Experimental bench capable of identifying cavitation of vane pump, and experimental method

Abstract

An experimental bench capable of identifying cavitation of a vane pump, and an experimental method. The experimental bench comprises: a test pump (1) to be tested, a flow meter (9), a loudspeaker (2), a flow regulating valve (10), and six pressure sensors (3, 4, 5, 6, 7, 8). The flow meter (9) is arranged on water outlet piping of said test pump (1) and is used for measuring the flow of the water outlet piping of the pump; the loudspeaker (2) is arranged on water inlet piping of said test pump (1), and when the loudspeaker (2) is used as an external sound source, the loudspeaker can radiate sound pressure waves of different acoustic loads into the water inlet piping by adjusting the frequency and intensity of acoustic loads of the loudspeaker (2); the flow regulating valve (10) is arranged on the water outlet piping of said test pump (1) and is used for regulating the flow of a pump system; and the six pressure sensors (3, 4, 5, 6, 7, 8) are data acquisition elements for monitoring noise produced during cavitation of said test pump (1), the water inlet piping and the water outlet piping of said test pump (1) each having arranged thereon three sensors used for monitoring sound pressure signals. By means of the experimental bench capable of identifying cavitation of a vane pump, and the experimental method, cavitation can be monitored at the initial stage of cavitation, so as to solve the problem of prediction at the initial stage of cavitation.

Description

An experimental setup and method for identifying cavitation in bladed pumps Technical Field

[0001] This invention belongs to the field of experimental technology for identifying cavitation characteristics of blade pumps, and particularly relates to an experimental platform and experimental method for identifying cavitation in blade pumps. Background Technology

[0002] As a widely used fluid transport device, the vane pump plays a crucial role in various industries such as chemical, energy, and water conservancy. However, a common problem during its operation—cavitation—poses a serious threat to the overall performance of the pump. The cavitation mechanism of vane pumps mainly stems from the high-speed flow generated by the impeller rotation. When liquid is accelerated through the impeller inlet, the local pressure at the impeller inlet drops below the saturated vapor pressure of the liquid at the current temperature, causing a large number of tiny bubbles to escape from the liquid.

[0003] As these bubbles and fluid enter the high-pressure area, they rapidly contract and collapse. The energy released in this process erodes the pump's inner wall and blades in the form of shock waves, accompanied by severe vibration and noise. This phenomenon of bubble formation, growth, and collapse significantly reduces the pump's efficiency and reliability, and may cause premature wear or even failure of mechanical components, seriously affecting the pump's safe, stable operation and service life. Therefore, in order to detect cavitation phenomena in a timely manner, prevent and mitigate the negative impacts of cavitation, and ensure the long-term stable and efficient operation of vane pumps, real-time monitoring and accurate identification of cavitation conditions are extremely important. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes an experimental platform and method for identifying cavitation in blade pumps, thereby resolving the issues present in the prior art.

[0005] To achieve the above objectives, the present invention provides an experimental platform capable of identifying cavitation in a vane pump, comprising:

[0006] The pump, flow meter, loudspeaker, flow regulating valve, and pressure sensor to be tested;

[0007] The flow meter is connected to the outlet pipe of the pump under test and is used to measure the flow rate of the pump outlet pipe.

[0008] The loudspeaker is connected to the inlet pipe of the pump under test and is used to radiate acoustic pressure waves of the acoustic load to the inlet pipe of the pump under test based on the frequency and intensity of the loudspeaker's acoustic load.

[0009] The flow regulating valve is connected to the outlet pipe of the pump under test and is used to regulate the flow rate of the pump under test.

[0010] The pressure sensor is connected to the outlet and inlet pipes of the pump under test, respectively, and is used to monitor the sound pressure signal.

[0011] To achieve the above objectives, the present invention provides an experimental method for an experimental platform capable of identifying cavitation in a vane pump, comprising:

[0012] The test pump is installed on the test bench and placed in a stationary state. The flow regulating valve is fully open. The frequency and intensity of the acoustic load of the loudspeaker are adjusted. The sound pressure signals of the outlet and inlet pipes of the test pump in a stationary state are collected based on the pressure sensor.

[0013] The acoustic scattering matrix of the test pump in a static state is constructed based on the sound pressure signals of the outlet and inlet pipes of the pump under test when the pump is stationary.

[0014] The test pump is installed on the test bench with the speaker off and the flow regulating valve at a certain opening. The test pump is in cavitation operation mode. The sound pressure signals of the outlet and inlet pipes of the test pump in cavitation operation mode are collected based on the pressure sensor.

[0015] The acoustic scattering matrix of the pump under test under cavitation operation is constructed based on the sound pressure signals of the outlet and inlet pipes of the pump under test under cavitation operation.

[0016] Cavitation of the impeller pump is identified based on the acoustic scattering matrix of the pump under test in a static state and the acoustic scattering matrix of the pump under test in a cavitation operation state.

[0017] Preferably, the process of constructing the acoustic scattering matrix of the test pump in a static state based on the sound pressure signals of the outlet and inlet pipes of the test pump in a static state includes:

[0018] Based on the sound pressure signals of the outlet and inlet pipes of the test pump in a static state, the sound pressure wave amplitudes pointing towards the pump inlet and away from the pump inlet in the upstream inlet pipe, and the sound pressure wave amplitudes pointing towards the pump outlet and away from the pump outlet in the downstream outlet pipe are obtained when the test pump is in a static state.

[0019] The acoustic scattering matrix of the pump under test in a static state is constructed based on the acoustic pressure wave amplitude values ​​pointing towards and away from the pump inlet in the upstream inlet pipe, and the acoustic pressure wave amplitude values ​​pointing towards and away from the pump outlet in the downstream outlet pipe.

[0020] Preferably, the expression for constructing the acoustic scattering matrix of the test pump in a static state is:

[0021] in, The amplitude of the sound pressure wave in the downstream outlet pipeline facing away from the pump outlet is measured with the pump under test in a stationary state. With the pump under test in a stationary state, the amplitude of the sound pressure wave in the upstream inlet pipe facing away from the pump inlet; S 无,11 and S 无,12 With the pump under test in a stationary state, the reflection coefficient and transmission coefficient at the pump inlet are measured; S 无,22 and S 无,21 This indicates that the pump under test is in a stationary state, and the reflection coefficient and transmission coefficient at the pump outlet are shown. The amplitude of the sound pressure wave pointing towards the pump inlet in the upstream inlet pipe is measured with the pump under test in a stationary state. With the pump under test in a stationary state, the amplitude of the sound pressure wave pointing from the pump outlet in the downstream water pipeline; S 无 The acoustic scattering matrix at the pump inlet and outlet ports is used to prevent cavitation.

[0022] Preferably, the process of constructing the acoustic scattering matrix of the pump under test in cavitation operation based on the sound pressure signals of the outlet and inlet pipes of the pump under test in cavitation operation includes:

[0023] Based on the acoustic pressure signals of the outlet and inlet pipes of the test pump under cavitation operation, the acoustic pressure wave amplitudes pointing towards the pump inlet and away from the pump inlet in the upstream inlet pipe and the acoustic pressure wave amplitudes pointing towards the pump outlet and away from the pump outlet in the downstream outlet pipe are obtained when the test pump is under cavitation operation.

[0024] Based on the acoustic pressure wave amplitude values ​​pointing towards and away from the pump inlet in the upstream water inlet pipeline, and the acoustic pressure wave amplitude values ​​pointing towards and away from the pump outlet in the downstream water outlet pipeline, an acoustic scattering matrix with cavitation phenomenon is constructed at the pump inlet and outlet ports.

[0025] Preferably, in the case of cavitation, the acoustic scattering matrix at the pump inlet and outlet ports is constructed using the following expressions:

[0026] Among them, S 有,11 and S 有,12 This indicates that the pump under test is in cavitation operation, and the reflection coefficient and transmission coefficient at the pump inlet are shown; S 有,22 and S 有,21 This indicates that the pump under test is in a cavitation operation state, and the reflection coefficient and transmission coefficient at the pump outlet are shown. The amplitude of the sound pressure wave in the downstream outlet pipeline facing away from the pump outlet is measured when the pump under test is in cavitation operation. The amplitude of the acoustic pressure wave in the upstream inlet pipeline facing away from the pump inlet is measured while the pump is in cavitation operation. The amplitude of the sound pressure wave pointing from the pump inlet in the upstream inlet pipeline is measured to indicate that the pump is in cavitation operation. The amplitude of the sound pressure wave pointing from the pump outlet in the downstream outlet pipeline is measured to indicate that the pump is operating in a cavitation state. 有 Acoustic scattering matrices at the pump inlet and outlet ports are used to detect cavitation.

[0027] Preferably, the reflection coefficient and transmission coefficient at the pump inlet and the reflection coefficient and transmission coefficient at the pump outlet are obtained by solving the least squares method.

[0028] Compared with the prior art, the present invention has the following advantages and technical effects:

[0029] This invention proposes a monitoring system and experimental method for identifying cavitation in a vane pump. With only one test pump, one flow meter, one loudspeaker, one flow regulating valve, two sets of six pressure sensors, and the relevant piping connecting these components, it can obtain experimental results of the acoustic scattering matrix at different frequencies at the inlet and outlet ports of the test pump under cavitation operation. This invention can monitor cavitation in its early stages, aiming to solve the urgent problem of predicting cavitation in the early stages in engineering applications. Experimental verification shows that the test bench has a compact structure, reasonable design, and high engineering value. Attached Figure Description

[0030] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0031] Figure 1 is a schematic diagram of the test bench for the monitoring system of cavitation monitoring pump under test according to an embodiment of the present invention;

[0032] Figure 2 is a schematic diagram of the distance between different pressure sensors in the inlet and outlet water pipes of the test pump according to an embodiment of the present invention;

[0033] Among them, 1. the pump to be tested; 2. the loudspeaker; 3. pressure sensor I; 4. pressure sensor II; 5. pressure sensor III; 6. pressure sensor IV; 7. pressure sensor V; 8. pressure sensor VI; 9. flow meter; 10. flow regulating valve; 11. water tank. Detailed Implementation

[0034] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0035] It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases the steps shown or described may be executed in a different order than that shown here.

[0036] Example 1

[0037] This embodiment provides an experimental platform and method for identifying cavitation in a vane pump, including:

[0038] One test pump 1, one flow meter 9, one loudspeaker 2, one flow regulating valve 10, two sets of six pressure sensors I to VI (3 to 8) and related pipelines connecting the components;

[0039] The flow meter 9 is arranged on the outlet pipe of the test pump 1 to measure the flow rate of the outlet pipe of the test pump 1.

[0040] The loudspeaker 2 is arranged on the inlet pipe of the pump 1 under test. The distance to the nearest pressure sensor 5 is 5 to 20 times the inner diameter of the pump port pipe. The smaller the inner diameter of the pipe, the larger the multiplier value is selected, and the larger the inner diameter of the pipe, the smaller the multiplier value is selected. When the loudspeaker 2 is used as an external sound source, the frequency and intensity of the acoustic load of the loudspeaker 2 can be adjusted to radiate sound pressure waves of different acoustic loads into the inlet pipe.

[0041] The flow regulating valve 10 is arranged on the outlet pipe of the pump 1 under test and is used to regulate the flow of the pump system.

[0042] The two sets of six pressure sensors (I-VI, 3-8) are data acquisition elements for monitoring the cavitation noise of the test pump 1. One set of three pressure sensors (I-III, 3-5) is arranged on the inlet pipe of the test pump 1, and another set of three pressure sensors (IV-VI, 6-8) is arranged on the outlet pipe of the test pump 1, respectively, to monitor the sound pressure signal. Based on the acoustic theory of sound pressure wave propagation in pipes, the distance between two adjacent pressure sensors in the inlet and outlet pipes is 10-30 times the inner diameter of the pump port pipe. The smaller the inner diameter of the pipe, the larger the multiple should be; the larger the inner diameter of the pipe, the smaller the multiple should be.

[0043] The experimental method for achieving real-time monitoring and accurate identification of cavitation status using the aforementioned monitoring system capable of identifying cavitation in vane pumps is as follows:

[0044] The test pump 1 is installed on the test bench and is in a static state. The flow regulating valve 10 is fully open. The frequency and intensity of the acoustic load of the speaker 2 are adjusted. The sound pressure signals collected by the data acquisition elements, pressure sensor I3, pressure sensor II4, and pressure sensor III5, are p. 无,Ⅰ,n (x,t), p 无,Ⅱ,n (x,t) and p 无,Ⅲ,n (x,t), the sound pressure signals collected by the data acquisition elements pressure sensors IV6, V7, and VI8 are p 无,Ⅳ,n (x,t), p 无,Ⅴ,n (x,t) and p 无,Ⅵ,n (x,t), where the subscript "none" indicates that the test pump 1 is in a static state, i.e., there is no cavitation phenomenon, n indicates the frequency and intensity of the acoustic load of the loudspeaker 2, and the number of different sound pressure signals collected by pressure sensors I to VI (3 to 8) in the pipeline.

[0045] Combining Figure 1 and Figure 2, based on the above method, and according to equations (1) and (2), the amplitude of the sound pressure wave pointing to the pump inlet in the inlet pipe of the pump 1 under test can be obtained respectively. (phase) ) and the amplitude of the sound pressure wave at the pump inlet (phase) According to equations (3) and (4), the amplitude of the sound pressure wave pointing to the pump inlet in the inlet pipe of the test pump 1 can be obtained respectively. (phase) ) and the amplitude of the sound pressure wave at the pump inlet (phase) According to equations (5) and (6), the amplitude of the sound pressure wave pointing to the pump inlet in the inlet pipe of the pump to be tested can be obtained respectively. (phase) ) and the amplitude of the sound pressure wave at the pump inlet (phase) ).

[0046] In the formula, t is time, ω=2πf represents angular frequency, f represents frequency, k=ω / c0 represents wave number, and c0 is the sound pressure speed in the fluid. Ⅰ and l Ⅱ Δl represents the distance from pressure sensor I3 and pressure sensor II4 to the inlet of the pump under test 1, respectively. Ⅰ-Ⅱ =l Ⅱ -l Ⅰ ;l Ⅰ and l Ⅲ Δl represents the distance from pressure sensor I3 and pressure sensor III5 to the inlet of the pump under test 1, respectively.Ⅰ-Ⅲ =l Ⅲ -l Ⅰ ;l Ⅱ and l Ⅲ Δl represents the distance from pressure sensor II4 and pressure sensor III5 to the inlet end of the test pump 1, respectively. Ⅱ-Ⅲ =l Ⅲ -l Ⅱ .

[0047] To improve the accuracy and reliability of sound pressure monitoring, the sound pressure wave amplitude values ​​obtained from equations (1) and (2) are... (phase) and sound pressure wave amplitude (phase) The amplitude of the sound pressure wave obtained by equations (3) and (4) (phase) and sound pressure wave amplitude (phase) The amplitude of the sound pressure wave obtained by equations (5) and (6) (phase) and sound pressure wave amplitude (phase) The average value is calculated to obtain the amplitude of the sound pressure wave pointing towards the pump inlet in the upstream inlet pipe of the pump under test 1. (phase) ) and the amplitude of the sound pressure wave at the pump inlet (phase) ).

[0048] Similarly, combining Figure 1 and Figure 2, based on the above method, and according to equations (7) and (8), the amplitude of the sound pressure wave pointing to the pump outlet in the water outlet pipeline of the test pump 1 can be obtained respectively. (phase) ) and the amplitude of the sound pressure wave facing away from the pump outlet (phase) According to equations (9) and (10), the amplitude of the sound pressure wave pointing to the pump outlet in the water outlet pipeline of the test pump 1 can be obtained respectively. (phase) ) and the amplitude of the sound pressure wave facing away from the pump outlet (phase) According to equations (11) and (12), the amplitude of the sound pressure wave pointing to the pump outlet in the water outlet pipeline of the test pump 1 can be obtained respectively. (phase) ) and the amplitude of the sound pressure wave facing away from the pump outlet (phase) ).

[0049] In the formula l Ⅳ and l Ⅴ Δl represents the distance from pressure sensors IV6 and V7 to the outlet of the test pump 1, respectively. Ⅳ-Ⅴ =l Ⅴ -l Ⅳ ;l Ⅳ and l Ⅵ Δl represents the distance from pressure sensors IV6 and VI8 to the outlet end of the test pump 1, respectively. Ⅳ-Ⅵ =l Ⅵ -l Ⅳ ;l Ⅴ and l Ⅵ Δl represents the distance from pressure sensor V7 and pressure sensor VI8 to the outlet end of the test pump 1, respectively. Ⅴ-Ⅵ =l Ⅵ -l Ⅴ .

[0050] To improve the accuracy and reliability of sound pressure monitoring, the sound pressure wave amplitude values ​​obtained from equations (7) and (8) are... (phase) and sound pressure wave amplitude (phase) The amplitude of the sound pressure wave obtained by equations (9) and (10) (phase) and sound pressure wave amplitude (phase) The amplitude of the sound pressure wave obtained by equations (11) and (12) (phase) and sound pressure wave amplitude (phase) The average value is calculated to obtain the amplitude of the sound pressure wave pointing from the pump outlet in the downstream outlet pipeline of the test pump 1. (phase) ) and the amplitude of the sound pressure wave facing away from the pump outlet (phase) ).

[0051] Based on the sound pressure wave amplitude value pointing towards the pump inlet in the upstream inlet pipe of the pump under test 1 (phase) ) and the amplitude of the sound pressure wave at the pump inlet (phase) ), and the amplitude of the sound pressure wave pointing towards the pump outlet in the downstream water outlet pipeline. (phase) ) and the amplitude of the sound pressure wave facing away from the pump outlet (phase) ), establish the acoustic scattering matrix [S] at the pump inlet and outlet ports when the pump 1 under test is in a static state, i.e., without cavitation. 无 The equation is as follows:

[0052] In the formula S 无,11 and S 无,12 This indicates the reflection coefficient and transmission coefficient at the pump inlet when the pump under test 1 is in a static state, i.e., without cavitation. 无,22 and S 无,21 This indicates the reflection coefficient and transmission coefficient at the pump outlet when the pump 1 under test is in a static state, i.e., without cavitation.

[0053] Since n represents the frequency and intensity of the acoustic load of the loudspeaker 2, and the number of different sound pressure signals collected by pressure sensors I to VI (3 to 8) in the pipeline, n data sets can be obtained from the upstream inlet pipeline and the downstream outlet pipeline of the pump under test 1. (phase) ), (phase) ), (phase) )and (phase) The overdetermined system of equations (13) can be solved using the least squares method to obtain S. 无,11 S 无,12 S 无,21 and S 无,22 Thus, the acoustic scattering matrix [S] at the inlet and outlet ports of the test pump 1 can be obtained when there is no cavitation phenomenon. 无 ].

[0054] Similarly, without requiring the disassembly and reassembly of the test pump 1 and related pipelines, the speaker 2 is in the off state, the flow regulating valve 10 is at a certain opening degree, and the test pump 1 is in cavitation operation. The sound pressure signals collected by the data acquisition elements pressure sensor I 3, pressure sensor II 4, and pressure sensor III 5 are respectively p 有,Ⅰ,n (x,t), p 有,Ⅱ,n (x,t) and p 有,Ⅲ,n (x,t), the sound pressure signals collected by the data acquisition elements pressure sensors IV6, V7, and VI8 are p 有,Ⅳ,n (x,t), p 有,Ⅴ,n (x,t) and p 有,Ⅵ,n (x,t), where the subscript "yes" indicates that the pump 1 to be tested is in a cavitation operation state, that is, there is cavitation phenomenon, n indicates the frequency and intensity of the acoustic load of the loudspeaker 2, and the number of different sound pressure signals collected by pressure sensors I to VI (3 to 8) in the pipeline.

[0055] Combining Figures 1 and 2, based on the above method, and according to equations (14) and (15), the amplitude of the sound pressure wave pointing from the pump inlet in the water inlet of the test pump 1 when it is in cavitation operation can be obtained respectively. (phase) ) and the amplitude of the sound pressure wave at the pump inlet (phase) According to equations (16) and (17), the amplitude of the sound pressure wave pointing to the pump inlet in the water inlet pipe of the test pump 1 when it is in cavitation operation can be obtained respectively. (phase) ) and the amplitude of the sound pressure wave at the pump inlet (phase) According to equations (18) and (19), the amplitude of the sound pressure wave pointing to the pump inlet in the water inlet of the test pump 1 when it is in cavitation operation can be obtained respectively. (phase) ) and the amplitude of the sound pressure wave at the pump inlet (phase) ).

[0056] In the formula, t is time, ω=2πf represents angular frequency, f represents frequency, k=ω / c0 represents wave number, and c0 is the sound pressure speed in the fluid. Ⅰ and l Ⅱ Δl represents the distance from pressure sensor I3 and pressure sensor II4 to the inlet of the pump under test 1, respectively. Ⅰ-Ⅱ =l Ⅱ -l Ⅰ ;l Ⅰ and l Ⅲ Δl represents the distance from pressure sensor I3 and pressure sensor III5 to the inlet of the pump under test 1, respectively. Ⅰ-Ⅲ =l Ⅲ -l Ⅰ ;l Ⅱ and l Ⅲ Δl represents the distance from pressure sensor II4 and pressure sensor III5 to the inlet end of the test pump 1, respectively. Ⅱ-Ⅲ =l Ⅲ -l Ⅱ .

[0057] To improve the accuracy and reliability of sound pressure monitoring, the sound pressure amplitude values ​​obtained from equations (14) and (15) are... (phase) and sound pressure wave amplitude (phase) The amplitude of the sound pressure wave obtained by equations (16) and (17) (phase) and sound pressure wave amplitude (phase) The amplitude of the sound pressure wave obtained by equations (18) and (19) (phase) and sound pressure wave amplitude (phase) The average value is calculated to obtain the amplitude of the sound pressure wave pointing towards the pump inlet in the upstream inlet pipe of the pump under test 1. (phase) ) and the amplitude of the sound pressure wave at the pump inlet (phase) ).

[0058] Similarly, combining Figure 1 and Figure 2, based on the above method, and according to equations (20) and (21), the amplitude of the sound pressure wave pointing to the pump outlet in the water outlet pipeline of the test pump 1 when it is in cavitation operation can be obtained respectively. (phase) ) and the amplitude of the sound pressure wave facing away from the pump outlet (phase) According to equations (22) and (23), the amplitude of the sound pressure wave pointing to the pump outlet in the water outlet pipeline of the test pump 1 when it is in cavitation operation can be obtained respectively. (phase) ) and the amplitude of the sound pressure wave facing away from the pump outlet (phase) According to equations (24) and (25), the amplitude of the sound pressure wave pointing to the pump outlet in the water outlet pipeline of the test pump 1 when it is in cavitation operation can be obtained respectively. (phase) ) and the amplitude of the sound pressure wave facing away from the pump outlet (phase) ).

[0059] In the formula l Ⅳ and l Ⅴ Δl represents the distance from pressure sensors IV6 and V7 to the outlet of the test pump 1, respectively. Ⅳ-Ⅴ =l Ⅴ -l Ⅳ ;l Ⅳ and l Ⅵ Δl represents the distance from pressure sensors IV6 and VI8 to the outlet end of the test pump 1, respectively. Ⅳ-Ⅵ =l Ⅵ -l Ⅳ ;l Ⅴ and l ⅥΔl represents the distance from pressure sensor V7 and pressure sensor VI8 to the outlet end of the test pump 1, respectively. Ⅴ-Ⅵ =l Ⅵ -l Ⅴ .

[0060] To improve the accuracy and reliability of sound pressure monitoring, the sound pressure amplitude values ​​obtained from equations (20) and (21) are... (phase) and sound pressure wave amplitude (phase) The amplitude of the sound pressure wave obtained by equations (22) and (23) (phase) and sound pressure wave amplitude (phase) The amplitude of the sound pressure wave obtained by equations (24) and (25) (phase) and sound pressure wave amplitude (phase) The average value is calculated to obtain the amplitude of the sound pressure wave pointing from the pump outlet in the downstream outlet pipeline of the test pump 1. (phase) ) and the amplitude of the sound pressure wave facing away from the pump outlet (phase) ).

[0061] Based on the sound pressure wave amplitude value pointing towards the pump inlet in the upstream inlet pipe of the pump under test 1 (phase) ) and the amplitude of the sound pressure wave at the pump inlet (phase) ), and the amplitude of the sound pressure wave pointing towards the pump outlet in the downstream water outlet pipeline. (phase) ) and the amplitude of the sound pressure wave facing away from the pump outlet (phase) ), establish the acoustic scattering matrix [S] at the pump inlet and outlet ports when the pump under test 1 is in cavitation operation state, i.e., cavitation phenomenon occurs. 有 The equation is as follows:

[0062] In the formula S 有,11 and S 有,12 This indicates that the pump under test 1 is in a cavitation operating state, that is, when cavitation occurs, the reflection coefficient and transmission coefficient at the pump inlet are S. 有,22 and S 有,21 This indicates that the test pump 1 is in a cavitation operation state, that is, when cavitation occurs, the reflection coefficient and transmission coefficient at the pump outlet end.

[0063] Since n represents the frequency and intensity of the acoustic load of the loudspeaker 2, and the number of different sound pressure signals collected by pressure sensors I to VI (3 to 8) in the pipeline, n data sets can be obtained from the upstream inlet pipeline and the downstream outlet pipeline of the pump under test 1. (phase) ), (phase) ), (phase) )and (phase) The overdetermined system of equations (26) can be solved using the least squares method to obtain S. 有,11 S 有,12 S 有,21 and S 有,22 Thus, the acoustic scattering matrix [S] at the inlet and outlet ports of the test pump 1 when cavitation occurs can be obtained. 有 ].

[0064] Finally, considering the case where gas overflows from the test pump 1, the sound velocity changes due to different media, and the transmission characteristics of sound pressure at the interface of different media change. As a result, the transmission characteristics of the test pump 1 will change significantly, that is, the sound pressure scattering matrix at the inlet and outlet ports of the test pump 1 will change. Therefore, the above monitoring system and experimental method can achieve real-time monitoring and accurate identification of cavitation state, and there is no need to disassemble or reassemble the test pump 1 and related pipelines during the process.

[0065] The above are merely preferred embodiments of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. An experimental platform for identifying cavitation in a vane pump, characterized in that, include: The pump, flow meter, loudspeaker, flow regulating valve, and pressure sensor to be tested; The flow meter is connected to the outlet pipe of the pump under test and is used to measure the flow rate of the pump outlet pipe. The loudspeaker is connected to the inlet pipe of the pump under test and is used to radiate acoustic pressure waves of the acoustic load to the inlet pipe of the pump under test based on the frequency and intensity of the loudspeaker's acoustic load. The flow regulating valve is connected to the outlet pipe of the pump under test and is used to regulate the flow rate of the pump under test. The pressure sensor is connected to the outlet and inlet pipes of the pump under test, respectively, and is used to monitor the sound pressure signal.

2. The experimental method for the test bench capable of identifying cavitation in a vane pump according to claim 1, characterized in that, Includes the following steps: The test pump is installed on the test bench and placed in a stationary state. The flow regulating valve is fully open. The frequency and intensity of the acoustic load of the loudspeaker are adjusted. The sound pressure signals of the outlet and inlet pipes of the test pump in a stationary state are collected based on the pressure sensor. The acoustic scattering matrix of the test pump in a static state is constructed based on the sound pressure signals of the outlet and inlet pipes of the pump under test when the pump is stationary. The test pump is installed on the test bench with the speaker off and the flow regulating valve at a certain opening. The test pump is in cavitation operation mode. The sound pressure signals of the outlet and inlet pipes of the test pump in cavitation operation mode are collected based on the pressure sensor. The acoustic scattering matrix of the pump under test under cavitation operation is constructed based on the sound pressure signals of the outlet and inlet pipes of the pump under test under cavitation operation. Cavitation of the impeller pump is identified based on the acoustic scattering matrix of the pump under test in a static state and the acoustic scattering matrix of the pump under test in a cavitation operation state.

3. The experimental method for the test bench capable of identifying cavitation in a vane pump according to claim 2, characterized in that, The process of constructing the acoustic scattering matrix of the test pump in a static state based on the sound pressure signals from the outlet and inlet pipes of the test pump includes: Based on the sound pressure signals of the outlet and inlet pipes of the test pump in a static state, the sound pressure wave amplitudes pointing towards the pump inlet and away from the pump inlet in the upstream inlet pipe, and the sound pressure wave amplitudes pointing towards the pump outlet and away from the pump outlet in the downstream outlet pipe are obtained when the test pump is in a static state. The acoustic scattering matrix of the pump under test in a static state is constructed based on the acoustic pressure wave amplitude values ​​pointing towards and away from the pump inlet in the upstream inlet pipe, and the acoustic pressure wave amplitude values ​​pointing towards and away from the pump outlet in the downstream outlet pipe.

4. The experimental method for the test bench capable of identifying cavitation in a vane pump according to claim 3, characterized in that, The expression for constructing the acoustic scattering matrix of the test pump in a static state is as follows: in, The amplitude of the sound pressure wave in the downstream outlet pipeline facing away from the pump outlet is measured with the pump under test in a stationary state. With the pump under test in a stationary state, the amplitude of the sound pressure wave in the upstream inlet pipe facing away from the pump inlet; S 无,11 and S 无,12 With the pump under test in a stationary state, the reflection coefficient and transmission coefficient at the pump inlet are measured; S 无,22 and S 无,21 This indicates that the pump under test is in a stationary state, and the reflection coefficient and transmission coefficient at the pump outlet are shown. The amplitude of the sound pressure wave pointing towards the pump inlet in the upstream inlet pipe is measured with the pump under test in a stationary state. With the pump under test in a stationary state, the amplitude of the sound pressure wave pointing from the pump outlet in the downstream water pipeline; S 无 The acoustic scattering matrix at the pump inlet and outlet ports is used to prevent cavitation.

5. The experimental method for the test bench capable of identifying cavitation in a vane pump according to claim 2, characterized in that, The process of constructing the acoustic scattering matrix of the pump under test under cavitation operation based on the sound pressure signals of the outlet and inlet pipes of the pump under test under cavitation operation includes: Based on the acoustic pressure signals of the outlet and inlet pipes of the test pump under cavitation operation, the acoustic pressure wave amplitudes pointing towards the pump inlet and away from the pump inlet in the upstream inlet pipe and the acoustic pressure wave amplitudes pointing towards the pump outlet and away from the pump outlet in the downstream outlet pipe are obtained when the test pump is under cavitation operation. Based on the acoustic pressure wave amplitude values ​​pointing towards and away from the pump inlet in the upstream water inlet pipeline, and the acoustic pressure wave amplitude values ​​pointing towards and away from the pump outlet in the downstream water outlet pipeline, an acoustic scattering matrix with cavitation phenomenon is constructed at the pump inlet and outlet ports.

6. The experimental method for the test bench capable of identifying cavitation in a bladed pump according to claim 5, characterized in that, The cavitation phenomenon is described, and the expressions for constructing the acoustic scattering matrices at the pump inlet and outlet ports are as follows: Among them, S 有,11 and S 有,12 This indicates that the pump under test is in cavitation operation, and the reflection coefficient and transmission coefficient at the pump inlet are shown; S 有,22 and S 有,21 This indicates that the pump under test is in a cavitation operation state, and the reflection coefficient and transmission coefficient at the pump outlet are shown. The amplitude of the sound pressure wave in the downstream outlet pipeline facing away from the pump outlet is measured when the pump under test is in cavitation operation. The amplitude of the acoustic pressure wave in the upstream inlet pipeline facing away from the pump inlet is measured while the pump is in cavitation operation. The amplitude of the sound pressure wave pointing towards the pump inlet in the upstream inlet pipeline is measured to indicate that the pump under test is in cavitation operation. The amplitude of the sound pressure wave pointing from the pump outlet in the downstream outlet pipeline is measured to indicate that the pump is operating in a cavitation state. 有 Acoustic scattering matrices at the pump inlet and outlet ports are used to detect cavitation.

7. The experimental method for the test bench capable of identifying cavitation in a bladed pump according to claim 6, characterized in that, The reflection coefficient and transmission coefficient at the pump inlet and the reflection coefficient and transmission coefficient at the pump outlet are obtained by solving using the least squares method.

Images