Experiment table capable of identifying cavitation of vane pump and experiment method

Abstract

The invention discloses an experiment table and an experiment method capable of identifying cavitation of a vane pump, and belongs to the technical field of vane pump cavitation characteristic identification experiments. The experiment table comprises a test pump to be tested, a flowmeter, a loudspeaker, a flow adjusting valve and six pressure sensors; the flow meter is arranged on a water outlet pipeline of a to-be-tested test pump and is used for measuring the flow of the water outlet pipeline of the pump; the loudspeaker is arranged on a water inlet pipeline of a test pump to be tested, and when the loudspeaker serves as an external sound source, the loudspeaker can radiate sound pressure waves with different acoustic loads into the water inlet pipeline by adjusting the frequency and strength of the acoustic loads of the loudspeaker. The flow regulating valve is arranged on a water outlet pipeline of the test pump to be tested and is used for regulating the flow of the pump system; the six pressure sensors are data acquisition elements for monitoring cavitation noise of the to-be-tested test pump, and three pressure sensors are respectively arranged on a water inlet pipeline and a water outlet pipeline of the to-be-tested test pump and are used for monitoring sound pressure signals.

Description

Technical Field

[0001] The invention belongs to the technical field of experiments for identifying cavitation characteristics of vane pumps, and in particular relates to an experimental platform and an experimental method capable of identifying cavitation of vane pumps. Background Art

[0002] As a widely used fluid medium transmission equipment, vane pumps play a key role in many industries such as chemical industry, energy, and water conservancy. However, a common problem in its operation - "cavitation" - poses a serious threat to the overall performance of the pump. The mechanism of vane pump cavitation mainly comes from the high-speed flow generated by the rotation of the impeller. When the 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 overflow from the liquid.

[0003] As these bubbles and fluids enter the high-pressure area, they shrink rapidly until they collapse. The energy released in this process erodes the inner wall and blades of the pump in the form of shock waves, accompanied by severe vibration and noise. The formation, growth and collapse of bubbles seriously reduce the working efficiency and reliability of the pump, and may cause early wear and even failure of mechanical parts, seriously affecting the safe and stable operation and service life of the pump. Therefore, in order to detect cavitation in time, prevent and reduce the negative impact of cavitation, and ensure the long-term stable and efficient operation of the vane pump, it is extremely important to be able to monitor and accurately identify the cavitation state in real time. Summary of the invention

[0004] In order to solve the above technical problems, the present invention proposes an experimental platform and an experimental method capable of identifying cavitation in a vane pump, so as to solve the problems existing in the above prior art.

[0005] To achieve the above object, the present invention provides a test bench capable of identifying cavitation in a vane pump, comprising:

[0006] Test pumps, flow meters, speakers, flow regulating valves and pressure sensors to be tested;

[0007] The flow meter is connected to the water outlet pipeline of the test pump to be tested and is used to measure the flow rate of the water outlet pipeline of the pump;

[0008] The loudspeaker is connected to the water inlet pipeline of the test pump to be tested, and is used to radiate the sound pressure wave of the acoustic load to the water inlet pipeline of the test pump to be tested based on the frequency and intensity of the acoustic load of the loudspeaker;

[0009] The flow regulating valve is connected to the water outlet pipeline of the test pump to be tested, and is used to adjust the flow of the test pump to be tested;

[0010] The pressure sensor is connected to the water outlet pipeline and the water inlet pipeline of the test pump to be tested, respectively, and is used to monitor the sound pressure signal.

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

[0012] The test pump to be tested is installed on the test bench, so that the test pump to be tested is in a stationary state, the flow regulating valve is in a fully open state, the frequency and intensity of the acoustic load of the speaker are adjusted, and the sound pressure signals of the water outlet pipe and the water inlet pipe of the test pump to be tested in a stationary state are collected based on the pressure sensor;

[0013] Constructing an acoustic scattering matrix of the test pump under test in a stationary state based on the sound pressure signals of the water outlet pipeline and the water inlet pipeline of the test pump under test in a stationary state;

[0014] The test pump to be tested is installed on the test bench, the speaker is in a closed state, the flow regulating valve is in a certain opening, the test pump to be tested is in a cavitation operation state, and the sound pressure signals of the water outlet pipe and the water inlet pipe of the test pump to be tested in the cavitation operation state are collected based on the pressure sensor;

[0015] Constructing an acoustic scattering matrix of the test pump under cavitation operation state based on the sound pressure signals of the water outlet pipe and the water inlet pipe of the test pump under cavitation operation state;

[0016] The cavitation of the vane pump is identified based on the acoustic scattering matrix of the test pump under the static state and the acoustic scattering matrix of the test pump under the cavitation operation state.

[0017] Preferably, the process of constructing the acoustic scattering matrix of the test pump to be tested in a stationary state based on the sound pressure signals of the water outlet pipeline and the water inlet pipeline of the test pump to be tested in a stationary state includes:

[0018] Acquire, based on the sound pressure signals of the water outlet pipeline and the water inlet pipeline of the test pump in a stationary state, the sound pressure wave amplitude in the upstream water inlet pipeline pointing to the pump inlet and the sound pressure wave amplitude in the opposite direction to the pump inlet, and the sound pressure wave amplitude in the downstream water outlet pipeline pointing to the pump outlet and the sound pressure wave amplitude in the opposite direction to the pump outlet when the test pump is in a stationary state;

[0019] An acoustic scattering matrix of the test pump under static state is constructed based on the sound pressure wave amplitude pointing to the pump inlet and the sound pressure wave amplitude facing away from the pump inlet in the upstream water inlet pipeline and the sound pressure wave amplitude pointing to the pump outlet and the sound pressure wave amplitude facing away from the pump outlet in the downstream water outlet pipeline.

[0020] Preferably, the construction expression of the acoustic scattering matrix of the test pump to be tested in a static state is:

[0021]

[0022] in, The amplitude of the sound pressure wave in the downstream outlet pipe facing away from the pump outlet when the pump to be tested is in a stationary state; S is the amplitude of the sound pressure wave in the upstream water inlet pipeline facing away from the pump inlet when the pump to be tested is in a stationary state; 无,11 and S 无,12 The reflection coefficient and transmission coefficient of the pump inlet when the pump to be tested is in a stationary state; S 无,22 and S 无,21 Indicates the reflection coefficient and transmission coefficient at the pump outlet when the pump under test is in a stationary state; The amplitude of the sound pressure wave in the upstream water inlet pipeline pointing to the pump inlet when the pump to be tested is in a stationary state; S is the amplitude of the sound pressure wave pointing to the pump outlet in the downstream outlet pipe when the pump to be tested is in a stationary state; 无 Acoustic scattering matrices at the pump inlet and outlet ports without cavitation.

[0023] Preferably, the process of constructing the acoustic scattering matrix of the test pump under test in the cavitation operation state based on the sound pressure signals of the water outlet pipeline and the water inlet pipeline of the test pump under test in the cavitation operation state includes:

[0024] Acquiring, based on the sound pressure signals of the water outlet pipeline and the water inlet pipeline of the test pump under cavitation operation, the sound pressure wave amplitude in the upstream water inlet pipeline pointing to the pump inlet and the sound pressure wave amplitude in the opposite direction to the pump inlet, and the sound pressure wave amplitude in the downstream water outlet pipeline pointing to the pump outlet and the sound pressure wave amplitude in the opposite direction to the pump outlet when the test pump under cavitation operation is under cavitation operation;

[0025] Based on the sound pressure wave amplitude pointing to the pump inlet and the sound pressure wave amplitude facing away from the pump inlet in the upstream water inlet pipeline, and the sound pressure wave amplitude pointing to the pump outlet and the sound pressure wave amplitude facing away from the pump outlet in the downstream water outlet pipeline, an acoustic scattering matrix at the pump inlet and outlet ports with cavitation phenomenon is constructed.

[0026] Preferably, in the presence of cavitation, the acoustic scattering matrix at the pump inlet and outlet ports is constructed by:

[0027]

[0028] Among them, S 有,11 and S 有,12 Indicates that the test pump is in cavitation operation, the reflection coefficient and transmission coefficient at the pump inlet; S 有,22 and S 有,21 Indicates that the test pump is in cavitation operation, the reflection coefficient and transmission coefficient at the pump outlet; The amplitude of the sound pressure wave in the downstream outlet pipe facing away from the pump outlet when the pump to be tested is in the cavitation operation state; The amplitude of the sound pressure wave in the upstream water inlet pipeline facing away from the pump inlet when the pump to be tested is in the cavitation operation state; The amplitude of the sound pressure wave in the upstream water inlet pipeline pointing to the pump inlet when the pump to be tested is in the cavitation operation state; S is the amplitude of the sound pressure wave pointing to the pump outlet in the downstream outlet pipe when the pump to be tested is in cavitation operation state; 有 Acoustic scattering matrices at the pump inlet and outlet ports with cavitation.

[0029] Preferably, the reflection coefficient and transmission coefficient at the pump inlet end and the reflection coefficient and transmission coefficient at the pump outlet end are obtained by solving the least square method.

[0030] Compared with the prior art, the present invention has the following advantages and technical effects:

[0031] The present invention proposes a monitoring system and experimental method capable of identifying cavitation in a vane pump. Under the condition that only one test pump to be tested, one flow meter, one speaker, one flow regulating valve, two groups of six pressure sensors and related pipelines connecting the components are needed, the test results of the acoustic scattering matrix at the inlet and outlet ports of the test pump to be tested at different frequencies can be completed when the test pump to be tested is in a cavitation operation state. The present invention can monitor cavitation at the early stage of cavitation in order to solve the problem of early stage cavitation prediction that needs to be solved urgently in engineering applications. The present invention has been verified by experiments that the test bench has a compact structure, a reasonable design and a high engineering value. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The drawings constituting a part of the present application are used to provide a further understanding of the present application. The illustrative embodiments and descriptions of the present application are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings:

[0033] Figure 1 Schematic diagram of a test bench for monitoring the cavitation of a pump to be tested according to an embodiment of the present invention;

[0034] Figure 2 A schematic diagram of the distances between different pressure sensors of the water inlet and outlet pipes of the test pump to be tested according to an embodiment of the present invention;

[0035] Among them, 1. Test pump to be tested; 2. Speaker; 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 DESCRIPTION

[0036] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0037] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0038] Embodiment 1

[0039] This embodiment provides an experimental platform and an experimental method for identifying cavitation in a vane pump, including:

[0040] A test pump 1, a flow meter 9, a speaker 2, a flow regulating valve 10, two groups of six pressure sensors Ⅰ~VI (3~8) and related pipes connecting the components;

[0041] The flow meter 9 is arranged on the outlet pipe of the test pump 1 to be tested, and is used to measure the flow rate of the outlet pipe of the test pump 1 to be tested;

[0042] The speaker 2 is arranged on the water inlet pipeline of the test pump 1, and the distance to the nearest pressure sensor 5 is 5 to 20 times the inner diameter of the pump port pipeline. The smaller the inner diameter of the pipeline, the larger the multiple value is selected, and the larger the inner diameter of the pipeline, the smaller the multiple value is selected. When the speaker 2 is used as an external sound source, the frequency and intensity of the acoustic load of the speaker 2 can be adjusted to radiate sound pressure waves of different acoustic loads into the water inlet pipeline;

[0043] The flow regulating valve 10 is arranged on the water outlet pipe of the test pump 1 to be tested, and is used to adjust the flow of the pump system;

[0044] The two groups of six pressure sensors I to VI (3 to 8) are data acquisition elements for monitoring the cavitation noise of the test pump 1 to be tested. A group of three pressure sensors I to III (3 to 5) is arranged on the water inlet pipe of the test pump 1 to be tested, and a group of three pressure sensors IV to VI (6 to 8) is arranged on the water outlet pipe of the test pump 1 to be tested, respectively, to monitor the sound pressure signal. According to the acoustic theory of the propagation of sound pressure waves in a pipeline, the distance between two adjacent pressure sensors of the inlet and outlet pipes is 10 to 30 times the inner diameter of the pump port pipe. The smaller the inner diameter of the pipe, the larger the multiple value is selected, and the larger the inner diameter of the pipe, the smaller the multiple value is selected.

[0045] The experimental method of achieving real-time monitoring and accurate identification of cavitation status through the monitoring system capable of identifying cavitation in vane pumps is as follows:

[0046] The test pump 1 to be tested is installed on the test bench. The test pump 1 to be tested is in a stationary state. The flow regulating valve 10 is in a fully open state. The frequency and intensity of the acoustic load of the speaker 2 are adjusted. The sound pressure signals collected by the data acquisition components pressure sensor Ⅰ3, pressure sensor Ⅱ4, and pressure sensor Ⅲ5 are respectively 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 components pressure sensor IV6, pressure sensor V7, and pressure sensor VI8 are respectively 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 stationary state, that is, there is no cavitation phenomenon, n represents the frequency and intensity of the acoustic load of the adjustable speaker 2, and the number of different sound pressure signals collected by the pressure sensors Ⅰ~VI (3~8) in the pipeline.

[0047] Combination Figure 1 and Figure 2 Based on the above method, according to equations (1) and (2), the amplitude of the sound pressure wave pointing to the pump inlet in the water inlet pipeline of the test pump 1 can be obtained respectively: (Phase ) and the amplitude of the sound pressure wave facing away from the pump inlet (Phase ); According to equations (3) and (4), the amplitude of the acoustic pressure wave pointing to the pump inlet in the water inlet pipeline of the test pump 1 can be obtained respectively: (Phase ) and the amplitude of the sound pressure wave facing away from the pump inlet (Phase ); According to equations (5) and (6), the amplitude of the acoustic pressure wave pointing to the pump inlet in the water inlet pipeline of the test pump 1 can be obtained respectively: (Phase ) and the amplitude of the sound pressure wave facing away from the pump inlet (Phase ).

[0048]

[0049] Where t is time, ω = 2πf represents angular frequency, f represents frequency, k = ω / c0 represents wave number, and c0 is the speed of sound pressure in the fluid. Ⅰ and l Ⅱ are the distances from pressure sensor Ⅰ3 and pressure sensor Ⅱ4 to the inlet of the test pump 1, Δl Ⅰ-Ⅱ = l Ⅱ -l Ⅰ ; l Ⅰ and l Ⅲare the distances from pressure sensor Ⅰ3 and pressure sensor Ⅲ5 to the inlet of the test pump 1, Δl Ⅰ-Ⅲ = l Ⅲ -l Ⅰ ; l Ⅱ and l Ⅲ are the distances from pressure sensor II4 and pressure sensor III5 to the inlet of the test pump 1, Δl Ⅱ-Ⅲ = l Ⅲ -l Ⅱ .

[0050] In order to improve the accuracy and reliability of sound pressure monitoring, the sound pressure amplitude obtained by equation (1) and equation (2) is (Phase ) and the amplitude of the sound pressure wave (Phase ), equation (3) and equation (4) to obtain the sound pressure amplitude (Phase ) and the amplitude of the sound pressure wave (Phase ), equation (5) and equation (6) to obtain the sound pressure amplitude (Phase ) and the amplitude of the sound pressure wave (Phase ) to obtain the average value of the sound pressure wave amplitude in the upstream water inlet pipeline of the test pump 1 pointing to the pump inlet. (Phase ) and the amplitude of the sound pressure wave facing away from the pump inlet (Phase ).

[0051] Similarly: Combination Figure 1 and Figure 2 Based on the above method, according to equations (7) and (8), the amplitude of the sound pressure wave in the outlet pipe of the test pump 1 pointing to the pump outlet can be obtained respectively: (Phase ) and the sound pressure amplitude facing away from the pump outlet (Phase ); According to equations (9) and (10), the amplitude of the acoustic pressure wave in the outlet pipe of the test pump 1 pointing to the pump outlet can be obtained respectively: (Phase ) and the sound pressure amplitude facing away from the pump outlet (Phase ); According to equations (11) and (12), the amplitude of the acoustic pressure wave pointing to the pump outlet in the outlet pipe of the test pump 1 can be obtained respectively: (Phase ) and the sound pressure amplitude facing away from the pump outlet (Phase ).

[0052]

[0053]

[0054] Where l Ⅳ and l Ⅴ are the distances from the pressure sensor IV6 and the pressure sensor V7 to the outlet of the test pump 1, respectively, Δl Ⅳ-Ⅴ = l Ⅴ -l Ⅳ ; l Ⅳ and l Ⅵ are the distances from the pressure sensor IV6 and the pressure sensor VI8 to the outlet of the test pump 1, respectively, Δl Ⅳ-Ⅵ = l Ⅵ -l Ⅳ ; l Ⅴ and l Ⅵ are the distances from the pressure sensor V7 and the pressure sensor VI8 to the outlet of the test pump 1, respectively, Δl Ⅴ-Ⅵ = l Ⅵ -l Ⅴ .

[0055] In order to improve the accuracy and reliability of sound pressure monitoring, the sound pressure amplitude obtained by equation (7) and equation (8) is (Phase ) and the amplitude of the sound pressure wave (Phase ), equation (9) and equation (10) to obtain the sound pressure amplitude (Phase ) and the amplitude of the sound pressure wave (Phase ), equation (11) and equation (12) to obtain the sound pressure amplitude (Phase ) and the amplitude of the sound pressure wave (Phase ) to obtain the average value, and finally obtain the sound pressure wave amplitude in the downstream outlet pipe of the test pump 1 pointing to the pump outlet (Phase ) and the sound pressure amplitude facing away from the pump outlet (Phase ).

[0056] Based on the sound pressure wave amplitude in the upstream water inlet pipeline of the test pump 1 pointing to the pump inlet (Phase ) and the amplitude of the sound pressure wave facing away from the pump inlet (Phase ), and the amplitude of the sound pressure wave in the downstream outlet pipe pointing to the pump outlet (Phase ) and the sound pressure amplitude facing away from the pump outlet (Phase ), establish the acoustic scattering matrix [S 无 ], the equation is as follows:

[0057]

[0058] Where S 无,11 and S 无,12 It indicates the reflection coefficient and transmission coefficient at the pump inlet when the test pump 1 is in a stationary state, that is, when there is no cavitation phenomenon. 无,22 and S 无,21 It indicates the reflection coefficient and transmission coefficient at the pump outlet when the test pump 1 is in a stationary state, that is, when there is no cavitation phenomenon.

[0059] Since n represents the frequency and intensity of the acoustic load of the adjustable speaker 2, and the number of different sound pressure signals collected by the pressure sensors Ⅰ~Ⅵ(3~8) in the pipeline, n data sets can be obtained in the upstream water inlet pipeline and the downstream water outlet pipeline of the test pump 1. (Phase ), (Phase ), (Phase )and (Phase ). The overdetermined equations (13) can be solved by the least squares method to obtain S 无,11 , S 无,12 , S 无,21 and S 无,22 , we can get the acoustic scattering matrix [S 无 ].

[0060] Similarly, without disassembling the test pump 1 and related pipelines, the speaker 2 is in a closed state, the flow control valve 10 is at a certain opening, the test pump 1 is in a cavitation operation state, and the sound pressure signals collected by the data acquisition components pressure sensor I3, pressure sensor II4, and pressure sensor III5 are 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 components pressure sensor IV6, pressure sensor V7, and pressure sensor VI8 are respectively p 有,Ⅳ,n (x,t),p 有,Ⅴ,n (x,t) and p 有,Ⅵ,n(x, t), where the subscript "has" indicates that the test pump 1 is in a cavitation operation state, that is, there is cavitation phenomenon, n represents the frequency and intensity of the acoustic load of the adjustable speaker 2, and the number of different sound pressure signals collected by the pressure sensors Ⅰ~VI (3~8) in the pipeline.

[0061] Combination Figure 1 and Figure 2 Based on the above method, according to equations (14) and (15), the amplitude of the acoustic pressure wave in the water inlet pipe pointing to the pump inlet when the test pump 1 is in the cavitation operation state can be obtained respectively: (Phase ) and the amplitude of the sound pressure wave facing away from the pump inlet (Phase ); According to equations (16) and (17), the amplitude of the acoustic pressure wave in the water inlet pipe pointing to the pump inlet when the test pump 1 is in the cavitation operation state can be obtained respectively: (Phase ) and the amplitude of the sound pressure wave facing away from the pump inlet (Phase ); According to equations (18) and (19), the amplitude of the acoustic pressure wave in the water inlet pipe pointing to the pump inlet when the test pump 1 is in the cavitation operation state can be obtained respectively: (Phase ) and the amplitude of the sound pressure wave facing away from the pump inlet (Phase ).

[0062]

[0063] Where t is time, ω = 2πf represents angular frequency, f represents frequency, k = ω / c0 represents wave number, and c0 is the speed of sound pressure in the fluid. Ⅰ and l Ⅱ are the distances from pressure sensor Ⅰ3 and pressure sensor Ⅱ4 to the inlet of the test pump 1, Δl Ⅰ-Ⅱ = l Ⅱ -l Ⅰ ; l Ⅰ and l Ⅲ are the distances from pressure sensor Ⅰ3 and pressure sensor Ⅲ5 to the inlet of the test pump 1, Δl Ⅰ-Ⅲ = l Ⅲ -l Ⅰ ; l Ⅱ and l Ⅲ are the distances from pressure sensor II4 and pressure sensor III5 to the inlet of the test pump 1, Δl Ⅱ-Ⅲ = l Ⅲ -l Ⅱ .

[0064] In order to improve the accuracy and reliability of sound pressure monitoring, the sound pressure amplitude obtained by equation (14) and equation (15) is (Phase ) and the amplitude of the sound pressure wave (Phase ), equation (16) and equation (17) to obtain the sound pressure amplitude (Phase ) and the amplitude of the sound pressure wave (Phase ), equation (18) and equation (19) to obtain the sound pressure amplitude (Phase ) and the amplitude of the sound pressure wave (Phase ) to obtain the average value of the sound pressure wave amplitude in the upstream water inlet pipeline of the test pump 1 pointing to the pump inlet. (Phase ) and the amplitude of the sound pressure wave facing away from the pump inlet (Phase ).

[0065] Similarly: Combination Figure 1 and Figure 2 Based on the above method, according to equations (20) and (21), the amplitude of the sound pressure wave in the outlet pipe pointing to the pump outlet when the test pump 1 is in the cavitation operation state can be obtained respectively: (Phase ) and the sound pressure amplitude facing away from the pump outlet (Phase ); According to equations (22) and (23), the amplitude of the acoustic pressure wave in the outlet pipe pointing to the pump outlet when the test pump 1 is in the cavitation operation state can be obtained respectively: (Phase ) and the sound pressure amplitude facing away from the pump outlet (Phase ); According to equations (24) and (25), the amplitude of the acoustic pressure wave in the outlet pipe pointing to the pump outlet when the test pump 1 is in the cavitation operation state can be obtained respectively: (Phase ) and the sound pressure amplitude facing away from the pump outlet (Phase ).

[0066]

[0067] Where l Ⅳ and l Ⅴ are the distances from the pressure sensor IV6 and the pressure sensor V7 to the outlet of the test pump 1, respectively, Δl Ⅳ-Ⅴ = l Ⅴ -lⅣ ; l Ⅳ and l Ⅵ are the distances from the pressure sensor IV6 and the pressure sensor VI8 to the outlet of the test pump 1, respectively, Δl Ⅳ-Ⅵ = l Ⅵ -l Ⅳ ; l Ⅴ and l Ⅵ are the distances from the pressure sensor V7 and the pressure sensor VI8 to the outlet of the test pump 1, respectively, Δl Ⅴ-Ⅵ = l Ⅵ -l Ⅴ .

[0068] In order to improve the accuracy and reliability of sound pressure monitoring, the sound pressure amplitude obtained by equation (20) and equation (21) is (Phase ) and the amplitude of the sound pressure wave (Phase ), equation (22) and equation (23) to obtain the sound pressure amplitude (Phase ) and the amplitude of the sound pressure wave (Phase ), equation (24) and equation (25) to obtain the sound pressure amplitude (Phase ) and the amplitude of the sound pressure wave (Phase ) to obtain the average value, and finally obtain the sound pressure wave amplitude in the downstream outlet pipe of the test pump 1 pointing to the pump outlet (Phase ) and the sound pressure amplitude facing away from the pump outlet (Phase ).

[0069] Based on the sound pressure wave amplitude in the upstream water inlet pipeline of the test pump 1 pointing to the pump inlet (Phase ) and the amplitude of the sound pressure wave facing away from the pump inlet (Phase ), and the amplitude of the sound pressure wave in the downstream outlet pipe pointing to the pump outlet (Phase ) and the sound pressure amplitude facing away from the pump outlet (Phase ), establish the acoustic scattering matrix [S 有 ], the equation is as follows:

[0070]

[0071] Where S 有,11and S 有,12 It indicates that the test pump 1 is in the cavitation operation state, that is, when there is cavitation phenomenon, the reflection coefficient and transmission coefficient at the pump inlet end, S 有,22 and S 有,21 It indicates that the test pump 1 is in the cavitation operation state, that is, the reflection coefficient and transmission coefficient at the pump outlet when there is cavitation phenomenon.

[0072] Since n represents the frequency and intensity of the acoustic load of the adjustable speaker 2, and the number of different sound pressure signals collected by the pressure sensors Ⅰ~Ⅵ(3~8) in the pipeline, n data sets can be obtained in the upstream water inlet pipeline and the downstream water outlet pipeline of the test pump 1. (Phase ), (Phase ), (Phase )and (Phase ). The overdetermined equations (26) can be solved by the least squares method to obtain S 有,11 , S 有,12 , S 有,21 and S 有,22 , we can get the acoustic scattering matrix [S 有 ].

[0073] Finally, when there is gas overflow in the test pump 1, the sound speed changes due to different media, and the transmission characteristics of the sound pressure at the interface of different media change. Then, 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-mentioned monitoring system and experimental method can realize real-time monitoring and accurate identification of cavitation status, and there is no need to disassemble the test pump 1 and related pipelines during the process.

[0074] The above are only preferred specific implementations of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed in the present application should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A test bench capable of identifying cavitation in a vane pump, characterized in that: include: Test pumps, flow meters, speakers, flow regulating valves and pressure sensors to be tested; The flow meter is connected to the water outlet pipeline of the test pump to be tested and is used to measure the flow rate of the water outlet pipeline of the pump; The loudspeaker is connected to the water inlet pipeline of the test pump to be tested, and is used to radiate the sound pressure wave of the acoustic load to the water inlet pipeline of the test pump to be tested based on the frequency and intensity of the acoustic load of the loudspeaker; The flow regulating valve is connected to the water outlet pipeline of the test pump to be tested, and is used to adjust the flow of the test pump to be tested; The pressure sensor is connected to the water outlet pipeline and the water inlet pipeline of the test pump to be tested, respectively, and is used to monitor the sound pressure signal.

2. The experimental method of the experimental bench capable of identifying cavitation in a vane pump according to claim 1, characterized in that: The following steps are involved: The test pump to be tested is installed on the test bench, so that the test pump to be tested is in a stationary state, the flow regulating valve is in a fully open state, the frequency and intensity of the acoustic load of the speaker are adjusted, and the sound pressure signals of the water outlet pipe and the water inlet pipe of the test pump to be tested in a stationary state are collected based on the pressure sensor; Constructing an acoustic scattering matrix of the test pump under test in a stationary state based on the sound pressure signals of the water outlet pipeline and the water inlet pipeline of the test pump under test in a stationary state; The test pump to be tested is installed on the test bench, the speaker is in a closed state, the flow regulating valve is in a certain opening, the test pump to be tested is in a cavitation operation state, and the sound pressure signals of the water outlet pipe and the water inlet pipe of the test pump to be tested in the cavitation operation state are collected based on the pressure sensor; Constructing an acoustic scattering matrix of the test pump under cavitation operation state based on the sound pressure signals of the water outlet pipe and the water inlet pipe of the test pump under cavitation operation state; The cavitation of the vane pump is identified based on the acoustic scattering matrix of the test pump under the static state and the acoustic scattering matrix of the test pump under the cavitation operation state.

3. The experimental method of the experimental 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 under test in a stationary state based on the sound pressure signals of the water outlet pipeline and the water inlet pipeline of the test pump under test in a stationary state includes: Acquire, based on the sound pressure signals of the water outlet pipeline and the water inlet pipeline of the test pump in a stationary state, the sound pressure wave amplitude in the upstream water inlet pipeline pointing to the pump inlet and the sound pressure wave amplitude in the opposite direction to the pump inlet, and the sound pressure wave amplitude in the downstream water outlet pipeline pointing to the pump outlet and the sound pressure wave amplitude in the opposite direction to the pump outlet when the test pump is in a stationary state; An acoustic scattering matrix of the test pump under static state is constructed based on the sound pressure wave amplitude pointing to the pump inlet and the sound pressure wave amplitude facing away from the pump inlet in the upstream water inlet pipeline and the sound pressure wave amplitude pointing to the pump outlet and the sound pressure wave amplitude facing away from the pump outlet in the downstream water outlet pipeline.

4. The experimental method of the experimental bench capable of identifying cavitation in a vane pump according to claim 3, characterized in that: The construction expression of the acoustic scattering matrix of the test pump under test in a static state is: in, The amplitude of the sound pressure wave in the downstream outlet pipe facing away from the pump outlet when the pump to be tested is in a stationary state; S is the amplitude of the sound pressure wave in the upstream water inlet pipeline facing away from the pump inlet when the pump to be tested is in a stationary state; 无,11 and S 无,12 The reflection coefficient and transmission coefficient of the pump inlet when the pump to be tested is in a stationary state; S 无,22 and S 无,21 Indicates the reflection coefficient and transmission coefficient at the pump outlet when the pump under test is in a stationary state; The amplitude of the sound pressure wave in the upstream water inlet pipeline pointing to the pump inlet when the pump to be tested is in a stationary state; S is the amplitude of the sound pressure wave pointing to the pump outlet in the downstream outlet pipe when the pump to be tested is in a stationary state; 无 Acoustic scattering matrices at the pump inlet and outlet ports without cavitation.

5. The experimental method of the experimental 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 under cavitation operation state based on the sound pressure signals of the water outlet pipe and the water inlet pipe of the test pump under cavitation operation state includes: Acquiring, based on the sound pressure signals of the water outlet pipeline and the water inlet pipeline of the test pump under cavitation operation, the sound pressure wave amplitude in the upstream water inlet pipeline pointing to the pump inlet and the sound pressure wave amplitude in the opposite direction to the pump inlet, and the sound pressure wave amplitude in the downstream water outlet pipeline pointing to the pump outlet and the sound pressure wave amplitude in the opposite direction to the pump outlet when the test pump under cavitation operation is under cavitation operation; Based on the sound pressure wave amplitude pointing to the pump inlet and the sound pressure wave amplitude facing away from the pump inlet in the upstream water inlet pipeline, and the sound pressure wave amplitude pointing to the pump outlet and the sound pressure wave amplitude facing away from the pump outlet in the downstream water outlet pipeline, an acoustic scattering matrix at the pump inlet and outlet ports with cavitation phenomenon is constructed.

6. The experimental method of the experimental bench capable of identifying cavitation in a vane pump according to claim 5, characterized in that: The acoustic scattering matrix at the pump inlet and outlet ports with cavitation is constructed as follows: Among them, S 有,11 and S 有,12 Indicates that the test pump is in cavitation operation, the reflection coefficient and transmission coefficient at the pump inlet; S 有,22 and S 有,21 Indicates that the test pump is in cavitation operation, the reflection coefficient and transmission coefficient at the pump outlet; The amplitude of the sound pressure wave in the downstream outlet pipe facing away from the pump outlet when the pump to be tested is in the cavitation operation state; The amplitude of the sound pressure wave in the upstream water inlet pipeline facing away from the pump inlet when the pump to be tested is in the cavitation operation state; The amplitude of the sound pressure wave in the upstream water inlet pipeline pointing to the pump inlet when the pump to be tested is in the cavitation operation state; S is the amplitude of the sound pressure wave pointing to the pump outlet in the downstream outlet pipe when the pump to be tested is in cavitation operation state; 有 Acoustic scattering matrices at the pump inlet and outlet ports with cavitation.

7. The experimental method of the experimental bench capable of identifying cavitation in a vane pump according to claim 6, characterized in that: The reflection coefficient and transmission coefficient at the pump inlet end and the reflection coefficient and transmission coefficient at the pump outlet end are obtained by solving the least square method.

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