Combined type pre-cooling system for ground ejection and pressurization coupled liquid rocket basic-stage engine

Abstract

The invention relates to a combined type pre-cooling system for a ground ejection and pressurization coupled liquid rocket basic-stage engine. The combined type pre-cooling system comprises a low-temperature propellant storage tank, a storage tank exhaust valve, an oxygen conveying pipeline, an oxygen backflow pipeline, an ejector, a pre-cooling discharge valve, an oxygen discharge pipeline, a pre-cooling discharge valve control pipeline, an ejection pressurization pipeline, an oxygen discharge pipeline and an exhaust valve control pipeline. The low-temperature propellant storage tank is communicated with the storage tank exhaust valve, and the bottom end of the low-temperature propellant storage tank is communicated with the oxygen conveying pipeline; the oxygen conveying pipeline is communicated with the oxygen conveying pipeline; the precooling discharge valve is communicated with the engine and the ejector; the ejector is communicated with the oxygen return pipeline; the oxygen return pipeline is communicated with the low-temperature propellant storage tank; the oxygen discharge pipeline is communicated with the pre-cooling discharge valve; the pre-cooling discharge valve control pipeline is communicated with the pre-cooling discharge valve control air port; the ejection pressurizing pipeline is communicated with the ejector; the oxygen exhaust pipeline is communicated with the storage tank exhaust valve; and the exhaust valve control pipeline is communicated with the storage box exhaust valve control air port. According to the application, random switching between circulation and discharge pre-cooling can be realized.

Description

Technical Field

[0001] The present application relates to the field of rocket technology, and in particular to a combined precooling system for a liquid rocket basic-stage engine coupled with ground ejection and pressurization. Background Art

[0002] Before the ignition and launch of a cryogenic liquid rocket, the engine must be in a state of "precooling" and "supercharging" before it can be ignited and launched. Usually, the liquid rocket engine is precooled through the ground support system combined with the onboard tank, and the onboard tank is pressurized to a certain pressure before launching, so that the engine has both the "precooling" and "supercharging" states. Before ignition, the cryogenic liquid rocket engine must precool the engine and its delivery system. Precooling refers to the use of propellants or other cryogenic media to cool the engine (mainly the turbopump) and its delivery system before ignition of an engine using cryogenic liquid propellants, so as to reach the temperature allowed for engine start-up and ensure the reliable operation of the turbopump. When the cryogenic propellant enters the engine pump at room temperature or overheated state, violent boiling will occur, generating a gas-liquid two-phase flow. If precooling is not done or precooling is insufficient, the temperature of the delivery pipeline and the engine will be higher than that of the liquid propellant, and the engine will not work properly. Because the propellant is heated and strongly vaporized in the delivery pipeline and engine flow channel, during the engine startup process, when the gas-liquid two-phase flow enters the pump, the droplets will impact the pump, which will cause pump cavitation, idling, stall, etc., causing pressure and flow fluctuations, oxygen-rich combustion, etc., resulting in extended engine start-up time and thrust climb time, and in severe cases, it may also cause complete failure of the start. The cavitation of the pump will affect the inducer profile, reduce pump efficiency and bring additional engine vibration, and in severe cases damage the turbo pump. Idling will cause the pump speed to be too high and the bearings to wear. In severe cases, it will cause the pump to collide and the oxygen pump may cause an explosion. Therefore, for cryogenic rocket engines that use cryogenic propellants such as liquid oxygen, it is essential to precool the engine and its delivery system before the engine is ignited. Before starting, key components such as the turbo pump need to be precooled to reduce the temperature of engine pumps and other components to a reasonable temperature range to avoid gas-liquid two-phase flow in the pump during the startup process. Rocket engine precooling is divided into immersion precooling, discharge precooling and circulation precooling according to the precooling method. For the rocket base stage, the engine must be precooled by ground precooling before ignition and takeoff. The most common precooling methods at home and abroad are discharge precooling or circulation precooling. As shown in Figure 1, discharge precooling is a way to precool the turbopump system by directly discharging cryogenic propellant. According to the driving force used, it can be divided into self-flow discharge precooling relying on its own liquid level height (such as Figure 1a ) and boost exhaust precooling relying on external pressure (as shown Figure 1bAs shown). Usually, a discharge precooling system is used. Generally, discharge precooling is carried out when the oxygen tank is filled. The oxygen tank filling and parking stages are all natural discharge precooling methods. The tank is pressurized through ground air supply a certain time before firing. On the one hand, it ensures that the engine inlet pressure meets the ignition conditions. On the other hand, pressurized discharge can increase the discharge flow of cryogenic propellant, greatly improve the precooling efficiency, and achieve rapid cooling of the engine. The system adopts cycle precooling. The precooling before firing generally includes two stages, namely the natural circulation precooling stage and the ejection circulation precooling stage. As shown Figure 2a As shown in the figure, circulating precooling is a way to achieve precooling requirements by setting a precooling pipeline after the pump as needed to form a precooling circulation loop. Natural circulating precooling is a way to form a circulating reflux through the density difference of cryogenic propellant caused by external heat leakage. Its flow characteristics are determined by external conditions and system pipeline characteristics, and it is a passive precooling method. Figure 2b As shown, the ejector circulation precooling sets a gas injection device (ejector) in the reflux pipeline, and forces a circulating flow in the system through external energy input, which is an active precooling method.

[0003] Although the above-mentioned discharge precooling system is simple and has high precooling efficiency, it has the following main problems: First, the discharge precooling starts when liquid oxygen is added and lasts until the engine is ignited. This period lasts at least about 6 hours, and a large amount of liquid oxygen will be discharged, so the liquid oxygen consumption is relatively large. Second, the pre-launch process using discharge precooling is relatively complicated. Since it involves the addition of cryogenic propellants, the process is very complicated. First, pressurize, then release the pressure for replenishment, and then pressurize for launch. Although the use of cyclic precooling greatly simplifies the pre-launch process and does not consume a large amount of cryogenic propellant, it does not affect the addition of propellant at all during the natural circulation precooling process. The tank is pre-pressurized before launch, but the precooling flow rate in the natural circulation precooling stage is small, and the precooling efficiency is low. Although the helium injection cycle before ignition can increase the precooling flow rate, the injection after the tank exhaust valve is closed is controlled by the tank pressure, because the injected injection gas will also enter the tank, causing the tank pressure to increase. After reaching the upper limit, the injection must be stopped. There is a risk that the engine cannot reach the "precooling good" state before ignition. Currently, liquid rockets use either exhaust pre-cooling or circulation pre-cooling. Therefore, no matter which pre-cooling method is used, a separate tank ground pressurization system is required to pressurize the tank on the ground before launch.

[0004] Therefore, how to propose a system that can both pre-cool the engine and pressurize the tank is a technical problem that technicians in this field urgently need to solve. Summary of the invention

[0005] The present application provides a combined precooling system for a liquid rocket basic-stage engine coupled with ground ejection and pressurization, comprising: a cryogenic propellant tank, a tank exhaust valve, an oxygen delivery pipeline, an oxygen return pipeline, an ejector, a precooling exhaust valve, an oxygen exhaust pipeline, a precooling exhaust valve control pipeline, an ejector pressurization pipeline, an oxygen exhaust pipeline, and an exhaust valve control pipeline; the top end of the cryogenic propellant tank is connected to the tank exhaust valve, and the bottom end of the cryogenic propellant tank is connected to the oxygen delivery pipeline; the oxygen delivery pipeline is connected to the oxygen delivery pipeline; the precooling exhaust valve is connected to the engine and the ejector respectively; the ejector is connected to the oxygen return pipeline; the oxygen return pipeline is connected to the bottom of the cryogenic propellant tank; the oxygen exhaust pipeline is connected to the precooling exhaust valve; the precooling exhaust valve control pipeline is connected to the precooling exhaust valve control air port; the ejector pressurization pipeline is connected to the ejector; the oxygen exhaust pipeline is connected to the tank exhaust valve; the exhaust valve control pipeline is connected to the tank exhaust valve control air port.

[0006] As described above, the combined precooling system for the liquid rocket basic-stage engine with ground-injection and pressurization coupling is further connected to a first orifice plate and a first solenoid valve on the oxygen discharge pipeline.

[0007] As described above, in the combined precooling system for the liquid rocket basic stage engine coupled with ground injection and pressurization, one end of the first orifice plate is connected to the oxygen exhaust pipeline through a 0s pull-out connector, and the other end of the first orifice plate is connected to the first solenoid valve.

[0008] As described above, the combined precooling system for the liquid rocket basic stage engine coupled with ground injection and pressurization, the precooling discharge valve control pipeline is also connected to a second solenoid valve, and the precooling discharge valve control pipeline is connected to the second solenoid valve through a 0s pull-out connector.

[0009] As described above, the combined precooling system for the liquid rocket basic stage engine with ground injection and pressurization coupled, the injection and pressurization pipeline is also connected to a one-way valve, a filter, a third orifice plate, a fourth orifice plate, a third solenoid valve and a fourth solenoid valve.

[0010] In the combined precooling system for the liquid rocket basic-stage engine with ground-based injection and pressurization coupled as described above, the injection and pressurization pipeline is connected to one end of the one-way valve, the other end of the one-way valve is connected to one end of the filter, the other end of the filter is connected to one end of the third orifice plate and the fourth orifice plate respectively through a 0s pull-out connector, the other end of the third orifice plate is connected to the third solenoid valve, and the other end of the fourth orifice plate is connected to the fourth solenoid valve.

[0011] As described above, the combined precooling system for the liquid rocket basic stage engine with ground-based injection and pressurization coupling has multiple one-way valves.

[0012] As described above, the combined precooling system for the liquid rocket basic-stage engine coupled with ground injection and pressurization also has a fifth orifice plate and a fifth solenoid valve connected to the oxygen exhaust pipeline.

[0013] In the combined precooling system of the liquid rocket basic stage engine coupled with ground injection and pressurization as described above, the oxygen discharge pipeline is connected to one end of the fifth orifice plate, and the other end of the fifth orifice plate is connected to the fifth solenoid valve.

[0014] As described above, the combined precooling system for the liquid rocket basic-stage engine with ground-injection and pressurization coupling is also connected to the top of the cryogenic propellant tank to perform pressure detection on the entire cryogenic propellant tank.

[0015] Compared with the above background technology, the present application can integrate two modes, namely, circulation precooling and discharge precooling, in one system, and couple the ground pressurization system. During most of the precooling time, the circulation precooling method is used to precool the engine to a certain temperature, reducing the large amount of propellant discharge consumption. Before ignition, the engine can be quickly cooled by short-term concentrated discharge to achieve a "good precooling" state. Before firing, it switches back to the circulation precooling mode, which not only maintains the "good precooling" state of the engine, but also quickly pressurizes the tank to achieve a "good pressurization" condition, and avoids the disadvantage of the more complicated discharge precooling process before firing. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0017] Figure 1a It is a schematic diagram of gravity discharge precooling in the prior art;

[0018] Figure 1b It is a schematic diagram of supercharging exhaust precooling in the prior art;

[0019] Figure 2a It is a schematic diagram of the gravity circulation precooling principle in the prior art;

[0020] Figure 2b It is a schematic diagram of the ejection cycle precooling principle in the prior art;

[0021] Figure 3 It is a structural schematic diagram of a combined precooling system for a liquid rocket basic-stage engine coupled with ground ejection and pressurization provided in an embodiment of the present application;

[0022] Figure 4 It is a flow chart of a method for precooling and pressurizing a liquid rocket before launch of a combined precooling system for a liquid rocket basic-stage engine based on ground-injection and pressurization coupling provided in an embodiment of the present application. DETAILED DESCRIPTION

[0023] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. In addition, spatial relationship terms such as "upper", "lower", "left", "right", "front", "rear", etc. are used to facilitate description to explain the positional relationship between two components. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and are not to be construed as limitations on the present invention.

[0024] The present application provides a novel liquid rocket engine precooling system, which can realize both engine precooling and tank pressurization. The precooling system can realize the switching between discharge precooling and circulation precooling. In the long period from filling to parking, the discharge consumption of cryogenic propellant is reduced by circulation precooling. A certain time before firing, the discharge precooling is switched to realize rapid cooling of the engine, and the circulation precooling mode is switched to before firing, thereby reducing the complexity of the pre-firing process. The system also has the tank ground pressurization function, and there is no need to set up a special tank ground pressurization system.

[0025] like Figure 3 As shown, the present application provides a combined precooling system for a liquid rocket basic-stage engine coupled with ground ejection and pressurization, comprising: a cryogenic propellant tank 310, a tank exhaust valve 320, an oxygen delivery pipeline 330, an oxygen reflux pipeline 340, an ejector 350, a precooling exhaust valve 360, an oxygen exhaust pipeline 370, a precooling exhaust valve control pipeline 380, an ejection pressurization pipeline 390, an oxygen exhaust pipeline 3100, and an exhaust valve control pipeline 3110.

[0026] The tank exhaust valve 320 is connected to the top of the cryogenic propellant tank 310 .

[0027] The bottom end of the cryogenic propellant tank 310 is connected to the oxygen delivery pipeline 330, the inlet of the oxygen delivery pipeline 330 is connected to the cryogenic propellant tank 310, and the outlet of the oxygen delivery pipeline 330 is connected to the outlet of the engine.

[0028] The oxygen delivery pipeline 330 is also in contact with a heater.

[0029] The outlet of the engine is also connected to the inlet of the precooling exhaust valve 360 ​​, the outlet of the precooling exhaust valve 360 ​​is connected to the inlet of the ejector 350 , and the outlet of the ejector 350 is connected to the inlet of the oxygen return line 340 .

[0030] The outlet of the oxygen reflux line 340 is in communication with the bottom of the cryogenic propellant tank 310 .

[0031] The outlet of the oxygen return line 340 extends into the cryogenic propellant tank 310 at a specified height.

[0032] The inlet of the oxygen discharge pipeline 370 is connected to the pre-cooling discharge valve 360 ​​, and the outlet of the oxygen discharge pipeline 370 is connected to the first orifice plate 371 and the first solenoid valve 372 .

[0033] One end of the first orifice plate 371 is connected to the outlet of the oxygen exhaust pipeline 370 through a 0s pull-out connector 373 , and the other end of the first orifice plate 371 is connected to the first solenoid valve 372 .

[0034] An inlet of the precooling exhaust valve control line 380 is communicated with the precooling exhaust valve 360 ​​, and an outlet of the precooling exhaust valve control line 380 is communicated with the second solenoid valve 381 .

[0035] The outlet of the precooling discharge valve control pipeline 380 is connected to the second solenoid valve 381 through a 0s pull-out connector.

[0036] The inlet of the ejection boost pipeline 390 is connected to the ejector 350 , and the ejection boost pipeline 390 is also connected to a one-way valve 391 , a filter 392 , a third orifice plate 393 , a fourth orifice plate 394 , a third solenoid valve 395 , and a fourth solenoid valve 396 .

[0037] The outlet of the ejection boost pipeline 390 is connected to one end of the one-way valve 391, the other end of the one-way valve 391 is connected to one end of the filter 392, the other end of the filter 392 is connected to one end of the third orifice plate 393 and the fourth orifice plate 394 through the 0s pull-out connector respectively, the other end of the third orifice plate 193 is connected to the third solenoid valve 395, and the other end of the fourth orifice plate 394 is connected to the fourth solenoid valve 396.

[0038] There are multiple one-way valves, preferably two.

[0039] The inlet of the oxygen exhaust pipeline 3100 is connected to the tank exhaust valve 320, and the outlet is connected to the fifth orifice plate 3101 and the fifth solenoid valve 3102 through a 0s pull-out connector.

[0040] The outlet of the oxygen discharge pipeline 3100 is connected to one end of the fifth orifice plate 3101 , and the other end of the fifth orifice plate 3101 is connected to the fifth solenoid valve 3102 .

[0041] The inlet of the exhaust valve control pipeline 3110 is connected to the tank exhaust valve 320 , and the outlet is connected to the sixth solenoid valve 3111 .

[0042] The outlet of the exhaust valve control pipeline 3110 is connected to the sixth solenoid valve 3111 through a 0s pull-out connector.

[0043] The second solenoid valve 382 and the sixth solenoid valve 3111 are two-position three-way solenoid valves, and the first, third to fifth solenoid valves are two-position two-way solenoid valves.

[0044] The top of the cryogenic propellant tank 310 is also connected to an oxygen tank pressure sensor 3120 , which can detect the pressure of the entire liquid oxygen tank 310 .

[0045] The opening and closing of the tank exhaust valve 320 is controlled by the sixth solenoid valve 3111. When the sixth solenoid valve 3111 is powered on, the tank exhaust valve 320 controls the gas supply and the tank exhaust valve is opened. When the sixth solenoid valve 3111 is powered off, the tank exhaust valve 320 controls the gas withdrawal and the tank exhaust valve 320 is closed.

[0046] The first solenoid valve 372 controls the air supply for the oxygen discharge pipeline 3110. When the pre-cooling mode is cyclic pre-cooling (i.e., the pre-cooling discharge valve 360 ​​is in the reflux state), the first solenoid valve 372 needs to be powered on to seal the oxygen discharge pipeline 3110 to prevent outside air from entering due to back suction due to low temperature, thereby avoiding condensation and frost on the pipeline.

[0047] The orifice plate connected to the first solenoid valve 372 has a flow limiting function to control the gas supply volume of the gas seal.

[0048] Since the precooling discharge valve 360 ​​is a two-position three-way valve, when the second solenoid valve 381 is powered on, the air supply of the air pipe 380 is controlled, and the precooling discharge valve 360 ​​is in the discharge state. The liquid oxygen transported into the engine through the oxygen delivery pipeline 330 enters the precooling discharge valve 360 ​​from the engine outlet, and then flows out from the oxygen discharge pipeline 370 for discharge.

[0049] When the second solenoid valve 381 is powered off, the control air pipe 380 is de-energized, the pre-cooling exhaust valve 360 ​​is in a reflux state, and the liquid oxygen transported into the engine through the oxygen transport pipeline 330 enters the pre-cooling exhaust valve 360 ​​from the engine outlet, and then flows back to the cryogenic propellant tank 310 from the oxygen reflux pipeline 340.

[0050] The third solenoid valve 395 and the fourth solenoid valve 396 are used to control the ejection cycle and the tank pressurization. When the third solenoid valve 395 or the fourth solenoid valve 396 is powered on, the ground helium passes through the third solenoid valve 395 (or the fourth solenoid valve 396), the third orifice plate 393 (or the fourth orifice plate 394), the gas filter 392 and the one-way valve 391 to enter the ejector 350 for precooling the ejection cycle. When the tank exhaust valve 320 is in the closed position, the ejection gas enters the cryogenic propellant tank 310 and plays a role of pressurization.

[0051] The third orifice plate 393 and the fourth orifice plate 394 have different sizes and are used to adjust different injection and pressurization processes to adapt to the processes at different stages.

[0052] The fifth solenoid valve 3102 controls the air supply for the oxygen discharge pipeline 3110. When the tank exhaust valve 320 is closed, the fifth solenoid valve 3102 needs to be powered on to seal the oxygen discharge pipeline 3110 to prevent the outside air from entering due to back suction due to low temperature, thereby avoiding condensation and frost in the pipeline.

[0053] The orifice plate connected to the fifth solenoid valve 3102 has a flow limiting function to control the gas supply to the gas seal.

[0054] When the cryogenic propellant is filled, the engine precooling begins, and the cryogenic propellant enters the engine through the oxygen delivery pipeline 330 and enters the precooling discharge valve 360 ​​from the engine outlet. The flow direction of the propellant is determined according to the state of the precooling discharge valve 360.

[0055] When the cryogenic propellant is being filled, the sixth solenoid valve 3111 is powered on, the tank exhaust valve 320 is opened, and the engine precooling begins at the same time. In this stage, the natural circulation precooling method is adopted, the second solenoid valve 382 is powered off, and the precooling discharge valve 360 ​​is in a reflux state, that is, the propellant enters the engine from the tank 310 through the oxygen delivery pipeline 330, and after only precooling the engine, it returns to the cryogenic propellant tank 310 through the precooling discharge valve 360 ​​and the ejector 350 through the oxygen return pipeline 340. The oxygen return pipeline 340 extends into the tank to a certain height. The propellant flow driving force at this stage is mainly realized by the temperature difference. Generally, the insulation method of the oxygen delivery pipe 330 is much higher than that of the oxygen return pipeline 340, resulting in the cryogenic propellant density in the delivery pipe being greater than the propellant density in the return pipe, and the difference in the reflux driving pressure difference is achieved to realize the natural reflux precooling of the engine.

[0056] If the third solenoid valve 395 or the fourth solenoid valve 396 is opened in the natural reflux precooling state, the ejector cycle precooling is started, and the momentum exchange between gas and liquid occurs by injecting high-pressure and high-speed ejector gas into the ejector 350, so that the gas carries the liquid to flow, thereby realizing fast cycle precooling. When the tank exhaust valve 320 is closed, the ejector gas simultaneously enters the cryogenic propellant tank 310, realizing the pressurization function of the tank.

[0057] Embodiment 2

[0058] like Figure 4 As shown, a liquid rocket pre-launch pre-cooling and pressurizing method is proposed based on the ground-injection and pressurizing coupled liquid rocket basic-stage engine combined pre-cooling system provided in Example 1, which specifically includes the following steps:

[0059] Step S1: Perform natural circulation precooling stage.

[0060] The filling of the basic stage (i.e. the first stage) of a liquid rocket generally includes three processes: filling, parking and adding supercooled propellant with conventional cryogenic propellant. At the beginning of filling, engine precooling starts at the same time. As the filling progresses, natural circulation precooling is gradually established, and the natural circulation precooling mode is maintained from filling to T1 stage.

[0061] At the beginning of the natural circulation precooling stage, the sixth solenoid valve is energized, opening the tank exhaust valve, and the engine precooling begins at the same time. The second solenoid valve is de-energized, and the precooling discharge valve is in a reflux state. The propellant enters the engine from the tank through the oxygen delivery pipeline. After only precooling the engine, it passes through the precooling discharge valve and the ejector through the oxygen reflux pipeline and returns to the cryogenic propellant tank.

[0062] Step S2: Perform the ejection cycle precooling stage.

[0063] In the stage from T2 (close to the end of supercooling supplement) to T3, in order to further improve the engine precooling efficiency, the ground injection air supply is turned on. In this stage, the solenoid valve 395 or 396 is opened to further reduce the engine temperature.

[0064] In the ejector cycle precooling state, the third solenoid valve (or the fourth solenoid valve) is opened to power on the third solenoid valve (or the fourth solenoid valve), and the ground helium passes through the third solenoid valve (or the fourth solenoid valve), the third orifice plate (or the fourth orifice plate), the gas filter and the one-way valve in sequence to enter the ejector for ejector cycle precooling.

[0065] Step S3: Perform the boost discharge precooling stage.

[0066] During the T3-T4 stage, the tank exhaust valve 320 is closed, and the second solenoid valve 381 is opened to switch the precooling mode to the exhaust precooling. At the same time, the solenoid valve 395 or 396 is opened to pressurize the tank to achieve pressurized exhaust precooling, further rapidly reducing the engine temperature to a "good precooling" state.

[0067] When the second solenoid valve 381 is powered on, the precooling discharge valve controls the air supply of the air pipe 330, and the precooling discharge valve 360 ​​is in the discharge state. The liquid oxygen transported into the engine through the oxygen delivery pipeline 330 enters the precooling discharge valve 360 ​​from the engine outlet, and then flows out from the oxygen discharge pipeline 370 for discharge.

[0068] When the second solenoid valve 381 is powered off, the precooling discharge valve controls the air pipe 330 to be evacuated, and the precooling discharge valve 360 ​​is in a reflux state. The liquid oxygen transported into the engine through the oxygen transport pipeline 330 enters the precooling discharge valve 360 ​​from the engine outlet, and then flows back to the cryogenic propellant tank 310 from the oxygen reflux pipeline 340.

[0069] It should be noted at this stage that the opening and closing of the third solenoid valve 395 and the fourth solenoid valve 396 are controlled by the tank pressure (see the following description for details). If the cryogenic propellant tank 310 is discharged to the target liquid level, this stage must also be ended to stop the discharge of the propellant.

[0070] Step S4: perform the injection pressurization precooling stage.

[0071] In the T4-0s stage, the system switches back to the ejection pressurization precooling stage. When the ejection cycle precooling is performed, the tank exhaust valve is closed, and the third solenoid valve 395 and the fourth solenoid valve 396 are opened at the same time, and the ejection gas enters the cryogenic propellant tank for pressurization. On the one hand, the ejection cycle precooling is maintained to keep the engine in a "good precooling" state, and on the other hand, the system is quickly pressurized to reach a "good pressurization" state, and the conditions for ignition and launch are met.

[0072] Specifically, by injecting high-pressure and high-speed ejector gas into the ejector 350, momentum exchange occurs between gas and liquid, and gas carries liquid to flow, thereby realizing fast cycle precooling. When the tank exhaust valve 320 is closed, the ejector gas simultaneously enters the cryogenic propellant tank 310, realizing the pressurization function of the tank.

[0073] During the injection boost cycle phase after the tank exhaust valve 320 is closed, the third solenoid valve 395 and the fourth solenoid valve 396 are controlled by the tank pressure at the same time. Specifically, different upper and lower pressure limits are set for the third solenoid valve 395 and the fourth solenoid valve 396 in the control system, as shown in mark 1.

[0074] Table 1

[0075]

[0076] The pressure value of the tank pressure sensor is p. The controller compares the real-time tank pressure p obtained by the pressure sensor with the preset upper and lower control limits:

[0077] For the third solenoid valve 395: When p <p l_3时，第三电磁阀395打开；当p>When Pu_3, the third solenoid valve 395 is closed; when P l_3≤p≤Pu_3, the third solenoid valve 395 maintains the current state.

[0078] For the fourth solenoid valve 396: When p <p l_4时，第四电磁阀396打开；当p>When Pu_4, the fourth solenoid valve 396 is closed; when P l_4≤p≤Pu_4, the fourth solenoid valve 396 maintains the current state.

[0079] Beneficial effects of this application:

[0080] The present application can integrate the two modes of circulation precooling and discharge precooling in one system, and couple the ground pressurization system. The circulation precooling method is used for most of the precooling time to precool the engine to a certain temperature, reducing the large amount of propellant discharge consumption, and can quickly cool the engine through short-term concentrated discharge before ignition to achieve a "good precooling" state. Before firing, it switches back to the circulation precooling mode, which not only maintains the "good precooling" state of the engine, but also quickly pressurizes the tank to achieve a "good pressurization" condition, and also avoids the disadvantage of the more complicated discharge precooling process before firing.

[0081] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0082] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A combined precooling system for a liquid rocket basic-stage engine coupled with ground-based ejection and pressurization, characterized in that: include: Cryogenic propellant tank, tank exhaust valve, oxygen delivery pipeline, oxygen reflux pipeline, ejector, precooling discharge valve, oxygen discharge pipeline, precooling discharge valve control pipeline, ejector pressurization pipeline, oxygen exhaust pipeline, exhaust valve control pipeline; The top end of the cryogenic propellant tank is connected to the tank exhaust valve, and the bottom end of the cryogenic propellant tank is connected to the oxygen delivery pipeline; the oxygen delivery pipeline is connected to the oxygen delivery pipeline; the precooling exhaust valve is connected to the engine and the ejector respectively; the ejector is connected to the oxygen return pipeline; the oxygen return pipeline is connected to the bottom of the cryogenic propellant tank; the oxygen exhaust pipeline is connected to the precooling exhaust valve; the precooling exhaust valve control pipeline is connected to the precooling exhaust valve control air port; the ejector boost pipeline is connected to the ejector; the oxygen exhaust pipeline is connected to the tank exhaust valve; the exhaust valve control pipeline is connected to the tank exhaust valve control air port.

2. The combined precooling system for the liquid rocket basic-stage engine coupled with ground-launching and pressurization as claimed in claim 1 is characterized in that: The oxygen discharge pipeline is also connected to a first orifice plate and a first solenoid valve. One end of the first orifice plate is connected to the oxygen exhaust pipeline through a 0s pull-out connector, and the other end of the first orifice plate is connected to the first solenoid valve.

3. The novel liquid rocket supercharging system combining self-generated supercharging and heated supercharging as claimed in claim 1 is characterized in that: The precooling discharge valve control pipeline is also connected to a second solenoid valve, and the precooling discharge valve control pipeline is connected to the second solenoid valve through a 0s pull-out connector.

4. The novel liquid rocket supercharging system combining self-generated supercharging and heated supercharging as claimed in claim 1 is characterized in that: The ejection booster pipeline is also connected with a one-way valve, a filter, a third orifice plate, a fourth orifice plate, a third solenoid valve and a fourth solenoid valve; The ejection boost pipeline is connected to one end of the one-way valve, the other end of the one-way valve is connected to one end of the filter, the other end of the filter is connected to one end of the third orifice plate and the fourth orifice plate through a 0s pull-out connector, the other end of the third orifice plate is connected to the third solenoid valve, and the other end of the fourth orifice plate is connected to the fourth solenoid valve.

5. The novel liquid rocket supercharging system combining autogenous supercharging and heating supercharging as claimed in claim 1 is characterized in that: The oxygen exhaust pipeline is also connected to a fifth orifice plate and a fifth solenoid valve; The oxygen discharge pipeline is communicated with one end of the fifth orifice plate, and the other end of the fifth orifice plate is communicated with the fifth solenoid valve.

6. A method for precooling and pressurizing a liquid rocket before launch based on a combined precooling system for a liquid rocket basic-stage engine coupled with ground ejection and pressurization as described in any one of claims 1 to 5, characterized in that: The following steps are involved: Carry out natural circulation precooling stage; Carry out the precooling stage of the ejection cycle; Performing a boost discharge precooling stage; Carry out the injection boost pre-cooling stage.

7. The method for precooling and pressurizing a liquid rocket before launch according to claim 5, characterized in that: The natural circulation precooling stage includes: the sixth solenoid valve is powered on, the tank exhaust valve is opened, and the engine precooling starts at the same time, the second solenoid valve is powered off, the precooling exhaust valve is in a reflux state, and the propellant enters the engine from the tank through the oxygen delivery pipeline. After only precooling the engine, it returns to the cryogenic propellant tank through the precooling exhaust valve and the ejector through the oxygen reflux pipeline.

8. The method for precooling and pressurizing a liquid rocket before launch as claimed in claim 6, characterized in that: The ejector cycle precooling stage includes opening the third solenoid valve under the natural reflux precooling state, powering on the third solenoid valve, and allowing ground helium to enter the ejector through the third solenoid valve, the third orifice plate, the gas filter and the one-way valve in sequence to perform ejector cycle precooling.

9. The method for precooling and pressurizing a liquid rocket before launch according to claim 7, characterized in that: The pressurized discharge precooling stage includes closing the tank exhaust valve and keeping the second solenoid valve open. When the second solenoid valve is powered on, the precooling discharge valve controls the air supply of the air pipe, the precooling discharge valve is in a discharge state, and liquid oxygen enters the precooling discharge valve from the engine outlet and then flows out from the oxygen discharge pipeline for discharge. When the second solenoid valve is powered off, the precooling discharge valve controls the air pipe to evacuate air, the precooling discharge valve is in a reflux state, liquid oxygen enters the precooling discharge valve from the engine outlet, and then flows back to the cryogenic propellant tank from the oxygen reflux pipeline.

10. The method for precooling and pressurizing a liquid rocket before launch according to claim 7, characterized in that: The ejection pressurization and discharge stage includes closing the tank exhaust valve during ejection cycle precooling, and simultaneously opening the third solenoid valve and the fourth solenoid valve, so that the ejection gas enters the cryogenic propellant tank for pressurization.

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