A self-starting engine system and method for a natural combustion propellant oxygen-rich staged combustion cycle

Abstract

A self-igniting propellant oxygen-rich staged combustion cycle self-starting engine system and method, belonging to the technical field of engines. In the present invention, a fuel primary pump, a fuel secondary pump, an oxidizer pump, and a gas turbine are coaxially connected in sequence. The fuel primary pump and the fuel secondary pump are both used to pressurize the fuel, the oxidizer pump is used to pressurize the oxidizer, and the gas turbine is used to drive the shaft to rotate; the thrust chamber is used to provide thrust; the gas generator is used to generate oxygen-rich gas to drive the gas turbine; the fuel start valve is used to isolate the engine from the fuel at the inlet before starting; the flow stabilizer is used to control the fuel flow into the gas generator at the end of engine starting, and the stage change valve is used to control the fuel flow into the gas generator in the middle and early stages of engine starting; the fuel main valve is used to control the fuel flow into the thrust chamber; the oxidizer start valve is used to isolate the engine from the oxidizer at the inlet before starting. The present invention can successfully complete the starting process without relying on external energy sources.

Description

Technical Field

[0001] The present invention relates to a self-starting engine system and method for a self-igniting propellant oxygen-enriched staged combustion cycle, belonging to the technical field of engines. Background Art

[0002] At present, the starting methods adopted by existing staged combustion cycle engines include self-starting with a starting box and forced starting with a pyrotechnic starter. The former uses a high-pressure starting box to supply fuel for initial ignition to the gas generator and keeps the flow stabilizer in a steady-flow working state throughout the process, thereby controlling the fuel flow entering the gas generator; the latter uses the gas generated by the pyrotechnic starter to spin the turbopump, and after the engine climbs to a certain operating condition, it is relayed by the oxygen-enriched gas generated by the gas generator. To a certain extent, both rely on external energy sources to assist the engine to complete the starting process. Summary of the Invention

[0003] The technical problem solved by the present invention is: overcoming the deficiencies of the prior art, providing a self-starting engine system and method for a self-igniting propellant oxygen-enriched staged combustion cycle, enabling the engine to successfully complete the starting process without relying on external energy sources.

[0004] The technical solution of the present invention is: a self-starting engine system for a self-igniting propellant oxygen-enriched staged combustion cycle, including a fuel start valve, a fuel primary pump, a fuel secondary pump, a flow stabilizer, a staging valve, a fuel main valve, a thrust chamber, a gas generator, a gas turbine, an oxidizer pump, and an oxidizer start valve;

[0005] The fuel start valve is located at the fuel inlet of the engine, and its outlet is connected to the inlet of the fuel primary pump, and is used to isolate the engine from the fuel at the inlet before starting;

[0006] The fuel primary pump, the fuel secondary pump, the oxidizer pump, and the gas turbine are coaxially connected in sequence. The fuel primary pump and the fuel secondary pump are both used to pressurize the fuel, the oxidizer pump is used to pressurize the oxidizer, and the gas turbine is used to drive the shaft to rotate;

[0007] The flow stabilizer is connected to the staging valve and is located between the fuel secondary pump and the gas generator. The flow stabilizer is used to control the fuel flow entering the gas generator at the end stage of engine starting, and the staging valve is used to control the fuel flow entering the gas generator in the middle and early stages of engine starting;

[0008] The fuel main valve is located between the fuel primary pump and the thrust chamber and is used to control the fuel flow entering the thrust chamber;

[0009] The inlet of the thrust chamber is respectively connected to the outlet of the gas turbine and the outlet of the fuel primary pump, and the outlet is connected to the outside and is used to provide thrust;

[0010] The inlet of the gas generator is respectively connected to the outlet of the fuel secondary pump and the outlet of the oxidizer pump, and the outlet is connected to the inlet of the gas turbine, and is used to generate oxygen-rich gas for driving the gas turbine;

[0011] The oxidizer start valve is located at the engine oxidizer inlet, and the outlet is connected to the oxidizer pump inlet, and is used to isolate the engine from the oxidizer at the inlet before startup.

[0012] Further, during the engine startup process, the stage valve and the flow stabilizer jointly control the fuel flow rate entering the gas generator.

[0013] Further, the stage valve is initially in a small opening state; after a given trigger signal, its flow area begins to gradually increase until it reaches the maximum flow area.

[0014] Further, the flow stabilizer is in a fixed opening state when the pressure difference between the inlet and outlet is less than the threshold value; after the pressure difference between the inlet and outlet is greater than the threshold value, it can stabilize the outflow flow rate by adjusting the flow area within a certain pressure difference range.

[0015] Further, during the process of the flow stabilizer transitioning from the fixed opening state to the steady flow working state, the response rate of its flow rate is positively correlated with the change rate of the pressure difference between the inlet and outlet.

[0016] Further, the main fuel valve is initially in a small opening state; after a given trigger signal, its flow area rapidly increases to the maximum flow area.

[0017] Further, after the stage valve and the main fuel valve are turned to the maximum flow area, they can maintain the state where the valve core is fully opened under the action of the inlet and outlet pressures.

[0018] Further, the fuel start valve and the oxidizer start valve are initially in the closed state, and quickly turn to the fully open state after a given trigger signal.

[0019] According to the self-starting method for a self-igniting propellant oxygen-rich staged combustion cycle engine implemented by the self-starting engine system for a self-igniting propellant oxygen-rich staged combustion cycle, it includes:

[0020] Before the engine starts, the fuel start valve and the oxidizer start valve are in the closed state, and the propellant is filled in front of the start valve. At this time, both the stage valve and the main fuel valve are in the initial small opening state;

[0021] The fuel start valve and the oxidizer start valve are opened in sequence, and the two propellants respectively start to fill the engine cavity. At this time, the engine cavity is in a fully open state;

[0022] When both propellants are filled into the gas generator, spontaneous ignition combustion begins, and the oxygen-rich gas generated drives the gas turbine to start rotating. The speed of the engine turbopump gradually climbs, and the pressure after the pump increases accordingly. At this time, the fuel has been freely filled behind the fuel main valve;

[0023] When the speed of the engine turbopump climbs to the first starting condition, the flow areas of the stage-changing valve and the fuel main valve start to increase successively under the action of the trigger signal. The fuel flow rate into the gas generator increases, the speed of the engine turbopump accelerates, and the forced filling process of the thrust chamber passage also speeds up;

[0024] When the fuel is forced to fill the fuel nozzle of the thrust chamber, the thrust chamber starts to ignite and build pressure; when the speed of the engine turbopump climbs to the second starting condition, the flow stabilizer starts to transition from the fixed opening state to the steady flow working state, and the operating condition of the engine turbopump transitions to the rated condition.

[0025] Furthermore, the first starting condition is 30% - 45% of the rated condition, and the second starting condition is 80% - 95% of the rated condition.

[0026] The advantages of the present invention compared with the prior art are as follows:

[0027] (1) The self-starting engine system of the spontaneous combustion propellant oxygen-rich staged combustion cycle of the present invention can successfully complete the starting process without relying on external energy sources. Existing oxygen-rich staged combustion cycle engines rely on external energy sources such as high-pressure gas or pyrotechnic starters to assist in completing the starting process. However, in the present invention, the engine can successfully complete the starting process only relying on the tank pressure.

[0028] (2) The self-starting engine system of the spontaneous combustion propellant oxygen-rich staged combustion cycle of the present invention has a simple structure and is convenient to use. Different from existing oxygen-rich staged combustion cycle engines, three starting valves in front of the gas generator and the thrust chamber are cancelled in the present invention, and the ignition sequence of the gas generator and the thrust chamber is ensured through the filling process, simplifying the system structure and being convenient to use.

[0029] (3) The self-starting engine of the spontaneous combustion propellant oxygen-rich staged combustion cycle of the present invention has high starting acceleration. In the present invention, the fuel main valve is initially in a small opening state, reducing the load of the fuel primary pump, which is beneficial to the rapid climb of the engine operating condition. When the thrust chamber is filled with fuel, the fuel main valve is in a fully open state, and the thrust chamber ignites under a large flow rate, shortening the time from thrust chamber ignition to the engine reaching the rated thrust and improving the starting acceleration of the engine. Brief Description of the Drawings

[0030] Figure 1 It is a system diagram of the engine of the present invention;

[0031] Figure 2 It is a starting timing diagram of the engine of the present invention;

[0032] Figure 3 It is a dimensionless rotational speed change curve graph during the engine starting process. Specific implementation manners

[0033] In order to better understand the above technical solution, the technical solution of the present application will be described in detail below through the accompanying drawings and specific embodiments. It should be understood that the embodiments of the present application and the specific features in the embodiments are detailed descriptions of the technical solution of the present application, rather than limitations on the technical solution of the present application. Without conflict, the technical features in the embodiments of the present application and the embodiments can be combined with each other.

[0034] The following further details a self-igniting propellant oxygen-rich staged combustion self-starting engine system and method provided by the embodiments of the present application in conjunction with the accompanying drawings of the specification. The specific implementation manners may include (as shown in Figure 1 、 2 and 3): a fuel start valve 1, a fuel primary pump 2, a fuel secondary pump 3, a flow stabilizer 4, a staging valve 5, a fuel main valve 6, a thrust chamber 7, a gas generator 8, a gas turbine 9, an oxidizer pump 10, and an oxidizer start valve 11. The fuel primary pump 2, the fuel secondary pump 3, the oxidizer pump 10, and the gas turbine 9 are coaxially connected in sequence. The fuel primary pump 2 and the fuel secondary pump 3 are both used to pressurize the fuel, the oxidizer pump 10 is used to pressurize the oxidizer, and the gas turbine 9 is used to drive the shaft to rotate; the inlet of the thrust chamber 7 is respectively connected to the outlet of the gas turbine 9 and the outlet of the fuel primary pump 2, and the outlet is communicated with the outside, and is used to provide thrust; the inlet of the gas generator 8 is respectively connected to the outlet of the fuel secondary pump 3 and the outlet of the oxidizer pump 10, and the outlet is connected to the inlet of the gas turbine 9, and is used to generate oxygen-rich gas for driving the gas turbine 9; the fuel start valve 1 is located at the fuel inlet of the engine, and the outlet is connected to the inlet of the fuel primary pump 2, and is used to isolate the engine from the fuel at the inlet before starting; the flow stabilizer 4 is connected to the staging valve 5 and is located between the fuel secondary pump 3 and the gas generator 8. The flow stabilizer 4 is used to control the fuel flow rate entering the gas generator 8 at the end of the engine starting period, and the staging valve 5 is used to control the fuel flow rate entering the gas generator 8 in the middle and early stages of the engine starting; the fuel main valve 6 is located between the fuel primary pump 2 and the thrust chamber 7, and is used to control the fuel flow rate entering the thrust chamber 7; the oxidizer start valve 11 is located at the oxidizer inlet of the engine, and the outlet is connected to the inlet of the oxidizer pump 10, and is used to isolate the engine from the oxidizer at the inlet before starting.

[0035] Furthermore, in a possible implementation manner, during the engine starting process, the staging valve 5 and the flow stabilizer 4 jointly control the fuel flow rate entering the gas generator 8.

[0036] In a possible implementation, the stage conversion valve 5 is initially in a small opening state; after a given trigger signal is provided, its flow area gradually increases until it reaches the maximum flow area.

[0037] Furthermore, the flow stabilizer 4 is in a fixed opening state when the pressure difference between the inlet and outlet is less than the threshold value; after the pressure difference between the inlet and outlet is greater than the threshold value, it can stabilize the outflow flow rate by adjusting the flow area within a certain pressure difference range.

[0038] In a possible implementation, during the process of the flow stabilizer 4 transitioning from the fixed opening state to the steady flow working state, the response rate of its flow rate is positively correlated with the change rate of the pressure difference between the inlet and outlet.

[0039] Optionally, in a possible implementation, the main fuel valve 6 is initially in a small opening state; after a given trigger signal is provided, its flow area rapidly increases to the maximum flow area.

[0040] In a possible implementation, after the stage conversion valve 5 and the main fuel valve 6 are converted to the maximum flow area, they can maintain the state where the valve core is fully opened under the action of the inlet and outlet pressures.

[0041] Furthermore, in a possible implementation, the fuel start valve 1 and the oxidizer start valve 11 are initially in the closed state and rapidly turn to the fully opened state after a given trigger signal is provided.

[0042] To enable the staged combustion cycle engine to successfully complete startup without relying on external energy, the present invention proposes a self-igniting propellant self-starting staged combustion cycle engine system.

[0043] The engine system is composed as Figure 1 shown, and the working principle during the engine startup process is as follows:

[0044] (1) Before the engine starts, the fuel and oxidizer start valves 1 and 11 are in the closed state, and the propellant is filled in front of the start valves. At this time, both the stage conversion valve 5 and the main fuel valve 6 are in the initial small opening state.

[0045] (2) The fuel start valve 1 and the oxidizer start valve 11 are opened in sequence, and the two propellants start to fill the engine cavity. At this time, the engine cavity is in a fully open state.

[0046] (3) When both propellants are filled into the gas generator 8, self-ignition combustion starts, and the generated oxygen-rich gas drives the gas turbine 9 to start rotating. The engine turbopump speed gradually climbs, and the pressure after the pump increases accordingly. At this time, the fuel has freely filled behind the main fuel valve 6.

[0047] (4) When the engine turbine pump speed climbs to the first starting condition, the flow areas of the stage transition valve 5 and the main fuel valve 6 start to increase successively under the action of the trigger signal. The flow areas of the stage transition valve 5 and the main fuel valve 6 start to increase, the fuel flow rate into the gas generator 8 rises rapidly, the output power of the gas turbine 9 increases rapidly, resulting in an accelerated climbing rate of the engine operating condition. At the same time, the forced filling process of the fuel behind the pump for the cooling channel cavity of the thrust chamber 7 also accelerates.

[0048] (5) When the fuel is forced to fill the fuel nozzle of the thrust chamber, the thrust chamber 7 starts to ignite and build pressure, and the pressure ratio of the gas turbine 9 decreases, and the climbing rate of the engine operating condition slows down accordingly. When the engine turbine pump speed climbs to the second starting condition, the flow stabilizer 4 starts to transition from the fixed opening state to the steady flow working state. The flow stabilizer 4 in the steady flow working state restricts the further increase of the fuel flow rate into the gas generator 8, making the flow rate stable at the rated design value, so that the engine speed operating condition transitions to the rated condition.

[0049] Furthermore, the first starting condition is 30% - 45% of the rated condition, and the second starting condition is 80% - 95% of the rated condition.

[0050] The measure to achieve self - starting without external energy in the present invention is: a starting system composed of a stage transition valve, a flow stabilizer, and a main fuel valve is proposed. Among them, the stage transition valve and the flow stabilizer jointly control the fuel flow rate into the gas generator, and the main fuel valve controls the fuel flow rate into the thrust chamber.

[0051] The self - starting method proposed by the present invention has been verified through the simulation of the engine starting process. By establishing a dynamic simulation model for the starting process of the oxygen - rich staged combustion cycle engine applying this starting method, the engine starting timing used in the starting calculation is as Figure 2 shown, and the dimensionless speed climbing curve of the turbine pump is as Figure 3 shown. The turbine pump speed climbs rapidly and smoothly during the climbing process. The simulation calculation results show that: the oxygen - rich staged combustion cycle engine system proposed by the present invention can achieve self - starting without relying on external energy.

[0052] Obviously, those skilled in the art can make various changes and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and variations of this application fall within the scope of the claims of this application and their equivalent technologies, this application also intends to include these changes and modifications.

[0053] The content not detailedly described in the specification of the present invention belongs to the well - known technology of those skilled in the art.

Claims

1. A self-igniting propellant oxygen-rich afterburning cycle self-starting engine system, characterized in that: It includes a fuel start valve (1), a primary fuel pump (2), a secondary fuel pump (3), a flow stabilizer (4), a stage transition valve (5), a main fuel valve (6), a thrust chamber (7), a gas generator (8), a gas turbine (9), an oxidizer pump (10) and an oxidizer start valve (11); The fuel start valve (1) is located at the engine fuel inlet. The outlet of the fuel start valve (1) is connected to the inlet of the primary fuel pump (2). The fuel start valve (1) is used to isolate the engine from the fuel at the engine fuel inlet before startup; The secondary fuel pump (3), the primary fuel pump (2), the oxidizer pump (10) and the gas turbine (9) are coaxially connected in sequence. Both the primary fuel pump (2) and the secondary fuel pump (3) are used to pressurize the fuel. The oxidizer pump (10) is used to pressurize the oxidizer. The gas turbine (9) is used to drive the shaft to rotate; The flow stabilizer (4) is connected to the stage transition valve (5) and is located between the secondary fuel pump (3) and the gas generator (8). The flow stabilizer (4) is used to control the fuel flow into the gas generator (8) at the end of engine startup. The stage transition valve (5) is used to control the fuel flow into the gas generator (8) in the middle and early stages of engine startup; The main fuel valve (6) is located between the primary fuel pump (2) and the thrust chamber (7) and is used to control the fuel flow into the thrust chamber (7); The inlet of the thrust chamber (7) is respectively connected to the outlet of the gas turbine (9) and the outlet of the primary fuel pump (2). The outlet of the thrust chamber (7) is in communication with the outside. The thrust chamber (7) is used to provide thrust; The inlet of the gas generator (8) is respectively connected to the outlet of the secondary fuel pump (3) and the outlet of the oxidizer pump (10). The outlet of the gas generator (8) is connected to the inlet of the gas turbine (9). The gas generator (8) is used to generate oxygen-rich gas to drive the gas turbine (9); The oxidizer start valve (11) is located at the engine oxidizer inlet. The outlet of the oxidizer start valve (11) is connected to the inlet of the oxidizer pump (10). The oxidizer start valve (11) is used to isolate the engine from the oxidizer at the engine oxidizer inlet before startup; Before engine startup, the fuel start valve (1) and the oxidizer start valve (11) are in the closed state. The propellant is filled in front of the start valve. At this time, both the stage transition valve (5) and the main fuel valve (6) are in the initial small opening state; Open the fuel start valve (1) and the oxidizer start valve (11) in sequence. The two propellants start to fill the engine cavity respectively. At this time, the engine cavity is in a fully open state; When both propellants are filled into the gas generator (8), spontaneous ignition combustion starts, and the generated oxygen-rich gas drives the gas turbine (9) to start rotating. The engine turbopump speed gradually climbs; When the engine turbopump speed climbs to the first startup condition, the flow areas of the stage transition valve (5) and the main fuel valve (6) start to increase successively under the action of the trigger signal. The fuel flow into the gas generator (8) increases. The engine turbopump speed accelerates to climb, and the forced filling process of the thrust chamber (7) cavity also speeds up; After the fuel is forced to fill into the fuel nozzle of the thrust chamber, the thrust chamber (7) starts to ignite and build pressure; when the engine turbopump speed climbs to the second starting condition, the flow stabilizer (4) starts to transition from the fixed opening state to the steady flow working state, and the engine turbopump speed condition transitions to the rated condition; The stage change valve (5) is initially in a small opening state; after a given trigger signal, its flow area starts to gradually increase until it reaches the maximum flow area; The flow stabilizer (4) is in a fixed opening state when the pressure difference between the inlet and outlet is less than the threshold value; after the pressure difference between the inlet and outlet is greater than the threshold value, it can stabilize the outflow flow rate by adjusting the flow area within a certain pressure difference range; During the process of the flow stabilizer (4) transitioning from the fixed opening state to the steady flow working state, the response rate of its flow rate is positively correlated with the change rate of the pressure difference between the inlet and outlet; The main fuel valve (6) is initially in a small opening state; after a given trigger signal, its flow area rapidly increases to the maximum flow area.

2. The self-starting engine system of a self-igniting propellant oxygen-enriched afterburning cycle according to claim 1, characterized in that: After the stage change valve (5) and the main fuel valve (6) are switched to the maximum flow area, they can maintain the state where the valve core is fully opened under the action of the inlet and outlet pressures.

3. A self-igniting propellant oxygen-enriched afterburning cycle self-starting engine system according to claim 1, characterized in that: The fuel start valve (1) and the oxidizer start valve (11) are initially in the closed state and rapidly switch to the fully open state after a given trigger signal.

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