An ignition control system and method based on jet oscillator

Abstract

The invention discloses an ignition control system based on a jet oscillator, comprising a duty flame stabilizer, a plurality of jet oscillators arranged on the duty flame stabilizer, and a fuel system. The jet oscillator is connected to a duty area behind the duty flame stabilizer, and the fuel system sprays fuel into the inlet of the jet oscillator. The outlets of the inner channel and the outer channel are provided with paddles, and the paddles rotate around the outer wall of the inner channel. The paddles control the source of air entering the jet oscillator, and the active control of the oxygen content in the combustion chamber is realized, the oxygen content is increased, ignition is realized at a smaller oil-gas ratio, and the ignition boundary is widened; when the paddles are adjusted to a suitable position, the airflow entering the jet oscillator is adjusted, so that the oxygen content and fuel distribution in the duty area can be adjusted.

Description

Technical Field

[0001] The invention relates to an aviation power propulsion system, and in particular to an ignition control system and method based on a jet oscillator. Background Art

[0002] The turbine outlet temperature of the new generation of aircraft engines is as high as 1200-1300K, which puts forward many new and almost harsh design requirements for the afterburner / ramjet combustion chamber. In the afterburner / ramjet combustion chamber, due to its complex working environment and two-phase combustion, ignition and flame stability will be disturbed by many factors. For turbulent non-premixed two-phase ignition, aerodynamic conditions such as airflow temperature, pressure, velocity, and turbulence intensity will affect the success of ignition; in addition, the concentration and distribution of the oil-gas mixture at the ignition position are also important factors affecting the success rate of ignition.

[0003] In order to prevent excessive pressure pulsation during combustion chamber startup from adversely affecting engine performance, afterburner / ramjet combustion chambers generally use on-duty ignition to perform soft ignition, using the on-duty flame to ignite the global flame to reduce the ignition oil-gas ratio and widen the ignition boundary. In addition, the reflux zone formed by the backward step of the sudden expansion on-duty stabilizer is used to widen the flameout boundary of the combustion chamber and improve combustion efficiency. However, on-duty fuel supply will cause local oil enrichment in the combustion chamber, which will affect the combustion stability of the engine. Summary of the invention

[0004] Purpose of the invention: In view of the above shortcomings, the present invention provides an ignition control system based on a jet oscillator for improving the combustion stability of the combustion chamber.

[0005] The invention also provides an ignition control method based on the jet oscillator.

[0006] Technical solution: To solve the above problems, the present invention adopts an ignition control system based on a jet oscillator, including a duty flame stabilizer, a plurality of jet oscillators arranged on the duty flame stabilizer, and a fuel system, wherein the duty flame stabilizer includes a horizontally extending front plate, an inclined plate connected to the rear end of the front plate and extending obliquely upward, and a rear plate connected to the rear end of the inclined plate and extending horizontally, the jet oscillator includes an inlet and an outlet, the inlet of the jet oscillator is located on the front plate, the outlet of the jet oscillator is connected to the inclined plate, and is connected to the duty area behind the inclined plate, and the fuel system includes a fuel nozzle, which is used to spray fuel into the inlet of the jet oscillator;

[0007] The inner channel and the outer channel are located at the front end of the front plate, the outer wall of the inner channel is the inner wall of the outer channel, and paddles are arranged at the outlets of the inner channel and the outer channel. The paddles are arranged on the outer wall of the inner channel, the paddles rotate around the outer wall of the inner channel, and the paddle axis is perpendicular to the extension direction of the inner channel. When the plane where the paddle is located is parallel to the extension direction of the inner channel, the plane where the paddle is located is located outside the plane where the front plate of the on-duty flame stabilizer is located; rotating the paddle inward guides the gas in the outer channel to flow to the inlet of the jet oscillator.

[0008] Furthermore, a plurality of paddles are evenly arranged on the outer wall of the inner channel in the circumferential direction, and one paddle corresponds to one jet oscillator. The rotating shaft of each paddle is connected to an independent driving motor, and the driving motor drives the rotating shaft of the paddle to rotate.

[0009] Furthermore, the angle between the jet oscillator and the inclined plate of the on-duty flame stabilizer is 0° to 90°. The jet oscillator includes an inlet, an inlet throat, a main channel, an outlet throat, and an outlet arranged in sequence, and a left feedback channel and a right feedback channel symmetrically arranged on the left and right sides of the main channel, and both ends of the left feedback channel and the right feedback channel are connected to the inlet throat and the main channel. The ratio of the inlet throat width to the inlet width is 1:2.3-2.8; the ratio of the inlet throat width to the left feedback channel or the right feedback channel width is 1:1-1.3; the ratio of the left feedback channel to the right feedback channel width is 1:1; the ratio of the inlet throat width to the main channel inlet and outlet width is 1:1.3-1.8:4-5; the ratio of the inlet throat width to the outlet throat width is 1:1; the ratio of the inlet throat width to the outlet width is 1:1.3-1.8; the ratio of the inlet to inlet throat distance to the left feedback channel or the right feedback channel length is 1:2.3-2.8; the ratio of the inlet to inlet throat distance to the outlet throat to outlet distance is 1:0.5-1.

[0010] Furthermore, the fuel system includes a fuel injection rod located in front of the jet oscillator, and a plurality of fuel nozzles for injecting fuel into the jet oscillator are formed on the fuel injection rod.

[0011] The present invention also adopts an ignition control method based on a jet oscillator. When used as an oxygen content adjustment system, the paddle rotation angle is adjusted so that pure air from the outer duct enters the duty area through the jet oscillator to adjust the oxygen content in the duty area. At this time, the fuel system does not work; when used as a pre-evaporation fuel supply system, the paddle is rotated to be parallel to the outer duct channel, and the air entering the jet oscillator is basically high-temperature air from the inner duct. The fuel is sprayed vertically into the inlet of the jet oscillator through the fuel nozzle, oscillates with the incoming flow, and part of the oil droplets evaporate to enter the duty area. Under the action of the jet oscillator, the fuel is evenly distributed circumferentially in the combustion chamber, and ignites and burns under the ignition energy. The paddle position is adjusted so that the airflow entering the jet oscillator contains both pure air and high-temperature combustion gas. At this time, the fuel system works and the oxygen content and fuel concentration in the duty area are adjusted at the same time.

[0012] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0013] 1. By using a jet oscillator to inject fuel, a more uniform fuel distribution can be obtained with fewer injection points. That is, when a jet oscillator is used for fuel injection, the oil droplets can oscillate periodically with a certain frequency in the circumferential direction with the air, thus widening the circumferential fuel distribution range and reducing the number of fuel injection points when using an ordinary evaporative stabilizer.

[0014] 2. Fuel injection through a jet oscillator can improve combustion instability in the combustion chamber. The pressure in the combustion chamber will pulsate periodically and with a large amplitude over time, and the atomization process is considered to be one of the disturbance sources of combustion instability; using a jet oscillator to inject fuel, the fuel pulsation frequency is superimposed on the combustion chamber vibration frequency, thereby controlling combustion instability.

[0015] 3. By controlling the spatial position and angle of the jet oscillator, the spatial distribution of the fuel in the combustion chamber can be adjusted, thereby adjusting the temperature distribution in the combustion chamber. By adjusting the position and angle of the jet oscillator outlet, a partial low-temperature air curtain can be formed in the duty stabilizer at a suitable position to prevent wall ablation.

[0016] 4. The source of air entering the jet oscillator is controlled by the paddle to realize active control of the oxygen content in the combustion chamber. That is, when the paddle is adjusted to the front section of the duty stabilizer, the external airflow enters the jet oscillator, the fuel supply system does not work, and the oxygen content in the duty area is adjusted. Due to the increase in oxygen content, ignition can be achieved at a smaller oil-gas ratio, thereby widening the ignition boundary; when the paddle is adjusted to be parallel to the front section of the duty stabilizer, the airflow entering the jet oscillator is basically the internal high-temperature airflow, the fuel system works, and the fuel is vertically sprayed into the jet oscillator entrance through the injection rod and the injection hole, and enters the duty area with the oscillation of the incoming flow and the evaporation of some oil droplets. Under the action of the jet oscillator, the fuel is evenly distributed in the circumferential direction of the combustion chamber, and ignites and burns at the appropriate ignition energy; when the paddle is adjusted to the appropriate position, the airflow entering the jet oscillator contains both pure air and high-temperature combustion gas, which can simultaneously adjust the oxygen content and fuel distribution in the duty area. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the connection structure between a single jet oscillator and a flame stabilizer on duty in the present invention;

[0018] Figure 2 It is a structural schematic diagram of a plurality of jet oscillators arranged circumferentially on the duty flame stabilizer in the present invention;

[0019] Figure 3 It is a structural schematic diagram of the on-duty flame stabilizer in the present invention being arranged in the combustion chamber;

[0020] Figure 4 It is a schematic diagram of the structure in which parallel paddles are arranged in front of the jet oscillator in the present invention;

[0021] Figure 5 It is a schematic diagram of the structure of the paddle in the combustion chamber of the present invention;

[0022] Figure 6 It is a structural schematic diagram of the present invention when the paddle is rotated by a certain angle;

[0023] Figure 7 It is a schematic diagram of the structure in the combustion chamber when the paddle is rotated by a certain angle in the present invention;

[0024] Figure 8 for Figure 7 Rear view in;

[0025] Fig. 9 Schematic diagram of the paddle structure;

[0026] Fig.10 It is a schematic diagram of the structure when several paddles are deflected at a certain angle. DETAILED DESCRIPTION

[0027] like Figures 1 to 3As shown, in this embodiment, an ignition control system based on a jet oscillator includes an on-duty flame stabilizer 1, a jet oscillator 2 arranged at the inclined section of the stabilizer, and an igniter 4. The igniter 4 is inserted into the inner side of the stabilizer through the opening of the rear section of the on-duty stabilizer, releases energy, and ignites under appropriate oil-gas mixture conditions.

[0028] The duty flame stabilizer 1 is divided into a front section 13, a middle oblique section 12 and a rear section 11. The front section 13 and the rear section 11 are parallel to the casing, and the axial length of the front section is adapted to the radial stabilizer and consistent with the length of the rear section; the radial height and inclination angle of the duty stabilizer are adjusted by the middle oblique section. The jet oscillator 2 is fixed to the middle oblique section of the duty stabilizer at a certain angle by welding, and the outlet of the jet oscillator is connected to the duty area behind the middle oblique section to ensure that the incoming flow can enter the inner side of the duty flame stabilizer through the jet oscillator, and the jet oscillator and the duty stabilizer are arranged at 0° (parallel) to 90° (vertical); in this embodiment, the length of the front section and the rear section are both 100mm, the radial height is 40mm, and the inclination angle is 60°.

[0029] A jet oscillator 2 with two feedback channels is adopted, which includes an inlet, an inlet throat, a main channel, an outlet throat and an outlet arranged in sequence, and a left feedback channel and a right feedback channel symmetrically arranged on the left and right sides of the main channel, and both ends of the left feedback channel and the right feedback channel are connected to the inlet throat and the main channel; in this embodiment, for the convenience of description, the "left" and "right" are relative positions, and the left side of the jet oscillator along the flow is "left" and the other side is "right"; its oscillation mechanism is based on the fluid being transferred away from the main jet and returning to the oscillator inlet through the feedback channel, causing the jet to flip to the other side at the inlet; the larger the inlet airflow rate, the shorter the time for the flow through the feedback channel to return to the inlet, and the faster the jet oscillation frequency.

[0030] The ratio of the inlet throat width to the inlet width is 1:2.3-2.8; the ratio of the inlet throat width to the left feedback channel or the right feedback channel width is 1:1-1.3; the ratio of the left feedback channel to the right feedback channel width is 1:1; the ratio of the inlet throat width to the inlet and outlet width of the main channel is 1:1.3-1.8:4-5; the ratio of the inlet throat width to the outlet throat width is 1:1; the ratio of the inlet throat width to the outlet width is 1:1.3-1.8. The ratio of the inlet to inlet throat distance to the left feedback channel or the right feedback channel length is 1:2.3-2.8; the ratio of the inlet to inlet throat distance to the outlet throat to outlet distance is 1:0.5-1.

[0031] The fuel system 3 comprises a fuel injection rod located in front of the jet oscillator, and a plurality of nozzles for injecting into the jet oscillator are formed on the fuel injection rod.

[0032] like Figure 4-8As shown, there are inner channel and outer channel at the front end of the flame stabilizer on duty, the outer channel surrounds the outer side of the inner channel, the outer wall of the inner channel is the inner wall of the outer channel, and the outlets of the inner channel and the outer channel are provided with a paddle 5, which is arranged between the inner and outer channels and can rotate around the axis, and the paddle 5 is arranged on the outer wall of the inner channel, as shown in FIG. Fig. 9 As shown, the paddle rotates around the outer wall of the inner channel, and the rotating shaft of the paddle 5 is perpendicular to the extension direction of the inner channel. The rotating shaft of each paddle is connected to an independent driving motor 51, and the driving motor 51 drives the rotating shaft of the paddle to rotate. When the plane where the paddle is located is parallel to the extension direction of the inner channel, the plane where the paddle 5 is located is located outside the plane where the front plate of the on-duty flame stabilizer is located; Fig.10 As shown, rotating the dial plate inwardly guides the gas in the outer duct to flow toward the inlet of the jet oscillator.

[0033] like Figure 4 and Figure 5 As shown, the adjustment paddle 5 is rotated outward and gradually becomes parallel to the casing. At this time, the external airflow is parallel to the paddle and flows to the outside of the duty flame stabilizer 1, and the internal combustion gas enters the duty area through the jet oscillator. At this time, the fuel system is working, and the fuel is vertically sprayed into the jet oscillator through the injection nozzle on the injection rod. The atomized fuel vapor and small-sized oil droplets enter the duty area to organize combustion.

[0034] like Figures 6 to 8 As shown, the oxygen content in the duty area is adjusted by adjusting the jet oscillator through the paddle. When the outer duct air with a higher oxygen content is adjusted to enter the duty area through the jet oscillator, the paddle rotates inward and abuts against the upper side of the front section of the duty stabilizer. At this time, it is mainly the outer duct airflow that enters the duty area through the jet oscillator, and the fuel system does not work. Fuel is supplied to the duty area through other fuel systems and combustion is organized.

Claims

1. An ignition control system based on a jet oscillator, characterized in that: It includes a duty flame stabilizer, a plurality of jet oscillators arranged on the duty flame stabilizer, and a fuel system. The duty flame stabilizer includes a horizontally extending front plate, an inclined plate connected to the rear end of the front plate and extending obliquely upward, and a rear plate connected to the rear end of the inclined plate and extending horizontally. The jet oscillator includes an inlet and an outlet. The inlet of the jet oscillator is located on the front plate, and the outlet of the jet oscillator is connected to the inclined plate and communicated with the duty area behind the inclined plate. The fuel system includes a fuel nozzle, which is used to spray fuel into the inlet of the jet oscillator. The inner channel and the outer channel are located at the front end of the front plate, the outer wall of the inner channel is the inner wall of the outer channel, and paddles are arranged at the outlets of the inner channel and the outer channel. The paddles are arranged on the outer wall of the inner channel, the paddles rotate around the outer wall of the inner channel, and the paddle axis is perpendicular to the extension direction of the inner channel. When the plane where the paddle is located is parallel to the extension direction of the inner channel, the plane where the paddle is located is located outside the plane where the front plate of the on-duty flame stabilizer is located; rotating the paddle inward guides the gas in the outer channel to flow to the inlet of the jet oscillator.

2. The ignition control system according to claim 1, characterized in that: A plurality of paddles are evenly arranged on the outer wall of the inner channel in the circumferential direction, and one paddle corresponds to one jet oscillator.

3. The ignition control system according to claim 2, characterized in that: The rotating shaft of each paddle is connected to an independent driving motor, and the driving motor drives the rotating shaft of the paddle to rotate.

4. The ignition control system according to claim 1, characterized in that: The angle between the jet oscillator and the inclined plate of the on-duty flame stabilizer is 0°~90°.

5. The ignition control system according to claim 4, characterized in that: The jet oscillator comprises an inlet, an inlet throat, a main channel, an outlet throat, an outlet which are arranged in sequence, and a left feedback channel and a right feedback channel which are symmetrically arranged on the left and right sides of the main channel.

6. The ignition control system according to claim 5, characterized in that: The ratio of the inlet throat width to the inlet width is 1:2.3-2.8; the ratio of the inlet throat width to the left feedback channel or the right feedback channel width is 1:1-1.3; the ratio of the left feedback channel to the right feedback channel width is 1:1; the ratio of the inlet throat width to the main channel inlet and outlet width is 1:1.3-1.8:4-5; the ratio of the inlet throat width to the outlet throat width is 1:1; the ratio of the inlet throat width to the outlet width is 1:1.3-1.8; the ratio of the inlet to inlet throat distance to the left feedback channel or the right feedback channel length is 1:2.3-2.8; the ratio of the inlet to inlet throat distance to the outlet throat to outlet distance is 1:0.5-1.

7. The ignition control system according to claim 1, characterized in that: The fuel system comprises a fuel injection rod located in front of the jet oscillator, and a plurality of fuel injection nozzles for injecting fuel into the jet oscillator are formed on the fuel injection rod.

8. An ignition control method of the ignition control system based on a fluidic oscillator according to claim 1, characterized in that: When used as an oxygen content adjustment system, by adjusting the rotation angle of the paddle, the pure air from the outer duct enters the duty area through the jet oscillator, and the oxygen content in the duty area is adjusted. At this time, the fuel system does not work; when used as a pre-evaporation fuel supply system, the paddle is rotated to be parallel to the outer duct channel, and the air entering the jet oscillator is basically the internal high-temperature airflow. The fuel is sprayed vertically into the inlet of the jet oscillator through the fuel nozzle, oscillates with the incoming flow and part of the oil droplets evaporate to enter the duty area. Under the action of the jet oscillator, the fuel is evenly distributed circumferentially in the combustion chamber, and ignites and burns under the ignition energy. Adjust the position of the paddle so that the airflow entering the jet oscillator contains both pure air and high-temperature combustion gas. At this time, the fuel system works and the oxygen content and fuel concentration in the duty area are adjusted at the same time.

Images