CN102493894A - Nozzle exhaust mixing method and device based on pneumatic tab technique - Google Patents

Abstract

The invention discloses a nozzle exhaust mixing method and device based on the aerodynamic protruding piece technology. The nozzle exhaust mixing method is provided with aerodynamic protruding pieces with different airflow injection directions near the exhaust port of the main nozzle of the engine. , so that the main flow area near the exhaust port of the main nozzle of the engine and the air flow outside the main flow area both form a flow direction vortex, so as to realize the mixing of the main flow area near the exhaust port of the main nozzle of the engine and the external air flow. It can be seen from this that the pneumatic tab technology of the present invention can not only maintain the better blending effect brought by the solid small tab blender, but also effectively reduce the The resulting flow loss, at the same time, compared with the lobe blender, its processing difficulty is significantly reduced, and it is easy to implement.

Description

Nozzle Exhaust Mixing Method and Device Based on Pneumatic Tab Technology

technical field

The invention relates to a nozzle mixing device and method based on pneumatic tab technology. the

Background technique

The aircraft exhaust system is a hot gas generating device, its components have a high temperature, and the exhaust itself has a high temperature, so due to thermodynamic and aerodynamic heating, the infrared radiation intensity generated in the infrared window band is much higher than that generated by the background Infrared radiation intensity. According to statistics, the forward detection range of the airborne infrared search and track system (IRST) for fighter jets can reach 185 Km, which seriously threatens the survivability of aircraft. In addition, data shows that the exhaust system is a strong source of infrared radiation. If an advanced stealth exhaust system is used, the infrared radiation intensity of the aircraft can be reduced by 90%, which will reduce the range of the enemy's infrared detector by 68%. The infrared characteristics of the small exhaust system, the most important thing is to strengthen the rapid mixing of the high-temperature nozzle exhaust mainstream and the surrounding cold air, thereby reducing the exhaust temperature and high-temperature area. the

The current exhaust gas mixing devices are mainly lobe mixers and solid small tab mixers. Although these technologies have better mixing effects, they will cause greater flow loss to the nozzle. Under working conditions, the blender cannot be adjusted flexibly. In addition, the more complex shape brings more difficulties to the processing and manufacturing. Therefore, it is imminent to design a low-resistance, high-performance nozzle exhaust mixing device. the

Contents of the invention

Aiming at the deficiencies of the prior art, the present invention provides a nozzle exhaust mixing method based on the aerodynamic tab technology, which provides an aerodynamic tab jet near the exhaust outlet of the main nozzle of the engine to form Flow to the vortex, thereby improving the mixing effect of the outlet airflow of the main nozzle of the engine and the external airflow. the

For realizing above technical purpose, the present invention will take following technical scheme:

A nozzle exhaust mixing method based on aerodynamic tab technology, by setting aerodynamic tabs with different airflow injection directions near the exhaust port of the main nozzle of the engine, the main flow area near the exhaust port of the main nozzle of the engine and The outer airflow in the mainstream area forms a flow direction vortex, which realizes the mixing of the mainstream area near the exhaust port of the main nozzle of the engine and the external airflow.

A device based on the nozzle exhaust mixing method described above, comprising the main nozzle of the engine, the inner aerodynamic tab facing the jet flow in the main flow area of the main nozzle of the engine and the diverging The outer aerodynamic tabs of the jet stream in the main flow area of the main nozzle of the engine, the inner aerodynamic tabs and the outer aerodynamic tabs are all evenly arranged circumferentially on the inner runner pipe wall near the exhaust port of the main nozzle of the engine, and The inner pneumatic tabs and the outer pneumatic tabs are arranged alternately. the

Both the inner aerodynamic tab and the outer aerodynamic tab include a jet injection channel and a jet control mechanism that automatically adjusts the injection flow rate in the jet injection channel according to the actual working conditions of the engine. On the pipe wall of the inner runner near the exhaust port of the nozzle, and the air inlet of the jet injection runner is connected with the bypass airflow, and at the same time, the pressure of the jet ejected from the jet injection runner is higher than that of the main flow area of the main nozzle of the engine In addition, the axis of the jet injection runner is inclined to the axis of the main nozzle of the engine. the

The included angle between the axis of the jet injection channel and the axis of the main nozzle of the engine is 30-150°C. the

The bypass airflow is the high-pressure stage airflow of the engine compressor or the engine cooling airflow or the bypass airflow. the

The main nozzle of the engine is a bypass nozzle, and the jet injection channel is opened on the inner channel of the nozzle near the exhaust port of the bypass nozzle. the

The jet flow control mechanism is provided with a pulse control device for controlling the jet injection channel to perform pulse jet flow.

According to the above technical scheme, the following beneficial effects can be achieved:

1. In the nozzle exhaust mixing device based on the pneumatic tab technology of the present invention, jet injection flow channels are arranged inside and outside near the outlet of the nozzle, and the total number is 4 or more. When the aerodynamic tab is working, it will form an aerodynamic cylinder in the main channel of the main nozzle of the engine. The orderly arrangement can ensure that the main flow will form a relatively uniform flow vortex along the circumference of the nozzle outlet during the injection process. Happening point. The inner aerodynamic protruding piece injecting airflow inward can better form a flow vortex in the mainstream area; the inner aerodynamic protruding piece injecting airflow outward can better form a flow vortex in the outer airflow of the main flow area. The development of the flow direction vortex to the downstream leads to a good mixing of the main flow of the nozzle and the external air flow, thereby shortening the core area of the potential flow of the main nozzle and increasing the entrainment capacity of the main flow of the nozzle, so that the main flow can be obtained in a short distance A very good blending effect.

2. The jet flow rate of the pneumatic protruding piece is adjusted by the jet flow control mechanism. The injection flow can be continuous injection or injection according to a certain constant or changing frequency. This measure enables the pneumatic tab technology to independently adjust and adapt according to the actual working conditions of the nozzle, and adjust the injection flow according to different working conditions, thereby changing the aerodynamic shape of the pneumatic tab and improving the mixing effect at any time . Simultaneous pulse injection and continuous injection, the two injection methods, make the pneumatic tab more flexible and the mixing effect better. the

3. The jet airflow is taken from the high-pressure stage of the engine compressor or the engine cooling airflow and other bypass or external airflow, so that the source of airflow is very rich, and the equipment can be selected according to its actual situation, which improves the applicability of the technology and flexibility. the

4. Compared with the commonly used solid small tab blender in the prior art, the pneumatic tab technology adopted in the present invention has the following advantages: in the subsonic flow of the main flow of the nozzle, the research result of the inventor of the present application It shows that using the secondary flow rate less than 1% of the mainstream flow rate to produce aerodynamic fins can bring the same mixing effect as solid fins, and its potential flow core area is smaller, with higher center velocity decay rate and Better air entrainment effect. Since the aerodynamic fins only need a small part of the mainstream airflow, it will not have a great impact on the engine performance, and the aerodynamic fins increase the mixing without causing a loss of engine thrust, and may also Increase the total thrust of the engine, which is the biggest advantage of the aerodynamic tab; it can be seen that the aerodynamic tab technology of the present invention can not only maintain the better mixing effect brought by the solid small tab blender , and at the same time, it can effectively reduce the flow loss caused by the use of the solid small tab blender; at the same time, compared with the lobe blender, its processing difficulty is significantly reduced and it is easy to implement. the

Description of drawings

Fig. 1 is the three-dimensional structure schematic diagram that the present invention is applied to common nozzle;

Fig. 2 is the three-dimensional structure schematic diagram that the present invention is applied to ducted nozzle;

Among them: main nozzle 1, aerodynamic protruding piece 2, inner duct of nozzle 3, outer duct of nozzle 4, aerodynamic protruding piece 5.

Detailed ways

The accompanying drawings disclose, without limitation, the structural schematic diagrams of the preferred embodiments involved in the present invention; the technical solution of the present invention will be described in detail below in conjunction with the accompanying drawings. the

Example 1

As shown in Figure 1, it discloses the common nozzle exhaust mixing device based on the aerodynamic tab technology of the present invention, including the main nozzle 1 and the aerodynamic tab 2, and the aerodynamic tab mainly relies on being arranged on the main nozzle The air injection point near the outlet is formed by injecting the aerodynamic cylinder formed by high-pressure air; The outer aerodynamic tabs of the jet flow in the main flow area of the tube, the inner aerodynamic tabs and the outer aerodynamic tabs are all evenly arranged circumferentially on the inner flow channel wall near the exhaust port of the main nozzle of the engine, and the inner aerodynamic tabs The pneumatic tabs and the outer pneumatic tabs are arranged alternately; the total number of the pneumatic tabs 2 is more than 4, and the specific number is determined according to the specific conditions of the nozzle, and the pneumatic tabs 2 are composed of a jet injection channel and a jet control mechanism . When the aerodynamic tabs are in operation, an aerodynamic cylinder will be formed in the main channel, and the orderly arrangement can ensure that the main flow will form a relatively uniform flow direction vortex generation point along the circumference of the nozzle outlet during the injection process. The inner aerodynamic protruding piece injecting airflow inward can better form a flow vortex in the mainstream area; the inner aerodynamic protruding piece injecting airflow outward can better form a flow vortex in the outer airflow of the main flow area. The development of the flow direction vortex to the downstream leads to the good mixing of the main flow of the nozzle and the external air flow, thereby shortening the core area of the potential flow of the main nozzle, increasing the entrainment capacity of the main flow of the nozzle, and making the main flow in a short distance A good blending effect was obtained.

The shape of the jet injection channel can be circular, elliptical, rectangular or any polygon. The axial direction of the jet injection channel is 30° to 150° from the axial direction of the main nozzle. The jet flow control mechanism independently adjusts the injection flow of the secondary flow injected by the jet injection channel of the aerodynamic tab according to the actual working conditions of the engine. The injection flow can be continuous injection or can be carried out according to a certain constant or changing frequency Pulse jet. That is, the injection flow rate of the pneumatic tab is regulated by the jet flow control mechanism. The jet flow control mechanism includes a control chip integrated with a control program. The control program is compiled according to the actual working conditions of the engine and the requirements for the mixing effect. Generally speaking, the actual working conditions of the engine use parameters such as engine outlet temperature and pressure. Therefore, the control chip monitors the temperature and pressure of the nozzle inlet of the engine (the temperature and pressure parameters are obtained through the measurement of the sensor installed at the inlet of the nozzle), combined with the actual needs of the mixing effect of the nozzle (the target is the infrared radiation characteristics of the engine Minimum), select the injection flow rate and injection mode of the pneumatic protruding nozzle, it can be seen that this measure promotes the independent adjustment and adaptation of the pneumatic protruding technology according to the actual working conditions of the nozzle, and adjusts according to different working conditions Injection flow, thereby changing the aerodynamic shape of the aerodynamic tab, and improving the mixing effect at any time. When the engine outlet temperature increases, in order to reduce the increased infrared radiation characteristics, the aerodynamic tab injection pressure increases; when the engine outlet pressure increases, in order to obtain the same infrared radiation characteristics, the aerodynamic tab injection pressure also increases big. the

For the engine, the smaller the injection flow rate of the aerodynamic tab nozzle, the more favorable it is, so the pulse injection method is often selected, but sometimes when the airflow pressure and temperature at the engine outlet are too high, the pulse injection method cannot be used in a short time. To destroy the high-temperature air mass faster, continuous injection will be selected at this time. The injection flow rate and injection mode of each pneumatic tab nozzle can be independent of each other, and can also cooperate with each other to obtain a certain effect. the

The two injection methods of pulse injection and continuous injection make the pneumatic tab more flexible and the mixing effect is better. The fluid of the injection flow may come from the high-pressure stage of the engine compressor or the engine cooling airflow and other bypasses. the

Similar to this embodiment, the axisymmetric ordinary nozzle is selected, and the binary nozzle can also be applied according to the claims. the

Example 2

As shown in Figure 2, it discloses the ducted nozzle exhaust mixing device based on the aerodynamic tab technology of the present invention, including the inner duct 3 of the nozzle, the outer duct 4 of the nozzle and the aerodynamic tab 5, the The pneumatic tab 5 is composed of a jet injection channel and a control mechanism. The jet injection flow channel is arranged axially around the inner channel of the nozzle, and is intersected inside and outside near the outlet of the nozzle. The total number is 4 or more, which is determined according to the specific conditions of the nozzle. When the aerodynamic tab is working, it will form an aerodynamic cylinder in the main flow channel. Through the orderly arrangement, it can ensure that the main flow of the inner channel of the nozzle will form a relatively uniform flow direction along the circumference of the nozzle outlet during the injection process. vortex point. The aerodynamic tabs injecting airflow inwardly can better form a flow vortex in the main flow of the inner channel of the nozzle; the aerodynamic tabs injecting airflow outward can better form a flow vortex in the outer airflow. The development of the flow direction vortex to the downstream leads to a good mixing of the main flow of the nozzle and the external air flow, thereby shortening the core area of the potential flow of the main nozzle and increasing the entrainment capacity of the main flow of the nozzle, so that the main flow of the inner channel of the nozzle is relatively small. Good blending results are obtained over short distances.

The shape of the jet injection channel can be circular, elliptical, rectangular or any polygon. The axial direction of the jet injection channel is 30° to 150° from the axial direction of the main nozzle. The control mechanism self-adjusts according to the actual working conditions of the engine through the control program, and the injection flow rate of the secondary flow of the pneumatic tab jet injection channel, the injection flow rate can be continuous injection or according to a certain constant or variable frequency To spray. the

Claims (7)

1. A nozzle exhaust mixing method based on aerodynamic tab technology, characterized in that, by arranging aerodynamic tabs of different airflow injection directions near the exhaust port of the main nozzle of the engine, the main nozzle of the engine is exhausted The main flow area near the main nozzle and the outer air flow in the main flow area both form a flow direction vortex, which realizes the mixing of the main flow area near the exhaust port of the main nozzle of the engine and the external air flow. 2. A device based on the nozzle exhaust mixing method of claim 1, comprising the main nozzle of the engine, characterized in that: the main nozzle of the main nozzle of the engine is respectively provided with a main flow facing the main nozzle of the engine The inner aerodynamic tabs of the zone jet flow and the outer aerodynamic tabs of the mainstream zone jet flow away from the engine main nozzle, the inner aerodynamic tabs and the outer aerodynamic tabs are evenly arranged circumferentially at the exhaust port of the engine main nozzle On the pipe wall of the nearby inner runner, and the inner pneumatic tabs and the outer pneumatic tabs are arranged alternately. 3. The device based on the nozzle exhaust mixing method according to claim 2, characterized in that: the inner aerodynamic tab and the outer aerodynamic tab both include a jet injection channel and are automatically adjusted according to the actual working conditions of the engine. The jet flow control mechanism of the injection flow in the jet injection flow channel, the jet injection flow channel is set on the inner flow channel wall near the exhaust port of the main nozzle pipe of the engine, and the air inlet and the side of the jet injection flow channel The air flow of the jet injection channel is connected with the air flow, and the air pressure of the jet ejected by the jet injection channel is higher than the air pressure in the main flow area of the main nozzle of the engine; in addition, the axis of the jet injection channel is inclined to the axis of the main nozzle of the engine. 4. The device based on the nozzle exhaust mixing method according to claim 3, characterized in that: the angle between the axis of the jet injection channel and the axis of the main nozzle of the engine is 30-150°C. 5 . The device based on the nozzle exhaust mixing method according to claim 3 , wherein the bypass airflow is the high-pressure airflow of the engine compressor or the cooling airflow of the engine or the external airflow. 6 . 6. The device based on the nozzle exhaust mixing method according to claim 3, characterized in that: the main nozzle of the engine is a bypass nozzle, and the jet injection flow channel is opened in the bypass nozzle. On the inner channel of the nozzle near the exhaust port of the nozzle. 7 . The device based on the nozzle exhaust mixing method according to claim 3 , characterized in that: the jet control mechanism is provided with a pulse control device for controlling the jet injection channel to perform pulse jet flow. 8 .

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