A wide range combined engine ignition and flame stabilization method

Abstract

The present invention relates to an engine ignition method, and in particular to a wide range combination engine ignition and flame stabilization method, which is used to solve the shortcomings that electric ignition, hydrogen or ethylene guided ignition cannot take into account the multiple ignition, combustion support, enhanced combustion, simple system, reliable operation and other requirements of the wide range combination engine. The wide range combination engine ignition and flame stabilization method generates a high-temperature hydrogen-rich fuel gas jet at the concave cavity of the ramjet combustion chamber through an ignition and flame stabilization device, thereby achieving the functions of ignition, combustion support and enhanced combustion of the wide range combination engine combustion chamber; the present invention does not require an additional electric ignition device, does not require carrying an additional hydrogen supply device (tank, valve, etc.), and has a simple system.

Description

Technical Field

[0001] The invention relates to an engine ignition method, in particular to a wide range combined engine ignition and flame stabilization method. Background Art

[0002] Ignition and flame stabilization methods have an important impact on the flight missions of wide-range combined engines. For rocket-based combined cycle (RBCC) engines that work in a wide range, the airflow parameters at the combustion chamber inlet vary widely, and there are complex flow phenomena such as shock waves, expansion waves, flow separation, shock wave / boundary layer interference, and supersonic jet shear during combustion. The airflow speed ranges from subsonic to transonic and then to supersonic. It is very difficult to achieve efficient release of fuel chemical energy in the limited space of the combustion chamber and to achieve reliable ignition, flame stabilization, and efficient combustion of the engine in multiple modes such as ramjet, rocket / ramjet, etc.

[0003] During a complex flight, flameout or weak combustion may occur, requiring multiple ignitions or combustion support and enhanced combustion to achieve continuous thrust stable output. Electric ignition can achieve multiple repeated ignitions, but the ignition energy output time is only in milliseconds, and it is impossible to achieve combustion support and enhanced combustion. Hydrogen or ethylene induced ignition can achieve ignition, combustion support, and enhanced combustion, but it requires carrying an additional electric ignition system (igniting a mixture of room temperature hydrogen or ethylene and air), hydrogen or ethylene supply and regulation system, the system is complex, the working reliability is not high, and the structural mass is large. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings that electric ignition, hydrogen or ethylene guided ignition cannot take into account the requirements of multiple ignition, combustion support, enhanced combustion, simple system, reliable operation, etc. of a wide range combination engine, and to provide an ignition and flame stabilization method for a wide range combination engine.

[0005] In order to solve the deficiencies of the above-mentioned prior art, the present invention provides the following technical solutions:

[0006] A wide range combined engine ignition and flame stabilization system, which is special in that it includes an air inlet, a ramjet combustion chamber and a nozzle arranged in sequence along the airflow direction, and an ignition and flame stabilization device and a rocket thrust chamber arranged in sequence in the ramjet combustion chamber along the airflow direction;

[0007] The ignition and flame stabilization device is arranged at the concave cavity of the ramjet combustion chamber, and comprises an oxidant conduit, a fuel conduit, a propellant injection disk and a body, wherein the body comprises a cylindrical section, a contraction section and an expansion section connected in sequence, and a fuel gas flow channel is arranged inside the body, and the fuel gas flow channel is communicated with the concave cavity flow channel;

[0008] The oxidant conduit is provided with an oxidant, and the fuel conduit is provided with fuel. One end of the oxidant conduit and the fuel conduit are respectively connected to the oxidant inlet and the fuel inlet on the front end surface of the propellant injection disk. A plurality of injectors are provided in the propellant injection disk, and the rear end of the propellant injection disk is connected to the front end of the cylindrical section of the body.

[0009] Furthermore, the direction of the gas output from the gas flow channel is perpendicular to the direction of the gas flow in the concave cavity flow channel, so that the high-temperature hydrogen-rich gas at the outlet of the ignition and flame stabilization device can more easily penetrate the mainstream, thereby achieving wide-range ignition and flame stabilization.

[0010] Furthermore, the oxidant is nitro and the fuel is hydrazine.

[0011] Furthermore, the oxidant is nitrogen tetroxide, and the fuel is anhydrous hydrazine. The nitrogen tetroxide / anhydrous hydrazine is spontaneously combusted to produce high-temperature hydrogen-rich fuel gas, thereby achieving the functions of ignition, combustion support, and combustion enhancement in the combustion chamber of a wide range of combined engines.

[0012] Furthermore, the mass ratio between the nitrogen tetroxide and anhydrous hydrazine is 0.2-0.6:1.

[0013] Furthermore, the ignition and flame stabilization device is located at the center of the cavity, and the expansion section is connected to the cavity through a flange.

[0014] At the same time, the present invention provides a wide range combination engine ignition and flame stabilization method, which is special in that the wide range combination engine ignition and flame stabilization system is used, including the following steps:

[0015] Step 1: Determine the total temperature of the gas, the ignition energy, and the airflow pressure of the cavity of the ignition and flame stabilization device according to the inlet airflow parameter requirements of the ramjet combustion chamber; the inlet of the ramjet combustion chamber is the junction of the air inlet duct and the ramjet combustion chamber; the inlet airflow parameters include flow rate, pressure, temperature, and speed;

[0016] Step 2: Determine the propellant and the mixing ratio of the ignition and flame stabilization device according to the total temperature of the fuel gas of the ignition and flame stabilization device;

[0017] Step 3: Determine the chamber pressure of the ignition and flame stabilization device according to the airflow pressure of the cavity;

[0018] Step 4: Determine the total fuel gas flow rate of the ignition and flame stabilization device propellant according to the ignition energy;

[0019] Step 5, according to the mixing ratio of the propellant obtained in step 2, the chamber pressure obtained in step 3, and the total flow rate of the fuel gas obtained in step 4, the structural parameters of the ignition and flame stabilization device are determined, wherein the structural parameters include the diameter and length of the cylindrical section, the length and outlet area of ​​the contraction section, the length and outlet area of ​​the expansion section, and the number and aperture of the injectors of the propellant injection disk;

[0020] Step 6: prepare an ignition and flame stabilization device according to the structural parameters determined in step 5, and set it in the concave cavity of the ramjet combustion chamber. When the ignition and flame stabilization device is working, the high-temperature hydrogen-rich fuel gas jet generated acts on the air and kerosene mixture in the ramjet combustion chamber to ignite, assist combustion and enhance combustion.

[0021] Furthermore, in step 2, the propellant is a nitrogen tetroxide / anhydrous hydrazine propellant combination, and the mass ratio of nitrogen tetroxide to anhydrous hydrazine in the ignition and flame stabilization device propellant is 0.2~0.6:1.

[0022] Furthermore, in step 3, the chamber pressure of the ignition and flame stabilization device is 0.5 MPa ~ 1.0 MPa, which has strong permeability to the air / kerosene mixed airflow, and is easy to achieve reliable ignition and flame stabilization.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) The present invention provides a wide-range combined engine ignition and flame stabilization method, which adopts a wide-range combined engine ignition and flame stabilization system, including an air inlet, a ramjet combustion chamber and a nozzle, as well as an ignition and flame stabilization device and a rocket thrust chamber arranged in the ramjet combustion chamber; the present invention generates a high-temperature hydrogen-rich fuel gas jet in the concave cavity of the ramjet combustion chamber through the ignition and flame stabilization device, thereby achieving the functions of ignition, combustion assistance and enhanced combustion of the wide-range combined engine combustion chamber; the present invention does not require an additional electric ignition device, does not require carrying an additional hydrogen supply device (tank, valve, etc.), and the system is simple.

[0025] (2) The ignition and flame stabilization device in the wide-range combined engine ignition and flame stabilization system of the present invention adopts a nitrogen tetroxide / anhydrous hydrazine combination as a propellant. The nitrogen tetroxide and anhydrous hydrazine spontaneously ignite upon contact, and the operation is reliable, the working time is adjustable, and the start can be repeated many times, thus meeting the requirements of multiple start-up ignition, long-term flame maintenance, and combustion enhancement of the combined engine under wide-range multiple maneuvers and complex trajectories.

[0026] (3) The present invention provides a wide range combination engine ignition and flame stabilization method, which determines the total temperature of the combustion gas, the ignition energy, and the gas flow pressure of the cavity of the ignition and flame stabilization device according to the inlet airflow parameters and the mixing ratio requirements of the ramjet combustion chamber, and obtains the mixing ratio of the propellant of the flame stabilization device, the chamber pressure and the total flow rate of the combustion gas, and finally determines the structural parameters of the wide range combination engine ignition and flame stabilization system, so that the high temperature hydrogen-rich combustion gas jet generated by the ignition and flame stabilization device can ignite, assist combustion, and enhance combustion of the air / kerosene mixture in the ramjet combustion chamber. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a structural schematic diagram of an embodiment of a wide range combined engine ignition and flame stabilization system of the present invention;

[0028] Figure 2 It is a schematic diagram of the structure of the ignition and flame stabilization device in an embodiment of the present invention.

[0029] The reference numerals are as follows: 1-ignition and flame stabilization device, 11-oxidizer conduit, 12-fuel conduit, 13-propellant injection disk, 14-body, 141-cylindrical section, 142-contraction section, 143-expansion section; 2-air inlet; 3-ramjet combustion chamber, 31-concave cavity; 4-nozzle; 5-rocket thrust chamber. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with the accompanying drawings and exemplary embodiments.

[0031] Reference Figure 1 and Figure 2 A wide range combined engine ignition and flame stabilization system comprises an air inlet 2, a ramjet combustion chamber 3 and a nozzle 4 which are sequentially arranged along the flow direction of an airflow, and an ignition and flame stabilization device 1 and a rocket thrust chamber 5 which are sequentially arranged in the ramjet combustion chamber 3 along the flow direction of an airflow.

[0032] The ignition and flame stabilization device 1 is arranged at the center of the surface of the concave cavity 31 of the ramjet combustion chamber 3. The ignition and flame stabilization device 1 includes an oxidant conduit 11, a fuel conduit 12, a propellant injection disk 13 and a body 14. The body 14 includes a cylindrical section 141, a contraction section 142 and an expansion section 143 connected in sequence. A fuel gas flow channel is arranged inside the body 14, and the fuel gas flow channel is connected to the flow channel of the concave cavity 31. The oxidant conduit 11 is arranged with an oxidant, the fuel conduit 12 is arranged with a fuel, and the oxidant conduit 13 is arranged with a fuel. One end of the chemical agent conduit 11 and the fuel conduit 12 are respectively connected to the oxidant inlet and the fuel inlet of the front end face of the propellant injection disk 13, wherein a plurality of injectors are arranged in the propellant injection disk 13, and the rear end of the propellant injection disk 13 is connected to the front end of the cylindrical section 141 of the body 14; the propellant of the ignition and flame stabilization device 1 adopts a combination of nitrogen tetroxide / anhydrous hydrazine, wherein nitrogen tetroxide is an oxidant and anhydrous hydrazine is a fuel, and the mass ratio between nitrogen tetroxide and anhydrous hydrazine is selected to be 0.2~0.6:1. High-temperature hydrogen-rich gas is generated by the spontaneous combustion of nitrogen tetroxide / anhydrous hydrazine, and the high-temperature hydrogen-rich gas is vertically injected into the ramjet combustion chamber 3 through the concave cavity 31, so as to realize the functions of ignition, combustion support and enhanced combustion of the combustion chamber of the wide range combination engine.

[0033] Based on the above wide range combination engine ignition and flame stabilization system, the present invention provides a wide range combination engine ignition and flame stabilization method, comprising the following steps:

[0034] Step 1: According to the inlet airflow parameters and mixing ratio requirements of the ramjet combustion chamber 3, determine that the total temperature of the gas of the ignition and flame stabilization device 1 is ≥1800K, the ignition energy is ≥0.1MW, and the airflow pressure of the cavity 31 is ≤0.5MPa; the inlet of the ramjet combustion chamber 3 is the junction of the air inlet duct 2 and the ramjet combustion chamber 3;

[0035] Step 2, selecting the propellant of the ignition and flame stabilization device 1 as a combination of dinitrogen tetroxide and anhydrous hydrazine; according to the total temperature of the fuel gas of the ignition and flame stabilization device 1, determining the mass ratio between dinitrogen tetroxide and anhydrous hydrazine to be 0.3:1;

[0036] Step 3: According to the airflow pressure of the cavity 31, the chamber pressure of the ignition and flame stabilization device 1 is determined to be 0.5 MPa;

[0037] Step 4: According to the ignition energy, determine the total flow rate of the propellant gas of the ignition and flame stabilization device 1 to be 0.025 kg / s;

[0038] Step 5, according to the mixing ratio of the propellant obtained in step 2, the chamber pressure obtained in step 3, and the total flow rate of the fuel gas obtained in step 4, the structural parameters of the ignition and flame stabilization device 1 are determined, wherein the structural parameters include the diameter and length of the cylindrical section 141, the length and outlet area of ​​the contraction section 142, the length and outlet area of ​​the expansion section 143, and the number and aperture of the injectors of the propellant injection disk 13;

[0039] Step 6. Prepare the ignition and flame-stabilizing device 1 according to the structural parameters determined in step 5, and set it in the concave cavity 31 of the ramjet combustion chamber 3. When the ignition and flame-stabilizing device 1 is working, the high-temperature hydrogen-rich fuel gas jet generated acts on the air and kerosene mixture in the ramjet combustion chamber 3 to ignite, assist combustion and enhance combustion.

[0040] The above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit them. For ordinary professional and technical personnel in the field, the specific technical solutions recorded in the aforementioned embodiments can be modified, or some of the technical features therein can be replaced by equivalents, and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions protected by the present invention.

Claims

1. A wide range combined engine ignition and flame stabilization method, using a wide range combined engine ignition and flame stabilization system, the wide range combined engine ignition and flame stabilization system comprising an air inlet (2), a ramjet combustion chamber (3) and a nozzle (4) arranged in sequence along the flow direction of an airflow, and an ignition and flame stabilization device (1) and a rocket thrust chamber (5) arranged in sequence in the ramjet combustion chamber (3) along the flow direction of an airflow; The ignition and flame stabilization device (1) is arranged at the concave cavity (31) of the ramjet combustion chamber (3), the ignition and flame stabilization device (1) comprises an oxidant conduit (11), a fuel conduit (12), a propellant injection disk (13) and a body (14), the body (14) comprises a cylindrical section (141), a contraction section (142) and an expansion section (143) connected in sequence, a fuel gas flow channel is arranged inside the body (14), and the fuel gas flow channel is communicated with the flow channel of the concave cavity (31); The oxidant conduit (11) is provided with an oxidant, the fuel conduit (12) is provided with a fuel, one end of the oxidant conduit (11) and the fuel conduit (12) are respectively connected to the oxidant inlet and the fuel inlet at the front end of the propellant injection disk (13), the propellant injection disk (13) is provided with a plurality of injectors, and the rear end of the propellant injection disk (13) is connected to the front end of the cylindrical section (141) of the body (14); It is characterized in that The steps include: Step 1: Determine the total temperature of the fuel gas, the ignition energy, and the airflow pressure of the cavity (31) of the ignition and flame stabilization device (1) according to the inlet airflow parameter requirements of the ramjet combustion chamber (3); the inlet of the ramjet combustion chamber (3) is the junction of the air inlet duct (2) and the ramjet combustion chamber (3); the inlet airflow parameters include flow rate, pressure, temperature, and speed; Step 2: Determine the propellant and the mixing ratio of the ignition and flame stabilization device (1) according to the total temperature of the fuel gas of the ignition and flame stabilization device (1); Step 3, determining the chamber pressure of the ignition and flame stabilization device (1) according to the airflow pressure of the cavity (31); Step 4: Determine the total fuel gas flow rate of the ignition and flame stabilization device (1) propellant according to the ignition energy; Step 5, determining the structural parameters of the ignition and flame stabilization device (1) according to the mixing ratio of the propellant obtained in step 2, the chamber pressure obtained in step 3, and the total flow rate of the fuel gas obtained in step 4, wherein the structural parameters include the diameter and length of the cylindrical section (141), the length and outlet area of ​​the contraction section (142), the length and outlet area of ​​the expansion section (143), and the number and aperture of the injectors of the propellant injection disk (13); Step 6: prepare an ignition and flame stabilization device (1) according to the structural parameters determined in step 5, and set it in the concave cavity (31) of the ramjet combustion chamber (3). When the ignition and flame stabilization device (1) is working, the high-temperature hydrogen-rich fuel gas jet generated acts on the air and kerosene mixture in the ramjet combustion chamber (3) to ignite, assist combustion and enhance combustion.

2. A wide range combined engine ignition and flame stabilization method according to claim 1, characterized in that: In step 2, the propellant is a nitrogen tetroxide / anhydrous hydrazine propellant combination, and the mass ratio of nitrogen tetroxide to anhydrous hydrazine in the ignition and flame stabilization device (1) propellant is 0.2-0.6:

1.

3. A wide range combined engine ignition and flame stabilization method according to claim 2, characterized in that: In step 3, the chamber pressure of the ignition and flame stabilization device (1) is 0.5 MPa to 1.0 MPa.

4. A wide range combined engine ignition and flame stabilization method according to claim 1, characterized in that: The direction of the gas outputted from the gas flow channel is perpendicular to the direction of the gas flow in the flow channel of the concave cavity (31).

5. A wide range combined engine ignition and flame stabilization method according to claim 4, characterized in that: The oxidant is nitro and the fuel is hydrazine.

6. A wide range combined engine ignition and flame stabilization method according to claim 5, characterized in that: The oxidant is nitrogen tetroxide, and the fuel is anhydrous hydrazine.

7. A wide range combined engine ignition and flame stabilization method according to claim 6, characterized in that: The mass ratio of the nitrogen tetroxide to anhydrous hydrazine is 0.2-0.6:

1.

8. A wide range combined engine ignition and flame stabilization method according to any one of claims 4 to 7, characterized in that: The ignition and flame stabilization device (1) is located at the center of the concave cavity (31), and the expansion section (143) is connected to the concave cavity (31) via a flange.

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