurement results than the traditional time difference method, especially under relatively high flow conditions.

[0114] It should be noted that the method and system disclosed in the present invention are not limited to the air medium and circular pipe involved in the embodiments, and can be applied to the reliable measurement of flow velocity and flow rate in various pipes such as gas phase, liquid phase, and multiphase flow.

[0115] In other embodiments, the fluid flow channel is a jet, and when used to measure the jet velocity or flow rate, a third acoustic wave sensor is further included, wherein the third acoustic wave sensor is arranged on the opposite side of the cross section relative to the first acoustic wave sensor. The three acoustic wave sensors are respectively installed at Figure 2 At points A, B, and C shown.

[0116] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or some technical features can be replaced by equivalents, including for application objects in which the static sound velocity and medium flow velocity in the flow channel cross section vary significantly along the space, based on the principles and models disclosed in the present invention, the two acoustic wave sensors are expanded into two layers of acoustic wave sensors along the axial direction, and the corresponding measurements and reconstructions are used to obtain the distribution of the axial flow velocity in the cross section to be measured, or to further obtain a more accurate flow rate; without departing from the spirit of the technical solution of the present invention, they should all be included in the scope of the technical solution for protection of the present invention.

Claims

1. A method for measuring axial flow velocity or flow rate using an acoustic wave sensor, characterized in that: include: A first acoustic wave sensor, having the capability of transmitting and receiving acoustic waves, is disposed on one side of the cross section to be measured of the fluid flow channel, and is used to transmit acoustic waves to the fluid and receive echoes; A second acoustic wave sensor, having the ability to receive acoustic waves, is disposed on the opposite side or the same side of the fluid flow channel relative to the first acoustic wave sensor, and is axially offset by a certain distance relative to the cross section where the first acoustic wave sensor is located, and is used to receive the acoustic waves emitted by the first acoustic wave sensor; The sound wave emitted by the first sound wave sensor is reflected by the wall of the opposite fluid flow channel and then received by the first sound wave sensor, forming a first effective sound wave propagation path, which is a path along the cross section to be measured; The sound wave emitted by the first sound wave sensor is received by the second sound wave sensor on the opposite side, or is reflected by the wall of the fluid flow channel on the opposite side and then received by the second sound wave sensor on the same side, forming a second effective sound wave propagation path, which is an inclined path; Combining the sound wave propagation time of the first effective sound wave propagation path and the sound wave propagation time of the second effective sound wave propagation path, and based on the principle of sound line bending, a reconstruction model algorithm is constructed, and the static sound velocity and axial flow velocity of the medium are measured and reconstructed at the same time, or the flow rate is further calculated.

2. The method for measuring axial flow velocity or flow rate using an acoustic wave sensor according to claim 1, characterized in that: The formula for constructing the reconstruction model algorithm is expressed as follows: c(x,y) 2 =c i,xy (x,y) 2 +c i,z (x,y) 2 (3) c(x,y) 2 =c xy (x,y) 2 +c z (x,y) 2 (6) Among them, x and y represent the horizontal and vertical coordinates of the rectangular coordinate system in the cross section of the measurement area respectively; t AC represents the time taken for the sound wave emitted by the first sound wave sensor to propagate to the second sound wave sensor; ΔY represents the axial offset distance of the installation position of the second acoustic wave sensor relative to the cross section where the first acoustic wave sensor is located; c(x,y) represents the acoustic wave propagation velocity under static conditions of the fluid medium to be measured in the fluid flow channel, c i,xy (x, y) is the radial component of the static sound velocity of the medium along the inclined curved sound path along the cross section, c i,z (x, y) is the axial component of the static sound velocity of the medium along the inclined curved sound path; c xy (x, y) is the radial component of the static sound velocity of the medium along the curved sound path in the cross-sectional direction, c z (x,y) the axial component of the static sound velocity of the medium along the curved sound path in the cross-sectional direction; t AB represents the time it takes for the sound wave emitted by the first sound wave sensor to propagate to the opposite side and reflect back to the first sound wave sensor; l AB The straight line integral path representing the acoustic path in the cross-sectional direction or the projection corresponding to the inclined acoustic path along the cross-sectional surface; u(x,y) represents the axial flow velocity of the fluid medium to be measured in the fluid flow channel under the flow state; When there is only one first effective acoustic wave path and one second effective acoustic wave path, the static sound velocity and flow velocity of the medium obtained by measurement and reconstruction are both correspondingly average values ​​along the measurement section.

3. The method for measuring axial flow velocity or flow rate using an acoustic wave sensor according to claim 1 or 2, characterized in that: The fluid flow channel is a circular pipe or a rectangular pipe.

4. The method for measuring axial flow velocity or flow rate using an acoustic wave sensor according to claim 1, characterized in that: The first acoustic wave sensor and the second acoustic wave sensor are installed on the inner wall or the outer wall of the fluid flow channel.

5. The method for measuring axial flow velocity or flow rate using an acoustic wave sensor according to claim 1, characterized in that: When the fluid flow channel is a jet and is used to measure the jet velocity or flow rate, it also includes a third acoustic wave sensor, which is arranged on the opposite side of the cross section where the first acoustic wave sensor is located.

6. A system for measuring axial flow velocity or flow rate using an acoustic wave sensor, characterized in that: It includes an acoustic signal data processing module, a first acoustic wave sensor and a second acoustic wave sensor; The first acoustic wave sensor has the capability of transmitting and receiving acoustic waves, is disposed on one side of the cross section to be measured of the fluid flow channel, and is used to transmit acoustic waves to the fluid and receive echoes; The second acoustic wave sensor has the ability to receive acoustic waves, is arranged on the opposite side or the same side of the fluid flow channel relative to the first acoustic wave sensor, and is axially offset by a certain distance relative to the cross section where the first acoustic wave sensor is located, and is used to receive the acoustic waves emitted by the first acoustic wave sensor; The sound wave emitted by the first sound wave sensor is reflected by the wall surface of the opposite fluid flow channel and then received by the first sound wave sensor, thereby forming a first effective sound wave propagation path; The sound wave emitted by the first sound wave sensor is received by the second sound wave sensor on the opposite side, or is reflected by the wall of the fluid flow channel on the opposite side and then received by the second sound wave sensor on the same side, thereby forming a second effective sound wave propagation path; The acoustic signal data processing module is used to collect signals from the first acoustic wave sensor and the second acoustic wave sensor.

7. The system for measuring axial flow velocity or flow rate using an acoustic wave sensor according to claim 6, characterized in that: The acoustic signal data processing module is provided with a reconstruction model algorithm program for processing the collected signals of the first acoustic wave sensor and the second acoustic wave sensor. The formula of the reconstruction model algorithm is expressed as follows: c(x,y) 2 =c i,xy (x,y) 2 +c i,z (x,y) 2 (3) c(x,y) 2 =c xy (x,y) 2 +c z (x,y) 2 (6) Among them, x and y represent the horizontal and vertical coordinates of the rectangular coordinate system in the cross section of the measurement area respectively; t AC represents the time taken for the sound wave emitted by the first sound wave sensor to propagate to the second sound wave sensor; ΔY represents the axial offset distance of the installation position of the second acoustic wave sensor relative to the cross section where the first acoustic wave sensor is located; c(x,y) represents the acoustic wave propagation velocity under static conditions of the fluid medium to be measured in the fluid flow channel, c i,xy (x, y) is the radial component of the static sound velocity of the medium along the inclined curved sound path along the cross section, c i,z (x, y) is the axial component of the static sound velocity of the medium along the inclined curved sound path; c xy (x, y) is the radial component of the static sound velocity of the medium along the curved sound path in the cross-sectional direction, c z (x,y) the axial component of the static sound velocity of the medium along the curved sound path in the cross-sectional direction; t AB represents the time it takes for the sound wave emitted by the first sound wave sensor to propagate to the opposite side and reflect back to the first sound wave sensor; l AB The straight line integral path representing the acoustic path in the cross-sectional direction or the projection corresponding to the inclined acoustic path along the cross-sectional surface; u(x, y) represents the axial flow velocity of the fluid medium to be measured in the fluid flow channel under the flow state.

8. The system for measuring axial flow velocity or flow rate using an acoustic wave sensor according to claim 6 or 7, characterized in that: The fluid flow channel is a circular pipe or a rectangular pipe.

9. The system for measuring axial flow velocity or flow rate using an acoustic wave sensor according to claim 6, characterized in that: The first acoustic wave sensor and the second acoustic wave sensor are installed on the inner wall or the outer wall of the fluid flow channel.

10. The system for measuring axial flow velocity or flow rate using an acoustic wave sensor according to claim 6, characterized in that: When the fluid flow channel is a jet and is used to measure the jet velocity or flow rate, it also includes a third acoustic wave sensor, which is arranged on the opposite side of the cross section where the first acoustic wave sensor is located.

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