A test bench for testing the acoustic transmission characteristics of the ports of a vane pump

Abstract

The present invention belongs to the technical field of experimental tooling, and specifically discloses a test bench for testing the acoustic transmission characteristics of the ports of a vane pump, which includes a test pump, an auxiliary pump as a sound source, a water tank, a flowmeter, a piezoelectric pressure sensor, a flow regulating valve I, waterway regulating valves II to XII, and related pipeline systems. By only using one test pump, one auxiliary pump and related pipeline systems, through adjusting the frequency conversion drive of the auxiliary pump, the opening degree of the flow regulating valve I on the outlet pipeline of the auxiliary pump, and the opening and closing of the waterway regulating valves II to XII along the pipeline, and without disassembling and assembling the test pump and the auxiliary pump, the test of the acoustic transmission characteristics of the ports of the test pump at different frequencies can be completed, reducing the workload and greatly improving the work efficiency.

Description

Technical Field

[0001] The present invention belongs to the technical field of experimental tooling, and particularly relates to a test bench for testing the acoustic transmission characteristics of a vane pump port. Background Art

[0002] As a core device for fluid medium transportation in a waterway system, the vane pump has very important applications in fields such as urban municipal administration, food and medicine, chemical engineering and metallurgy, energy and power, aviation and navigation. In recent years, with the development of vane pumps in various fields towards high power, high speed, high reliability, and centralization, as the most important noise source in the waterway system, the research on the acoustic transmission characteristics of the vane pump port has important practical significance. Existing test benches usually use hydrophones or pressure sensors installed on the wall surfaces of the inlet and outlet pipelines of the vane pump, and directly use the sound pressure measured at a certain position in the inlet and outlet pipelines of the vane pump to reflect the acoustic transmission characteristics of the vane pump port. However, this directly measured sound pressure not only depends on the monitoring position where the hydrophone or pressure sensor is installed, but also depends on the acoustic response of the pipeline system. That is to say, the measurement results often vary greatly with the system and the measurement position, and cannot directly reflect the port acoustic transmission characteristics of the vane pump itself. Thus, it can be seen that the existing test bench still has great limitations in testing the acoustic transmission characteristics of the vane pump port. Summary of the Invention

[0003] In order to overcome the problems existing in the existing test technology, the present invention proposes a test bench for testing the acoustic transmission characteristics of a vane pump port, which only uses one test pump, one auxiliary pump as a sound source, two flow meters, two groups of piezoelectric pressure sensors and related pipeline systems. By adjusting the frequency conversion drive of the auxiliary pump, the opening degree of the flow regulating valve I on the outlet pipeline of the auxiliary pump, and the opening and closing of the water regulating valves II - XII along the pipeline, the acoustic load generated by the auxiliary pump as an external sound source at different frequencies and the different acoustic impedances of the pipeline configuration are changed. The sound pressure amplitudes at the upstream and downstream monitoring points of the test pump at different frequencies under different external sound source acoustic loads and different acoustic impedances of the pipeline configuration are collected, the modeling and solution of the test data are completed, and the acoustic transmission characteristics of the vane pump port at different frequencies are obtained through the test, and there is no need to disassemble and assemble the test pump and the auxiliary pump during the process.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A test bench for testing the acoustic transmission characteristics of a vane pump port, comprising a test pump, an auxiliary pump as a sound source, a water tank, a flow meter, a piezoelectric pressure sensor, a flow regulating valve I, water regulating valves II - XII and related water pipeline systems;

[0006] The auxiliary pump and the test pump are connected by pipelines, and both the auxiliary pump and the test pump are connected to the water tank through pipelines, forming the main loop of the water circulation system; flow meters are installed on the outlet pipelines of the auxiliary pump and the test pump.

[0007] The test bench can be divided into a monitoring system and a regulating and controlling system. The monitoring system is composed of two groups of four piezoelectric pressure sensors, which are respectively located on the inlet pipeline and the outlet pipeline of the test pump. Each group includes two piezoelectric pressure sensors, used to monitor the sound pressure signals at different frequencies excited by the auxiliary pump at the inlet pipeline and the outlet pipeline of the test pump; the regulating and controlling system includes a first waterway regulating valve group arranged between the auxiliary pump and the test pump and a flow regulating valve I arranged on the outlet pipeline of the auxiliary pump, a second waterway regulating valve group arranged between the test pump and the water tank and a waterway regulating valve IX arranged on the outlet pipeline of the test pump; the regulating and controlling system adjusts the external sound source or external acoustic impedance received by the test pump; the first waterway regulating valve group includes a waterway regulating valve IV, a waterway regulating valve V and a waterway regulating valve VI arranged in parallel, and a waterway regulating valve II and a waterway regulating valve VII are respectively connected in series on both sides of the waterway regulating valve IV and the waterway regulating valve V, and a waterway regulating valve III and a waterway regulating valve VIII are respectively connected in series on both sides of the waterway regulating valve V and the waterway regulating valve VI; the second waterway regulating valve group includes a waterway regulating valve X, a waterway regulating valve XI and a waterway regulating valve XII arranged in parallel.

[0008] The adjustment steps of the regulating and controlling system include: adjusting the frequency conversion drive of the auxiliary pump to change its speed, and then changing the sound pressure amplitude and frequency of the auxiliary pump as the sound source; controlling the opening degree of the flow regulating valve I on the outlet pipeline of the auxiliary pump, and then changing the sound pressure amplitude of the auxiliary pump as the sound source; adjusting different waterway regulating valves II - XII on the branch pipeline between the test pump and the auxiliary pump to make the pipeline configuration have different acoustic impedances.

[0009] The water system also includes loops I, II, III, IV, V, VI, VII, VIII, IX, X, XI, XII.

[0010] For loop I, the flow regulating valve I, the waterway regulating valve II, the waterway regulating valve III, the waterway regulating valve VI, the waterway regulating valve IX, and the waterway regulating valve X are opened, and the rest of the waterway regulating valves are closed.

[0011] For loop II, the flow regulating valve I, the waterway regulating valve II, the waterway regulating valve V, the waterway regulating valve VIII, the waterway regulating valve IX, and the waterway regulating valve X are opened, and the rest of the waterway regulating valves are closed.

[0012] For loop III, the flow regulating valve I, the waterway regulating valve IV, the waterway regulating valve VII, the waterway regulating valve VIII, the waterway regulating valve IX, and the waterway regulating valve X are opened, and the rest of the waterway regulating valves are closed.

[0013] Circuit Ⅳ opens Flow Regulating Valve Ⅰ, Waterway Regulating Valves Ⅲ, Ⅳ, Ⅴ, Ⅵ, Ⅶ, Ⅸ, and Ⅹ, and closes the remaining waterway regulating valves.

[0014] Circuit Ⅴ opens Flow Regulating Valve Ⅰ, Waterway Regulating Valves Ⅱ, Ⅲ, Ⅵ, Ⅸ, and Ⅺ, and closes the remaining waterway regulating valves.

[0015] Circuit Ⅵ opens Flow Regulating Valve Ⅰ, Waterway Regulating Valves Ⅱ, Ⅴ, Ⅷ, Ⅸ, and Ⅺ, and closes the remaining waterway regulating valves.

[0016] Circuit Ⅶ opens Flow Regulating Valve Ⅰ, Waterway Regulating Valves Ⅳ, Ⅶ, Ⅷ, Ⅸ, and Ⅺ, and closes the remaining waterway regulating valves.

[0017] Circuit Ⅷ opens Flow Regulating Valve Ⅰ, Waterway Regulating Valves Ⅲ, Ⅳ, Ⅴ, Ⅵ, Ⅶ, Ⅸ, and Ⅺ, and closes the remaining waterway regulating valves.

[0018] Circuit Ⅸ opens Flow Regulating Valve Ⅰ, Waterway Regulating Valves Ⅱ, Ⅲ, Ⅵ, Ⅸ, and Ⅻ, and closes the remaining waterway regulating valves.

[0019] Circuit Ⅹ opens Flow Regulating Valve Ⅰ, Waterway Regulating Valves Ⅱ, Ⅴ, Ⅷ, Ⅸ, and Ⅻ, and closes the remaining waterway regulating valves.

[0020] Circuit Ⅺ opens Flow Regulating Valve Ⅰ, Waterway Regulating Valves Ⅳ, Ⅶ, Ⅷ, Ⅸ, and Ⅻ, and closes the remaining waterway regulating valves.

[0021] Circuit Ⅻ opens Flow Regulating Valve Ⅰ, Waterway Regulating Valves Ⅲ, Ⅳ, Ⅴ, Ⅵ, Ⅶ, Ⅸ, and Ⅻ, and closes the remaining waterway regulating valves.

[0022] The waterway system also includes closing Waterway Regulating Valve Ⅸ in Circuits Ⅰ, Ⅱ, Ⅲ, Ⅳ, Ⅴ, Ⅵ, Ⅶ, Ⅷ, Ⅸ, Ⅹ, Ⅺ, and Ⅻ, and keeping the remaining regulating valves unchanged.

[0023] Two groups of four piezoelectric pressure sensors are arranged in sequence at the inlet and outlet pipelines of the test pump. The distance between each group of sensors at the inlet pipeline and the outlet pipeline is 10 - 20 times the inner diameter of the pipeline. The smaller the inner diameter of the pipeline, the larger the multiple value, and the larger the inner diameter of the pipeline, the smaller the multiple value.

[0024] The beneficial effects of the present invention are as follows:

[0025] A test bench for testing the acoustic transmission characteristics of a vane pump port proposed by the present invention can complete the acoustic transmission characteristic tests of the vane pump port at different frequencies by adjusting the frequency conversion drive of the auxiliary pump and the opening degree of the regulating valves along the pipeline. Only one test pump, one auxiliary pump as the sound source, two groups of piezoelectric pressure sensors and the relevant pipeline system are required, reducing the workload and greatly improving the work efficiency and the accuracy of test measurement. During the test process of the acoustic transmission characteristics of the vane pump port, this test bench can avoid the influence of environmental background noise and the damping of the pump peripheral wall in the indirect measurement method. In addition, this test bench can avoid the influence that the acoustic characteristics of the vane pump cause obvious differences in the measurement results due to the differences in the test system and the measurement position in the direct measurement method. This test bench can directly reflect the acoustic characteristics of the vane pump itself, providing a theoretical basis and scientific basis for the research on the noise mechanism of centrifugal pumps, verifying noise reduction measures and designing low-noise products.

[0026] The present invention has been verified by experiments and has good effects. Description of the Drawings

[0027] Appendix Figure 1 The system schematic diagram of the present invention is shown as follows;

[0028] Description of the marks in the schematic diagram: In the figure, the oval dotted line frame A and the oval dotted line frame B represent the regulating valve group. By adjusting the opening and closing of the water regulating valves II-XII along the pipeline, different acoustic impedances of the pipeline configuration are changed;

[0029] 1 - Auxiliary pump, 2 - Test pump, 3, 4 - Flow meters, 5, 6 - Piezoelectric pressure sensors, 7 - Flow regulating valve I, 8 - Water regulating valve II, 9 - Water regulating valve III, 10 - Water regulating valve IV, 11 - Water regulating valve V, 12 - Water regulating valve VI, 13 - Water regulating valve VII, 14 - Water regulating valve VIII, 15 - Water regulating valve IX, 16 - Water regulating valve X, 17 - Water regulating valve XI, 18 - Water regulating valve XII, 19 - Water tank. Detailed Embodiment

[0030] Now, in combination with the appendix Figure 1 The specific implementation method of the present invention will be described:

[0031] The waterway system of the test bench consists of an auxiliary pump 1, a test pump 2, flow meters 3(4), a flow regulating valve I 7, water regulating valves II-XII (8-18) and a water tank 19. The auxiliary pump 1 and the test pump 2 are connected by pipelines, and both the auxiliary pump 1 and the test pump 2 are connected to the water tank 19 by pipelines, forming the main loop of the waterway circulation system; Flow meters 3 and 4 are installed on the outlet pipelines of the auxiliary pump 1 and the test pump 2.

[0032] The test bench can be divided into a monitoring system and a regulating and controlling system. The monitoring system consists of two groups of four piezoelectric pressure sensors in total. One group consists of two piezoelectric pressure sensors 5 in total, and the other group consists of two piezoelectric pressure sensors 6 in total, which are used to monitor the sound pressure signals at different frequencies excited by the auxiliary pump 1 at the inlet and outlet pipelines of the test pump 2. The regulating and controlling system consists of three parts. One is the flow regulating valve I 7, the second is composed of the waterway regulating valve groups II - VIII (8 - 14) in the elliptical dotted line frame A connected in series and parallel, and the third is composed of the waterway regulating valve IX 15 and the waterway regulating valve groups X - XII (16 - 18) in the elliptical dotted line frame B connected in parallel. The regulating and controlling system adjusts and controls the external sound source or external acoustic impedance received by the test pump 2 through the following methods: adjusting the frequency conversion drive of the auxiliary pump 1 to change its rotational speed, and then changing the sound pressure amplitude and frequency of the auxiliary pump 1 as the sound source; controlling the opening degree of the flow regulating valve I 7 on the outlet pipeline of the auxiliary pump 1, that is, adjusting the flow rate of the auxiliary pump 1, and then changing the sound pressure amplitude of the auxiliary pump 1 as the sound source; adjusting different waterway regulating valves II - XII (8 - 18) on the branch pipeline between the test pump 2 and the auxiliary pump 1 to make the pipeline configuration have different acoustic impedances.

[0033] A flow regulating valve I 7 is provided on the outlet pipeline of the auxiliary pump 1, and a waterway regulating valve IX 15 is provided on the outlet pipeline of the test pump 2; between the auxiliary pump 1 and the test pump 2, the regulating and controlling system includes the flow regulating valve I 7 and the first waterway regulating valve group in the elliptical dotted line frame A; between the test pump 2 and the water tank 19, the regulating and controlling system includes the waterway regulating valve IX 15 and the second waterway regulating valve group in the elliptical dotted line frame B.

[0034] The first regulating valve group in the elliptical dotted line frame A is composed of the waterway regulating valve II 8, the waterway regulating valve III 9, the waterway regulating valve IV 10, the waterway regulating valve V 11, the waterway regulating valve VI 12, the waterway regulating valve VII 13 and the waterway regulating valve VIII 14 connected in series and parallel. The second waterway regulating valve group in the elliptical dotted line frame B is composed of the waterway regulating valve X 16, the waterway regulating valve XI 17 and the waterway regulating valve XII 18 connected in parallel.

[0035] The waterway system also includes loops I, II, III, IV, V, VI, VII, VIII, IX, X, XI, XII.

[0036] For loop I, the flow regulating valve I 7, the waterway regulating valve II 8, the waterway regulating valve III 9, the waterway regulating valve VI 12, the waterway regulating valve IX 15, and the waterway regulating valve X 16 are opened, and the rest of the waterway regulating valves are closed.

[0037] For loop II, the flow regulating valve I 7, the waterway regulating valve II 8, the waterway regulating valve V 11, the waterway regulating valve VIII 14, the waterway regulating valve IX 15, and the waterway regulating valve X 16 are opened, and the rest of the waterway regulating valves are closed.

[0038] Circuit Ⅲ has the flow regulating valve Ⅰ7, waterway regulating valve Ⅳ10, waterway regulating valve Ⅶ13, waterway regulating valve Ⅷ14, waterway regulating valve Ⅸ15, and waterway regulating valve Ⅹ16 open, and the rest of the waterway regulating valves closed.

[0039] Circuit Ⅳ has the flow regulating valve Ⅰ7, waterway regulating valve Ⅲ9, waterway regulating valve Ⅳ10, waterway regulating valve Ⅴ11, waterway regulating valve Ⅵ12, waterway regulating valve Ⅶ13, waterway regulating valve Ⅸ15, and waterway regulating valve Ⅹ16 open, and the rest of the waterway regulating valves closed.

[0040] Circuit Ⅴ has the flow regulating valve Ⅰ7, waterway regulating valve Ⅱ8, waterway regulating valve Ⅲ9, waterway regulating valve Ⅵ12, waterway regulating valve Ⅸ15, and waterway regulating valve Ⅺ17 open, and the rest of the waterway regulating valves closed.

[0041] Circuit Ⅵ has the flow regulating valve Ⅰ7, waterway regulating valve Ⅱ8, waterway regulating valve Ⅴ11, waterway regulating valve Ⅷ14, waterway regulating valve Ⅸ15, and waterway regulating valve Ⅺ17 open, and the rest of the waterway regulating valves closed.

[0042] Circuit Ⅶ has the flow regulating valve Ⅰ7, waterway regulating valve Ⅳ10, waterway regulating valve Ⅶ13, waterway regulating valve Ⅷ14, waterway regulating valve Ⅸ15, and waterway regulating valve Ⅺ17 open, and the rest of the waterway regulating valves closed.

[0043] Circuit Ⅷ has the flow regulating valve Ⅰ7, waterway regulating valve Ⅲ9, waterway regulating valve Ⅳ10, waterway regulating valve Ⅴ11, waterway regulating valve Ⅵ12, waterway regulating valve Ⅶ13, waterway regulating valve Ⅸ15, and waterway regulating valve Ⅺ17 open, and the rest of the waterway regulating valves closed.

[0044] Circuit Ⅸ has the flow regulating valve Ⅰ7, waterway regulating valve Ⅱ8, waterway regulating valve Ⅲ9, waterway regulating valve Ⅵ12, waterway regulating valve Ⅸ15, and waterway regulating valve Ⅻ18 open, and the rest of the waterway regulating valves closed.

[0045] Circuit Ⅹ has the flow regulating valve Ⅰ7, waterway regulating valve Ⅱ8, waterway regulating valve Ⅴ11, waterway regulating valve Ⅷ14, waterway regulating valve Ⅸ15, and waterway regulating valve Ⅻ18 open, and the rest of the waterway regulating valves closed.

[0046] Circuit Ⅺ has the flow regulating valve Ⅰ7, waterway regulating valve Ⅳ10, waterway regulating valve Ⅶ13, waterway regulating valve Ⅷ14, waterway regulating valve Ⅸ15, and waterway regulating valve Ⅻ18 open, and the rest of the waterway regulating valves closed.

[0047] Circuit Ⅻ has the flow regulating valve Ⅰ7, waterway regulating valve Ⅲ9, waterway regulating valve Ⅳ10, waterway regulating valve Ⅴ11, waterway regulating valve Ⅵ12, waterway regulating valve Ⅶ13, waterway regulating valve Ⅸ15, and waterway regulating valve Ⅻ18 open, and the rest of the waterway regulating valves closed.

[0048] The waterway system also includes closing the waterway regulating valve IX15 in circuits I, II, III, IV, V, VI, VII, VIII, IX, X, XI, and XII, and keeping the other regulating valves unchanged.

[0049] When conducting the acoustic transmission characteristic test of the vane pump port at different frequencies on the test bench, without modifying the pipeline, relevant tests can be completed through the adjustment of the frequency conversion drive of the auxiliary pump 1, the adjustment of the opening degree of the flow regulating valve I7, and the mutual cooperation of different waterway regulating valves II8 - XII18 on the branch pipeline. The following is an explanation of some specific implementation processes:

[0050] The first test process: During the test, the waterway system selects circuit I, the test pump 2 is in a stationary state, the auxiliary pump 1 is running and at a certain rotational speed. Only the opening degree of the flow regulating valve I7 is adjusted, and then the sound source intensity of the auxiliary pump 1 as the sound source changes. Thus, different sound pressure amplitude results measured by the piezoelectric pressure sensor group 5 and the piezoelectric pressure sensor group 6 on the inlet and outlet pipelines of the test pump 2 can be obtained when the auxiliary pump 1 operates as the sound source under different flow conditions.

[0051] The second test process: Referring to the first test process above, the difference is that only the selection scheme of the waterway system circuit during the test is changed at this time, such as circuits II - XII, that is, the acoustic impedance of the waterway system outside the test pump 2 is changed, and the other conditions remain unchanged. Different sound pressure amplitude results measured by the piezoelectric pressure sensor 5 and the piezoelectric pressure sensor 6 on the inlet and outlet pipelines of the test pump 2 can be obtained when the auxiliary pump 1 operates as the sound source under different flow conditions for each waterway system circuit scheme.

[0052] The third test process: Referring to the first test process above, the difference is that the flow regulating valve I7 maintains a certain opening degree at this time, and only the rotational speed of the auxiliary pump 1 is adjusted through frequency conversion drive. Then, the sound source intensity and the sound source frequency of the auxiliary pump 1 as the sound source change. Thus, different sound pressure amplitude results measured by the piezoelectric pressure sensor group 5 and the piezoelectric pressure sensor group 6 on the inlet and outlet pipelines of the test pump 2 can be obtained when the auxiliary pump 1 operates as the sound source at different rotational speeds and different frequencies.

[0053] The fourth test process: Similarly, close the waterway regulating valve IX15 in circuits I, II, III, IV, V, VI, VII, VIII, IX, X, XI, and XII, and keep the other regulating valves unchanged, and complete the first test process, the second test process, and the third test process above respectively.

[0054] Calculation process: According to the different sound pressure amplitudes measured by the piezoelectric pressure sensor 5 on the inlet pipeline of the test pump 2 in the first test process, the second test process, the third test process, and the fourth test process above, list the following equations:

[0055]

[0056] Δl up = x2 - x1 (3)

[0057] where p 1,up (x, t) and p 2up (x, t) respectively represent the sound pressure amplitudes measured by two piezoelectric pressure sensors on the inlet pipeline of the test pump 2; and respectively represent the plane sound pressure amplitudes propagating in the positive and negative directions in the inlet pipeline of the test pump 2, and and respectively represent the phases of the plane sound pressure, where the positive direction propagation means that the sound pressure wave propagation direction points to the inlet direction of the pump, and the negative direction propagation means that the sound pressure wave propagation direction is away from the inlet direction of the pump; x1 and x2 are the distances from the two piezoelectric pressure sensors in the piezoelectric pressure sensor group 5 to the inlet end of the test pump 2 respectively; represents the distance between the two piezoelectric pressure sensors in the piezoelectric pressure sensor group 5; is the imaginary unit, ω = 2πf represents the angular frequency, f represents the frequency, represents the wave number, and is the sound speed in the medium. Solving according to equations (1) - (3) gives:

[0058]

[0059] Similarly, according to the different sound pressure amplitudes measured by the piezoelectric pressure sensor group 6 on the outlet pipeline of the test pump 2 in the above first test process, second test process, third test process, and fourth test process, the following equations are listed:

[0060]

[0061] Δl down = x4 - x3 (8)

[0062] where p 1,down (x, t) and p 2,down (x, t) respectively represent the sound pressure amplitudes measured by two piezoelectric pressure sensors in the piezoelectric pressure sensor group 6 on the outlet pipeline of the test pump 2; and respectively represent the plane sound pressure amplitudes propagating in the positive and negative directions in the outlet pipeline of the test pump 2, and and respectively represent the phases of the plane sound pressure, where the positive direction propagation means that the sound pressure wave propagation direction points to the outlet direction of the pump, and the negative direction propagation means that the sound pressure wave propagation direction is away from the outlet direction of the pump; x3 and x4 are the distances from the two piezoelectric pressure sensors in the piezoelectric pressure sensor group 6 to the outlet end of the test pump 2 respectively; represents the distance between the two piezoelectric pressure sensors in the piezoelectric pressure sensor group 6. Solving according to equations (6) - (8) gives:

[0063]

[0064] Based on the n data groups obtained by solving equations (1) - (3) and (6) - (8) and the following system of equations is listed:

[0065]

[0066] The overdetermined equations (11) and (12) can be solved by the least squares method to obtain the reflection coefficient S at the inlet end of the test pump 2 11 , the transmission coefficient S at the inlet end 12 , the reflection coefficient S at the outlet end 22 , the transmission coefficient S at the outlet end 21 , which are the port acoustic transmission characteristic parameters of the test pump 2

[0067] The above are only the preferred implementation schemes of the present invention. For those skilled in the art of the present technology, any improvement to the present invention without any creative labor belongs to the protection scope of the present invention

Claims

1. A test bench for testing the acoustic transmission characteristics of a vane pump port, characterized in that, It includes an auxiliary pump, a test pump, a flowmeter, a flow regulating valve I, waterway regulating valves II - XII, a water tank and its waterway system; the auxiliary pump and the test pump are connected by pipelines, and both the auxiliary pump and the test pump are connected to the water tank through pipelines, forming the main loop of the waterway circulation system; flowmeters are installed on the outlet pipelines of both the auxiliary pump and the test pump; The test bench can be divided into a monitoring system and a regulating and controlling system; the monitoring system is composed of two groups of four piezoelectric pressure sensors, which are respectively located on the inlet pipeline and the outlet pipeline of the test pump, and each group includes two piezoelectric pressure sensors, used to monitor the sound pressure signals at different frequencies excited by the auxiliary pump at the inlet pipeline and the outlet pipeline of the test pump; the regulating and controlling system includes a first waterway regulating valve group arranged between the auxiliary pump and the test pump and a flow regulating valve I arranged on the outlet pipeline of the auxiliary pump, a second waterway regulating valve group arranged between the test pump and the water tank and a waterway regulating valve IX arranged on the outlet pipeline of the test pump; the regulating and controlling system regulates the external sound source or external acoustic impedance received by the test pump; the first waterway regulating valve group includes waterway regulating valves IV, V and VI arranged in parallel, and waterway regulating valves II and VII are respectively connected in series on both sides of waterway regulating valve IV and waterway regulating valve V, and waterway regulating valves III and VIII are respectively connected in series on both sides of waterway regulating valve V and waterway regulating valve VI; the second waterway regulating valve group includes waterway regulating valves X, XI and XII arranged in parallel.

2. The test bench for testing the acoustic transmission characteristics of the port of a vane pump according to claim 1, characterized in that, The adjustment steps of the regulating and controlling system include: adjusting the frequency conversion drive of the auxiliary pump to change its speed, and then changing the sound pressure amplitude and frequency of the auxiliary pump as the sound source; controlling the opening of the flow regulating valve I on the outlet pipeline of the auxiliary pump, and then changing the sound pressure amplitude of the auxiliary pump as the sound source; adjusting different waterway regulating valves II - XII on the branch pipeline between the test pump and the auxiliary pump to make the pipeline configuration have different acoustic impedances.

3. The test bench for testing the acoustic transmission characteristics of the port of a vane pump according to claim 2, characterized in that, The adjustment steps include a first test process, a second test process, a third test process, a fourth test process and a calculation process; First test process: During the test, the waterway system selects loop I, the test pump is in a stationary state, the auxiliary pump runs at a preset speed, and the opening of the flow regulating valve I is adjusted. Then, the sound source intensity of the auxiliary pump as the sound source changes, so that different sound pressure amplitude results measured by the piezoelectric pressure sensor group and the piezoelectric pressure sensor group on the inlet and outlet pipelines of the test pump can be obtained when the auxiliary pump as the sound source operates under different flow conditions; Second test process: On the basis of the first test process, change the selection scheme of the waterway system loop during the test, select loops II - XII, change the acoustic impedance of the external waterway system of the test pump, and keep the other conditions unchanged. Different sound pressure amplitude results measured by the piezoelectric pressure sensor and the piezoelectric pressure sensor on the inlet and outlet pipelines of the test pump can be obtained when the auxiliary pump as the sound source operates under different flow conditions for each waterway system loop scheme; The third test process: On the basis of the first test process, keep the flow regulating valve I at the preset opening degree, adjust the rotational speed of the auxiliary pump through frequency conversion drive, and then the sound source intensity and sound source frequency of the auxiliary pump as the sound source change. Thus, different sound pressure amplitude results measured by the piezoelectric pressure sensor groups on the inlet and outlet pipelines of the test pump can be obtained when the auxiliary pump as the sound source operates at different rotational speeds and different frequencies; The fourth test process: On the basis of the first test process, close the waterway regulating valve IX in the circuits I, II, III, IV, V, VI, VII, VIII, IX, X, XI, XII, and keep the other regulating valves unchanged, and complete the first test process, the second test process, and the third test process respectively; Calculation process: Calculate the port acoustic transmission characteristic parameters of the test pump according to the different sound pressure amplitudes measured by the piezoelectric pressure sensor groups on the inlet pipeline of the test pump in the first test process, the second test process, the third test process, and the fourth test process.

4. A test bench for testing the acoustic transmission characteristics of the ports of a vane pump, characterized in that, The port acoustic transmission characteristic parameters of the test pump include the inlet end reflection coefficient S of the test pump 11 , the inlet end transmission coefficient S 12 , the outlet end reflection coefficient S 22 , and the outlet end transmission coefficient S 21 .

5. The test bench for testing the acoustic transmission characteristics of the vane pump ports according to claim 3, characterized in that, The said calculation process includes: List the following equations according to the different sound pressure amplitudes measured by the piezoelectric pressure sensor groups on the inlet pipeline of the test pump in the first test process, the second test process, the third test process, and the fourth test process; Δl up = x2 - x1 (3) where p 1,up (x, t) and p 2up (x, t) respectively represent the sound pressure amplitudes measured by two piezoelectric pressure sensors in the piezoelectric pressure sensor group on the inlet pipeline of the test pump; and respectively represent the plane sound pressure amplitudes propagating in the positive and negative directions in the inlet pipeline of the test pump, and are the phases of the plane sound pressure respectively, where the positive direction propagation means that the sound pressure wave propagation direction points to the inlet direction of the pump, and the negative direction propagation means that the sound pressure wave propagation direction is away from the inlet direction of the pump; x1 and x2 are the distances from the two piezoelectric pressure sensors in the piezoelectric pressure sensor group to the inlet end of the test pump respectively; Δl up represents the distance between the two piezoelectric pressure sensors in the piezoelectric pressure sensor group; is the imaginary unit, ω = 2πf represents the angular frequency, f represents the frequency, k = ω / c0 represents the wave number, and c0 is the sound speed in the medium; Solved according to equations (1) to (3): List the following equations according to the different sound pressure amplitudes measured by the piezoelectric pressure sensor groups on the outlet pipeline of the test pump in the first test process, the second test process, the third test process, and the fourth test process; Δl down = x4 - x3 (8) where p 1,down (x, t) and p 1,down (x, t) respectively represent the sound pressure amplitudes measured by two piezoelectric pressure sensors in the piezoelectric pressure sensor group on the outlet pipeline of the test pump; and respectively represent the plane sound pressure amplitudes propagating in the positive and negative directions in the outlet pipeline of the test pump, and are the phases of the plane sound pressure respectively, where the positive direction propagation means that the sound pressure wave propagation direction points to the outlet direction of the pump, and the negative direction propagation means that the sound pressure wave propagation direction is away from the outlet direction of the pump; x3 and x4 are the distances from two piezoelectric pressure sensors in the piezoelectric pressure sensor group to the outlet end of the test pump respectively; Δl down represents the distance between two piezoelectric pressure sensors in the piezoelectric pressure sensor group; obtained by solving according to equations (6) to (8): The n data sets obtained by solving according to equations (1) to (3) and (6) to (8) and List the following system of equations: The overdetermined equations (11) and (12) can be solved by the least squares method to obtain the reflection coefficient S at the inlet end of the test pump 11 , the transmission coefficient S at the inlet end 12 , the reflection coefficient S at the outlet end 22 , and the transmission coefficient S at the outlet end 21 .

6. The test bench for testing the acoustic transmission characteristics of the ports of a vane pump according to claim 1, characterized in that, The distance between the two piezoelectric pressure sensors in each group at the inlet pipeline and the outlet pipeline is 10 to 20 times the inner diameter of the pipeline.

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