A non-destructive testing system and method for calibrating the response performance of a cold gas thruster

Abstract

The present application relates to a kind of nondestructive testing system and method for calibrating cold gas thruster response performance, in the system, the inlet of stop valve is connected to external air source, the outlet of stop valve is connected to the inlet of pressure reducing valve, the outlet of pressure reducing valve is connected to the inlet of first pressure sensor, the outlet of first pressure sensor is connected to the inlet of first sealing device, the outlet of first sealing device is connected to the inlet of cold gas thruster, the nozzle of cold gas thruster is connected to gas collector through second sealing device;Vacuum pump is connected to gas collector by metal hose, vacuum pump starts before detection, gas in gas collector is extracted, and the vacuum environment required for cold gas thruster to work is established.The present application adopts in vitro diagnostic method, measures local gas pressure change, calibrates cold gas thruster dynamic response time, improves detection efficiency through standardized sealing interface design, and is convenient and reliable to operate.

Description

Technical Field

[0001] This invention relates to a non-destructive testing system and method for calibrating the response performance of a cold gas thruster, belonging to the field of spacecraft propulsion system measurement and application technology. Background Technology

[0002] The thrust performance of a cold gas thruster includes steady-state performance and dynamic performance. The former is generally characterized by steady-state thrust, which can be directly measured using a thrust measurement device; the latter is generally characterized by dynamic response performance, which includes two time constants: thrust build-up time and thrust shut-off time.

[0003] Methods for measuring the dynamic response performance of cold gas thrusters include direct and indirect methods. For millisecond-level fast-response cold gas thrusters, the short thrust duration makes it difficult to match the response speed of the thrust measurement system, hindering direct measurement of the dynamic response performance. Indirect thrust measurement typically involves measuring combustion chamber pressure (combustion pressure), converting the result using theoretical formulas to obtain the thrust value, and then extrapolating the dynamic response performance of the thrust.

[0004] Using combustion pressure to measure the dynamic performance of cold gas thrusters requires adding pressure gauges to the thruster structure, which can damage the thruster itself. Therefore, this method is mostly used for qualification tests or batch performance sampling tests of cold gas thrusters and is not suitable for flight-grade components. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a non-destructive testing system and method for calibrating the response performance of a cold gas thruster, so as to quickly obtain dynamic response constants such as thrust build-up time and thrust shut-off time.

[0006] The technical solution adopted in this invention is: a non-destructive testing system for calibrating the response performance of a cold gas thruster, the system comprising a shut-off valve, a pressure reducing valve, a first pressure sensor, a second pressure sensor, a first sealing device, a second sealing device, a vacuum pump, and a gas collector;

[0007] The inlet of the shut-off valve is connected to an external air source, the outlet of the shut-off valve is connected to the inlet of the pressure reducing valve, the outlet of the pressure reducing valve is connected to the inlet of the first pressure sensor, the outlet of the first pressure sensor is connected to the inlet of the first sealing connection device to measure the pressure of the gas entering the first sealing device, the outlet of the first sealing connection device is connected to the inlet of the cold gas thruster, and the nozzle of the cold gas thruster is connected to the first interface of the gas collector through the second sealing device; the second pressure sensor is connected to the second interface of the gas collector to measure the pressure of the gas inside the gas collector; and the vacuum pump is connected to the third interface of the gas collector to evacuate the gas collector to a vacuum state.

[0008] Preferably, the first sealing device is connected to the cold air thruster by a metal ball head-metal cone surface screw connection hard seal method, and a non-metallic gasket is added between the metal ball head and the metal cone surface to protect the contact surface.

[0009] Preferably, the second sealing device is connected to the gas collector by a planar compression structure and sealed by a non-metallic sealing ring soft seal; the second sealing device is connected to the cold gas thruster by a flange structure and fixed with standard screws.

[0010] Preferably, the cold gas thruster is an inert gas type cold gas thruster or a liquefied gas type cold gas thruster.

[0011] Another technical solution of the present invention is: a non-destructive testing method for calibrating the dynamic response performance of a cold gas thruster based on the above system, the method including the detection steps of thrust build-up time and thrust shut-off time:

[0012] Connect to an external gas source;

[0013] Open the shut-off valve, open the pressure reducing valve, observe the reading of the first pressure sensor, and adjust the output pressure of the pressure reducing valve to the first set value;

[0014] Turn on the vacuum pump to extract the residual gas in the gas collector, observe the reading of the second pressure sensor, and turn off the vacuum pump when the second pressure sensor measures that the pressure in the gas collector has reached the second set value.

[0015] Send the set cold gas thruster operating pulse command to cause the gas propellant, adjusted by the pressure reducing valve, to be injected into the gas collector through the cold gas thruster, and record the start time t of the sent command. open and termination time t close ;

[0016] The pressure change curve inside the gas collector is measured by the second pressure sensor, and the first pressure inflection time t1 and the second pressure inflection time t2 are recorded to calculate the thrust build-up time t. 90 and thrust shut-off time t 10 .

[0017] Preferably, the thrust build-up time t 90 and thrust shut-off time t 10 Calculate using the following formula:

[0018] t90=(t1-t open )×90%

[0019] t 10 =(t close -t2)×90%

[0020] Preferably, the method for determining the first pressure inflection time t1 is as follows: the time when the readings of the second pressure sensor 6 at adjacent measurement moments satisfy the following condition is defined as t1:

[0021]

[0022] The method for determining the second pressure inflection time t2 is as follows: the time when the readings of the second pressure sensor at adjacent measurement moments satisfy the following condition is defined as t2:

[0023]

[0024] P i Let P be the reading at the i-th measurement time. i-1 P is the reading at the (i-1)th measurement time. i+1 This is the reading at the (i+1)th measurement time.

[0025] The third technical solution of the present invention is: a non-destructive testing system for calibrating the dynamic response performance of a cold gas thruster, the system further comprising a mass spectrometer and a standard leak.

[0026] The gas collector is connected to the mass spectrometer via the fourth interface and to the standard leak via the fifth interface.

[0027] The fourth technical solution of the present invention is: a non-destructive testing method for calibrating the response performance of a cold gas thruster, including a step of detecting the internal leakage rate of the cold gas thruster:

[0028] Replace the external gas source medium with tracer gas;

[0029] Open the first shut-off valve and adjust the output pressure of the pressure reducing valve to the third set value;

[0030] Turn on the vacuum pump to extract the residual gas in the gas collector, and at the same time observe the reading of the second pressure sensor. When the second pressure sensor measures that the pressure of the gas collector reaches the fourth set value, turn on the mass spectrometer.

[0031] After the mass spectrometer readings stabilize, record the background leak rate I before inflation. 01 And the leakage rate indicator value I1 after inflation;

[0032] Open the second shut-off valve, connect the standard leak orifice, and after the mass spectrometer reading stabilizes, record the background leak rate value I before opening the standard leak orifice. 02 And the indicator value I2 after opening the standard leak hole;

[0033] Calculate the internal leakage rate Q of the cold air thruster.

[0034] Preferably, the leakage rate of the cold air thruster is calculated using the following formula:

[0035]

[0036] Where Q0 is the nominal value of the vacuum standard leak rate.

[0037] The advantages of this invention compared to the prior art are:

[0038] (1) The dynamic response performance testing system for cold gas thrusters proposed in this invention adopts a non-destructive testing method in the form of "external diagnosis" to overcome the shortcomings of existing technologies in terms of measurement applicability;

[0039] (2) This invention uses a vacuum container with good sealing and a specific volume to collect the gas ejected from the thruster. A high-frequency pressure sensor is used to measure the pressure change in the gas collection container. The collected pressure data is modeled and processed to quickly obtain dynamic response constants such as thrust build-up time and thrust shut-off time.

[0040] (3) This invention has a leakage rate detection function for cold gas thrusters. The system is simple to operate, convenient and fast, and is suitable for the dynamic response performance of millisecond-level fast-response cold gas thrusters.

[0041] (4) This invention can install multiple cold air thrusters simultaneously through an array interface, allowing for multiple measurements with one installation, and has the advantages of high speed, high precision, and convenient operation.

[0042] (5) The dynamic response performance testing system for cold gas thrusters proposed in this invention can also detect the internal leakage rate of cold gas thrusters without changing the hardware configuration, which reduces the number of times the cold gas thrusters are disassembled and assembled during the test, reduces the risk of contamination by excess material in the cold gas thrusters, and helps to shorten the product development cycle.

[0043] (6) The dynamic response performance testing system for cold gas thrusters proposed in this invention adopts a standardized testing operation process and an automated post-processing module, which can effectively avoid measurement errors introduced by human factors; it has strong scalability and is applicable to both conventional inert gas cold gas propellants and liquefied gas cold gas propellants. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the non-destructive testing system for calibrating the dynamic response performance of a cold gas thruster according to the present invention.

[0045] Figure 2 This is a schematic diagram showing the pressure measurement results inside the gas collector according to an embodiment of the present invention. Detailed Implementation

[0046] The present invention will be further described below with reference to the embodiments.

[0047] like Figure 1As shown, a non-destructive testing system for calibrating the dynamic response performance of a cold gas thruster includes a shut-off valve 1, a pressure reducing valve 2, a first pressure sensor 3, a second pressure sensor 6, a first sealing device 4, a second sealing device 5, a vacuum pump 7, and a gas collector 8.

[0048] In the non-destructive testing system for the dynamic response performance of the cold gas thruster, the inlet of the shut-off valve 1 is connected to an external air source, the outlet of the shut-off valve 1 is connected to the inlet of the pressure reducing valve 2, the outlet of the pressure reducing valve 2 is connected to the inlet of the first pressure sensor 3, the outlet of the first pressure sensor 3 is connected to the inlet of the first sealing device 4, and the outlet of the first sealing device 4 is connected to the inlet of the cold gas thruster 9 to measure the pressure of the gas entering the first sealing device 4. The nozzle of the cold gas thruster 9 is connected to the outer end of the first interface 8-1 of the gas collector 8 through the second sealing device 5. The second pressure sensor 6 is connected to the second interface 8-2 of the gas collector 8 to measure the pressure of the gas inside the gas collector 8. The vacuum pump 7 is connected to the third interface 8-3 of the gas collector 8 to evacuate the gas collector 8 to a vacuum state.

[0049] Preferably, the first sealing device 4 and the cold air thruster 9 are connected by a metal ball head-metal cone surface screw connection hard seal method, and a non-metallic gasket is added between the metal ball head and the metal cone surface to protect the contact surface.

[0050] The second sealing device 5 is connected to the gas collector 8 by a planar compression structure and sealed by a non-metallic sealing ring soft seal; the second sealing device 5 is connected to the cold gas thruster 9 by a flange structure and fixed with standard screws. The cold gas thruster 9 is an inert gas type cold gas thruster, and the injected gas propellant is nitrogen, helium, hydrogen, oxygen, xenon, carbon dioxide or carbon tetrafluoride; the cold gas thruster 9 can also be a liquefied gas type cold gas thruster 9, and the injected liquefied gas propellant is ammonia, butane, propane, nitrous oxide, sulfur hexafluoride, dichlorofluoromethane (HFC-R22), tetrafluoroethane (HFC-R134a) or hexafluoropropane (HFC-R236fa).

[0051] Preferably, the first sealing device 4 and the second sealing device 5 can be configured with an interface array, and multiple cold air thrusters 9 can be pre-installed to perform multiple measurements at once, thereby improving testing efficiency.

[0052] In the non-destructive testing system for the dynamic response performance of a cold gas thruster, the specific implementation method for testing the dynamic response performance of the cold gas thruster 9 includes the following steps:

[0053] Step (1): Connect the external gas source 13; In a specific embodiment of the present invention, when the gas output by the gas source 13 is an inert gas, the output gas pressure is not lower than 5MPa; when the gas output by the gas source 13 is a liquefied gas, the output gas pressure is not lower than the saturated vapor pressure of the gas under standard conditions.

[0054] Step (II): Open the shut-off valve 1, open the pressure reducing valve 2, observe the reading of the first pressure sensor 3, and adjust the output pressure of the pressure reducing valve 2 to the first set value; in a specific embodiment of the present invention, the range of the first set value is 0.1 to 5 MPa.

[0055] Step (3): Turn on vacuum pump 7 to extract residual gas from gas collector 8, and observe the reading of the second pressure sensor 6. When the second pressure sensor 6 measures that the pressure in gas collector 8 reaches the second set value, turn off vacuum pump 7; the range of the second set value is 10. 3 ~10 -3 Pa.

[0056] Step (four): Send the set working pulse command for the cold gas thruster 9, so that the gas propellant adjusted by the pressure reducing valve 2 is injected into the gas collector 8 through the cold gas thruster 9, and record the start time t of the sent command. open and termination time t close ;t open With t close The interval between them shall not be less than 50ms.

[0057] Step (5): Measure the pressure change curve inside the gas collector 8 using the second pressure sensor 6, record the first pressure inflection time t1 and the second pressure inflection time t2, and calculate the thrust build-up time t. 90 and thrust shut-off time t 10 .like Figure 2 As shown.

[0058] Thrust buildup time t 90 and thrust shut-off time t 10 Calculate using the following formula:

[0059] t 90 =(t1-t) open )×90%

[0060] t 10 =(t close -t2)×90%

[0061] The method for determining the first pressure inflection time t1 is as follows: the time when the readings of the second pressure sensor 6 at adjacent measurement moments satisfy the following condition is defined as t1:

[0062]

[0063] The method for determining the second pressure inflection time t2 is as follows: the time when the readings of the second pressure sensor 6 at adjacent measurement moments satisfy the following condition is defined as t2:

[0064]

[0065] P i Let P be the reading at the i-th measurement time. i-1 P is the reading at the (i-1)th measurement time. i+1 This is the reading at the (i+1)th measurement time.

[0066] In the non-destructive testing system for the dynamic response performance of the cold gas thruster, the gas collector 8 is also connected to the mass spectrometer via the fourth interface 8-4 for detecting the internal leakage rate of the cold gas thruster 9. The gas collector 8 is connected to a standard leak via the fifth interface 8-5 for mass spectrometer leak rate calibration.

[0067] The aforementioned non-destructive testing system for the dynamic response performance of the cold gas thruster can also detect the internal leakage rate of the cold gas thruster 9. The specific implementation method for detecting the internal leakage rate of the cold gas thruster 9 includes the following steps:

[0068] Step (1): Replace the external gas source 13 with tracer gas; the tracer gas can be helium or sulfur hexafluoride;

[0069] Step (2): Open the first shut-off valve 1 and adjust the output pressure of the pressure reducing valve 2 to the third set value, the value of which is 0.1-5MPa.

[0070] Step (3): Turn on vacuum pump 7 to extract residual gas from gas collector 8, and simultaneously observe the reading of second pressure sensor 6. When the second pressure sensor 6 measures that the pressure in gas collector 8 reaches the set value, turn on the mass spectrometer; the range of the fourth set value is 10. -5 ~10 -3 Pa.

[0071] Step (5): After the mass spectrometer readings stabilize, record the background leak rate I before gas filling. 01 And the leakage rate indicator value I1 after inflation;

[0072] Step (5): Open the second shut-off valve 12 and connect the standard leak hole. The nominal leakage rate of the standard leak hole is Q0.

[0073] Step (VI): After the mass spectrometer reading stabilizes, open the second shut-off valve 12 to connect the standard leak orifice. After the mass spectrometer reading stabilizes, record the background leak rate value I before opening the standard leak orifice. 02The internal leakage rate value Q of the cold gas thruster 9 is calculated based on the indicated value I2 after opening the standard leak hole. In a specific embodiment of the present invention, the mass spectrometer reading is considered stable when the output value of the mass spectrometer does not change by more than 5% of the average value for 10 consecutive minutes.

[0074] The leakage rate of the cold air thruster 9 is calculated using the following formula:

[0075]

[0076] Where Q0 is the nominal value of the vacuum standard leak rate.

[0077] Although the present invention has been disclosed above with reference to 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 solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A non-destructive testing method for calibrating the dynamic response performance of a cold gas thruster, characterized in that, This is achieved using a non-destructive testing system, including the detection steps for thrust build-up and thrust shut-off times. Connect to an external gas source (13); Open the shut-off valve (1), open the pressure reducing valve (2), observe the reading of the first pressure sensor (3), and adjust the output pressure of the pressure reducing valve (2) to the first set value; Turn on the vacuum pump (7) to extract the residual gas in the gas collector (8), observe the reading of the second pressure sensor (6), and turn off the vacuum pump (7) when the second pressure sensor (6) measures that the pressure of the gas collector (8) reaches the second set value. Send the set working pulse command for the cold gas thruster (9) to cause the gas propellant regulated by the pressure reducing valve (2) to be injected into the gas collector (8) through the cold gas thruster (9), and record the start time t of the sent command. open and termination time t close ; The pressure change curve inside the gas collector (8) is measured by the second pressure sensor (6), the first pressure inflection time t1 and the second pressure inflection time t2 are recorded, and the thrust build-up time t is calculated. 90 and thrust shut-off time t 10； The non-destructive testing system includes a shut-off valve (1), a pressure reducing valve (2), a first pressure sensor (3), a second pressure sensor (6), a first sealing device (4), a second sealing device (5), a vacuum pump (7), and a gas collector (8). The inlet of the shut-off valve (1) is connected to an external air source, the outlet of the shut-off valve (1) is connected to the inlet of the pressure reducing valve (2), the outlet of the pressure reducing valve (2) is connected to the inlet of the first pressure sensor (3), the outlet of the first pressure sensor (3) is connected to the inlet of the first sealing connection device (4) to measure the pressure of the gas entering the first sealing device (4), the outlet of the first sealing connection device (4) is connected to the inlet of the cold gas thruster (9), and the nozzle of the cold gas thruster (9) is connected to the first interface (8-1) of the gas collector (8) through the second sealing device (5); the second pressure sensor (6) is connected to the second interface (8-2) of the gas collector (8) to measure the pressure of the gas inside the gas collector (8); the vacuum pump (7) is connected to the third interface (8-3) of the gas collector (8) to evacuate the gas collector (8) to a vacuum state.

2. The non-destructive testing method for calibrating the dynamic response performance of a cold gas thruster according to claim 1, characterized in that... Thrust buildup time t 90 and thrust shut-off time t 10 Calculate using the following formula: 。 3. The non-destructive testing method for calibrating the dynamic response performance of a cold gas thruster according to claim 1, characterized in that: The method for determining the first pressure inflection time t1 is as follows: the time when the readings of the second pressure sensor (6) at adjacent measurement moments satisfy the following conditions is t1: The method for determining the second pressure inflection time t2 is as follows: the time when the readings of the second pressure sensor (6) at adjacent measurement moments satisfy the following conditions is t2: For the first The reading at the time of measurement. For the first The reading at the time of measurement. For the first The reading at the time of measurement.

4. The non-destructive testing method for calibrating the dynamic response performance of a cold gas thruster according to claim 1, characterized in that: The non-destructive testing system also includes a mass spectrometer and a standard leak. The gas collector (8) is connected to the mass spectrometer via the fourth interface (8-4) and to the standard leak via the fifth interface (8-5).

5. The non-destructive testing method for calibrating the dynamic response performance of a cold gas thruster according to claim 4, characterized in that, The detection steps include the internal leakage rate detection of the cold air thruster (9): Replace the external gas source (13) medium with tracer gas; Open the first shut-off valve (1) and adjust the output pressure of the pressure reducing valve (2) to the third set value; Turn on the vacuum pump (7) to extract the residual gas in the gas collector (8), and observe the reading of the second pressure sensor (6). When the second pressure sensor (6) measures that the pressure of the gas collector (8) reaches the fourth set value, turn on the mass spectrometer. After the mass spectrometer readings stabilize, record the background leak rate I before inflation. 01 And the leakage rate indicator value I1 after inflation; Open the second shut-off valve (12), connect the standard leak orifice, and after the mass spectrometer reading stabilizes, record the background leak rate I before opening the standard leak orifice. 02 And the indicator value I2 after opening the standard leak hole; Calculate the internal leakage rate Q of the cold air thruster (9).

6. The non-destructive testing method for calibrating the dynamic response performance of a cold gas thruster according to claim 5, characterized in that, The leakage rate of the cold air thruster (9) is calculated using the following formula: in, This is the nominal value of the leakage rate of the vacuum standard leak hole.

7. The non-destructive testing method for calibrating the dynamic response performance of a cold gas thruster according to claim 1, characterized in that, The first sealing device (4) and the cold air thruster (9) are connected by a metal ball head-metal cone surface screw connection hard seal method, and a non-metal gasket is added between the metal ball head and the metal cone surface to protect the contact surface.

8. The non-destructive testing method for calibrating the dynamic response performance of a cold gas thruster according to claim 1 is characterized in that, The second sealing device (5) and the gas collector (8) are connected by a planar pressing structure and sealed by a non-metallic sealing ring soft seal; the second sealing device (5) and the cold air thruster (9) are connected by a flange structure and fixed with standard screws.

9. The non-destructive testing method for calibrating the dynamic response performance of a cold gas thruster according to claim 1, characterized in that, The cold gas thruster (9) is an inert gas type cold gas thruster or a liquefied gas type cold gas thruster (9).

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