A multiple ignition system and method for a liquid rocket engine

Abstract

The application provides a multiple ignition system and method of a liquid rocket engine, and relates to the technical field of liquid rocket engines.The system comprises a differential storage tank, a gas cavity isolation valve, a liquid cavity isolation valve, an ignition agent control valve, a first blow-off check valve, an ignition agent check valve, a second blow-off check valve and an ignition agent discharge valve; the interior of the differential storage tank is a cavity, a differential piston is arranged in the cavity, and the differential piston divides the cavity into a liquid cavity and a gas cavity; the gas cavity isolation valve is in communication with a gas cavity inlet; the liquid cavity isolation valve is in communication with a liquid cavity outlet; the ignition agent control valve is in communication with an output end of the liquid cavity isolation valve; the ignition agent discharge valve and the first blow-off check valve are both connected to a pipeline between the liquid cavity isolation valve and the ignition agent control valve; the ignition agent check valve is arranged on a main line of an outlet of the ignition agent control valve; and the second blow-off check valve is connected to a bypass of the outlet of the ignition agent control valve.The application reduces the pressure requirement of the ignition agent, and shortens the turnaround time of the rocket engine and the rocket or the interval time of repeated use.

Description

Technical Field

[0001] This application relates to the field of liquid rocket engine technology, and in particular to a liquid rocket engine multiple ignition system and method. Background Technology

[0002] Currently, the ignition module must undergo a complete process of disassembly, replacement, reassembly, and refilling after each test or flight mission.

[0003] Existing patent publication number CN110030116B discloses a single- or multiple-ignition suction-compression semi-diaphragm ignition module, its working method, and an ignition agent loading method. Existing patent publication number CN115523060B discloses a multiple-ignition module system, loading method, and post-test processing method, which discloses the operation of the multiple-ignition module, the loading method, and the post-test processing method. Existing patent publication number CN112211750B discloses a rocket engine ignition agent storage and supply device. All of these existing patents use diaphragm-type or non-metallic diaphragm ignition agent tanks. After multiple test runs or flight operations, the residual ignition agent in the multiple-ignition module and engine piping needs to be cleaned, the ignition module removed, and replaced with a disposable component such as a diaphragm valve. The ignition module is then refilled with ignition agent and reassembled onto the engine. The existing technology has the following drawbacks: In existing technologies, both the inlet and outlet of the ignition propellant tank use single-use valves (diaphragm valves). These valves rely on the physical rupture of the diaphragm to open, and once activated, they cause irreversible structural damage. Therefore, the diaphragm valve must be replaced after each mission. Replacement requires removing the entire multiple ignition module from the engine piping, involving the disconnection and reconnection of multiple piping interfaces, each requiring foreign object protection and airtightness testing. After multiple test runs or flight operations, the ignition module must be removed and replaced, increasing the engine's single turnaround time (typically several working days from mission completion to readiness for reuse) and reuse interval.

[0004] Currently, liquid oxygen / kerosene engines typically use chemical ignition agents, composed of 85% triethylboron and 15% triethylaluminum, which are flammable and explosive hazardous chemicals. Triethylboron / triethylaluminum ignition agents are spontaneously combustible (igniting automatically upon exposure to air) and extremely sensitive to moisture. Existing diaphragm-type storage tanks have complex structures with blind cavities and dead zones, making it impossible to completely remove residual ignition agents through simple purging. Module disassembly for offline cleaning and passivation is necessary, resulting in lengthy drying and testing cycles after cleaning.

[0005] Furthermore, in liquid rocket engine ignition systems, the igniter needs to be injected into the thrust chamber and gas generator at sufficiently high pressure and precise flow rate to ensure reliable mixing and ignition with the main propellant (liquid oxygen / kerosene). In existing diaphragm / capsule propellant tanks, the gas and liquid chambers have essentially equal force-bearing areas, and the diaphragm exhibits elastic restoring force and frictional resistance, requiring the gas chamber pressure to be higher than the liquid chamber pressure to drive the igniter output. This high igniter pressurization requirement is detrimental to engine operation and maintenance. For example, it increases the mass and structural complexity of the high-pressure gas source system, imposes stricter safety requirements on the high-pressure system, and increases the difficulty of maintenance operations, hindering repeated rapid use and maintenance of the engine and field support. In existing technologies, the diaphragm / capsule structure simultaneously performs both isolation and force transmission functions, but the optimal design of these two functions conflicts. Good isolation requires elastic deformation capacity, while efficient force transmission requires a rigid area difference.

[0006] Therefore, the urgent technical problem to be solved is how to address the issues in existing technologies where both the inlet and outlet of the ignition propellant tank use single-use valves, which significantly extends the turnaround and reuse interval of the engine and rocket, and where the high pressurization pressure requirement of the ignition propellant is detrimental to engine use and maintenance. Summary of the Invention

[0007] The purpose of this application is to provide a liquid rocket engine multiple ignition system and method to reduce the ignition propellant pressurization pressure requirement and shorten the preparation cycle, rocket turnaround time or liquid rocket engine reuse interval between multiple ignition missions.

[0008] To achieve the above objectives, as a first aspect of this application, this application provides a multiple ignition system for a liquid rocket engine. The system includes: a differential tank, a gas chamber isolation valve, a liquid chamber isolation valve, an ignition agent control valve, a first purge check valve, an ignition agent check valve, a second purge check valve, and an ignition agent discharge valve. The differential tank has an internal cavity, within which a differential piston is installed, dividing the cavity into a liquid chamber and a gas chamber. The gas chamber isolation valve is connected to the inlet of the gas chamber. The gas chamber isolation valve is used to control the flow of high-pressure gas into the gas chamber. The liquid chamber isolation valve is connected to the outlet of the liquid chamber; the ignition agent control valve is connected to the output end of the liquid chamber isolation valve through a pipeline; the ignition agent discharge valve and the first purge check valve are both connected to the pipeline between the liquid chamber isolation valve and the ignition agent control valve through pipelines; the ignition agent discharge valve is used to discharge the ignition agent between the liquid chamber isolation valve and the ignition agent control valve; the ignition agent check valve is located on the main pipeline of the outlet of the ignition agent control valve; the second purge check valve is connected to the bypass pipeline of the outlet of the ignition agent control valve.

[0009] In the liquid rocket engine multiple ignition system described above, the gas chamber inlet integrates a first filling and venting valve and a gas chamber pressure measuring port; the first filling and venting valve is used to connect to the gas filling fixture to perform nitrogen purging or filling of the gas chamber; when the gas filling fixture is not connected, the gas chamber is depressurized; the gas chamber pressure measuring port is used to monitor the internal pressure of the gas chamber and provide pressure feedback for the pressurization process.

[0010] In the liquid rocket engine multiple ignition system described above, the outlet of the liquid chamber is integrated with a second refueling and venting valve, which is used to connect to the liquid circuit refueling fixture; nitrogen gas is introduced into the gas chamber from the first refueling and venting valve, the differential piston is pushed to one side of the liquid chamber, and the liquid chamber is refueled with igniter through the second refueling and venting valve.

[0011] In the liquid rocket engine multiple ignition system described above, both the first refueling vent valve and the second refueling vent valve are refueling vent valves that allow repeated opening and closing, used for repeated refueling of the differential tank.

[0012] In the liquid rocket engine multiple ignition system described above, the differential piston includes a large end and a small end; the large end is a disc-shaped head, and the small end is a piston rod; the piston rod and the disc-shaped head are an integral structure; the disc-shaped head is disposed on one side of the gas chamber; the piston rod is disposed on one side of the liquid chamber; the diameter of the disc-shaped head is larger than the diameter of the piston rod; the diameter of the mating surface formed by the disc-shaped head and the inner wall of the differential propellant tank is larger than the diameter of the mating surface formed by the piston rod and the differential propellant tank. The effective pressure-bearing area corresponding to the large end sealing surface is greater than the effective pressure-bearing area corresponding to the small end sealing surface. The pressure difference between the effective pressure-bearing areas corresponding to the large end sealing surface and the small end sealing surface is used to reduce the pressure increase requirement of the air chamber.

[0013] In the liquid rocket engine multiple ignition system described above, the large end of the differential piston is sealed to the housing of the differential propellant tank using an X-shaped rubber sealing ring, and the small end of the differential piston is sealed to the housing of the differential propellant tank using a double O-ring rubber sealing ring.

[0014] In the liquid rocket engine multiple ignition system described above, the outlet of the ignition agent check valve is connected to the thrust chamber and the ignition agent inlet of the gas generator.

[0015] As a second aspect of this application, this application provides a method for multiple ignition of a liquid rocket engine, applied to the aforementioned multiple ignition system of a liquid rocket engine. The method includes: a pre-engine operation stage: sequentially opening the gas chamber isolation valve, the liquid chamber isolation valve, and the ignition agent control valve; high-pressure gas enters the gas chamber of the differential storage tank from the gas source inlet through the gas chamber isolation valve, pushing the differential piston to pressurize the ignition agent in the liquid chamber; the pressurized ignition agent then sequentially enters the thrust chamber and the gas generator ignition agent inlet through the liquid chamber isolation valve, the ignition agent control valve, and the ignition agent check valve, respectively; a post-engine operation stage: sequentially closing the gas chamber isolation valve, the liquid chamber isolation valve, and the ignition agent control valve; determining whether re-ignition is required; if so, performing the ignition agent handling process after the test or flight; otherwise, ending the mission; and determining whether ignition agent needs to be added; if so, performing the ignition agent adding process; otherwise, the system is in standby mode.

[0016] The liquid rocket engine multiple ignition method described above includes the following steps: connecting the first and second refueling drain valves to a gas refueling fixture and a liquid refueling fixture, respectively; opening the first and second refueling drain valves through the gas and liquid refueling fixtures to purge the gas chamber, liquid chamber, and refueling pipeline of the differential tank with nitrogen; after nitrogen purging, continuing to introduce nitrogen through the first refueling drain valve to push the differential piston to one side of the liquid chamber, evacuating the liquid chamber through the second refueling drain valve, and then refueling the liquid chamber with igniter through the second refueling drain valve.

[0017] As described above, the ignition agent handling process after the test or flight of a liquid rocket engine using multiple ignition methods includes: When the ignition agent pressurization gas source is depressurized, the gas chamber isolation valve is opened simultaneously to release the gas in the differential storage tank gas chamber; Nitrogen gas is introduced through the purging inlet, and the gas purges the ignition agent downstream of the ignition agent check valve through the second purging check valve. The ignition agent between the liquid chamber isolation valve and the ignition agent control valve is replaced and drained by introducing kerosene through the replacement inlet, and this process is repeated at least 3 times. Nitrogen gas is introduced through the displacement inlet to replace and drain the ignition agent and kerosene mixture between the liquid cavity isolation valve and the ignition agent control valve, and this process is repeated at least 5 times. Kerosene is introduced through the purge inlet to replace and drain the residual ignition agent downstream of the ignition agent check valve; Nitrogen gas is introduced through the purge inlet to replace and drain the ignition agent and kerosene mixture between the liquid chamber isolation valve and the ignition agent control valve, repeating this process at least 5 times. After the above steps are completed, repeat the ignition agent injection process.

[0018] The beneficial effects achieved by this application are as follows: (1) The gas chamber isolation valve and liquid chamber isolation valve of this application adopt self-locking valves, which can be repeatedly opened and closed. When reused, there is no need to disassemble and replace the valve or remove the module. The refill can be repeated without disassembly, reducing the disassembly and testing links, eliminating the repeated verification process, and shortening the turnaround and reuse interval of rocket engine and rocket.

[0019] (2) This application adopts a differential piston structure, which utilizes the area difference formed by the large end working area being larger than the small end working area to achieve a pressure amplification effect, so that a lower gas source pressure can generate a higher liquid chamber output pressure, and the gas chamber pressure can be lower than the liquid chamber pressure, further reducing the gas source pressure requirement. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0021] Figure 1 This is a schematic diagram of the structure of a liquid rocket engine multiple ignition system according to an embodiment of this application.

[0022] Figure 2 This is a flowchart illustrating a method for multiple ignition of a liquid rocket engine according to an embodiment of this application.

[0023] Reference numerals in the attached figures: 1-Differential tank; 2-Gas chamber isolation valve; 3-Liquid chamber isolation valve; 4-Ignition agent control valve; 5-First purge check valve; 6-Ignition agent check valve; 7-Second purge check valve; 8-Ignition agent discharge valve; 21-Gas source inlet; 22-Replacement inlet; 23-Purge inlet; 111-Liquid chamber; 112-Gas chamber; 113-Differential piston; 114-First filling and discharge valve; 115-Second filling and discharge valve; 116-Gas chamber pressure measuring port. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0025] Example 1 like Figure 1As shown, this application provides a multiple ignition system for a liquid rocket engine. The system includes: a differential tank 1, a gas chamber isolation valve 2, a liquid chamber isolation valve 3, an ignition agent control valve 4, a first purge check valve 5, an ignition agent check valve 6, a second purge check valve 7, and an ignition agent discharge valve 8. The differential tank 1 has an internal cavity, within which a differential piston 113 is installed, dividing the cavity into a liquid chamber 111 and a gas chamber 112. The gas chamber isolation valve 2 is connected to the inlet of the gas chamber 112. The gas chamber isolation valve 2 is used to control the entry of a high-pressure gas source into the gas chamber 112. On / off; the outlet of the liquid cavity isolation valve 3 is connected to the outlet of the liquid cavity 111; the igniter control valve 4 is connected to the output end of the liquid cavity isolation valve 3 through a pipeline; the igniter discharge valve 8 and the first purge check valve 5 are both connected to the pipeline between the liquid cavity isolation valve 3 and the igniter control valve 4 through pipelines; the igniter discharge valve 8 is used to discharge the igniter between the liquid cavity isolation valve 3 and the igniter control valve 4; the first purge check valve 5 is used to introduce medium from the replacement inlet 22 after test run or flight to replace and purge the medium in the pipeline between the liquid cavity isolation valve 3 and the igniter control valve 4. The igniter check valve 6 is located on the main pipeline at the outlet of the igniter control valve 4; the second purge check valve 7 is connected to the bypass pipeline at the outlet of the igniter control valve 4.

[0026] like Figure 1 As shown, the input end of the liquid chamber isolation valve 3 is connected to the outlet of the liquid chamber 111 of the differential tank 1, and is used to receive the pressurized ignition agent from the liquid chamber 111; the output end of the liquid chamber isolation valve 3 is connected to the input end of the ignition agent control valve 4, and is used to deliver the pressurized ignition agent to the ignition agent control valve 4.

[0027] Preferably, the liquid cavity isolation valve 3 is a reusable self-locking valve. It closes after engine operation, cutting off the connection between the liquid cavity 111 and downstream pipelines to prevent ignition agent leakage. Before engine operation, the liquid cavity isolation valve 3 opens, allowing the pressurized ignition agent to flow to the ignition agent control valve 4. The liquid cavity isolation valve 3, in conjunction with the ignition agent discharge valve 8 and the first refueling discharge valve 114, enables repeated refueling of the ignition agent without disassembling the module. The liquid cavity isolation valve 3 is not a disposable diaphragm valve, eliminating the need for disassembly and replacement after each use. It allows for direct and repeated refueling, shortening the preparation cycle between multiple ignition missions of the liquid rocket engine, reducing the turnaround time of the liquid rocket engine or rocket, or the interval between reusable uses of the liquid rocket engine. The area difference between the liquid cavity isolation valve 3 and the differential piston 113 works synergistically, resulting in low opening resistance during normal operation, without additional pressure loss in the liquid cavity 111, thus reducing the pressurization pressure requirement.

[0028] As a specific embodiment of the present invention, after the test run or flight is completed, the liquid cavity isolation valve 3 is closed, and in conjunction with the ignition agent discharge valve 8 and the first purge check valve 5, the residual ignition agent in the downstream pipeline is safely discharged and replaced. Kerosene is introduced through the replacement inlet 22 to replace and discharge the ignition agent between the liquid cavity isolation valve 3 and the ignition agent control valve 4. The closure of the liquid cavity isolation valve 3 ensures that the replacement medium will not flow back into the liquid cavity 111 and contaminate the newly added ignition agent. The liquid cavity 111 is physically isolated from the downstream processing pipeline to ensure operational safety.

[0029] like Figure 1 As shown, the inlet of the gas chamber 112 integrates a first filling and draining valve 114 and a gas chamber pressure measuring port 116; the first filling and draining valve 114 is used to connect to the gas filling tool to perform nitrogen replacement or filling of the gas chamber 112; when the gas filling tool is not connected, the gas chamber 112 is depressurized; the gas chamber pressure measuring port 116 is used to monitor the internal pressure of the gas chamber 112 and provide pressure feedback for the pressurization process.

[0030] like Figure 1 As shown, the outlet of the liquid chamber 111 integrates a second filling and drain valve 115, which is used to connect to the liquid filling fixture. The second filling and drain valve 115 and the liquid chamber isolation valve 3 together constitute the external interface of the liquid chamber 111. During nitrogen purging before the first filling, the second filling and drain valve 115 is connected to the liquid filling fixture, and the valve of the second filling and drain valve 115 is opened to purge the liquid chamber 111 and the filling pipeline with nitrogen, removing air and moisture. During vacuum filling of the ignition agent, the second filling and drain valve 115 is connected to the liquid filling fixture, and the valve of the second filling and drain valve 115 is opened. After the differential piston 113 is pushed to one side of the liquid chamber 111, the liquid chamber 111 is evacuated and the ignition agent is filled. During repeated filling using the squeeze method, the second filling and drain valve 115 is connected to the liquid filling fixture. After the gas chamber 112 is purged with nitrogen, the igniter is replenished to the liquid chamber 111 using the squeeze method. During the draining operation, the second filling and drain valve 115 is opened to drain the medium from the liquid chamber 111 as needed.

[0031] As a specific embodiment of the present invention, nitrogen gas is introduced into the gas chamber 112 from the first filling and draining valve 114, the differential piston 113 is pushed to one side of the liquid chamber 111, and the liquid chamber 111 is filled with igniter through the second filling and draining valve 115.

[0032] As a specific embodiment of the present invention, both the first filling and draining valve 114 and the second filling and draining valve 115 are filling and draining valves that allow repeated opening and closing (repeatedly open and closeable), used for repeated filling of the differential tank 1. The second filling and draining valve 115, together with the first filling and draining valve 114 and the liquid chamber isolation valve 3, constitute a complete non-disassembly repeated filling technical solution. The second filling and draining valve 115 supports in-situ repeated filling: the ignition agent can be replenished directly through this valve without disassembling the differential tank 1 or the liquid chamber isolation valve 3; it ensures filling safety: the second filling and draining valve 115 and the liquid chamber isolation valve 3 form a double-valve isolation, and the liquid chamber isolation valve 3 is closed during filling to prevent the ignition agent from leaking downstream; it eliminates the need for disassembly, replacement, and reinstallation of modules, achieving rapid reuse.

[0033] like Figure 1 As shown, the input end of the first purge check valve 5 is provided with a displacement inlet 22. Kerosene can be introduced through the displacement inlet 22 to displace and drain the ignition agent between the liquid chamber isolation valve 3 and the ignition agent control valve 4; nitrogen can be introduced through the displacement inlet 22 to displace and drain the mixture of ignition agent and kerosene between the liquid chamber isolation valve 3 and the ignition agent control valve 4.

[0034] As a specific embodiment of the present invention, the first purge check valve 5 is unidirectional, allowing external replacement medium (kerosene / nitrogen) to enter from the replacement inlet 22 and flow to the pipeline between the liquid cavity isolation valve 3 and the ignition agent control valve 4; preventing the ignition agent or replacement medium in the pipeline between the liquid cavity isolation valve 3 and the ignition agent control valve 4 from flowing back to the external pipeline connected to the replacement inlet 22.

[0035] like Figure 1 As shown, the input end of the second purge check valve 7 is provided with a purge inlet 23. Nitrogen gas is introduced through the purge inlet 23, and the gas purges the ignition agent downstream of the ignition agent check valve 6 through the second purge check valve 7. Kerosene is introduced through the purge inlet 23 to replace and drain the residual ignition agent downstream of the ignition agent check valve 6. Nitrogen gas is introduced through the purge inlet 23 to replace and drain the mixture of ignition agent and kerosene between the liquid chamber isolation valve 3 and the ignition agent control valve 4, repeating this process at least 5 times. The first purge check valve 5 is responsible for the upstream section (the pipeline between the liquid chamber isolation valve 3 and the ignition agent control valve 4), and the second purge check valve 7 is responsible for the downstream section (downstream of the ignition agent check valve 6 to before the thrust chamber / gas generator inlet), together achieving full pipeline cleaning of the ignition agent and providing conditions for repeated refilling.

[0036] As a specific embodiment of the present invention, the second purge check valve 7 has a one-way characteristic, allowing external purge media (nitrogen / kerosene) to enter from the purge inlet 23 and flow to the downstream main line of the ignition agent control valve 4, preventing the ignition agent from flowing into the bypass from the main line during normal operation, or preventing the purge media from flowing out in reverse. This ensures that during normal operation, all ignition agent flows to the thrust chamber / gas generator via the main line, and the bypass does not interfere with the main line flow. During purge operation, the purge media can enter the pipeline downstream of the ignition agent control valve 4 to the ignition agent check valve 6 and further downstream pipelines to remove residual ignition agent.

[0037] In a specific embodiment of the present invention, the differential piston 113 includes a large end and a small end; the large end is a disc-shaped head, and the small end is a piston rod; the piston rod and the disc-shaped head are an integral structure; the disc-shaped head is disposed on one side of the gas chamber 112; the piston rod is disposed on one side of the liquid chamber 111; the diameter of the disc-shaped head is larger than the diameter of the piston rod; the diameter of the mating surface formed by the disc-shaped head and the inner wall of the differential storage tank 1 is larger than the diameter of the mating surface formed by the piston rod and the differential storage tank 1; the effective pressure-bearing area corresponding to the sealing surface of the large end is larger than the effective pressure-bearing area corresponding to the sealing surface of the small end, and the pressure difference between the effective pressure-bearing area (actual area) corresponding to the sealing surface of the large end and the effective pressure-bearing area (actual area) corresponding to the sealing surface of the small end reduces the pressure boosting requirement of the gas chamber 112. The large end and the small end achieve a pressure amplification effect through the difference in effective pressure-bearing areas, enabling a higher output pressure of the liquid chamber 111 to be generated with a lower gas source pressure. The effective pressure-bearing area corresponding to the large end sealing surface is located on the side of the gas chamber 112, on the surface where the high-pressure gas acts, while the effective pressure-bearing area corresponding to the small end sealing surface is located on the side of the liquid chamber 111, on the surface where the ignition agent is output.

[0038] In a specific embodiment of the present invention, the large end of the differential piston 113 is sealed to the housing of the differential tank 1 using an X-shaped rubber sealing ring, and the small end of the differential piston 113 is sealed to the housing of the differential tank 1 using a double O-ring rubber sealing ring. The X-shaped rubber sealing ring and the double O-ring rubber sealing ring are existing standard sealing elements.

[0039] In a specific embodiment of the present invention, the outlet of the ignition agent check valve 6 is connected to the thrust chamber and the ignition agent inlet of the gas generator. An ignition agent check valve 6 is installed on the main line after the ignition agent control valve 4 to prevent downstream medium from flowing back to the outlet of the ignition agent control valve 4. The pressurized ignition agent sequentially passes through the liquid chamber isolation valve 3, the ignition agent control valve 4, and the ignition agent check valve 6 to enter the thrust chamber and the gas generator ignition agent inlet, respectively. The ignition agent check valve 6 prevents downstream medium backflow, ensuring the reliability of multiple ignitions and normal operation. During the first ignition, the ignition agent check valve 6 allows the ignition agent to flow to the thrust chamber / gas generator; during the ignition interval, the ignition agent check valve 6 closes to isolate and prevent the main system medium from entering the ignition agent pipeline; during the second to Nth ignitions, the ignition agent check valve 6 ensures the purity of the ignition agent pipeline, accurate valve timing, and reliable ignition.

[0040] As a specific embodiment of the present invention, a pressure sensing device is provided at the air chamber pressure measuring port 116. The pressure sensing device monitors the boost pressure of the air chamber 112 in real time to ensure that the design value is reached. It works in conjunction with the air chamber isolation valve 2 to achieve precise pressure control and prevent the air chamber 112 from being over-pressurized or under-pressurized. It can also verify the working status of the differential piston 113. By the correspondence between the pressure of the air chamber 112 and the output pressure of the liquid chamber 111, it can be determined whether the differential piston 113 is working normally and whether the seal is intact.

[0041] Example 2 like Figure 2 As shown, this application provides a method for multiple ignition of a liquid rocket engine, applied to a multiple ignition system for a liquid rocket engine. The method includes: Step S1, engine pre-operation stage: sequentially open the gas chamber isolation valve 2, the liquid chamber isolation valve 3 and the ignition control valve 4. High-pressure gas enters the gas chamber 112 of the differential storage tank 1 from the gas source inlet 21 through the gas chamber isolation valve 2, pushing the differential piston 113 to pressurize the ignition agent in the liquid chamber 111. The pressurized ignition agent sequentially enters the thrust chamber and the gas generator ignition agent inlet through the liquid chamber isolation valve 3, the ignition control valve 4 and the ignition one-way valve 6 respectively.

[0042] Step S2, after the engine starts: sequentially close the gas chamber isolation valve 2, the liquid chamber isolation valve 3, and the ignition control valve 4.

[0043] Step S3: Determine whether re-ignition is required. If so, perform the ignition agent disposal process after the test or flight. Otherwise, end the mission.

[0044] Step S4: Determine whether ignition agent needs to be added. If so, execute the ignition agent adding process; otherwise, the system is in standby mode.

[0045] As a specific embodiment of the present invention, the ignition agent charging process includes: connecting the first charging drain valve 114 and the second charging drain valve 115 to the gas charging fixture and the liquid charging fixture, respectively; opening the first charging drain valve 114 and the second charging drain valve 115 through the gas charging fixture and the liquid charging fixture, respectively, to purge the gas chamber 112, the liquid chamber 111 and the charging pipeline of the differential storage tank 1 with nitrogen; after the nitrogen purge is completed, nitrogen is continued to be introduced from the first charging drain valve 114 to push the differential piston 113 to one side of the liquid chamber 111, and the liquid chamber 111 is evacuated from the second charging drain valve 115; after the evacuation is completed, the ignition agent is charged into the liquid chamber 111 through the second charging drain valve 115.

[0046] As a specific embodiment of the present invention, the ignition agent treatment process after test run or flight includes: When the ignition agent pressurization gas source is depressurized, the gas chamber isolation valve 2 is opened at the same time to release the gas in the differential storage tank 1 gas chamber 112; Nitrogen gas is introduced through purge inlet 23, and the gas purges the ignition agent downstream of ignition agent check valve 6 through the second purge check valve 7. Kerosene is introduced through displacement inlet 22 to replace and drain the ignition agent between the liquid chamber isolation valve 3 and the ignition agent control valve 4, repeating this process at least 3 times. Nitrogen gas is introduced through displacement inlet 22 to replace and drain the ignition agent and kerosene mixture between liquid chamber isolation valve 3 and ignition agent control valve 4, repeating at least 5 times. The residual ignition agent downstream of the ignition agent check valve 6 is replaced and discharged by kerosene introduced through the purging inlet 23; The mixture of ignition agent and kerosene between the liquid chamber isolation valve 3 and the ignition agent control valve 4 is replaced and drained by introducing nitrogen gas through the purging inlet 23, and this process is repeated at least 5 times. After the above steps are completed, repeat the ignition agent charging process.

[0047] The ignition agent charging method is repeated as follows: The first charging drain valve 114 and the second charging drain valve 115 are respectively connected to the gas charging fixture and the liquid charging fixture. The first charging drain valve 114 is opened through the gas charging fixture to purge the gas chamber 112 of the differential storage tank 1 with nitrogen again. The second charging drain valve 115 is opened through the liquid charging fixture to charge the liquid chamber 111 using a compression method.

[0048] The beneficial effects achieved by this application are as follows: (1) The gas chamber isolation valve and liquid chamber isolation valve of this application adopt self-locking valves, which can be repeatedly opened and closed. When reused, there is no need to disassemble and replace the valve or remove the module. The refill can be repeated without disassembly, reducing the disassembly and testing links, eliminating the repeated verification process, and shortening the turnaround and reuse interval of rocket engine and rocket.

[0049] (2) This application adopts a differential piston structure, which utilizes the area difference formed by the large end working area being larger than the small end working area to achieve a pressure amplification effect, so that a lower gas source pressure can generate a higher liquid chamber output pressure, and the gas chamber pressure can be lower than the liquid chamber pressure, further reducing the gas source pressure requirement.

[0050] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0051] In the description of this application, the word "for example" is used to mean "used as an example, illustration, or description." Any embodiment described as "for example" in this application is not necessarily to be construed as being more preferred or advantageous than other embodiments. The following description is provided to enable any person skilled in the art to make and use the invention. Details are set forth in the following description for purposes of explanation. It should be understood that those skilled in the art will recognize that the invention can be made without using these specific details. In other instances, well-known structures and processes will not be described in detail to avoid obscuring the description of the invention with unnecessary detail. Therefore, the invention is not intended to be limited to the embodiments shown, but is consistent with the broadest scope of the principles and features disclosed in this application.

[0052] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A liquid rocket engine multiple ignition system, characterized in that, The system includes: Differential storage tank, gas chamber isolation valve, liquid chamber isolation valve, igniter control valve, first purge check valve, igniter check valve, second purge check valve and igniter discharge valve; The differential tank has an internal cavity, and a differential piston is installed inside the cavity, which divides the cavity into a liquid cavity and a gas cavity. The air chamber isolation valve is connected to the inlet of the air chamber; the air chamber isolation valve is used to control the opening and closing of the high-pressure air source entering the air chamber. The liquid cavity isolation valve is connected to the outlet of the liquid cavity; The ignition agent control valve is connected to the output end of the liquid chamber isolation valve via a pipeline; The ignition agent discharge valve and the first purge check valve are both connected to the pipeline between the liquid chamber isolation valve and the ignition agent control valve via pipelines; the ignition agent discharge valve is used to discharge the ignition agent between the liquid chamber isolation valve and the ignition agent control valve; The ignition agent check valve is located on the main line of the ignition agent control valve outlet; The second purge check valve is connected to the bypass of the outlet of the ignition agent control valve.

2. The liquid rocket engine multiple ignition system according to claim 1, characterized in that, The air chamber inlet integrates a first filling and venting valve and an air chamber pressure measuring port; The first filling and venting valve is used to connect to the gas filling fixture to perform nitrogen replacement or filling of the gas chamber; when the gas filling fixture is not connected, it depressurizes the gas chamber. The pressure measuring port of the air chamber is used to monitor the internal pressure of the air chamber and provide pressure feedback for the pressurization process.

3. The liquid rocket engine multiple ignition system according to claim 2, characterized in that, The liquid chamber outlet is integrated with a second filling and drain valve. The second filling and draining valve is used to connect to the liquid filling fixture; Nitrogen gas is introduced into the gas chamber through the first filling and draining valve, and the differential piston is pushed to one side of the liquid chamber. Ignition agent is then added to the liquid chamber through the second filling and draining valve.

4. The liquid rocket engine multiple ignition system according to claim 3, characterized in that, Both the first filling and draining valve and the second filling and draining valve are filling and draining valves that allow repeated opening and closing, and are used for repeated filling of the differential tank.

5. The liquid rocket engine multiple ignition system according to claim 1, characterized in that, The differential piston includes a large end and a small end; The large end is a disc-shaped head, and the small end is a piston rod; the piston rod and the disc-shaped head are an integral structure. The disc-shaped head is disposed on one side of the gas chamber; the piston rod is disposed on one side of the liquid chamber; The diameter of the disc-shaped head is larger than the diameter of the piston rod; The diameter of the mating surface formed between the disc-shaped head and the inner wall of the differential storage tank is larger than the diameter of the mating surface formed between the piston rod and the differential storage tank. The effective pressure-bearing area corresponding to the large end sealing surface is greater than the effective pressure-bearing area corresponding to the small end sealing surface. The pressure difference between the effective pressure-bearing areas corresponding to the large end sealing surface and the small end sealing surface is used to reduce the pressure increase requirement of the air chamber.

6. The liquid rocket engine multiple ignition system according to claim 5, characterized in that, The large end of the differential piston is sealed to the housing of the differential tank using an X-shaped rubber sealing ring, and the small end of the differential piston is sealed to the housing of the differential tank using a double O-ring rubber sealing ring.

7. The liquid rocket engine multiple ignition system according to claim 1, characterized in that, The outlet of the ignition agent check valve is connected to the thrust chamber and the ignition agent inlet of the gas generator.

8. A method for multiple ignition of a liquid rocket engine, characterized in that, Applied to the system according to any one of claims 1-7, the method comprises: Before engine operation: The gas chamber isolation valve, the liquid chamber isolation valve, and the ignition agent control valve are opened in sequence. High-pressure gas enters the gas chamber of the differential reservoir from the gas source inlet through the gas chamber isolation valve, pushing the differential piston to pressurize the ignition agent in the liquid chamber. The pressurized ignition agent enters the thrust chamber and the gas generator ignition agent inlet in sequence through the liquid chamber isolation valve, the ignition agent control valve, and the ignition agent check valve. After the engine starts: Sequentially close the gas chamber isolation valve, the liquid chamber isolation valve, and the ignition agent control valve; Determine whether re-ignition is required. If so, perform the ignition agent disposal procedure after the test or flight. Otherwise, terminate the mission. Determine whether ignition agent needs to be added. If so, proceed with the ignition agent addition process; otherwise, the system will remain in standby mode.

9. The method for multiple ignition of a liquid rocket engine according to claim 8, characterized in that, The ignition agent refueling process includes: Connect the first filling and draining valve and the second filling and draining valve to the gas filling fixture and the liquid filling fixture, respectively; By opening the first filling and drain valve and the second filling and drain valve respectively through the gas filling fixture and the liquid filling fixture, nitrogen is used to replace the gas chamber, liquid chamber and filling pipeline of the differential storage tank; After nitrogen purging is completed, nitrogen continues to flow through the first filling and draining valve to push the differential piston to one side of the liquid chamber. The liquid chamber is then evacuated through the second filling and draining valve. After evacuation is completed, ignition agent is added to the liquid chamber through the second filling and draining valve.

10. The method for multiple ignition of a liquid rocket engine according to claim 8 or 9, characterized in that, The ignition agent disposal process after the test run or flight includes: When the ignition agent pressurization gas source is depressurized, the gas chamber isolation valve is opened simultaneously to release the gas in the differential storage tank gas chamber; Nitrogen gas is introduced through the purging inlet, and the gas purges the ignition agent downstream of the ignition agent check valve through the second purging check valve. The ignition agent between the liquid chamber isolation valve and the ignition agent control valve is replaced and drained by introducing kerosene through the replacement inlet, and this process is repeated at least 3 times. Nitrogen gas is introduced through the displacement inlet to replace and drain the ignition agent and kerosene mixture between the liquid cavity isolation valve and the ignition agent control valve, and this process is repeated at least 5 times. Kerosene is introduced through the purge inlet to replace and drain the residual ignition agent downstream of the ignition agent check valve; Nitrogen gas is introduced through the purge inlet to replace and drain the ignition agent and kerosene mixture between the liquid chamber isolation valve and the ignition agent control valve, repeating this process at least 5 times. After the above steps are completed, repeat the ignition agent injection process.

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