Liquid rocket engine purge check valve dynamic working characteristics test system and method

Abstract

A liquid rocket engine purge check valve dynamic working characteristic test system and method, the test system comprises: a first high-pressure gas cylinder, a second high-pressure gas cylinder, a first filter, a second filter, a third filter, a mass flow meter, a first stop valve, a second stop valve, a third stop valve, a fourth stop valve, a fifth stop valve, a throttle ring, a first pressure reducing valve and a gas pulsation excitation system. The present invention can obtain the working state of the check valve under the condition of rapid changes in inlet and outlet pressures and accompanied by large pulsating pressure under the ground simulation dynamic engine working state, and evaluate the working performance and reliability of the check valve.

Description

Technical Field

[0001] The invention belongs to the technical field of dynamic characteristics of rocket engine check valves, in particular to a system and method for testing dynamic working characteristics of liquid rocket engine purge check valves. Background Art

[0002] Liquid rocket engines require extremely high reliability due to the particularity of their operating environment, but the engine's working process is complex, with violent energy release, and complex physical processes such as combustion, fluid excitation, and two-phase mixing. There are more excitation sources, and the adaptability of components is more stringent than other industrial products. Especially for moving components such as one-way valves, their working characteristics are strongly coupled with the engine system, and the working characteristics under dynamic processes and complex excitation conditions have a great impact on the reliability of the engine.

[0003] The working conditions of the rocket engine check valve are changeable, including long-term operation with small pressure drop during the pre-cooling stage, and rapid changes in pressure drop during the startup and shutdown stages, accompanied by pressure oscillations at the inlet and outlet. As a result, the check valve often operates at a small opening or is in unfavorable conditions such as self-excited oscillation and forced oscillation. The check valve is prone to jamming and wear during operation, losing its normal working function and affecting the reliable operation of the engine.

[0004] At present, a lot of research has been carried out on the steady-state working characteristics of engine check valve components, but the stability of the check valve under fluid excitation and mechanical vibration conditions still needs to be evaluated through whole machine test runs. There is no clear and effective ground simulation test method and simulation criteria. The test cost is high, and it is difficult to decouple from the system after a fault occurs. It is urgent to establish a method and test system that can evaluate and verify the dynamic working state of the check valve and the working process under excitation conditions under ground conditions, so as to obtain the working characteristics of the check valve under dynamic processes and pulsating pressure. Summary of the invention

[0005] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art, to provide a liquid rocket engine purge check valve dynamic working characteristics test system and method, to solve the problems of dynamic flow resistance measurement of the check valve and rapid life measurement of the check valve, self-excited oscillation, forced oscillation characteristics, pulsating pressure propagation characteristics in the pipeline, etc.

[0006] The technical solution of the present invention is:

[0007] First,

[0008] A liquid rocket engine blow-off check valve dynamic working characteristics simulation test system, comprising: a first high-pressure gas cylinder, a second high-pressure gas cylinder, a first filter, a second filter, a third filter, a mass flow meter, a first stop valve, a second stop valve, a third stop valve, a fourth stop valve, a fifth stop valve, a throttle ring and a first pressure reducing valve;

[0009] The input end of the first high-pressure gas cylinder is connected to the outlet end of the second stop valve through the first input pipeline, and the outlet end of the second stop valve is provided with a second filter; the second filter is used to filter impurities in the gas to prevent the impurities from entering the first input pipeline; the second stop valve is used to control the on-off of the external input high-pressure gas, thereby increasing the pressure of the first high-pressure gas cylinder;

[0010] A first discharge pipeline is provided on the first input pipeline, and a third stop valve is provided at the outlet of the first discharge pipeline. The first discharge pipeline is used to discharge the gas in the first high-pressure gas cylinder, and the pressure of the first high-pressure gas cylinder is reduced or the pressure of the first high-pressure gas cylinder after the test is completed is relieved by opening the third stop valve;

[0011] The output end of the first high-pressure gas cylinder is connected to the output end of the second high-pressure gas cylinder through an output pipeline;

[0012] The output pipeline is provided with a first filter, a first pressure reducing valve, a mass flow meter, a first stop valve, a throttle ring and a one-way valve to be measured in sequence from the output end of the first high-pressure gas cylinder to the output end of the second high-pressure gas cylinder;

[0013] The input end of the second high-pressure gas cylinder is connected to the outlet end of the fourth stop valve through the second input pipeline, and a third filter is arranged at the outlet end of the fourth stop valve; the third filter is used to filter impurities in the gas to prevent the impurities from entering the second input pipeline; the fourth stop valve is used to control the on-off of the external input high-pressure gas, thereby increasing the pressure of the second high-pressure gas cylinder;

[0014] A second discharge pipeline is provided on the second input pipeline, and a fifth stop valve is provided at the outlet of the second discharge pipeline. The second discharge pipeline is used to discharge the gas in the second high-pressure gas cylinder. By opening the fifth stop valve, the pressure of the second high-pressure gas cylinder is reduced or the pressure of the second high-pressure gas cylinder after the test is completed is relieved;

[0015] The first pressure reducing valve is used to adjust the inlet pressure of the one-way valve being tested;

[0016] Pressure measuring points are arranged on the first high-pressure gas cylinder, between the one-way valve under test and the throttle ring, between the one-way valve under test and the second high-pressure gas cylinder, and on the second high-pressure gas cylinder, namely pressure measuring point P1, pressure measuring point P2, pressure measuring point P3 and pressure measuring point P4. The pressure measuring points are used to monitor the pressure values.

[0017] By opening the second stop valve or the third stop valve, the pressure of the first high-pressure gas cylinder is adjusted;

[0018] The pressure of the second high-pressure gas cylinder is adjusted by opening the fourth stop valve or the fifth stop valve.

[0019] Second,

[0020] A method for measuring flow resistance of a check valve during a dynamic working process using the liquid rocket engine blow-off check valve dynamic working characteristic simulation test system as described in the first aspect comprises:

[0021] Step 001: Open the second stop valve and the fourth stop valve, and inflate the first high-pressure gas cylinder and the second high-pressure gas cylinder according to the preset pressure. After reaching the preset pressure, close the second stop valve and the fourth stop valve. At this time, the pressure at the pressure measuring point P1 on the first high-pressure gas cylinder is higher than the pressure at the pressure measuring point P4 on the second high-pressure gas cylinder.

[0022] Step 002: Open the first stop valve to allow the gas in the first high-pressure gas cylinder to flow into the second high-pressure gas cylinder through the output pipeline, and at the same time control the opening or closing of the second stop valve, the third stop valve, the fourth stop valve, and the fifth stop valve to make the pressure at the pressure measuring point P1 on the first high-pressure gas cylinder consistent with the pressure at the pressure measuring point P4 on the second high-pressure gas cylinder, so that the simulation test system can work stably;

[0023] Step 003: Control the opening of the first pressure reducing valve, and control the opening or closing of the fourth stop valve and the fifth stop valve, so that the pressures at the pressure measuring points P2 and P4 change according to the preset test pressure curve, and at the same time control the opening or closing of the second stop valve and the third stop valve, and keep the pressure at the pressure measuring point P1 on the first high-pressure gas cylinder unchanged, so as to simulate the pressure change process of the upstream and downstream of the one-way valve under test at different working moments of the engine;

[0024] Step 004: Collect the pressure-time curve at the pressure measuring point P2 and the pressure-time curve at the pressure measuring point P3 during the test, and calculate the difference between the pressure value at the pressure measuring point P2 and the pressure value at the pressure measuring point P3 as the flow resistance-time curve of the one-way valve being tested;

[0025] Step 005: collecting the gas flow rate Q in the output pipeline during the test, calculating the gas velocity-time curve of the one-way valve under test according to the gas flow rate Q and the pressure value of the pressure measuring point P2, and converting it into a Mach number-time curve;

[0026] Step 006: According to the corresponding relationship between the flow resistance-time curve and the Mach number-time curve, the dynamic flow resistance characteristics of the one-way valve under different Mach numbers are obtained.

[0027] Thirdly,

[0028] A method for quickly determining the life of a check valve using the liquid rocket engine blow-off check valve dynamic operating characteristics simulation test system as described in the first aspect comprises:

[0029] Step 101: Open the second stop valve and the fourth stop valve, and inflate the first high-pressure gas cylinder and the second high-pressure gas cylinder according to a preset pressure. After reaching the preset pressure, close the second stop valve and the fourth stop valve. At this time, the pressure of the first high-pressure gas cylinder is higher than that of the second high-pressure gas cylinder.

[0030] Step 102: Open the first stop valve to allow the gas in the first high-pressure gas cylinder to flow into the second high-pressure gas cylinder through the output pipeline, and at the same time control the opening or closing of the second stop valve, the third stop valve, the fourth stop valve, and the fifth stop valve to make the pressure at the pressure measuring point P1 on the first high-pressure gas cylinder consistent with the pressure at the pressure measuring point P4 on the second high-pressure gas cylinder, so that the simulation test system works stably;

[0031] Step 103: Control the opening or closing of the second stop valve and the third stop valve to ensure that the pressure at the pressure measuring point P1 on the first high-pressure gas cylinder is always consistent with the preset pressure and is higher than the upstream preset pressure P2' in the preset life test pressure curve, and adjust the first pressure reducing valve according to the life test preset pressure curve to make the pressure change at the pressure measuring point P2 consistent with the upstream preset pressure P2';

[0032] The fourth stop valve and the fifth stop valve are opened or closed according to the preset pressure curve of the life test, so that the pressure at the pressure measuring point P4 changes periodically according to the downstream preset pressure P4' in the preset life test pressure curve. Each cycle T takes no more than 3s. The requirements for the entire periodic change process are:

[0033] When P4>P2, 1.2*dP <P4-P2<1.3*dP

[0034] When P2>P4, 1.2*dP <P2-P4<1.3*dP

[0035] Where dP is the minimum differential pressure required to open the one-way valve under test;

[0036] Step 104: Collect the gas flow Q, pressure measuring point P2 and pressure measuring point P3 of the output pipeline during the test, and judge the state of the one-way valve under test according to the gas flow Q and the pressure measuring point P2 and pressure measuring point P3. If it is judged that the one-way valve under test has lost its normal function, proceed to step 105; otherwise, repeat step 103 until it is judged that the one-way valve under test has lost its normal function, and proceed to step 105;

[0037] Step 105: close the second stop valve and the fourth stop valve, and simultaneously open the third stop valve and the fifth stop valve to depressurize the simulation test system;

[0038] Step 106: Obtain the life of the one-way valve according to the number of opening and closing cycles of the one-way valve being tested, wherein the period between two adjacent opening moments of the valve is recorded as one opening and closing cycle period.

[0039] Preferably, in step 104, the method for determining the state of the one-way valve being tested is specifically as follows:

[0040] During the rapid life measurement process, if P3>P2 exists and the gas flow rate Q is not 0, or if P2>P3 exists and the gas flow rate Q is always 0, it indicates that the one-way valve being tested has lost its normal function.

[0041] Fourthly,

[0042] According to the liquid rocket engine blow-off check valve dynamic working characteristic simulation test system described in the first aspect, the simulation test system also includes a gas pulsation excitation system, and the gas pulsation excitation system includes: a third high-pressure gas cylinder, a fourth filter, a sixth stop valve, a second pressure reducing valve, a first check valve, a piston chamber, a motor, and a second check valve;

[0043] The third high-pressure gas cylinder, the fourth filter, the sixth stop valve, the second pressure reducing valve, the first one-way valve, the piston chamber and the second one-way valve are connected in sequence through an excitation-generating pipeline; the output end of the second one-way valve is connected to the output pipeline;

[0044] A motor is installed on the piston chamber, and the motor is used to compress the gas. The excitation generating pipeline between the piston chamber and the second one-way valve generates an airflow with pulsating pressure, which is transmitted along the airflow to the output pipeline between the one-way valve to be tested and the second high-pressure gas cylinder, and then transmitted to the downstream of the output pipeline;

[0045] A first measuring surface, a second measuring surface and a third measuring surface are respectively arranged on the output pipeline between the throttle ring and the one-way valve to be tested, between the one-way valve to be tested and the second one-way valve, and between the second one-way valve and the second high-pressure gas cylinder; the first measuring surface, the second measuring surface and the third measuring surface are respectively used to monitor the pulsating pressure response upstream and downstream of the one-way valve to be tested;

[0046] The distance between the first measuring surface and the throttle ring and the one-way valve being measured shall not be less than 15 times the diameter of the output pipeline;

[0047] The distance between the second measuring surface and the one-way valve to be measured shall be no less than 15 times the diameter of the output pipeline, and the distance between the second measuring surface and the second one-way valve shall be no less than 20 times the diameter of the output pipeline;

[0048] The distance between the third measuring surface and the second one-way valve shall be no less than 20 times the diameter of the output pipeline, and the distance between the third measuring surface and the second high-pressure gas cylinder shall be no less than 15 times the diameter of the output pipeline.

[0049] Fifthly,

[0050] A method for testing the self-excited oscillation characteristics of a check valve using the liquid rocket engine blow-off check valve dynamic operating characteristics simulation test system according to the fourth aspect comprises:

[0051] Step 201: adjusting the first pressure reducing valve and the second pressure reducing valve so that the pulsating pressure disturbance of the third pressure measuring surface is no greater than 10% of the pressure of the pressure measuring point P3;

[0052] Step 202: Control the output of the motor to drive the piston of the piston chamber to sweep the frequency at a preset frequency, and use the gas pulsation excitation system to provide pressure disturbances in a specific frequency range for the medium in the output pipeline;

[0053] Step 203: Collect the pulsating pressures of the first measuring surface, the second measuring surface and the third measuring surface, and obtain the amplification or attenuation coefficients of the pulsating pressures of the first measuring surface, the second measuring surface and the third measuring surface at different frequencies to determine the self-excited oscillation characteristics of the one-way valve under test.

[0054] Sixth,

[0055] A method for testing the forced oscillation characteristics of a check valve using the liquid rocket engine blow-off check valve dynamic operating characteristics simulation test system according to the fourth aspect comprises:

[0056] The range of the pulsating pressure disturbance amplitude applied to the output pipeline by the control gas pulsation excitation system is 30%~35% of the pressure at the pressure measuring point P3;

[0057] Change the motor's movement rate to sweep the frequency according to the preset frequency;

[0058] The pulsating pressures of the first measuring surface, the second measuring surface and the third measuring surface are collected to obtain the amplification or attenuation coefficients of the pulsating pressures of the first measuring surface, the second measuring surface and the third measuring surface at different frequencies, so as to determine the forced oscillation characteristics of the one-way valve under test. Meanwhile, the proportional relationship between the pulsating pressure values ​​of the first measuring surface, the second measuring surface and the third measuring surface is obtained to obtain the attenuation or amplification characteristics of the pulsating pressure when propagating in the upstream and downstream output pipelines of the one-way valve under test.

[0059] During the frequency sweep process, when the pulsating pressure of any pulsating pressure measuring surface is greater than 50% of the maximum pressure measuring point for 0.1s continuously or greater than the maximum pressure bearing capacity of the output pipeline at any time, the motor is turned off, and the third stop valve and the fifth stop valve are opened to release the pressure to ensure the safety of the simulation test system; wherein, the pulsating pressure measuring surfaces include: the first measuring surface, the second measuring surface and the third measuring surface.

[0060] Compared with the prior art, the advantages of the present invention are mainly reflected in the following aspects:

[0061] 1) The present invention proposes a dynamic working characteristic test system that can be used for a liquid rocket engine blow-off check valve. A variable pressure source, a flow control component (a first pressure reducing valve, a throttle ring), and a pressurization and pressure relief system are arranged upstream and downstream of the valve, so as to realize the full-process assessment of the full-open, small-open, and closed check valves for different media, and obtain the dynamic characteristics of the check valve.

[0062] 2) The present invention adopts a dynamic working characteristic test system for a liquid rocket engine blow-off check valve. By changing the downstream pressure of the test system, the one-way valve under test is put into a rapid, periodic opening and closing process, thereby quickly evaluating the working life of the one-way valve.

[0063] 3) The present invention proposes to add a gas pulsation excitation system to the test system to generate a preset pulsating pressure in the whole system, and obtain the self-excited oscillation characteristics, forced oscillation characteristics and response characteristics of the pulsating pressure propagation process of the one-way valve.

[0064] 4) The dynamic characteristics of the purge check valve and the response characteristics to pulsation that can be obtained by the present invention can be directly used to calculate the dynamic characteristics, response characteristics, etc. of the corresponding purge system of the engine, and discover in advance the influence of the purge check valve's own characteristics on the engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 This is a schematic diagram of a liquid rocket engine blow-off check valve dynamic working characteristics simulation test system;

[0066] Figure 2 It is a schematic diagram of the gas pulsation excitation system;

[0067] Figure 3 This is a schematic diagram of a typical test pressure curve;

[0068] Figure 4 Schematic diagram of preset pressure curve for life test. DETAILED DESCRIPTION

[0069] In order to better describe the present invention, the present invention is described in detail below with reference to schematic diagrams and examples.

[0070] The liquid rocket engine purge check valve dynamic working characteristic simulation test system of the present invention comprises: a first high-pressure gas cylinder 1, a second high-pressure gas cylinder 2, a first filter 3, a second filter 4, a third filter 5, a mass flow meter 6, a first stop valve 8, a second stop valve 9, a third stop valve 10, a fourth stop valve 11, a fifth stop valve 12, a throttle ring 13 and a first pressure reducing valve 14;

[0071] The input end of the first high-pressure gas cylinder 1 is connected to the outlet end of the second stop valve 9 through the first input pipeline, and the outlet end of the second stop valve 9 is provided with a second filter 4; the second filter 4 is used to filter impurities in the gas to prevent the impurities from entering the first input pipeline; the second stop valve 9 is used to control the on and off of the external input high-pressure gas, thereby increasing the pressure of the first high-pressure gas cylinder 1.

[0072] A first discharge pipeline is provided on the first input pipeline, and a third stop valve 10 is provided at the outlet of the first discharge pipeline. The first discharge pipeline is used to discharge the gas in the first high-pressure gas cylinder 1. By opening the third stop valve 10, the pressure of the first high-pressure gas cylinder 1 is reduced or the pressure of the first high-pressure gas cylinder 1 is relieved after the test is completed;

[0073] The second stop valve 9 and the third stop valve 10 are not opened at the same time.

[0074] The output end of the first high-pressure gas cylinder 1 is connected to the output end of the second high-pressure gas cylinder 2 through an output pipeline;

[0075] The output pipeline is provided from the output end of the first high-pressure gas cylinder 1 to the output end of the second high-pressure gas cylinder 2, and is provided with a first filter 3, a first pressure reducing valve 14, a mass flow meter 6, a first stop valve 8, a throttle ring 13 and a one-way valve 7 to be measured in sequence;

[0076] The input end of the second high-pressure gas cylinder 2 is connected to the outlet end of the fourth stop valve 11 through the second input pipeline, and the outlet end of the fourth stop valve 11 is provided with a third filter 5; the third filter 5 is used to filter impurities in the gas to prevent impurities from entering the second input pipeline; the fourth stop valve 11 is used to control the on and off of the external input high-pressure gas, thereby increasing the pressure of the second high-pressure gas cylinder 2.

[0077] A second discharge pipeline is provided on the second input pipeline, and a fifth stop valve 12 is provided at the outlet of the second discharge pipeline. The second discharge pipeline is used to discharge the gas in the second high-pressure gas cylinder 2. By opening the fifth stop valve 12, the pressure of the second high-pressure gas cylinder 2 is reduced or the pressure of the second high-pressure gas cylinder 2 after the test is completed is relieved;

[0078] The fourth stop valve 11 and the fifth stop valve 12 are not opened at the same time.

[0079] The first pressure reducing valve 14 is used for rapid adjustment Figure 1 The left inlet pressure of the one-way valve 7 under test.

[0080] Pressure measuring points are arranged on the first high-pressure gas cylinder 1, between the one-way valve 7 to be tested and the throttle ring 13, between the one-way valve 7 to be tested and the second high-pressure gas cylinder 2, and on the second high-pressure gas cylinder 2, namely pressure measuring point P1, pressure measuring point P2, pressure measuring point P3 and pressure measuring point P4. The pressure measuring points are used to monitor the pressure values ​​at various parts of the system.

[0081] By controlling the opening or closing of the second stop valve 9, the third stop valve 10, the fourth stop valve 11 and the fifth stop valve 12, the pressure of the first high-pressure gas cylinder 1 and the second high-pressure gas cylinder 2 are adjusted according to preset conditions.

[0082] The pressure of the first high-pressure gas cylinder 1 is adjusted by opening the second stop valve 9 or the third stop valve 10; the pressure of the second high-pressure gas cylinder 2 is adjusted by opening the fourth stop valve 11 or the fifth stop valve 12; the inlet pressure of the tested one-way valve 7 is adjusted by adjusting the output pressure of the first pressure reducing valve 14.

[0083] The present invention provides a method for measuring the flow resistance of a one-way valve during a dynamic working process. The method is applied to the above-mentioned liquid rocket engine blow-off one-way valve dynamic working characteristic simulation test system. The method for measuring the flow resistance of a one-way valve during a dynamic working process comprises the following steps:

[0084] Step 001: Open the second stop valve 9 and the fourth stop valve 11, and inflate the first high-pressure gas cylinder 1 and the second high-pressure gas cylinder 2 according to the preset pressure. After reaching the preset pressure, close the second stop valve 9 and the fourth stop valve 11, and the pressure at the pressure measuring point P1 on the first high-pressure gas cylinder 1 is higher than the pressure at the pressure measuring point P4 on the second high-pressure gas cylinder 2;

[0085] Step 002: Open the first stop valve 8 so that the gas in the first high-pressure gas cylinder 1 flows into the second high-pressure gas cylinder 2 through the output pipeline, and at the same time control the opening or closing of the second stop valve 9, the third stop valve 10, the fourth stop valve 11, and the fifth stop valve 12, so that the pressure at the pressure measuring point P1 on the first high-pressure gas cylinder 1 is consistent with the pressure at the pressure measuring point P4 on the second high-pressure gas cylinder 2, so that the simulation test system works stably;

[0086] Step 003: Control the opening of the first pressure reducing valve 14, and control the opening or closing of the fourth stop valve 11 and the fifth stop valve 12, so that the pressure at the pressure measuring point P2 and the pressure measuring point P4 is in accordance with the preset test pressure curve (refer to Figure 3 ) changes, and at the same time controls the second stop valve 9 and the third stop valve 10 to be opened or closed, and keeps the pressure of the pressure measuring point P1 on the first high-pressure gas cylinder 1 unchanged, so as to simulate the pressure changes of the upstream and downstream of the one-way valve 7 under test at different working moments of the engine, and controls the one-way valve 7 under test to sequentially undergo the working process of small pressure drop / small opening section, pressure dynamic change section, valve closing section, and long-time small flow section;

[0087] Step 004: Collect the pressure-time curve at the pressure measuring point P2 and the pressure-time curve at the pressure measuring point P3 during the test, and calculate the difference between the pressure value at the pressure measuring point P2 and the pressure value at the pressure measuring point P3 as the flow resistance-time curve of the tested one-way valve 7;

[0088] Step 005: collecting the gas flow Q in the output pipeline during the test, calculating the gas velocity-time curve of the tested one-way valve 7 according to the gas flow Q and the pressure value of the pressure measuring point P2, and converting it into a Mach number-time curve;

[0089] Step 006: According to the corresponding relationship between the flow resistance-time curve and the Mach number-time curve, the dynamic flow resistance characteristics of the one-way valve 7 under different Mach numbers are obtained.

[0090] The present invention provides a method for quickly determining the life of a check valve. The method is applied to the above-mentioned liquid rocket engine blow-off check valve dynamic working characteristic simulation test system, which can make the one-way valve 7 under test in a periodic rapid change of closed, half-open, fully open, half-open, and closed, so as to simulate multiple actions of the one-way valve 7 under test in actual work and assess its life. The time of each cycle is not more than 3s. Figure 4 As shown, the time interval between two adjacent opening moments of the one-way valve 7 under test is no more than 3s. The one-way valve life rapid determination method comprises the following steps:

[0091] Step 101: Open the second stop valve 9 and the fourth stop valve 11, and inflate the first high-pressure gas cylinder 1 and the second high-pressure gas cylinder 2 according to a preset pressure. After reaching the preset pressure, close the second stop valve 9 and the fourth stop valve 11. At this time, the pressure at the pressure measuring point P1 on the first high-pressure gas cylinder 1 is higher than the pressure at the pressure measuring point P4 on the second high-pressure gas cylinder 2.

[0092] Step 102: Open the first stop valve 8 so that the gas in the first high-pressure gas cylinder 1 flows into the second high-pressure gas cylinder 2 through the output pipeline, and at the same time control the opening or closing of the second stop valve 9, the third stop valve 10, the fourth stop valve 11, and the fifth stop valve 12, so that the pressure at the pressure measuring point P1 on the first high-pressure gas cylinder 1 is consistent with the pressure at the pressure measuring point P4 on the second high-pressure gas cylinder 2, so that the simulation test system works stably;

[0093] Step 103: Control the opening or closing of the second stop valve 9 and the third stop valve 10 to ensure that the pressure at the pressure measuring point P1 on the first high-pressure gas cylinder 1 is always consistent with the preset pressure and higher than Figure 4 The upstream preset pressure P2' in the life test preset pressure curve (refer to Figure 4 ) adjust the first pressure reducing valve 14 so that the pressure change at the pressure measuring point P2 is consistent with the upstream preset pressure P2' in the preset life test pressure curve; that is, in the process of keeping P2 and P2' consistent, P1 is always higher than P2'.

[0094] According to the preset pressure curve of life test (refer to Figure 4 ) controls the opening or closing of the fourth stop valve 11 and the fifth stop valve 12, so that the pressure at the pressure measuring point P4 is in accordance with the preset life test pressure curve (refer to Figure 4 ) changes periodically, and each cycle T takes no more than 3s. During the entire periodic change process, the absolute value of the pressure difference between the pressure measuring point P4 and the pressure measuring point P2 should be within the range of 1.2 to 1.3 times the minimum pressure difference dP required to open the one-way valve 7 being tested, that is:

[0095] When P4>P2, 1.2*dP <P4-P2<1.3*dP

[0096] When P2>P4, 1.2*dP <P2-P4<1.3*dP

[0097] Wherein, dP is the minimum pressure difference required for the one-way valve 7 to be tested to open, which is an inherent property of the one-way valve.

[0098] Step 104: Collect the gas flow Q, pressure measuring point P2 and pressure measuring point P3 of the output pipeline during the test, and judge the state of the one-way valve 7 under test according to the gas flow Q and the pressure measuring point P2 and the pressure measuring point P3. If it is judged that the state of the one-way valve 7 under test has lost its normal function, proceed to step 105; otherwise, repeat step 103 until it is judged that the state of the one-way valve 7 under test has lost its normal function, and proceed to step 105;

[0099] In step 104, the method for determining the state of the one-way valve 7 under test is specifically as follows:

[0100] During the rapid life measurement process, if the gas flow rate Q is not 0 when P3>P2, or the gas flow rate Q is always 0 when P2>P3, it indicates that the one-way valve 7 under test has lost its normal function.

[0101] Step 105: the system automatically closes the second stop valve 9 and the fourth stop valve 11, and simultaneously opens the third stop valve 10 and the fifth stop valve 12 to perform a simulated test system pressure relief;

[0102] Step 106: Obtain the life of the one-way valve according to the number of opening and closing cycles of the one-way valve 7 under test, wherein the period between two adjacent opening moments of the valve is recorded as one opening and closing cycle period.

[0103] The simulation test system also includes a gas pulsation excitation system 15, which is used to generate pressure disturbance to the output pipeline, thereby simulating the pressure disturbance applied to the output pipeline by the excitation source under the test condition. Figure 2 As shown, the gas pulsation excitation system 15 includes: a third high-pressure gas cylinder 21, a fourth filter 22, a sixth stop valve 23, a second pressure reducing valve 24, a first one-way valve 25, a piston chamber 26, a motor 27 and a second one-way valve 28.

[0104] The third high-pressure gas cylinder 21, the fourth filter 22, the sixth stop valve 23, the second pressure reducing valve 24, the first one-way valve 25, the piston chamber 26 and the second one-way valve 28 are sequentially connected through an excitation-generating pipeline; the output end of the second one-way valve 28 is connected to the output pipeline;

[0105] A motor 27 is installed on the piston chamber 26. The motor 27 is used to compress the gas. The excitation generating pipeline between the piston chamber 26 and the second one-way valve 28 generates an airflow with pulsating pressure, which is transmitted along with the airflow to the output pipeline between the one-way valve 7 to be tested and the second high-pressure gas cylinder 2, and then propagates to the downstream of the output pipeline.

[0106] like Figure 1 As shown, multiple pressure measuring points P1, P2, P3, and P4 and a pulsating pressure measuring surface are provided, and the pressure signal is used as a basis for determining working parameters such as flow rate, pressure drop, and working pressure range of the one-way valve 7 under test; the pulsating pressure measuring surface obtains the self-excited oscillation characteristics, forced oscillation characteristics, and response characteristics of the one-way valve 7 under test based on its time domain signal and frequency domain signal.

[0107] The pulsating pressure measurement surface includes: a first measurement surface, a second measurement surface and a third measurement surface. Specifically, in order to accurately capture the propagation direction of the pulsating pressure in the pipeline and the response of the components, the first measurement surface, the second measurement surface and the third measurement surface are respectively set on the output pipeline between the throttle ring 13 and the one-way valve 7 to be measured, between the one-way valve 7 to be measured and the second one-way valve 28 of the gas pulsation excitation system 15, and between the second one-way valve 28 of the gas pulsation excitation system 15 and the second high-pressure gas cylinder 2 (such as Figure 1 As shown); the first measuring surface, the second measuring surface and the third measuring surface are respectively used to monitor the pulsating pressure response of the upstream and downstream of the one-way valve 7 under test;

[0108] The first measuring surface should be at least 15 times the diameter of the output pipeline from the throttle ring 13 and the one-way valve 7 to be measured;

[0109] The distance between the second measuring surface and the second one-way valve 28 of the gas pulsation excitation system 15 should be at least 20 times the diameter of the output pipeline;

[0110] The third measuring surface should be at least 20 times the diameter of the output pipeline away from the second one-way valve 28 of the gas pulsation excitation system 15, and the third measuring surface should be at least 15 times the diameter of the output pipeline away from the second high-pressure gas cylinder 2.

[0111] See also Figure 1 The present invention provides a method for testing the self-excited oscillation characteristics of a one-way valve, which is applied to the above-mentioned liquid rocket engine purge one-way valve dynamic working characteristics simulation test system, and comprises the following steps:

[0112] Step 201: By adjusting the first pressure reducing valve 14 and the second pressure reducing valve 24, the pulsating pressure disturbance on the third pressure measuring surface is not greater than 10% of the pressure of the pressure measuring point P3; that is, by adjusting the output pressure of the first pressure reducing valve 14 to change the output pipeline flow, and adjusting the second pressure reducing valve 24 to change the flow of the excitation generating pipeline, the amplitude of the pulsating pressure disturbance applied to the output pipeline by the gas pulsation excitation system 15 is controlled by controlling the ratio of the two flow rates.

[0113] Step 202: performing frequency sweeping, specifically: controlling the output of the motor 27 to drive the piston of the piston chamber 26 to perform frequency sweeping motion at a preset frequency, and using the gas pulsation excitation system 15 to provide pressure disturbances in a specific frequency range for the medium in the output pipeline;

[0114] Step 203: Collect the pulsating pressures of the first measuring surface, the second measuring surface and the third measuring surface, and obtain the amplification or attenuation coefficients of the pulsating pressures of different measuring surfaces (the first measuring surface, the second measuring surface and the third measuring surface) at different frequencies to determine the self-excited oscillation characteristics of the one-way valve 7 under test.

[0115] During the self-excited oscillation characteristic test of the one-way valve, when the pulsating pressure of any pulsating pressure measuring surface is greater than 50% of the maximum pressure measuring point for 0.1s continuously or is greater than the maximum pressure bearing capacity of the output pipeline at any time, the measurement and control system quickly shuts down the motor 27 and opens the third stop valve 10 and the fifth stop valve 12 to release the pressure to ensure the safety of the simulation test system; wherein, the pulsating pressure measuring surfaces include: the first measuring surface, the second measuring surface and the third measuring surface.

[0116] The present invention provides a method for testing the forced oscillation characteristics of a check valve, which is applied to the above-mentioned liquid rocket engine blow-off check valve dynamic working characteristics simulation test system, comprising:

[0117] The amplitude of the pulsating pressure disturbance applied to the output pipeline by the gas pulsation excitation system 15 is increased, and the value range of the pulsating pressure disturbance amplitude applied to the output pipeline by the gas pulsation excitation system 15 is controlled to be 30%~35% of the pressure of the pressure measuring point P3, and the movement rate of the motor 27 is changed to perform a frequency sweep at a preset frequency. During the test, the pulsating pressures of the first measuring surface, the second measuring surface and the third measuring surface are collected to obtain the amplification or attenuation coefficients of the pulsating pressures of different measuring surfaces (the first measuring surface, the second measuring surface and the third measuring surface) at different frequencies to determine the forced oscillation characteristics of the one-way valve 7 under test, and at the same time, the proportional relationship between the pulsating pressure values ​​of the first measuring surface, the second measuring surface and the third measuring surface is obtained to obtain the attenuation or amplification characteristics of the pulsating pressure when propagating in the upstream and downstream output pipelines of the one-way valve 7 under test.

[0118] During the forced oscillation characteristic test of the one-way valve, when the pulsating pressure of any pulsating pressure measuring surface is greater than 50% of the maximum pressure measuring point for 0.1s continuously or is greater than the maximum pressure bearing capacity of the output pipeline at any time, the motor 27 is turned off, and the third stop valve 10 and the fifth stop valve 12 are opened to release the pressure to ensure the safety of the simulation test system; wherein, the pulsating pressure measuring surfaces include: a first measuring surface, a second measuring surface and a third measuring surface.

[0119] The one-way valve 7 under test described above is a blow-off one-way valve, which is used in liquid rocket engines.

[0120] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solution of the present invention by using the above disclosed methods and technical contents without departing from the spirit and scope of the present invention. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall belong to the protection scope of the technical solution of the present invention. In the absence of conflict, the embodiments of the present application and the technical features in the embodiments can be combined with each other.

[0121] The contents not described in detail in the specification of the present invention belong to the common knowledge of those skilled in the art.

Claims

1. Liquid rocket engine purge check valve dynamic working characteristics simulation test system, characterized by: include: A first high-pressure gas cylinder (1), a second high-pressure gas cylinder (2), a first filter (3), a second filter (4), a third filter (5), a mass flow meter (6), a first stop valve (8), a second stop valve (9), a third stop valve (10), a fourth stop valve (11), a fifth stop valve (12), a throttle ring (13), and a first pressure reducing valve (14); The input end of the first high-pressure gas cylinder (1) is connected to the outlet end of the second stop valve (9) via a first input pipeline, and the outlet end of the second stop valve (9) is provided with a second filter (4); the second filter (4) is used to filter impurities in the gas to prevent the impurities from entering the first input pipeline; the second stop valve (9) is used to control the on-off of external input high-pressure gas, thereby increasing the pressure of the first high-pressure gas cylinder (1); A first discharge pipeline is provided on the first input pipeline, and a third stop valve (10) is provided at the outlet of the first discharge pipeline. The first discharge pipeline is used to discharge gas in the first high-pressure gas cylinder (1). By opening the third stop valve (10), the pressure of the first high-pressure gas cylinder (1) is reduced or the pressure of the first high-pressure gas cylinder (1) is relieved after the test is completed. The output end of the first high-pressure gas cylinder (1) is connected to the output end of the second high-pressure gas cylinder (2) via an output pipeline; The output pipeline is provided with a first filter (3), a first pressure reducing valve (14), a mass flow meter (6), a first stop valve (8), a throttle ring (13) and a one-way valve (7) to be measured in sequence from the output end of the first high-pressure gas cylinder (1) to the output end of the second high-pressure gas cylinder (2); The input end of the second high-pressure gas cylinder (2) is connected to the outlet end of the fourth stop valve (11) via a second input pipeline, and a third filter (5) is provided at the outlet end of the fourth stop valve (11); the third filter (5) is used to filter impurities in the gas to prevent the impurities from entering the second input pipeline; the fourth stop valve (11) is used to control the on-off of the external input high-pressure gas, thereby increasing the pressure of the second high-pressure gas cylinder (2); A second discharge pipeline is provided on the second input pipeline, and a fifth stop valve (12) is provided at the outlet of the second discharge pipeline. The second discharge pipeline is used to discharge the gas in the second high-pressure gas cylinder (2). By opening the fifth stop valve (12), the pressure of the second high-pressure gas cylinder (2) is reduced or the pressure of the second high-pressure gas cylinder (2) is relieved after the test is completed. The first pressure reducing valve (14) is used to adjust the inlet pressure of the one-way valve (7) to be tested; Pressure measuring points are provided on the first high-pressure gas cylinder (1), between the one-way valve (7) to be tested and the throttle ring (13), between the one-way valve (7) to be tested and the second high-pressure gas cylinder (2), and on the second high-pressure gas cylinder (2), namely pressure measuring point P1, pressure measuring point P2, pressure measuring point P3 and pressure measuring point P4. The pressure measuring points are used to monitor pressure values.

2. The liquid rocket engine purge check valve dynamic working characteristics simulation test system according to claim 1 is characterized in that: By opening the second stop valve (9) or opening the third stop valve (10), the pressure of the first high-pressure gas cylinder (1) is adjusted; The pressure of the second high-pressure gas cylinder (2) is adjusted by opening the fourth stop valve (11) or opening the fifth stop valve (12).

3. A method for measuring flow resistance during the dynamic working process of a check valve using the liquid rocket engine blow-off check valve dynamic working characteristic simulation test system as claimed in claim 1 or 2, characterized in that: include: Step 001: Open the second stop valve (9) and the fourth stop valve (11), and inflate the first high-pressure gas cylinder (1) and the second high-pressure gas cylinder (2) according to a preset pressure. After the preset pressure is reached, close the second stop valve (9) and the fourth stop valve (11). At this time, the pressure at the pressure measuring point P1 on the first high-pressure gas cylinder (1) is higher than the pressure at the pressure measuring point P4 on the second high-pressure gas cylinder (2); Step 002: Open the first stop valve (8) so that the gas in the first high-pressure gas cylinder (1) flows into the second high-pressure gas cylinder (2) through the output pipeline, and at the same time control the opening or closing of the second stop valve (9), the third stop valve (10), the fourth stop valve (11), and the fifth stop valve (12) so that the pressure at the pressure measuring point P1 on the first high-pressure gas cylinder (1) and the pressure at the pressure measuring point P4 on the second high-pressure gas cylinder (2) are consistent, so that the simulation test system works stably; Step 003: Control the opening of the first pressure reducing valve (14), and control the opening or closing of the fourth stop valve (11) and the fifth stop valve (12), so that the pressures at the pressure measuring points P2 and P4 change according to a preset test pressure curve, and at the same time control the opening or closing of the second stop valve (9) and the third stop valve (10), so as to keep the pressure at the pressure measuring point P1 on the first high-pressure gas cylinder (1) unchanged, so as to simulate the pressure change process upstream and downstream of the one-way valve (7) under test at different working moments of the engine; Step 004: collecting the pressure-time curve at the pressure measuring point P2 and the pressure-time curve at the pressure measuring point P3 during the test, and calculating the difference between the pressure value at the pressure measuring point P2 and the pressure value at the pressure measuring point P3 as the flow resistance-time curve of the one-way valve (7) under test; Step 005: collecting the gas flow rate Q in the output pipeline during the test, calculating the gas velocity-time curve of the one-way valve (7) under test according to the gas flow rate Q and the pressure value of the pressure measuring point P2, and converting it into a Mach number-time curve; Step 006: According to the corresponding relationship between the flow resistance-time curve and the Mach number-time curve, the dynamic flow resistance characteristics of the one-way valve (7) under different Mach numbers are obtained.

4. A method for quickly determining the life of a check valve using the liquid rocket engine blow-off check valve dynamic working characteristic simulation test system as claimed in claim 1 or 2, characterized in that: include: Step 101: Open the second stop valve (9) and the fourth stop valve (11), and inflate the first high-pressure gas cylinder (1) and the second high-pressure gas cylinder (2) according to a preset pressure. After the preset pressure is reached, close the second stop valve (9) and the fourth stop valve (11). At this time, the pressure at the pressure measuring point P1 on the first high-pressure gas cylinder (1) is higher than the pressure at the pressure measuring point P4 on the second high-pressure gas cylinder (2); Step 102: Open the first stop valve (8) so that the gas in the first high-pressure gas cylinder (1) flows into the second high-pressure gas cylinder (2) through the output pipeline, and at the same time control the opening or closing of the second stop valve (9), the third stop valve (10), the fourth stop valve (11), and the fifth stop valve (12) so that the pressure at the pressure measuring point P1 on the first high-pressure gas cylinder (1) and the pressure at the pressure measuring point P4 on the second high-pressure gas cylinder (2) are consistent, so that the simulation test system works stably; Step 103: Control the opening or closing of the second stop valve (9) and the third stop valve (10) to ensure that the pressure at the pressure measuring point P1 on the first high-pressure gas cylinder (1) is always consistent with the preset pressure and is higher than the upstream preset pressure P2' in the preset life test pressure curve, and adjust the first pressure reducing valve (14) according to the preset life test pressure curve so that the pressure change at the pressure measuring point P2 is consistent with the upstream preset pressure P2'; The fourth stop valve (11) and the fifth stop valve (12) are controlled to be opened or closed according to the preset pressure curve of the life test, so that the pressure at the pressure measuring point P4 changes periodically according to the downstream preset pressure P4' in the preset life test pressure curve, and each cycle T takes no more than 3 seconds. During the entire periodic change process, it is required that: When P4>P2, 1.2*dP <P4-P2<1.3*dP When P2>P4, 1.2*dP <P2-P4<1.3*dP Wherein, dP is the minimum differential pressure required for the one-way valve (7) under test to open; Step 104: collecting the gas flow Q, pressure measuring point P2 and pressure measuring point P3 of the output pipeline during the test, and judging the state of the one-way valve (7) under test according to the gas flow Q and the pressure measuring point P2 and pressure measuring point P3. If it is judged that the one-way valve (7) under test has lost its normal function, proceed to step 105. Otherwise, repeat step 103 until it is judged that the one-way valve (7) under test has lost its normal function, and proceed to step 105. Step 105: close the second stop valve (9) and the fourth stop valve (11), and simultaneously open the third stop valve (10) and the fifth stop valve (12) to depressurize the simulated test system; Step 106: Obtain the life of the one-way valve according to the number of opening and closing cycles of the one-way valve (7) under test, wherein the period between two consecutive opening moments of the valve is recorded as one opening and closing cycle period.

5. A method for quickly determining the life of a one-way valve according to claim 4, characterized in that: In step 104, the method for determining the state of the one-way valve (7) under test is specifically as follows: During the rapid life measurement, if the gas flow rate Q is not 0 when P3>P2, or the gas flow rate Q is always 0 when P2>P3, it indicates that the one-way valve (7) under test has lost its normal function.

6. The liquid rocket engine purge check valve dynamic working characteristics simulation test system according to claim 1 or 2, characterized in that: The simulation test system further comprises a gas pulsation excitation system (15), the gas pulsation excitation system (15) comprising: a third high-pressure gas cylinder (21), a fourth filter (22), a sixth stop valve (23), a second pressure reducing valve (24), a first check valve (25), a piston chamber (26), a motor (27) and a second check valve (28); The third high-pressure gas cylinder (21), the fourth filter (22), the sixth stop valve (23), the second pressure reducing valve (24), the first one-way valve (25), the piston chamber (26) and the second one-way valve (28) are connected in sequence via an excitation generating pipeline; the output end of the second one-way valve (28) is connected to the output pipeline; A motor (27) is installed on the piston chamber (26). The motor (27) is used to compress the gas, and an airflow with pulsating pressure is generated in the excitation generation pipeline between the piston chamber (26) and the second one-way valve (28). The airflow is propagated along the airflow to the output pipeline between the one-way valve (7) to be tested and the second high-pressure gas cylinder (2), and then propagated downstream of the output pipeline. A first measuring surface, a second measuring surface and a third measuring surface are respectively arranged on the output pipeline between the throttle ring (13) and the one-way valve (7) to be tested, between the one-way valve (7) to be tested and the second one-way valve (28), and between the second one-way valve (28) and the second high-pressure gas cylinder (2); the first measuring surface, the second measuring surface and the third measuring surface are respectively used to monitor the pulsating pressure response upstream and downstream of the one-way valve (7) to be tested; The first measuring surface is at least 15 times the diameter of the output pipeline from the throttle ring (13) and the one-way valve (7) being measured; The distance between the second measuring surface and the one-way valve (7) to be measured is not less than 15 times the diameter of the output pipeline, and the distance between the second measuring surface and the second one-way valve (28) is not less than 20 times the diameter of the output pipeline; The distance between the third measuring surface and the second one-way valve (28) is not less than 20 times the diameter of the output pipeline, and the distance between the third measuring surface and the second high-pressure gas cylinder (2) is not less than 15 times the diameter of the output pipeline.

7. A method for testing the self-excited oscillation characteristics of a check valve using the liquid rocket engine blow-off check valve dynamic operating characteristics simulation test system as claimed in claim 6, characterized in that: include: Step 201: adjusting the first pressure reducing valve (14) and the second pressure reducing valve (24) so ​​that the pulsating pressure disturbance on the third pressure measuring surface is no greater than 10% of the pressure at the pressure measuring point P3; Step 202: Control the output of the motor (27) to drive the piston of the piston chamber (26) to sweep the frequency at a preset frequency, and use the gas pulsation excitation system (15) to provide a pressure disturbance within a specific frequency range for the medium in the output pipeline; Step 203: collecting the pulsating pressures of the first measuring surface, the second measuring surface and the third measuring surface, and obtaining the amplification or attenuation coefficients of the pulsating pressures of the first measuring surface, the second measuring surface and the third measuring surface at different frequencies, so as to determine the self-excited oscillation characteristics of the one-way valve (7) under test.

8. A one-way valve self-oscillation characteristic test method according to claim 7, characterized in that: Also includes: During the frequency sweep process, when the pulsating pressure of any pulsating pressure measuring surface is greater than 50% of the maximum pressure measuring point for 0.1s continuously or greater than the maximum pressure bearing capacity of the output pipeline at any time, the motor (27) is turned off, and the third stop valve (10) and the fifth stop valve (12) are opened to release the pressure to ensure the safety of the simulation test system; wherein the pulsating pressure measuring surface includes: a first measuring surface, a second measuring surface and a third measuring surface.

9. A method for testing the forced oscillation characteristics of a check valve using the liquid rocket engine blow-off check valve dynamic operating characteristics simulation test system as claimed in claim 6, characterized in that: The range of the pulsating pressure disturbance amplitude applied to the output pipeline by the control gas pulsation excitation system (15) is 30% to 35% of the pressure at the pressure measuring point P3; Changing the movement rate of the motor (27) to perform a frequency sweep according to a preset frequency; The pulsating pressures of the first measuring surface, the second measuring surface and the third measuring surface are collected to obtain the amplification or attenuation coefficients of the pulsating pressures of the first measuring surface, the second measuring surface and the third measuring surface at different frequencies, so as to determine the forced oscillation characteristics of the one-way valve (7) under test. At the same time, the proportional relationship between the pulsating pressure values ​​of the first measuring surface, the second measuring surface and the third measuring surface is obtained to obtain the attenuation or amplification characteristics of the pulsating pressure when propagating in the upstream and downstream output pipelines of the one-way valve (7) under test.

10. A one-way valve forced oscillation characteristic test method according to claim 9, characterized in that: Also includes: During the frequency sweep process, when the pulsating pressure of any pulsating pressure measuring surface is greater than 50% of the maximum pressure measuring point for 0.1s continuously or greater than the maximum pressure bearing capacity of the output pipeline at any time, the motor (27) is turned off, and the third stop valve (10) and the fifth stop valve (12) are opened to release the pressure to ensure the safety of the simulation test system; wherein the pulsating pressure measuring surface includes: a first measuring surface, a second measuring surface and a third measuring surface.

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