Precooling turbojet combination engine test system and device based on combustion heating mode

Abstract

The present invention belongs to the field of aeroengine technology and discloses a combustion-heating-based precooled turbojet combination engine test system and apparatus. The test system includes a normal-temperature air supply line for the engine, a normal-temperature air supply line for the combustion heater, an oxygen supply line for the combustion heater, a hydrogen fuel supply line for the combustion heater, a liquid nitrogen precooling medium supply line for the precooler, an aviation kerosene fuel supply line for the engine, and a combination of a combustion heater system and a high-temperature air supply line. During operation, the test system can achieve continuous variable and constant flow rates of normal-temperature air, high-temperature air, precooling medium, and aviation kerosene, meeting the requirements of direct-connected testing of precooled turbojet combination engines under different operating conditions.

Description

Technical Field

[0001] The present invention belongs to the technical field of aviation engines, and in particular relates to a pre-cooling turbojet combination engine test system and device based on a combustion heating mode. Background Art

[0002] As high-speed / hypersonic aircraft have become a research hotspot in the aerospace field, major aviation powers around the world have proposed a variety of new high-speed / hypersonic propulsion systems, including rocket engines, sub-scramjets / scramjets, turbine-based ramjet combination engines (TBCCs), and rocket-based ramjet combination engines (RBCCs). Among them, the turbine-based ramjet combination engine (TBCC) offers low operating costs, high specific impulse over a wide Mach number range, horizontal takeoff and landing capabilities, and reusability, combining the advantages of both turbojet engines and ramjet engines. However, for turbojet-based ramjet combination engines with Mach numbers greater than 4, they suffer from insufficient thrust during the transition between turbojet and ramjet engines (Mach numbers 2.5 to 3.0). To address this issue, it is necessary to ensure that the turbojet engine can operate stably at higher flight speeds.

[0003] However, as flight speed increases, the stagnation temperature of the airflow entering the turbojet engine also increases, which causes the performance of the turbojet engine's compressor to rapidly decrease, and the energy density that the compressor can impart to the incoming air also decreases, thereby significantly reducing the turbojet engine's operating performance and limiting the turbojet engine's operation at higher flight speeds. Integrating a precooler with a turbojet engine and using precooling to reduce the temperature of the air entering the engine can allow the turbojet engine to operate under low-temperature air flow conditions even when the aircraft is flying at high speeds. This can effectively improve the turbojet engine's operating performance and thrust under high-speed flight conditions, allowing the turbojet engine to operate stably at higher flight speeds.

[0004] When the precooler is matched with the turbojet engine, the high-temperature air flow will produce flow deflection when flowing through the complex structure of the precooler, resulting in flow field distortion. The flow field distortion will have an adverse effect on the turbojet engine and the stable operation of the turbojet engine.

[0005] Currently, there is an urgent need to develop a precooled turbojet combination engine test system and device based on a combustion heating mode, which can be used to conduct high-temperature direct-connection ground tests of precooled turbojet combination engines, so as to obtain the technical performance of the precooled turbojet combination engine and verify the control technology of the precooled turbojet combination engine. Among them, the precooled turbojet combination engine is a combination engine that combines a precooler with a turbojet engine. Under high-speed flight conditions, the incoming high-temperature air is compressed through the air inlet and cooled in the precooler. The cooled air enters the turbojet engine, is compressed by the fan, mixed with fuel, and enters the combustion chamber for combustion. The high-temperature combustion gas formed after combustion is discharged through the tail nozzle. The direct-connection test system is a ground test system used for hypersonic aircraft and engine performance assessment. The engine model is directly connected to the test system outlet. The precooled turbojet combination engine test system and device based on the combustion heating mode uses a "fuel + oxygen-enriched air" combustion heating method to generate a high-temperature airflow that can simulate the actual flight conditions of the aircraft or engine, which is used to conduct aircraft or engine performance tests. Summary of the Invention

[0006] The first technical problem to be solved by the present invention is to provide a pre-cooling turbojet combination engine test system based on a combustion heating mode; the second technical problem to be solved by the present invention is to provide a pre-cooling turbojet engine performance test device under normal temperature variable flow air supply conditions; the third technical problem to be solved by the present invention is to provide a pre-cooling turbojet engine performance test device under normal temperature constant flow air supply conditions; the fourth technical problem to be solved by the present invention is to provide a pre-cooling turbojet engine performance test device under high temperature variable flow air supply conditions; the last technical problem to be solved by the present invention is to provide a pre-cooling turbojet engine performance test device under high temperature constant flow air supply conditions.

[0007] The precooling turbojet combination engine test system based on the combustion heating mode of the present invention is characterized in that the precooling turbojet combination engine test system based on the combustion heating mode includes a normal temperature air supply pipeline for the engine, a normal temperature air supply pipeline for the combustion heater, an oxygen supply pipeline for the combustion heater, a hydrogen fuel supply pipeline for the combustion heater, a liquid nitrogen precooling medium supply pipeline for the precooler, an aviation kerosene fuel supply pipeline for the engine, and a combination of the combustion heater system and the high temperature air supply pipeline;

[0008] The normal temperature air supply pipeline for the engine includes AC1-Kac1-Pac1-Kac2-Pac2-Kac6-C connected in sequence. The pipeline starts from the air storage tank ⅠAC1, passes through the pressure reducer ⅠKac1, the front pressure sensor Pac1 of the air venturi tube Ⅰ, the air venturi tube ⅠKac2, the rear pressure sensor Pac2 of the air venturi tube Ⅰ, and the normal temperature air control valve Kac6, and finally connects to the precooler C, and supplies the normal temperature air to the engine D; the normal temperature air control valve Kac6 is also connected to the exhaust pipeline Ⅰ, and the exhaust pipeline Ⅰ includes Kac4-Kac5 connected in sequence; when the supply flow of normal temperature air needs to be changed, the opening of the normal temperature air control valve Kac6 is changed, and the pneumatic valves Kac4 and Kac5 of the exhaust pipeline are opened at the same time. Air Venturi II Kac5, part of the air is discharged into the atmosphere through exhaust pipe I, thereby realizing a variable flow rate supply of normal temperature air; the ratio of the mass flow rate of normal temperature air supplied to engine C to the mass flow rate of normal temperature air discharged to the atmosphere is equal to the ratio of the area of the flow channel of the regulating valve Kac6 to the minimum cross-sectional area of the air Venturi II Kac5; when normal temperature air is not needed, the exhaust pipe pneumatic valve Kac4 and the normal temperature air regulating valve Kac6 are closed, and normal temperature air is no longer supplied to the precooler C; wherein, the air Venturi I front pressure sensor Pac1 is used to measure the pressure before the air Venturi I Kac2, and the air Venturi I rear pressure sensor Pac2 is used to measure the pressure after the air Venturi I Kac2;

[0009] The normal temperature air supply pipeline for the combustion heater includes A1-Ka1-Pa1-Ka2-Pa2-Ka3-P2-A connected in sequence. The starting point of the pipeline is the air storage tank ⅡA1, and it passes through the pressure reducer ⅡKa1, the air venturi Ⅱ front pressure sensor Pa1, the air venturi ⅡKa2, the air venturi Ⅱ rear pressure sensor Pa2, the air venturi Ⅱ rear pneumatic valve Ka3, and is mixed with the oxygen in the oxygen supply pipeline for the combustion heater to form oxygen-enriched air. It enters the burner A through the oxygen-enriched air pipeline pressure sensor P2, mixes with hydrogen and burns to produce High-temperature gas is supplied to the precooler C through the process nozzle B to simulate the high-temperature air inhaled by the aircraft during high-speed flight. When the burner A is not in operation, the pneumatic valve Ka3 after the air venturi tube II is closed, and no air is supplied to the burner A. Among them, the pressure sensor Pa1 before the air venturi tube II is used to measure the pressure before the air venturi tube II Ka2, the pressure sensor Pa2 after the air venturi tube II is used to measure the pressure after the air venturi tube II Ka2, and the oxygen-enriched air pipeline pressure sensor P2 is used to measure the pressure of the oxygen-enriched air before entering the burner A.

[0010] The oxygen supply pipeline for the combustion heater includes O1-Ko1-Po1-Ko2-Po2-Ko3-P2-A connected in sequence. The starting point of the pipeline is the oxygen storage tank O1, and it passes through the oxygen pressure reducer Ko1, the oxygen venturi front pressure sensor Po1, the oxygen venturi Ko2, the oxygen venturi rear pressure sensor Po2, the oxygen venturi rear pneumatic valve Ko3, and is mixed with the air in the normal temperature air supply pipeline for the combustion heater to form oxygen-enriched air. It enters the burner A through the oxygen-enriched air pipeline pressure sensor P2, mixes with hydrogen and burns to produce high-temperature gas, which is supplied to the burner through the process nozzle B and pressure sensor P4. The precooler C should be used to simulate the high-temperature air inhaled by the aircraft during high-speed flight; when the burner A is not running, the pneumatic valve Ko3 after the oxygen venturi is closed, and oxygen is no longer supplied to the burner A; among them, the oxygen venturi front pressure sensor Po1 is used to measure the pressure before the oxygen venturi Ko2, the oxygen venturi rear pressure sensor Po2 is used to measure the pressure after the oxygen venturi Ko2, the oxygen-enriched air pipeline pressure sensor P2 is used to measure the pressure of the oxygen-enriched air before entering the burner A, and the pressure sensor P4 is used to measure the pressure of the oxygen-enriched air before entering the high-temperature air control valve Kah3;

[0011] The hydrogen fuel supply pipeline for the combustion heater includes H1-Kh1-Ph1-Kh2-Ph2-Kh3-P1-A connected in sequence. The starting point of the pipeline is the hydrogen storage tank H1, and it passes through the hydrogen pressure reducer Kh1, the hydrogen venturi front pressure sensor Ph1, the hydrogen venturi Kh2, the hydrogen venturi rear pressure sensor Ph2, the hydrogen venturi rear pneumatic valve Kh3, and enters the burner A through the hydrogen pipeline pressure sensor P1. After mixing with the oxygen-enriched air, it burns to produce high-temperature gas, which is supplied to the precooler C through the process nozzle B and pressure sensor P4 to simulate the flight. High-temperature air inhaled by the aircraft during high-speed flight; when burner A is not in operation, the pneumatic valve Kh3 behind the hydrogen venturi is closed, and hydrogen is no longer supplied to burner A; wherein, the hydrogen venturi front pressure sensor Ph1 is used to measure the pressure before the hydrogen venturi Kh2, the hydrogen venturi rear pressure sensor Ph2 is used to measure the pressure after the hydrogen venturi Kh2, the hydrogen pipeline pressure sensor P1 is used to measure the pressure of hydrogen before entering burner A, and the pressure sensor P4 is used to measure the pressure of oxygen-enriched air before entering the high-temperature air control valve Kah3;

[0012] The liquid nitrogen pre-cooling medium supply pipeline for the pre-cooler includes N1-Pn1-Kn1-Pn2-Kn2-Kn3-C connected in sequence. The starting point of the pipeline is the liquid nitrogen storage tank N1, passing through the liquid nitrogen cavitation tube front pressure sensor Pn1, liquid nitrogen cavitation tube Kn1, liquid nitrogen cavitation tube rear pressure sensor Pn2, liquid nitrogen flow regulating valve Kn2, liquid nitrogen pneumatic valve Kn3, and the pre-cooling medium flows into the interface to supply to the pre-cooler C, forming a cooling zone in the pre-cooler C to exchange the high-temperature gas generated by combustion. Thermal cooling converts high-temperature gas into normal-temperature gas and supplies it to engine D. The temperature of the normal-temperature gas after passing through the precooler is measured by temperature sensor T1, and the liquid nitrogen medium heated after heat exchange is discharged into the atmosphere through the precooling medium discharge interface; Among them, the liquid nitrogen cavitation tube front pressure sensor Pn1 is used to measure the pressure of liquid nitrogen before entering the liquid nitrogen cavitation tube Kn1, and the liquid nitrogen cavitation tube rear pressure sensor Pn2 is used to measure the pressure of liquid nitrogen between the liquid nitrogen cavitation tube Kn1 and the liquid nitrogen flow control valve Kn2;

[0013] The aviation kerosene fuel supply pipeline for the engine includes F1-Kf1-Pf1-Kf2-Kf3-Pf2-D, which are connected in sequence. The pipeline starts at fuel tank F1 and passes through fuel pump Kf1, aviation kerosene pump pressure sensor Pf1, aviation kerosene flowmeter Kf2, aviation kerosene pneumatic valve Kf3, and aviation kerosene pneumatic valve post-sensor Pf2, and is ultimately supplied to engine D. Aviation kerosene spray is formed in the turbojet engine combustion chamber, and is mixed with air supplied from the upstream engine normal temperature air supply pipeline, combusting to generate thrust. Among them, aviation kerosene pump post-pressure sensor Pf1 is used to measure the pressure after fuel pump Kf1, and aviation kerosene pneumatic valve post-sensor Pf2 is used to measure the fuel pressure before entering engine D.

[0014] The combustion heater system and high-temperature air supply pipeline assembly includes a combustion heater system and a high-temperature air supply pipeline assembly, and the combustion heater system and high-temperature air supply pipeline assembly includes AB-P4-Kah3-C connected in sequence; the combustion heater system consists of a burner A and a process nozzle B, hydrogen and oxygen-enriched air are burned in burner A to generate high-temperature combustion gas with an oxygen content of 21%, which is used to simulate the high-temperature air inhaled during high-speed flight of an aircraft. The high-temperature air enters the high-temperature air supply pipeline through the process nozzle B, and the high-temperature combustion gas at the outlet of the process nozzle B is defined as high-temperature air; the high-temperature air supply pipeline includes B-P4-Kah3-C connected in sequence, and the high-temperature air supply pipeline starts at the outlet of the process nozzle B, passes through the pressure sensor P4 and the high-temperature air control valve Kah3, and finally enters the precooler C. After heat exchange and cooling in the precooler C, it becomes normal-temperature air and is supplied to the engine D. ; The high-temperature air regulating valve Kah3 is also connected to the exhaust pipe II, and the exhaust pipe II includes Kah1-Kah2 connected in sequence; when it is necessary to change the supply flow of high-temperature air, the opening of the high-temperature air regulating valve Kah3 is changed, and the exhaust pipe high-temperature pneumatic valve Kah1 is opened at the same time, then part of the air is discharged into the atmosphere through the exhaust pipe high-temperature pneumatic valve Kah1 and the exhaust pipe venturi Kah2, thereby realizing variable flow supply of high-temperature air; the ratio of the mass flow rate of high-temperature air supplied to the engine C to the mass flow rate of high-temperature air discharged to the atmosphere is equal to the ratio of the area of the flow channel of the high-temperature air regulating valve Kah3 to the minimum cross-sectional area of the exhaust pipe venturi Kah2; when high-temperature air is not needed, the burner A is turned off, and high-temperature air is no longer supplied to the precooler C; wherein, the pressure sensor P4 is used to measure the high-temperature gas pressure before the high-temperature air regulating valve Kah3.

[0015] Furthermore, the combustion reaction of hydrogen and oxygen in the combustion chamber of the burner A is as follows:

[0016]

[0017] Where a is the molar flow rate of hydrogen; b is the molar flow rate of oxygen; c is the molar flow rate of air; Q is the heat released by combustion;

[0018] The mass and energy of the hydrogen, oxygen, and air flows in the combustion chamber of burner A before and after the reaction are conserved, which is expressed as the following equations:

[0019]

[0020] Where, T0 is the temperature before reaction; T t is the temperature after reaction; is the molar mass of hydrogen; is the molar mass of oxygen; is the molar mass of nitrogen; is the molar mass of water; is the specific enthalpy of hydrogen at the temperature T0 before the reaction; is the specific enthalpy of oxygen at the temperature T0 before the reaction; is the specific enthalpy of nitrogen at the temperature T0 before the reaction; The temperature of oxygen after the reaction is T t Specific enthalpy; is the specific enthalpy of nitrogen at the temperature Tt after the reaction; is the temperature of water vapor after the reaction t Specific enthalpy; is the total mass flow rate of the outlet gas;

[0021] Under different Mach number conditions, the total temperature of the airflow is T t The total flow is Under the pre-set wind tunnel nozzle dimensions, the nozzle outlet test gas parameters including total pressure, static pressure, and static temperature are determined, thereby determining the hydrogen, oxygen, and air flow rates required for combustion heating.

[0022] The calculation method of gas venturi flow rate is as follows:

[0023]

[0024] Where C d is the outflow coefficient of the gas venturi; C * is the critical flow function of the gas venturi; A th is the flow area of the gas venturi at the minimum diameter; P t is the total pressure of the inflowing gas; T t is the inflow gas temperature; R is the gas constant; M is the gas molar mass;

[0025] Among them, the calculation method of liquid nitrogen cavitation tube flow is as follows:

[0026]

[0027] Where, is the liquid nitrogen flow rate; A w C is the flow area at the minimum diameter of the liquid nitrogen cavitation tube; d is the flow coefficient of the liquid nitrogen cavitation tube; ρ is the density of liquid nitrogen; ΔP is the pressure difference between the upstream and downstream of the liquid nitrogen cavitation tube.

[0028] The pre-cooling turbojet engine performance test device under normal temperature and variable flow air supply conditions of the present invention includes the following contents:

[0029] The normal temperature air supply pipeline for the engine, i.e., the AC1-Kac1-Pac1-Kac2-Pac2-Kac6-C pipeline, realizes the normal temperature variable flow air supply. When the pressure in front of the normal temperature air regulating valve Kac6 is constant, the normal temperature air flow rate is changed by changing the opening of the normal temperature air regulating valve Kac6. When the exhaust pipeline pneumatic valve Kac4 and the normal temperature air regulating valve Kac6 are opened, the ratio of the mass flow rate of the normal temperature air supplied to the engine C to the mass flow rate of the normal temperature air discharged to the atmosphere is equal to the normal temperature air regulating valve Kac6. The ratio of the area of the flow channel to the minimum cross-sectional area of the air venturi II Kac5 is shown. The engine is supplied with aviation kerosene fuel by the engine's aviation kerosene fuel supply line, i.e., F1-Kf1-Pf1-Kf2-Kf3-Pf2-D. The engine's aviation kerosene fuel flow rate is adjusted by varying the power of the fuel pump Kf1. The liquid nitrogen flow control valve Kn2 of the liquid nitrogen precooling medium supply line for the precooler is in the closed state. The burner A is in the closed state, and the high-temperature air control valve Kah3 in the combustion heater and the high-temperature air supply line is in the closed state.

[0030] The pre-cooling turbojet engine performance test device under normal temperature and constant flow air supply conditions of the present invention includes the following contents:

[0031] A constant-flow normal-temperature air supply is achieved through the normal-temperature air supply pipeline for the engine, namely the AC1-Kac1-Pac1-Kac2-Pac2-Kac6-C pipeline. At this time, the exhaust pipeline pneumatic valve Kac4 is closed. When the pressure in front of the normal-temperature air control valve Kac6 is constant, a constant-flow normal-temperature air supply is achieved by adjusting the opening of the normal-temperature air control valve Kac6 in advance. The aviation kerosene fuel supply to the engine is achieved through the aviation kerosene fuel supply pipeline for the engine, namely the F1-Kf1-Pf1-Kf2-Kf3-Pf2-D pipeline. The pre-set power of the fuel pump Kf1 achieves the supply of aviation kerosene fuel to the engine at the rated flow rate. The liquid nitrogen flow control valve Kn2 of the liquid nitrogen precooling medium supply pipeline for the precooler is in the closed state. The burner A is in the off state, and the high-temperature air control valve Kah3 in the combustion heater and the high-temperature air supply pipeline is in the closed state.

[0032] The present invention provides a pre-cooled turbojet engine performance test device under high-temperature variable-flow air supply conditions, comprising the following contents:

[0033] The high-temperature variable-flow air supply is realized by the combination of the combustion heater system and the high-temperature air supply pipeline, i.e., the AB-P4-Kah3-C pipeline. The burner A is in the open state, and the high-temperature pneumatic valve Kah1 of the exhaust pipeline is in the open state. The gas flow of the high-temperature air supply pipeline, i.e., the B-P4-Kah3-C pipeline, is changed by adjusting the opening of the high-temperature air regulating valve Kah3. The excess high-temperature gas is discharged into the atmosphere through the exhaust pipeline II, i.e., the Kah1-Kah2 pipeline. When the high-temperature pneumatic valve Kah1 and the high-temperature air regulating valve Kah3 of the exhaust pipeline are opened, the ratio of the mass flow rate of the high-temperature air supplied to the engine C to the mass flow rate of the high-temperature air discharged to the atmosphere is equal to the area of the flow channel of the high-temperature air regulating valve Kah3 and The ratio of the minimum cross-sectional area of the exhaust pipe venturi Kah2; the supply of aviation kerosene fuel to the engine is achieved by the engine aviation kerosene fuel supply pipeline, namely the F1-Kf1-Pf1-Kf2-Kf3-Pf2-D pipeline, and the engine aviation kerosene fuel flow rate is adjusted by changing the power of the fuel pump Kf1; the liquid nitrogen pre-cooling medium supply pipeline for the precooler, namely the N1-Pn1-Kn1-Pn2-Kn2-Kn3-C pipeline, realizes the supply of liquid nitrogen to precooler C to cool the high-temperature air generated by burner A. When the pressure of the liquid nitrogen storage tank N1 is fixed, the liquid nitrogen supply flow rate is changed by adjusting the opening of the liquid nitrogen flow control valve Kn2; at this time, the normal temperature air control valve Kac6 of the normal temperature air supply pipeline for the engine is in the closed state.

[0034] The present invention provides a pre-cooled turbojet engine performance test device under high-temperature constant-flow air supply conditions, comprising the following contents:

[0035] The high-temperature constant-flow air supply is realized by the combustion heater system and the high-temperature air supply pipeline combination, namely the AB-P4-Kah3-C pipeline. The burner A is in the open state, the high-temperature pneumatic valve Kah1 of the exhaust pipeline is closed, and the supply flow of the high-temperature gas is fixed by the opening of the high-temperature air regulating valve Kah3 set in advance; the aviation kerosene fuel supply pipeline for the engine, namely the F1-Kf1-Pf1-Kf2-Kf3-Pf2-D pipeline, realizes the supply of aviation kerosene fuel to the engine. The power of the installed fuel pump Kf1 regulates the flow of aviation kerosene fuel to the engine. The precooler uses liquid nitrogen to precool the medium supply pipeline, that is, the N1-Pn1-Kn1-Pn2-Kn2-Kn3-C pipeline to supply liquid nitrogen to the precooler C to cool the high-temperature air generated by the burner A. When the pressure of the liquid nitrogen storage tank N1 is fixed, the opening of the pre-set liquid nitrogen flow control valve Kn2 is used to fix the supply flow of liquid nitrogen. At this time, the normal temperature air control valve Kac6 of the normal temperature air supply pipeline for the engine is in the closed state.

[0036] The present invention's combustion-heating-based precooled turbojet combination engine test system and device are based on the needs of high-temperature, direct-connected ground testing of precooled turbojet combination engines. A direct-connected test system based on the combustion-heating mode, which generates high-temperature gas, is designed. This system is capable of conducting direct-connected testing of precooled turbojet combination engines, providing hardware support for a test platform for conducting high-temperature ground testing of precooled turbojet combination engines. During operation, the test system can achieve continuous variable and constant flow rates of normal-temperature air, high-temperature air, precooling medium, and aviation kerosene. Performance tests of precooled turbojet engines under variable-flow normal-temperature air supply conditions, constant-flow normal-temperature air supply conditions, variable-flow high-temperature air supply conditions, and constant-flow high-temperature air supply conditions can be simultaneously conducted, meeting the needs of direct-connected testing of precooled turbojet combination engines under different operating conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram (overall diagram) of the structure of the pre-cooling turbojet combination engine test system based on the combustion heating mode of the present invention;

[0038] Figure 2 The structural diagram of the pre-cooling turbojet combined engine test system based on the combustion heating mode of the present invention (partial Figure I );

[0039] Figure 3 The structural diagram of the pre-cooling turbojet combined engine test system based on the combustion heating mode of the present invention (partial Figure II );

[0040] Figure 4 It is a structural schematic diagram (component diagram) of the pre-cooling turbojet combination engine test system based on the combustion heating mode of the present invention.

[0041] Figure 5 This is a diagram of the internal pressure of the combustion heater when the pre-cooling turbojet combination engine test system based on the combustion heating mode of the present invention is running (experimental result diagram). DETAILED DESCRIPTION

[0042] The present invention will be described in detail below with reference to the accompanying drawings and embodiments.

[0043] Example 1

[0044] like Figures 1 to 4As shown, the precooling turbojet combination engine test system based on the combustion heating mode of this embodiment is characterized in that the precooling turbojet combination engine test system based on the combustion heating mode includes a normal temperature air supply pipeline for the engine, a normal temperature air supply pipeline for the combustion heater, an oxygen supply pipeline for the combustion heater, a hydrogen fuel supply pipeline for the combustion heater, a liquid nitrogen precooling medium supply pipeline for the precooler, an aviation kerosene fuel supply pipeline for the engine, and a combination of the combustion heater system and the high temperature air supply pipeline;

[0045] The normal temperature air supply pipeline for the engine includes AC1-Kac1-Pac1-Kac2-Pac2-Kac6-C connected in sequence. The pipeline starts from the air storage tank ⅠAC1, passes through the pressure reducer ⅠKac1, the front pressure sensor Pac1 of the air venturi tube Ⅰ, the air venturi tube ⅠKac2, the rear pressure sensor Pac2 of the air venturi tube Ⅰ, and the normal temperature air control valve Kac6, and finally connects to the precooler C, and supplies the normal temperature air to the engine D; the normal temperature air control valve Kac6 is also connected to the exhaust pipeline Ⅰ, and the exhaust pipeline Ⅰ includes Kac4-Kac5 connected in sequence; when the supply flow of normal temperature air needs to be changed, the opening of the normal temperature air control valve Kac6 is changed, and the pneumatic valves Kac4 and Kac5 of the exhaust pipeline are opened at the same time. Air Venturi II Kac5, part of the air is discharged into the atmosphere through exhaust pipe I, thereby realizing a variable flow rate supply of normal temperature air; the ratio of the mass flow rate of normal temperature air supplied to engine C to the mass flow rate of normal temperature air discharged to the atmosphere is equal to the ratio of the area of the flow channel of the regulating valve Kac6 to the minimum cross-sectional area of the air Venturi II Kac5; when normal temperature air is not needed, the exhaust pipe pneumatic valve Kac4 and the normal temperature air regulating valve Kac6 are closed, and normal temperature air is no longer supplied to the precooler C; wherein, the air Venturi I front pressure sensor Pac1 is used to measure the pressure before the air Venturi I Kac2, and the air Venturi I rear pressure sensor Pac2 is used to measure the pressure after the air Venturi I Kac2;

[0046] The normal temperature air supply pipeline for the combustion heater includes A1-Ka1-Pa1-Ka2-Pa2-Ka3-P2-A connected in sequence. The starting point of the pipeline is the air storage tank ⅡA1, and it passes through the pressure reducer ⅡKa1, the air venturi Ⅱ front pressure sensor Pa1, the air venturi ⅡKa2, the air venturi Ⅱ rear pressure sensor Pa2, the air venturi Ⅱ rear pneumatic valve Ka3, and is mixed with the oxygen in the oxygen supply pipeline for the combustion heater to form oxygen-enriched air. It enters the burner A through the oxygen-enriched air pipeline pressure sensor P2, mixes with hydrogen and burns to produce High-temperature gas is supplied to the precooler C through the process nozzle B to simulate the high-temperature air inhaled by the aircraft during high-speed flight. When the burner A is not in operation, the pneumatic valve Ka3 after the air venturi tube II is closed, and no air is supplied to the burner A. Among them, the pressure sensor Pa1 before the air venturi tube II is used to measure the pressure before the air venturi tube II Ka2, the pressure sensor Pa2 after the air venturi tube II is used to measure the pressure after the air venturi tube II Ka2, and the oxygen-enriched air pipeline pressure sensor P2 is used to measure the pressure of the oxygen-enriched air before entering the burner A.

[0047] The oxygen supply pipeline for the combustion heater includes O1-Ko1-Po1-Ko2-Po2-Ko3-P2-A connected in sequence. The starting point of the pipeline is the oxygen storage tank O1, and it passes through the oxygen pressure reducer Ko1, the oxygen venturi front pressure sensor Po1, the oxygen venturi Ko2, the oxygen venturi rear pressure sensor Po2, the oxygen venturi rear pneumatic valve Ko3, and is mixed with the air in the normal temperature air supply pipeline for the combustion heater to form oxygen-enriched air. It enters the burner A through the oxygen-enriched air pipeline pressure sensor P2, mixes with hydrogen and burns to produce high-temperature gas, which is supplied to the burner through the process nozzle B and pressure sensor P4. The precooler C should be used to simulate the high-temperature air inhaled by the aircraft during high-speed flight; when the burner A is not running, the pneumatic valve Ko3 after the oxygen venturi is closed, and oxygen is no longer supplied to the burner A; among them, the oxygen venturi front pressure sensor Po1 is used to measure the pressure before the oxygen venturi Ko2, the oxygen venturi rear pressure sensor Po2 is used to measure the pressure after the oxygen venturi Ko2, the oxygen-enriched air pipeline pressure sensor P2 is used to measure the pressure of the oxygen-enriched air before entering the burner A, and the pressure sensor P4 is used to measure the pressure of the oxygen-enriched air before entering the high-temperature air control valve Kah3;

[0048] The hydrogen fuel supply pipeline for the combustion heater includes H1-Kh1-Ph1-Kh2-Ph2-Kh3-P1-A connected in sequence. The starting point of the pipeline is the hydrogen storage tank H1, and it passes through the hydrogen pressure reducer Kh1, the hydrogen venturi front pressure sensor Ph1, the hydrogen venturi Kh2, the hydrogen venturi rear pressure sensor Ph2, the hydrogen venturi rear pneumatic valve Kh3, and enters the burner A through the hydrogen pipeline pressure sensor P1. After mixing with the oxygen-enriched air, it burns to produce high-temperature gas, which is supplied to the precooler C through the process nozzle B and pressure sensor P4 to simulate the flight. High-temperature air inhaled by the aircraft during high-speed flight; when burner A is not in operation, the pneumatic valve Kh3 behind the hydrogen venturi is closed, and hydrogen is no longer supplied to burner A; wherein, the hydrogen venturi front pressure sensor Ph1 is used to measure the pressure before the hydrogen venturi Kh2, the hydrogen venturi rear pressure sensor Ph2 is used to measure the pressure after the hydrogen venturi Kh2, the hydrogen pipeline pressure sensor P1 is used to measure the pressure of hydrogen before entering burner A, and the pressure sensor P4 is used to measure the pressure of oxygen-enriched air before entering the high-temperature air control valve Kah3;

[0049] The liquid nitrogen pre-cooling medium supply pipeline for the pre-cooler includes N1-Pn1-Kn1-Pn2-Kn2-Kn3-C connected in sequence. The starting point of the pipeline is the liquid nitrogen storage tank N1, passing through the liquid nitrogen cavitation tube front pressure sensor Pn1, liquid nitrogen cavitation tube Kn1, liquid nitrogen cavitation tube rear pressure sensor Pn2, liquid nitrogen flow regulating valve Kn2, liquid nitrogen pneumatic valve Kn3, and the pre-cooling medium flows into the interface to supply to the pre-cooler C, forming a cooling zone in the pre-cooler C to exchange the high-temperature gas generated by combustion. Thermal cooling converts high-temperature gas into normal-temperature gas and supplies it to engine D. The temperature of the normal-temperature gas after passing through the precooler is measured by temperature sensor T1, and the liquid nitrogen medium heated after heat exchange is discharged into the atmosphere through the precooling medium discharge interface; Among them, the liquid nitrogen cavitation tube front pressure sensor Pn1 is used to measure the pressure of liquid nitrogen before entering the liquid nitrogen cavitation tube Kn1, and the liquid nitrogen cavitation tube rear pressure sensor Pn2 is used to measure the pressure of liquid nitrogen between the liquid nitrogen cavitation tube Kn1 and the liquid nitrogen flow control valve Kn2;

[0050] The aviation kerosene fuel supply pipeline for the engine includes F1-Kf1-Pf1-Kf2-Kf3-Pf2-D, which are connected in sequence. The pipeline starts at fuel tank F1 and passes through fuel pump Kf1, aviation kerosene pump pressure sensor Pf1, aviation kerosene flowmeter Kf2, aviation kerosene pneumatic valve Kf3, and aviation kerosene pneumatic valve post-sensor Pf2, and is ultimately supplied to engine D. Aviation kerosene spray is formed in the turbojet engine combustion chamber, and is mixed with air supplied from the upstream engine normal temperature air supply pipeline, combusting to generate thrust. Among them, aviation kerosene pump post-pressure sensor Pf1 is used to measure the pressure after fuel pump Kf1, and aviation kerosene pneumatic valve post-sensor Pf2 is used to measure the fuel pressure before entering engine D.

[0051] The combustion heater system and high-temperature air supply pipeline assembly includes a combustion heater system and a high-temperature air supply pipeline assembly, and the combustion heater system and high-temperature air supply pipeline assembly includes AB-P4-Kah3-C connected in sequence; the combustion heater system consists of a burner A and a process nozzle B, hydrogen and oxygen-enriched air are burned in burner A to generate high-temperature combustion gas with an oxygen content of 21%, which is used to simulate the high-temperature air inhaled during high-speed flight of an aircraft. The high-temperature air enters the high-temperature air supply pipeline through the process nozzle B, and the high-temperature combustion gas at the outlet of the process nozzle B is defined as high-temperature air; the high-temperature air supply pipeline includes B-P4-Kah3-C connected in sequence, and the high-temperature air supply pipeline starts at the outlet of the process nozzle B, passes through the pressure sensor P4 and the high-temperature air control valve Kah3, and finally enters the precooler C. After heat exchange and cooling in the precooler C, it becomes normal-temperature air and is supplied to the engine D. ; The high-temperature air regulating valve Kah3 is also connected to the exhaust pipe II, and the exhaust pipe II includes Kah1-Kah2 connected in sequence; when it is necessary to change the supply flow of high-temperature air, the opening of the high-temperature air regulating valve Kah3 is changed, and the exhaust pipe high-temperature pneumatic valve Kah1 is opened at the same time, then part of the air is discharged into the atmosphere through the exhaust pipe high-temperature pneumatic valve Kah1 and the exhaust pipe venturi Kah2, thereby realizing variable flow supply of high-temperature air; the ratio of the mass flow rate of high-temperature air supplied to the engine C to the mass flow rate of high-temperature air discharged to the atmosphere is equal to the ratio of the area of the flow channel of the high-temperature air regulating valve Kah3 to the minimum cross-sectional area of the exhaust pipe venturi Kah2; when high-temperature air is not needed, the burner A is turned off, and high-temperature air is no longer supplied to the precooler C; wherein, the pressure sensor P4 is used to measure the high-temperature gas pressure before the high-temperature air regulating valve Kah3.

[0052] Furthermore, the combustion reaction of hydrogen and oxygen in the combustion chamber of the burner A is as follows:

[0053]

[0054] Where a is the molar flow rate of hydrogen; b is the molar flow rate of oxygen; c is the molar flow rate of air; Q is the heat released by combustion;

[0055] The mass and energy of the hydrogen, oxygen, and air flows in the combustion chamber of burner A before and after the reaction are conserved, which is expressed as the following equations:

[0056]

[0057] Where, T0 is the temperature before reaction; T t is the temperature after reaction; is the molar mass of hydrogen; is the molar mass of oxygen; is the molar mass of nitrogen; is the molar mass of water; is the specific enthalpy of hydrogen at the temperature T0 before the reaction; is the specific enthalpy of oxygen at the temperature T0 before the reaction; is the specific enthalpy of nitrogen at the temperature T0 before the reaction; The temperature of oxygen after the reaction is T t Specific enthalpy; is the nitrogen temperature after the reaction T t Specific enthalpy; is the temperature of water vapor after the reaction t Specific enthalpy; is the total mass flow rate of the outlet gas;

[0058] Under different Mach number conditions, the total temperature of the airflow is T t The total flow is Under the pre-set wind tunnel nozzle dimensions, the nozzle outlet test gas parameters including total pressure, static pressure, and static temperature are determined, thereby determining the hydrogen, oxygen, and air flow rates required for combustion heating.

[0059] The calculation method of gas venturi flow rate is as follows:

[0060]

[0061] Where C d is the outflow coefficient of the gas venturi; C * is the critical flow function of the gas venturi; A th is the flow area of the gas venturi at the minimum diameter; P t is the total pressure of the inflowing gas; T t is the inflow gas temperature; R is the gas constant; M is the gas molar mass;

[0062] Among them, the calculation method of liquid nitrogen cavitation tube flow is as follows:

[0063]

[0064] Where, is the liquid nitrogen flow rate; A w C is the flow area at the minimum diameter of the liquid nitrogen cavitation tube; d is the flow coefficient of the liquid nitrogen cavitation tube; ρ is the density of liquid nitrogen; ΔP is the pressure difference between the upstream and downstream of the liquid nitrogen cavitation tube.

[0065] The pre-cooling turbojet engine performance test device under normal temperature and variable flow air supply conditions of this embodiment includes the following contents:

[0066] The normal temperature air supply pipeline for the engine, i.e., the AC1-Kac1-Pac1-Kac2-Pac2-Kac6-C pipeline, realizes the normal temperature variable flow air supply. When the pressure in front of the normal temperature air regulating valve Kac6 is constant, the normal temperature air flow rate is changed by changing the opening of the normal temperature air regulating valve Kac6. When the exhaust pipeline pneumatic valve Kac4 and the normal temperature air regulating valve Kac6 are opened, the ratio of the mass flow rate of the normal temperature air supplied to the engine C to the mass flow rate of the normal temperature air discharged to the atmosphere is equal to the normal temperature air regulating valve Kac6. The ratio of the area of the flow channel to the minimum cross-sectional area of the air venturi II Kac5 is shown. The engine is supplied with aviation kerosene fuel by the engine's aviation kerosene fuel supply line, i.e., F1-Kf1-Pf1-Kf2-Kf3-Pf2-D. The engine's aviation kerosene fuel flow rate is adjusted by varying the power of the fuel pump Kf1. The liquid nitrogen flow control valve Kn2 of the liquid nitrogen precooling medium supply line for the precooler is in the closed state. The burner A is in the closed state, and the high-temperature air control valve Kah3 in the combustion heater and the high-temperature air supply line is in the closed state.

[0067] The pre-cooling turbojet engine performance test device under normal temperature and constant flow air supply conditions of this embodiment is characterized by including the following contents:

[0068] A constant-flow normal-temperature air supply is achieved through the normal-temperature air supply pipeline for the engine, namely the AC1-Kac1-Pac1-Kac2-Pac2-Kac6-C pipeline. At this time, the exhaust pipeline pneumatic valve Kac4 is closed. When the pressure in front of the normal-temperature air control valve Kac6 is constant, a constant-flow normal-temperature air supply is achieved by adjusting the opening of the normal-temperature air control valve Kac6 in advance. The aviation kerosene fuel supply to the engine is achieved through the aviation kerosene fuel supply pipeline for the engine, namely the F1-Kf1-Pf1-Kf2-Kf3-Pf2-D pipeline. The pre-set power of the fuel pump Kf1 achieves the supply of aviation kerosene fuel to the engine at the rated flow rate. The liquid nitrogen flow control valve Kn2 of the liquid nitrogen precooling medium supply pipeline for the precooler is in the closed state. The burner A is in the off state, and the high-temperature air control valve Kah3 in the combustion heater and the high-temperature air supply pipeline is in the closed state.

[0069] The pre-cooled turbojet engine performance test device under high-temperature variable-flow air supply conditions of this embodiment includes the following contents:

[0070] The high-temperature variable-flow air supply is realized by the combination of the combustion heater system and the high-temperature air supply pipeline, i.e., the AB-P4-Kah3-C pipeline. The burner A is in the open state, and the high-temperature pneumatic valve Kah1 of the exhaust pipeline is in the open state. The gas flow of the high-temperature air supply pipeline, i.e., the B-P4-Kah3-C pipeline, is changed by adjusting the opening of the high-temperature air regulating valve Kah3. The excess high-temperature gas is discharged into the atmosphere through the exhaust pipeline II, i.e., the Kah1-Kah2 pipeline. When the high-temperature pneumatic valve Kah1 and the high-temperature air regulating valve Kah3 of the exhaust pipeline are opened, the ratio of the mass flow rate of the high-temperature air supplied to the engine C to the mass flow rate of the high-temperature air discharged to the atmosphere is equal to the area of the flow channel of the high-temperature air regulating valve Kah3 and The ratio of the minimum cross-sectional area of the exhaust pipe venturi Kah2; the supply of aviation kerosene fuel to the engine is achieved by the engine aviation kerosene fuel supply pipeline, namely the F1-Kf1-Pf1-Kf2-Kf3-Pf2-D pipeline, and the engine aviation kerosene fuel flow rate is adjusted by changing the power of the fuel pump Kf1; the liquid nitrogen pre-cooling medium supply pipeline for the precooler, namely the N1-Pn1-Kn1-Pn2-Kn2-Kn3-C pipeline, realizes the supply of liquid nitrogen to precooler C to cool the high-temperature air generated by burner A. When the pressure of the liquid nitrogen storage tank N1 is fixed, the liquid nitrogen supply flow rate is changed by adjusting the opening of the liquid nitrogen flow control valve Kn2; at this time, the normal temperature air control valve Kac6 of the normal temperature air supply pipeline for the engine is in the closed state.

[0071] The pre-cooled turbojet engine performance test device under the condition of high temperature constant flow air supply of this embodiment includes the following contents:

[0072] The high-temperature constant-flow air supply is realized by the combustion heater system and the high-temperature air supply pipeline combination, namely the AB-P4-Kah3-C pipeline. The burner A is in the open state, the high-temperature pneumatic valve Kah1 of the exhaust pipeline is closed, and the supply flow of the high-temperature gas is fixed by the opening of the high-temperature air regulating valve Kah3 set in advance; the aviation kerosene fuel supply pipeline for the engine, namely the F1-Kf1-Pf1-Kf2-Kf3-Pf2-D pipeline, realizes the supply of aviation kerosene fuel to the engine. The power of the installed fuel pump Kf1 regulates the flow of aviation kerosene fuel to the engine. The precooler uses liquid nitrogen to precool the medium supply pipeline, that is, the N1-Pn1-Kn1-Pn2-Kn2-Kn3-C pipeline to supply liquid nitrogen to the precooler C to cool the high-temperature air generated by the burner A. When the pressure of the liquid nitrogen storage tank N1 is fixed, the opening of the pre-set liquid nitrogen flow control valve Kn2 is used to fix the supply flow of liquid nitrogen. At this time, the normal temperature air control valve Kac6 of the normal temperature air supply pipeline for the engine is in the closed state.

[0073] Figure 5The pressure diagram inside the combustion heater measured during operation of the precooling turbojet combination engine test system based on the combustion heating mode of this embodiment is given. Figure 5 It can be seen that the burner pressure changes in a step-by-step manner. The pressure is lower before and after combustion and the pressure changes smoothly. The pressure is higher during combustion and the pressure changes smoothly, which meets the design requirements.

[0074] Although the embodiments of the present invention have been disclosed above, they are not limited to the applications listed in the description and exemplary embodiments. The present invention can be applied to various fields of aircraft engine technology to which the present invention pertains. Further modifications and variations will readily occur to those skilled in the art without departing from the principles of the present invention, and the present invention is not limited to the specific details and illustrations shown and described herein.

Claims

1. A pre-cooled turbojet combination engine test system based on combustion heating mode, characterized in that: The precooling turbojet combination engine test system based on the combustion heating mode includes a normal-temperature air supply pipeline for the engine, a normal-temperature air supply pipeline for the combustion heater, an oxygen supply pipeline for the combustion heater, a hydrogen fuel supply pipeline for the combustion heater, a liquid nitrogen precooling medium supply pipeline for the precooler, an aviation kerosene fuel supply pipeline for the engine, and a combination of the combustion heater system and the high-temperature air supply pipeline; The normal temperature air supply pipeline for the engine includes AC1-Kac1-Pac1-Kac2-Pac2-Kac6-C connected in sequence. The pipeline starts from the air storage tank ⅠAC1, passes through the pressure reducer ⅠKac1, the front pressure sensor Pac1 of the air venturi tube Ⅰ, the air venturi tube ⅠKac2, the rear pressure sensor Pac2 of the air venturi tube Ⅰ, and the normal temperature air control valve Kac6, and finally connects to the precooler C, and supplies the normal temperature air to the engine D; the normal temperature air control valve Kac6 is also connected to the exhaust pipeline Ⅰ, and the exhaust pipeline Ⅰ includes Kac4-Kac5 connected in sequence; when the supply flow of normal temperature air needs to be changed, the opening of the normal temperature air control valve Kac6 is changed, and the pneumatic valves Kac4 and Kac5 of the exhaust pipeline are opened at the same time. Air Venturi II Kac5, part of the air is discharged into the atmosphere through exhaust pipe I, thereby realizing a variable flow rate supply of normal temperature air; the ratio of the mass flow rate of normal temperature air supplied to engine C to the mass flow rate of normal temperature air discharged to the atmosphere is equal to the ratio of the area of the flow channel of the regulating valve Kac6 to the minimum cross-sectional area of the air Venturi II Kac5; when normal temperature air is not needed, the exhaust pipe pneumatic valve Kac4 and the normal temperature air regulating valve Kac6 are closed, and normal temperature air is no longer supplied to the precooler C; wherein, the air Venturi I front pressure sensor Pac1 is used to measure the pressure before the air Venturi I Kac2, and the air Venturi I rear pressure sensor Pac2 is used to measure the pressure after the air Venturi I Kac2; The normal temperature air supply pipeline for the combustion heater includes A1-Ka1-Pa1-Ka2-Pa2-Ka3-P2-A connected in sequence. The starting point of the pipeline is the air storage tank ⅡA1, and it passes through the pressure reducer ⅡKa1, the air venturi Ⅱ front pressure sensor Pa1, the air venturi ⅡKa2, the air venturi Ⅱ rear pressure sensor Pa2, the air venturi Ⅱ rear pneumatic valve Ka3, and is mixed with the oxygen in the oxygen supply pipeline for the combustion heater to form oxygen-enriched air. It enters the burner A through the oxygen-enriched air pipeline pressure sensor P2, mixes with hydrogen and burns to produce High-temperature gas is supplied to the precooler C through the process nozzle B to simulate the high-temperature air inhaled by the aircraft during high-speed flight. When the burner A is not in operation, the pneumatic valve Ka3 after the air venturi tube II is closed, and no air is supplied to the burner A. Among them, the pressure sensor Pa1 before the air venturi tube II is used to measure the pressure before the air venturi tube II Ka2, the pressure sensor Pa2 after the air venturi tube II is used to measure the pressure after the air venturi tube II Ka2, and the oxygen-enriched air pipeline pressure sensor P2 is used to measure the pressure of the oxygen-enriched air before entering the burner A. The oxygen supply pipeline for the combustion heater includes O1-Ko1-Po1-Ko2-Po2-Ko3-P2-A connected in sequence. The starting point of the pipeline is the oxygen storage tank O1, and it passes through the oxygen pressure reducer Ko1, the oxygen venturi front pressure sensor Po1, the oxygen venturi Ko2, the oxygen venturi rear pressure sensor Po2, the oxygen venturi rear pneumatic valve Ko3, and is mixed with the air in the normal temperature air supply pipeline for the combustion heater to form oxygen-enriched air. It enters the burner A through the oxygen-enriched air pipeline pressure sensor P2, mixes with hydrogen and burns to produce high-temperature gas, which is supplied to the burner through the process nozzle B and pressure sensor P4. The precooler C should be used to simulate the high-temperature air inhaled by the aircraft during high-speed flight; when the burner A is not running, the pneumatic valve Ko3 after the oxygen venturi is closed, and oxygen is no longer supplied to the burner A; among them, the oxygen venturi front pressure sensor Po1 is used to measure the pressure before the oxygen venturi Ko2, the oxygen venturi rear pressure sensor Po2 is used to measure the pressure after the oxygen venturi Ko2, the oxygen-enriched air pipeline pressure sensor P2 is used to measure the pressure of the oxygen-enriched air before entering the burner A, and the pressure sensor P4 is used to measure the pressure of the oxygen-enriched air before entering the high-temperature air control valve Kah3; The hydrogen fuel supply pipeline for the combustion heater includes H1-Kh1-Ph1-Kh2-Ph2-Kh3-P1-A connected in sequence. The starting point of the pipeline is the hydrogen storage tank H1, and it passes through the hydrogen pressure reducer Kh1, the hydrogen venturi front pressure sensor Ph1, the hydrogen venturi Kh2, the hydrogen venturi rear pressure sensor Ph2, the hydrogen venturi rear pneumatic valve Kh3, and enters the burner A through the hydrogen pipeline pressure sensor P1. After mixing with the oxygen-enriched air, it burns to produce high-temperature gas, which is supplied to the precooler C through the process nozzle B and pressure sensor P4 to simulate the flight. High-temperature air inhaled by the aircraft during high-speed flight; when burner A is not in operation, the pneumatic valve Kh3 behind the hydrogen venturi is closed, and hydrogen is no longer supplied to burner A; wherein, the hydrogen venturi front pressure sensor Ph1 is used to measure the pressure before the hydrogen venturi Kh2, the hydrogen venturi rear pressure sensor Ph2 is used to measure the pressure after the hydrogen venturi Kh2, the hydrogen pipeline pressure sensor P1 is used to measure the pressure of hydrogen before entering burner A, and the pressure sensor P4 is used to measure the pressure of oxygen-enriched air before entering the high-temperature air control valve Kah3; The liquid nitrogen pre-cooling medium supply pipeline for the pre-cooler includes N1-Pn1-Kn1-Pn2-Kn2-Kn3-C connected in sequence. The starting point of the pipeline is the liquid nitrogen storage tank N1, passing through the liquid nitrogen cavitation tube front pressure sensor Pn1, liquid nitrogen cavitation tube Kn1, liquid nitrogen cavitation tube rear pressure sensor Pn2, liquid nitrogen flow regulating valve Kn2, liquid nitrogen pneumatic valve Kn3, and the pre-cooling medium flows into the interface to supply to the pre-cooler C, forming a cooling zone in the pre-cooler C to exchange the high-temperature gas generated by combustion. Thermal cooling converts high-temperature gas into normal-temperature gas and supplies it to engine D. The temperature of the normal-temperature gas after passing through the precooler is measured by temperature sensor T1, and the liquid nitrogen medium heated after heat exchange is discharged into the atmosphere through the precooling medium discharge interface; Among them, the liquid nitrogen cavitation tube front pressure sensor Pn1 is used to measure the pressure of liquid nitrogen before entering the liquid nitrogen cavitation tube Kn1, and the liquid nitrogen cavitation tube rear pressure sensor Pn2 is used to measure the pressure of liquid nitrogen between the liquid nitrogen cavitation tube Kn1 and the liquid nitrogen flow control valve Kn2; The aviation kerosene fuel supply pipeline for the engine includes F1-Kf1-Pf1-Kf2-Kf3-Pf2-D, which are connected in sequence. The pipeline starts at fuel tank F1 and passes through fuel pump Kf1, aviation kerosene pump pressure sensor Pf1, aviation kerosene flowmeter Kf2, aviation kerosene pneumatic valve Kf3, and aviation kerosene pneumatic valve post-sensor Pf2, and is ultimately supplied to engine D. Aviation kerosene spray is formed in the turbojet engine combustion chamber, and is mixed with air supplied from the upstream engine normal temperature air supply pipeline, combusting to generate thrust. Among them, aviation kerosene pump post-pressure sensor Pf1 is used to measure the pressure after fuel pump Kf1, and aviation kerosene pneumatic valve post-sensor Pf2 is used to measure the fuel pressure before entering engine D. The combustion heater system and the high-temperature air supply pipeline assembly include AB-P4-Kah3-C connected in sequence; the combustion heater system consists of burner A and process nozzle B. Hydrogen and oxygen-enriched air are burned in burner A to generate high-temperature combustion gas with an oxygen content of 21%, which is used to simulate the high-temperature air inhaled during high-speed flight of the aircraft. The high-temperature air enters the high-temperature air supply pipeline through the process nozzle B, and the high-temperature combustion gas at the outlet of the process nozzle B is defined as high-temperature air; the high-temperature air supply pipeline includes B-P4-Kah3-C connected in sequence. The high-temperature air supply pipeline starts at the outlet of the process nozzle B, passes through the pressure sensor P4, and the high-temperature air control valve Kah3, and finally enters the precooler C. After heat exchange and cooling in the precooler C, it becomes normal-temperature air and is supplied to the engine D; the high-temperature air control valve Kah3 is also connected to the exhaust pipeline II , the exhaust line II includes Kah1-Kah2 connected in sequence; when the supply flow of high-temperature air needs to be changed, the opening of the high-temperature air control valve Kah3 is changed, and the high-temperature pneumatic valve Kah1 of the exhaust line is opened at the same time, and part of the air is discharged into the atmosphere through the high-temperature pneumatic valve Kah1 of the exhaust line and the venturi Kah2 of the exhaust line, thereby realizing the variable flow supply of high-temperature air; the ratio of the mass flow rate of high-temperature air supplied to the engine C to the mass flow rate of high-temperature air discharged to the atmosphere is equal to the ratio of the area of the flow channel of the high-temperature air control valve Kah3 to the minimum cross-sectional area of the venturi Kah2 of the exhaust line; when the supply of high-temperature air is not needed, the burner A is turned off, and high-temperature air is no longer supplied to the precooler C; wherein, the pressure sensor P4 is used to measure the high-temperature gas pressure before the high-temperature air control valve Kah3; During the operation of the test system, the supply of normal temperature air, high temperature air, pre-cooling medium and aviation kerosene with continuous variable flow and constant flow is realized. At the same time, the performance test of pre-cooled turbojet engine under variable flow normal temperature air supply conditions, the performance test of pre-cooled turbojet engine under constant flow normal temperature air supply conditions, the performance test of pre-cooled turbojet engine under variable flow high temperature air supply conditions, and the performance test of pre-cooled turbojet engine under constant flow high temperature air supply conditions are carried out to meet the needs of direct-connected tests of pre-cooled turbojet combination engines under different working conditions.

2. The pre-cooling turbojet combination engine test system based on the combustion heating mode according to claim 1 is characterized in that: The combustion reaction of hydrogen and oxygen in the combustion chamber of the burner A is as follows: ； in, is the molar flow rate of hydrogen; is the molar flow rate of oxygen; is the molar flow rate of air; Release heat for combustion; The mass and energy of the hydrogen, oxygen, and air flows in the combustion chamber of burner A before and after the reaction are conserved, which is expressed as the following equations: ； Where, is the temperature before reaction; is the temperature after reaction; is the molar mass of hydrogen; is the molar mass of oxygen; is the molar mass of nitrogen; is the molar mass of water; The temperature of hydrogen before the reaction Specific enthalpy when is the temperature of oxygen before reaction Specific enthalpy when The temperature of nitrogen before the reaction Specific enthalpy when The temperature of oxygen after the reaction Specific enthalpy; Nitrogen at the reaction temperature Specific enthalpy; The temperature of water vapor after the reaction Specific enthalpy; is the total mass flow rate of the outlet gas; Under different Mach number conditions, the total airflow temperature is The total flow is Under the pre-set wind tunnel nozzle dimensions, the nozzle outlet test gas parameters including total pressure, static pressure, and static temperature are determined, thereby determining the flow rates of hydrogen, oxygen, and air required for combustion heating. The calculation method of gas venturi flow rate is as follows: ； Where, is the outflow coefficient of the gas venturi; is the critical flow function of the gas venturi; is the flow area of the gas venturi at the minimum diameter; is the total pressure of the inflowing gas; is the inflow gas temperature; is the gas constant; is the molar mass of the gas; Among them, the calculation method of liquid nitrogen cavitation tube flow is as follows: ； Where, is the liquid nitrogen flow rate; is the flow area at the minimum diameter of the liquid nitrogen cavitation tube; is the liquid nitrogen cavitation tube flow coefficient; is the density of liquid nitrogen; is the pressure difference between upstream and downstream of the liquid nitrogen cavitation tube.

3. A pre-cooled turbojet engine performance test device under normal temperature and variable flow air supply conditions, which is implemented by the pre-cooled turbojet combined engine test system based on the combustion heating mode according to claim 2, characterized in that: Includes the following: The normal temperature air supply pipeline for the engine, i.e., the AC1-Kac1-Pac1-Kac2-Pac2-Kac6-C pipeline, realizes the normal temperature variable flow air supply. When the pressure in front of the normal temperature air regulating valve Kac6 is constant, the normal temperature air flow rate is changed by changing the opening of the normal temperature air regulating valve Kac6. When the exhaust pipeline pneumatic valve Kac4 and the normal temperature air regulating valve Kac6 are opened, the ratio of the mass flow rate of the normal temperature air supplied to the engine C to the mass flow rate of the normal temperature air discharged to the atmosphere is equal to the normal temperature air regulating valve Kac6. The ratio of the area of the flow channel to the minimum cross-sectional area of the air venturi II Kac5 is shown. The engine is supplied with aviation kerosene fuel by the engine's aviation kerosene fuel supply line, i.e., F1-Kf1-Pf1-Kf2-Kf3-Pf2-D. The engine's aviation kerosene fuel flow rate is adjusted by varying the power of the fuel pump Kf1. The liquid nitrogen flow control valve Kn2 of the liquid nitrogen precooling medium supply line for the precooler is in the closed state. The burner A is in the closed state, and the high-temperature air control valve Kah3 in the combustion heater and the high-temperature air supply line is in the closed state.

4. A pre-cooled turbojet engine performance test device under normal temperature and constant flow air supply conditions, which is implemented by the pre-cooled turbojet combination engine test system based on the combustion heating mode according to claim 2, characterized in that: Includes the following: The normal-temperature air supply pipeline for the engine, i.e., the AC1-Kac1-Pac1-Kac2-Pac2-Kac6-C pipeline, realizes the normal-temperature constant-flow air supply. At this time, the pneumatic valve Kac4 of the exhaust pipeline is closed. When the pressure in front of the normal-temperature air regulating valve Kac6 is constant, the normal-temperature air supply with a constant flow is realized by the pre-set opening of the normal-temperature air regulating valve Kac6. The aviation kerosene fuel supply to the engine is realized by the aviation kerosene fuel supply pipeline for the engine, i.e., the F1-Kf1-Pf1-Kf2-Kf3-Pf2-D pipeline. The aviation kerosene fuel supply to the engine is realized under the rated flow condition by the pre-set power of the fuel pump Kf1. The liquid nitrogen flow regulating valve Kn2 of the liquid nitrogen precooling medium supply pipeline for the precooler is in the closed state; the burner A is in the closed state, and the high-temperature air regulating valve Kah3 in the combustion heater and the high-temperature air supply pipeline is in the closed state.

5. A pre-cooled turbojet engine performance test device under high-temperature variable-flow air supply conditions, which is implemented by the pre-cooled turbojet combined engine test system based on the combustion heating mode according to claim 2, characterized in that: Includes the following: The high-temperature variable-flow air supply is realized by the combination of the combustion heater system and the high-temperature air supply pipeline, i.e., the AB-P4-Kah3-C pipeline. The burner A is in the open state, and the high-temperature pneumatic valve Kah1 of the exhaust pipeline is in the open state. The gas flow of the high-temperature air supply pipeline, i.e., the B-P4-Kah3-C pipeline, is changed by adjusting the opening of the high-temperature air regulating valve Kah3. The excess high-temperature gas is discharged into the atmosphere through the exhaust pipeline II, i.e., the Kah1-Kah2 pipeline. When the high-temperature pneumatic valve Kah1 and the high-temperature air regulating valve Kah3 of the exhaust pipeline are opened, the ratio of the mass flow rate of the high-temperature air supplied to the engine C to the mass flow rate of the high-temperature air discharged to the atmosphere is equal to the area of the flow channel of the high-temperature air regulating valve Kah3 and The ratio of the minimum cross-sectional area of the exhaust pipe venturi Kah2; the supply of aviation kerosene fuel to the engine is achieved by the engine aviation kerosene fuel supply pipeline, namely the F1-Kf1-Pf1-Kf2-Kf3-Pf2-D pipeline, and the engine aviation kerosene fuel flow rate is adjusted by changing the power of the fuel pump Kf1; the liquid nitrogen pre-cooling medium supply pipeline for the precooler, namely the N1-Pn1-Kn1-Pn2-Kn2-Kn3-C pipeline, realizes the supply of liquid nitrogen to precooler C to cool the high-temperature air generated by burner A. When the pressure of the liquid nitrogen storage tank N1 is fixed, the liquid nitrogen supply flow rate is changed by adjusting the opening of the liquid nitrogen flow control valve Kn2; at this time, the normal temperature air control valve Kac6 of the normal temperature air supply pipeline for the engine is in the closed state.

6. A pre-cooled turbojet engine performance test device under high-temperature constant-flow air supply conditions, which is implemented by the pre-cooled turbojet combined engine test system based on the combustion heating mode according to claim 2, characterized in that: Includes the following: The high-temperature constant-flow air supply is realized by the combustion heater system and the high-temperature air supply pipeline combination, namely the AB-P4-Kah3-C pipeline. The burner A is in the open state, the high-temperature pneumatic valve Kah1 of the exhaust pipeline is closed, and the supply flow of the high-temperature gas is fixed by the opening of the high-temperature air regulating valve Kah3 set in advance; the aviation kerosene fuel supply pipeline for the engine, namely the F1-Kf1-Pf1-Kf2-Kf3-Pf2-D pipeline, realizes the supply of aviation kerosene fuel to the engine. The power of the installed fuel pump Kf1 regulates the flow of aviation kerosene fuel to the engine. The precooler uses liquid nitrogen to precool the medium supply pipeline, that is, the N1-Pn1-Kn1-Pn2-Kn2-Kn3-C pipeline to supply liquid nitrogen to the precooler C to cool the high-temperature air generated by the burner A. When the pressure of the liquid nitrogen storage tank N1 is fixed, the opening of the pre-set liquid nitrogen flow control valve Kn2 is used to fix the supply flow of liquid nitrogen. At this time, the normal temperature air control valve Kac6 of the normal temperature air supply pipeline for the engine is in the closed state.

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