Ground test hydrogen-oxygen rocket engine mixing ratio control system

Abstract

The invention discloses a ground test hydrogen-oxygen rocket engine mixing ratio control system which comprises a liquid hydrogen storage tank, a hydrogen cavitation pipe, a liquid oxygen storage tank, an oxygen cavitation pipe, a combustion device, a gas nozzle, a liquid hydrogen storage tank pressure control system and a liquid oxygen storage tank pressure control system. Wherein the liquid hydrogen storage tank is connected with the liquid hydrogen storage tank pressure control system through a pipeline; the liquid oxygen storage tank is connected with the liquid oxygen storage tank pressure control system through a pipeline; the liquid hydrogen storage tank is connected with an inlet of the hydrogen cavitation pipe through a pipeline, and an outlet of the hydrogen cavitation pipe is connected with a hydrogen inlet of the combustion device through a pipeline; the liquid oxygen storage box is connected with an inlet of the oxygen cavitation pipe through a pipeline, and an outlet of the oxygen cavitation pipe is connected with an oxygen inlet of the combustion device through a pipeline. An outlet of the combustion device is connected with an inlet of the gas nozzle through a pipeline, and an outlet of the gas nozzle directly discharges gas outwards. The purposes of controlling the mixing ratio and prolonging the test duration are achieved, meanwhile, the safety of the engine and the test device is guaranteed, and the test cost is reduced.

Description

Technical Field

[0001] This invention belongs to the field of rocket engine technology, and in particular relates to a ground-tested hydrogen-oxygen rocket engine mixture ratio control system. Background Technology

[0002] Rocket engines provide power for launch vehicle flight and are one of the core components. With the rapid development of aerospace technology, launch vehicles face increasingly diverse and complex missions, requiring engines to have lower costs and higher reliability.

[0003] In traditional hydrogen-oxygen rocket engine testing, engine parameters are determined before the test and cannot be adjusted during the test. When test parameters exceed the engine's design requirements, the test must be terminated to ensure the safety of the engine and test equipment. This results in problems such as wasting propellant, increasing the number of tests, shortening test duration, and incomplete evaluation. Summary of the Invention

[0004] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a ground test hydrogen-oxygen rocket engine mixture ratio control system to achieve the purpose of mixture ratio control and test duration extension, while ensuring the safety of the engine and test equipment and reducing test costs.

[0005] The objective of this invention is achieved through the following technical solution: a ground-based experimental hydrogen-oxygen rocket engine mixture ratio control system, comprising: a liquid hydrogen tank, a hydrogen cavitation pipe, a liquid oxygen tank, an oxygen cavitation pipe, a combustion device, a gas nozzle, a liquid hydrogen tank pressure control system, and a liquid oxygen tank pressure control system; wherein, the liquid hydrogen tank and the liquid hydrogen tank pressure control system are connected by pipelines; the liquid oxygen tank and the liquid oxygen tank pressure control system are connected by pipelines; the liquid hydrogen tank is connected to the inlet of the hydrogen cavitation pipe by a pipeline, and the outlet of the hydrogen cavitation pipe is connected to the hydrogen inlet of the combustion device by a pipeline; the liquid oxygen tank is connected to the inlet of the oxygen cavitation pipe by a pipeline, and the outlet of the oxygen cavitation pipe is connected to the oxygen inlet of the combustion device by a pipeline; the outlet of the combustion device is connected to the inlet of the gas nozzle by a pipeline, and the outlet of the gas nozzle directly discharges to the outside.

[0006] In the aforementioned ground-tested hydrogen-oxygen rocket engine mixture control system, the pressure of the liquid hydrogen tank is controlled by the liquid hydrogen tank pressure control system. When the liquid hydrogen tank pressure control system injects hydrogen into the liquid hydrogen tank through pipelines, the pressure of the liquid hydrogen tank increases; when liquid hydrogen is consumed or the liquid hydrogen tank pressure control system removes hydrogen from the liquid hydrogen tank through pipelines, the pressure of the liquid hydrogen tank decreases. Similarly, the pressure of the liquid oxygen tank is controlled by the liquid oxygen tank pressure control system. When the liquid oxygen tank pressure control system injects nitrogen into the liquid oxygen tank through pipelines, the pressure of the liquid oxygen tank increases; when liquid hydrogen is consumed or the liquid oxygen tank pressure control system removes nitrogen from the liquid oxygen tank through pipelines, the pressure of the liquid oxygen tank decreases.

[0007] In the above-mentioned ground test hydrogen-oxygen rocket engine mixture ratio control system, the liquid hydrogen tank pressure control system uses PID to control the pressure of the liquid hydrogen tank, and the liquid oxygen tank pressure control system uses PID to control the pressure of the liquid oxygen tank.

[0008] In the above-mentioned ground test hydrogen-oxygen rocket engine mixture ratio control system, the PID control is obtained through the following formula: ; ; in, The target pressure of the storage tank; This refers to the real-time pressure of the storage tank. This is the real-time pressure deviation. For gas flow control in pressure control systems; This is the proportional gain value. This is the integral gain value; This is the differential gain value. For a moment, for Time period This is the cumulative amount of real-time pressure deviation.

[0009] In the aforementioned ground-tested hydrogen-oxygen rocket engine mixture control system, liquid hydrogen enters the hydrogen cavitation pipe after being pressurized by the liquid hydrogen storage tank, and the engine hydrogen flow rate is controlled by adjusting the pressure of the liquid hydrogen storage tank.

[0010] In the above-mentioned ground-tested hydrogen-oxygen rocket engine mixture control system, the engine hydrogen flow rate is obtained using the following formula: ; in, For engine hydrogen flow rate; The equivalent area of ​​the hydrogen cavitation tube; The pressure of the liquid hydrogen storage tank. The density of liquid hydrogen in front of the hydrogen cavitation tube; This is the saturated vapor pressure of liquid hydrogen.

[0011] In the above-mentioned ground test hydrogen-oxygen rocket engine mixture ratio control system, liquid oxygen enters the oxygen cavitation pipe after being pressurized by the liquid oxygen tank, and the oxygen flow rate of the engine is controlled by adjusting the pressure of the oxygen tank.

[0012] In the above-mentioned ground-tested hydrogen-oxygen rocket engine mixture control system, the engine oxygen flow rate is obtained using the following formula: ; in, For engine oxygen flow; The equivalent area of ​​the oxygen cavitation tube; Liquid oxygen tank pressure; This is the local saturated vapor pressure of liquid oxygen; The density of liquid oxygen in front of the oxygen cavitation tube.

[0013] In the aforementioned ground-tested hydrogen-oxygen rocket engine mixture control system, liquid hydrogen enters the combustion device after its flow rate is controlled by a hydrogen cavitation pipe, and liquid oxygen enters the combustion device after its flow rate is controlled by an oxygen cavitation pipe. The liquid hydrogen and liquid oxygen are burned in the combustion device after their flow rates are controlled, and the chamber pressure of the combustion device is controlled by the gas nozzle.

[0014] In the above-mentioned ground-tested hydrogen-oxygen rocket engine mixture control system, the engine mixture ratio is obtained by the following formula: ; Engine flow rate is obtained using the following formula: ; in, The engine air-fuel mixture ratio. For engine oxygen flow, For engine hydrogen flow rate, For engine flow rate, The equivalent area of ​​the gas nozzle. The combustion chamber pressure, The temperature of the combustion device. Let be the gas constant of the fuel gas. This is the specific heat ratio of the gas.

[0015] Compared with the prior art, the present invention has the following advantages: (1) This invention enhances the testing capabilities of engines that do not have adjustment capabilities, enabling multiple test conditions to be assessed in a single test; (2) The present invention improves the self-feedback control system of the storage tank pressure, realizes the safe adjustment of the pressure of liquid hydrogen and liquid oxygen storage tanks over a wide range, and realizes the adaptive adjustment of the storage tank pressure to the changes in storage tank temperature; (3) The present invention controls the engine mixture ratio to ensure that the test parameters are within the range of engine design requirements during the test, to ensure the test is carried out safely, and to avoid damage to the engine and test equipment; (4) This invention improves testing capabilities, extends testing time, increases assessment difficulty, fully assesses engine working adaptability, improves engine reliability, and reduces testing costs. Attached Figure Description

[0016] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings: Figure 1 This is a schematic diagram of the ground-based hydrogen-oxygen rocket engine mixture ratio control system provided in an embodiment of the present invention. Detailed Implementation

[0017] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0018] In order to achieve precise control of engine flow and air-fuel ratio during the test, thereby extending test time, reducing the number of tests, stabilizing engine parameters, improving test safety, enhancing test evaluation capabilities, and ultimately reducing test costs, improving test reliability, increasing engine test adaptability, and enhancing engine reliability.

[0019] Figure 1 This is a schematic diagram of the ground-based hydrogen-oxygen rocket engine mixture ratio control system provided in an embodiment of the present invention. Figure 1As shown, the ground-tested hydrogen-oxygen rocket engine mixture control system includes: a liquid hydrogen tank 1, a hydrogen cavitation pipe 2, a liquid oxygen tank 3, an oxygen cavitation pipe 4, a combustion device 5, a gas nozzle 6, a liquid hydrogen tank pressure control system 7, and a liquid oxygen tank pressure control system 8. The liquid hydrogen tank 1 is connected to the liquid hydrogen tank pressure control system 7 via a pipeline; the liquid oxygen tank 3 is connected to the liquid oxygen tank pressure control system 8 via a pipeline; the inlet of the liquid hydrogen tank 1 is connected to the hydrogen cavitation pipe 2 via a pipeline, and the outlet of the hydrogen cavitation pipe 2 is connected to the hydrogen inlet of the combustion device 5 via a pipeline; the inlet of the liquid oxygen tank 3 is connected to the oxygen cavitation pipe 4 via a pipeline, and the outlet of the oxygen cavitation pipe 3 is connected to the oxygen inlet of the combustion device 5 via a pipeline; the outlet of the combustion device 5 is connected to the inlet of the gas nozzle 6 via a pipeline, and the outlet of the gas nozzle 6 directly discharges gas.

[0020] The pressure of liquid hydrogen storage tank 1 is controlled by liquid hydrogen storage tank pressure control system 7. When liquid hydrogen storage tank pressure control system 7 injects hydrogen into liquid hydrogen storage tank 1 through pipeline, the pressure of liquid hydrogen storage tank 1 increases. When liquid hydrogen is consumed or liquid hydrogen storage tank pressure control system 7 removes hydrogen from liquid hydrogen storage tank 1 through pipeline, the pressure of liquid hydrogen storage tank 1 decreases.

[0021] The pressure of liquid oxygen storage tank 3 is controlled by liquid oxygen storage tank pressure control system 8. When liquid oxygen storage tank pressure control system 8 injects nitrogen into liquid oxygen storage tank 3 through pipeline, the pressure of liquid oxygen storage tank 3 increases. When liquid hydrogen is consumed or liquid oxygen storage tank pressure control system 8 removes nitrogen from liquid oxygen storage tank 3 through pipeline, the pressure of liquid oxygen storage tank 3 decreases.

[0022] The liquid hydrogen storage tank pressure control system 7 uses PID control to control the pressure of liquid hydrogen storage tank 1, and the liquid oxygen storage tank pressure control system 8 uses PID control to control the pressure of liquid oxygen storage tank 3.

[0023] PID control is obtained through the following formula: ; ; in, The target pressure of the storage tank; This refers to the real-time pressure of the storage tank. This is the real-time pressure deviation. For gas flow control in pressure control systems; This is the proportional gain value. This is the integral gain value; This is the differential gain value. For a moment, for Time period This is the cumulative amount of real-time pressure deviation.

[0024] Liquid hydrogen enters hydrogen cavitation pipe 2 after being pressurized by liquid hydrogen storage tank 1. The hydrogen flow rate of the engine is controlled by adjusting the pressure of liquid hydrogen storage tank.

[0025] The engine hydrogen flow rate is obtained using the following formula: ; in, For engine hydrogen flow rate; The equivalent area of ​​the hydrogen cavitation tube; The pressure of the liquid hydrogen storage tank. The density of liquid hydrogen in front of the hydrogen cavitation tube; This is the saturated vapor pressure of liquid hydrogen.

[0026] Liquid oxygen enters the oxygen cavitation pipe 4 after being pressurized by the liquid oxygen storage tank 3. The oxygen flow rate of the engine is controlled by adjusting the pressure of the oxygen storage tank.

[0027] Engine oxygen flow rate is obtained using the following formula: ; in, For engine oxygen flow; The equivalent area of ​​the oxygen cavitation tube; Liquid oxygen tank pressure; This is the local saturated vapor pressure of liquid oxygen; The density of liquid oxygen in front of the oxygen cavitation tube.

[0028] Liquid hydrogen enters combustion device 5 after its flow rate is controlled by a hydrogen cavitation pipe, and liquid oxygen enters combustion device 5 after its flow rate is controlled by an oxygen cavitation pipe. The liquid hydrogen and liquid oxygen are burned in combustion device 5 after their flow rates are controlled. The chamber pressure of combustion device 5 is controlled by gas nozzle 6.

[0029] The engine air-fuel ratio is obtained using the following formula: ; Engine flow rate is obtained using the following formula: ; in, The engine air-fuel mixture ratio. For engine oxygen flow, For engine hydrogen flow rate, For engine flow rate, The equivalent area of ​​the gas nozzle. The combustion chamber pressure, The temperature of the combustion device. Let be the gas constant of the fuel gas. This is the specific heat ratio of the gas.

[0030] The pressure control of liquid hydrogen and its storage tank both employ a PID control scheme, the principle of which is as follows: (1) (2) in, P set The target pressure of the storage tank; P (t) This refers to the real-time pressure of the storage tank. e (t) This is the real-time pressure deviation. u (t) For gas flow control in pressure control systems; K p This is the proportional gain value. K i This is the integral gain value; K d These are the differential gain values, and each gain value is confirmed through simulation and tank pressurization debugging.

[0031] Liquid hydrogen enters hydrogen cavitation pipe 2 after being pressurized in liquid hydrogen storage tank 1. The hydrogen flow rate in the engine is controlled by adjusting the pressure of the hydrogen storage tank. The hydrogen flow rate is calculated by the following formula: (3) in, qm f For engine hydrogen flow rate; uF f The equivalent area of ​​the hydrogen cavitation tube; P if Liquid hydrogen storage tank pressure, T if Liquid hydrogen storage tank temperature; r f The density of liquid hydrogen in front of the hydrogen cavitation tube is given by... P if Liquid hydrogen storage tank pressure and T if The temperature of the liquid hydrogen storage tank was confirmed by checking the standard property database. P sf For the saturated vapor pressure of liquid hydrogen, use T if The temperature of the liquid hydrogen storage tank can be confirmed by checking the standard property database.

[0032] Liquid oxygen enters the oxygen cavitation pipe (4) after being pressurized by the liquid oxygen storage tank (3). The oxygen flow rate of the engine is controlled by adjusting the pressure of the oxygen storage tank. The hydrogen flow rate is calculated by the following formula: (4) in, qm o For engine oxygen flow; uF o The equivalent area of ​​the oxygen cavitation tube; P io Liquid oxygen tank pressure,T io Liquid oxygen storage tank temperature; r o The density of liquid oxygen before the oxygen cavitation tube is given by... P io Liquid oxygen tank pressure and T io The temperature of the liquid oxygen storage tank was confirmed by checking the standard property database. The local saturated vapor pressure of liquid oxygen is given by... T io The temperature of the liquid oxygen storage tank was confirmed by checking the standard property database.

[0033] Based on the above flow formulas (3) and (4), the following relationship is defined: (5) (6) in, qm For engine flow rate; r This refers to the engine's air-fuel mixture ratio.

[0034] Liquid hydrogen and liquid oxygen, after their flow rates are controlled by the cavitation pipe, enter combustion device 5 for combustion. The chamber pressure of combustion device 5 is controlled by the gas nozzle 6. (6) (7) in, uF c The equivalent area of ​​the gas nozzle. P c The combustion chamber pressure, T c The temperature of the combustion device. R c Let be the gas constant of the fuel gas. k This is the specific heat ratio of the gas.

[0035] Based on the above principles and test system, after selecting the equivalent area of ​​hydrogen cavitation pipe 2, oxygen cavitation pipe 4 and gas nozzle 6, the engine flow rate, mixture ratio and other parameters are determined only by the pressure and temperature of liquid hydrogen storage tank 1 and liquid oxygen storage tank 3.

[0036] Based on engine development experience, it is necessary to determine the engine flow rate and mixing ratio before testing. During the test planning stage, multiple pressures of liquid hydrogen tank 1 and liquid oxygen tank 3 can be set according to development needs to achieve the test of multiple engine operating conditions in one test.

[0037] During the experiment, the tank pressure was increased by ambient temperature gas. As the experiment duration increased, the temperatures of liquid hydrogen tank 1 and liquid oxygen tank 3 gradually rose. When the temperature increased, the density of liquid hydrogen in front of the hydrogen cavitation pipe was [value missing]. rf Oxygen cavitation pipe inlet liquid oxygen density r o The saturated vapor pressure of liquid hydrogen will decrease accordingly. P sf saturated vapor pressure of liquid oxygen P so It will decrease accordingly. According to formulas (3) and (4), the engine hydrogen flow rate qm f Engine oxygen flow qm o All of these will decrease, causing changes in engine flow and mixture ratio, deviating from test requirements, failing to achieve the assessment objectives, and increasing test risks. Therefore, test time was previously limited.

[0038] According to the new test method, the tank pressure control system is added to monitor the tank temperature. As the temperature of liquid hydrogen tank 1 and liquid oxygen tank 3 changes, the pressure of liquid hydrogen tank 1 and liquid oxygen tank 3 is adaptively adjusted to achieve the purpose of controlling the engine flow rate and mixture ratio.

[0039] This embodiment can dynamically adjust the tank pressure to control the engine flow rate and mixture ratio, so the test time will no longer be limited by the tank temperature, thereby extending the test time.

[0040] In summary, this embodiment increases the adaptability of engine testing, extends the testing time, increases the difficulty of assessment, fully assesses the engine's operational adaptability, improves engine reliability, and reduces testing costs.

[0041] Prior to the test in this embodiment, the flow rates of liquid hydrogen and liquid oxygen in the engine were determined according to the engine test requirements. During the test, the temperature of the liquid hydrogen gradually increased, causing the flow rate of liquid hydrogen in the engine to decrease and the mixture ratio to increase. When the mixture ratio reached the engine design limit, the pressure of the liquid oxygen tank was reduced and adjusted to lower the engine mixture ratio back to the design requirements, thereby extending the test time.

[0042] This embodiment enhances the testing capabilities of engines that lack inherent adjustment capabilities, enabling the assessment of multiple test conditions in a single test. It also improves the tank pressure self-feedback control system, achieving safe, wide-range adjustment of liquid hydrogen and liquid oxygen tank pressures and adaptive adjustment of tank pressure to temperature changes. Furthermore, this embodiment controls the engine's mixture ratio, ensuring that test parameters remain within the engine's design requirements during the test, guaranteeing safe testing and preventing damage to the engine and testing equipment. Finally, this embodiment improves testing capabilities, extends test time, increases the difficulty of assessment, fully evaluates engine adaptability, enhances engine reliability, and reduces testing costs.

[0043] 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 ground-based test hydrogen-oxygen rocket engine mixture ratio control system, characterized in that... include: Liquid hydrogen storage tank (1), hydrogen cavitation pipe (2), liquid oxygen storage tank (3), oxygen cavitation pipe (4), combustion device (5), gas nozzle (6), liquid hydrogen storage tank pressure control system (7), and liquid oxygen storage tank pressure control system (8); among which, The liquid hydrogen storage tank (1) is connected to the liquid hydrogen storage tank pressure control system (7) via a pipeline; The liquid oxygen storage tank (3) is connected to the liquid oxygen storage tank pressure control system (8) via a pipeline; The liquid hydrogen storage tank (1) is connected to the inlet of the hydrogen cavitation pipe (2) through a pipeline, and the outlet of the hydrogen cavitation pipe (2) is connected to the hydrogen inlet of the combustion device (5) through a pipeline. The liquid oxygen storage tank (3) is connected to the inlet of the oxygen cavitation pipe (4) through a pipeline, and the outlet of the oxygen cavitation pipe (3) is connected to the oxygen inlet of the combustion device (5) through a pipeline. The outlet of the combustion device (5) is connected to the inlet of the gas nozzle (6) through a pipeline, and the outlet of the gas nozzle (6) is directly discharged to the outside.

2. The ground-based hydrogen-oxygen rocket engine mixture ratio control system according to claim 1, characterized in that: The pressure of the liquid hydrogen storage tank (1) is controlled by the liquid hydrogen storage tank pressure control system (7). When the liquid hydrogen storage tank pressure control system (7) injects hydrogen into the liquid hydrogen storage tank (1) through the pipeline, the pressure of the liquid hydrogen storage tank (1) increases. When liquid hydrogen is consumed or the liquid hydrogen storage tank pressure control system (7) removes hydrogen from the liquid hydrogen storage tank (1) through the pipeline, the pressure of the liquid hydrogen storage tank (1) decreases. The pressure of the liquid oxygen storage tank (3) is controlled by the liquid oxygen storage tank pressure control system (8). When the liquid oxygen storage tank pressure control system (8) injects nitrogen into the liquid oxygen storage tank (3) through the pipeline, the pressure of the liquid oxygen storage tank (3) increases. When liquid hydrogen is consumed or the liquid oxygen storage tank pressure control system (8) removes nitrogen from the liquid oxygen storage tank (3) through the pipeline, the pressure of the liquid oxygen storage tank (3) decreases.

3. The ground-based hydrogen-oxygen rocket engine mixture ratio control system according to claim 1, characterized in that: The liquid hydrogen storage tank pressure control system (7) uses PID to control the pressure of the liquid hydrogen storage tank (1), and the liquid oxygen storage tank pressure control system (8) uses PID to control the pressure of the liquid oxygen storage tank (3).

4. The ground-tested hydrogen-oxygen rocket engine mixture ratio control system according to claim 3, characterized in that: PID control is obtained through the following formula: ； ； in, The target pressure of the storage tank; This refers to the real-time pressure of the storage tank. This is the real-time pressure deviation. For gas flow control in pressure control systems; This is the proportional gain value. This is the integral gain value; This is the differential gain value. For a moment, For a period of time, This is the cumulative amount of real-time pressure deviation.

5. The ground-based hydrogen-oxygen rocket engine mixture ratio control system according to claim 1 or 2, characterized in that: Liquid hydrogen enters the hydrogen cavitation pipe (2) after being pressurized by the liquid hydrogen storage tank (1). The hydrogen flow rate of the engine is controlled by adjusting the pressure of the liquid hydrogen storage tank.

6. The ground-tested hydrogen-oxygen rocket engine mixture ratio control system according to claim 5, characterized in that: The engine hydrogen flow rate is obtained using the following formula: ； in, For engine hydrogen flow rate; The equivalent area of ​​the hydrogen cavitation tube; The pressure of the liquid hydrogen storage tank. The density of liquid hydrogen in front of the hydrogen cavitation tube; This is the saturated vapor pressure of liquid hydrogen.

7. The ground-based hydrogen-oxygen rocket engine mixture ratio control system according to claim 1 or 2, characterized in that: Liquid oxygen enters the oxygen cavitation pipe (4) after being pressurized by the liquid oxygen storage tank (3). The oxygen flow rate of the engine is controlled by adjusting the pressure of the oxygen storage tank.

8. The ground-tested hydrogen-oxygen rocket engine mixture ratio control system according to claim 7, characterized in that: Engine oxygen flow rate is obtained using the following formula: ； in, For engine oxygen flow; The equivalent area of ​​the oxygen cavitation tube; Liquid oxygen tank pressure; This is the local saturated vapor pressure of liquid oxygen; The density of liquid oxygen in front of the oxygen cavitation tube.

9. The ground-tested hydrogen-oxygen rocket engine mixture ratio control system according to claim 1, characterized in that: Liquid hydrogen enters the combustion device (5) after its flow rate is controlled by the hydrogen cavitation pipe, and liquid oxygen enters the combustion device (5) after its flow rate is controlled by the oxygen cavitation pipe. The liquid hydrogen and liquid oxygen are burned in the combustion device (5) after their flow rates are controlled. The chamber pressure of the combustion device (5) is controlled by the gas nozzle (6).

10. The ground-tested hydrogen-oxygen rocket engine mixture ratio control system according to claim 1, characterized in that: The engine air-fuel ratio is obtained using the following formula: ； Engine flow rate is obtained using the following formula: ； in, The engine air-fuel mixture ratio. For engine oxygen flow, For engine hydrogen flow rate, For engine flow rate, The equivalent area of ​​the gas nozzle. The combustion chamber pressure, The temperature of the combustion device. Let be the gas constant of the fuel gas. This is the specific heat ratio of the gas.

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