CN107091486A - A kind of after-burner annular flame barrel structure with cyclone - Google Patents

Abstract

The present invention provides an afterburner annular flame tube structure with a swirler. The structure is equipped with 6 swirlers in the middle of the afterburner, which can generate a large-scale recirculation zone in the afterburner. Thereby, the airflow velocity can be reduced to the greatest extent, and the stable combustion of the afterburner can be ensured. At the same time, the expansion air intake section is set at the tail of the afterburner tail cone, and the expansion air intake hole is set in the center of the swirler, which can greatly reduce the flow speed of the internal air flow in the afterburner afterburner through various ways, and provide space for stable combustion. After the airflow passes through the swirler, it can produce a shearing effect on the fuel, so that the fuel atomization is more thorough, so that the combustion can be more complete. After the airflow passes through the expanded air intake section, part of the airflow passes through the middle channel of the afterburner chamber and outer wall, which can effectively reduce the wall temperature of the afterburner chamber and improve the infrared stealth performance of the aircraft.

Description

An afterburner annular flame cylinder structure with a swirler

technical field

The invention belongs to the field of afterburner, and in particular relates to an afterburner annular flame tube structure with a swirler which can effectively adjust the flow state of airflow and greatly improve combustion stability and combustion efficiency.

Background technique

The afterburner is an important part of modern aviation gas turbines. It is mainly used for a short time in military aircraft to increase engine thrust and enhance aircraft maneuverability. The use of the afterburner can avoid the increase in the windward area and mass of the aircraft due to the use of engines with greater thrust.

The afterburner uses the remaining oxygen in the gas to re-inject fuel into the fuel for re-combustion, increasing the engine thrust by increasing the air temperature and airflow velocity. Turning on the afterburner can increase the maximum thrust of the aircraft by about 50%. However, the extremely high fuel consumption rate makes the afterburner only temporarily used during takeoff, climb or combat. The harsh combustion environment in the afterburner also brings great difficulties to combustion. The most important reason is that the air velocity in the afterburner is too high. Compared with the inlet air velocity of the main combustion chamber, the air intake velocity of the afterburner can reach 2 to 3 times that of the main combustion chamber (350m/s～ 450m/s). How to ignite and burn stably in high-speed airflow will determine the performance of an afterburner, which in turn will affect the performance of the entire engine.

In the main combustion chamber, most of the combustion chambers use a swirler to reduce the airflow velocity. The working principle of the swirler is: after the airflow passes through the swirler, the airflow rotates and moves forward, and expands outward, and the velocity of the outer airflow increases. The airflow has an entrainment effect, which leads to a decrease in the central air pressure; as the airflow moves backwards, the speed gradually decreases, and the central air pressure gradually increases, thereby creating a reverse pressure gradient at the center of the flame tube, and the gas backflows. Due to the generation of backflow, a low-velocity zone is created in the combustion chamber, which provides conditions for stable combustion of the flame.

In this solution, a swirler is added to the afterburner, so that a recirculation zone can be created to effectively improve the stable combustion area of the flame. At the same time, the swirler can make the fuel atomization more thorough, thereby ensuring the combustion efficiency of the afterburner.

Contents of the invention

The technical problem to be solved by the present invention is an annular flame tube structure with a swirler in the afterburner that can effectively adjust the flow state of the airflow and greatly improve the combustion stability and combustion efficiency. Compared with the existing technology, this solution installs 6 swirlers in the middle of the afterburner, which can generate a large-scale recirculation zone in the afterburner, thereby reducing the airflow velocity to the greatest extent and ensuring afterburner chamber for stable combustion. At the same time, the swirl structure can effectively reduce the pressure loss compared with the v-shaped groove and other blunt body flame stabilization structures. The swirling airflow can produce shearing effect on the fuel, so that the fuel atomization is more thorough, so that the combustion can be more complete.

Technical solutions

The object of the present invention is to provide an afterburner annular flame tube structure with a swirler that can effectively adjust the air flow state and greatly improve combustion stability and combustion efficiency.

The purpose of the present invention is achieved like this:

The annular flame tube structure of the afterburner adopts a layer of rectifying struts at the entrance of the afterburner, and the height of the struts is 1/3 to 1/2 of the height of the afterburner entrance. In the middle of the augmented caudal vertebra, the entrance of the diffuser section that expands gradually is adopted, and the expansion angle is 10°-20°, and the deflection angle should be smaller than the wall angle of the augmented caudal vertebra corresponding to this position. A swirler is arranged at the end of the afterburner tail cone, and 6 single-stage swirlers are arranged on the annular baffle. The deflection angle of the swirler blades is 15° to 30°, and the center of the swirler is provided with a gradually expanding circular inlet with a gradually expanding angle of 5° to 10°. The center height of the swirler is 1/5~1/4 of the channel height of the afterburner, the height of the primary blade can be set slightly higher than the center height of the swirler, and the total length of the swirler is 20mm~50mm, which can be adjusted according to the The size of the combustion chamber should be adjusted appropriately. The cyclone annular baffle is provided with two rows of air inlet holes, the first row of air inlet holes is located at the upper 1/5 of the annular baffle, and the holes are arranged alternately with the cyclone, with a diameter of 15mm to 20mm, a total of 6 holes . The second row of air intake holes is located at the lower 1/3 of the annular baffle, with a hole diameter of 20-25mm and a total of 6 holes.

The blade shape of the swirler adopts a streamlined design, in which the blade head adopts a circular arc with a diameter of 1-1.5mm, and the blade body adopts a circular arc with a radius of 500-1000mm to ensure the streamlined design of the swirl blade.

Adopt the present invention can obtain following beneficial effect:

1. The present invention adopts the combined design of rectifying struts and swirlers to decelerate the air flow, which can generate a wide range of recirculation areas, thereby ensuring stable combustion of the flame inside the afterburner chamber.

2. The swirler structure is adopted, which can effectively change the air flow state in the afterburner, and can effectively shear and atomize the fuel to improve the fineness of the fuel, thereby ensuring more complete combustion of the fuel.

3. The afterburner is equipped with an inner wall, which can effectively cool the wall of the afterburner and reduce the infrared radiation of the afterburner, thereby improving the stealth performance of the aircraft.

Description of drawings

Figure 1: Sectional view of the afterburner;

Figure 2: Cyclone layout;

Figure 3: Schematic diagram of a cyclone;

Figure 4: Perspective view of the afterburner;

In Fig. 1: 1- afterburner inlet rectifying strut, 2- afterburner tail cone, 3- swirler, 4- central annular baffle, afterburner outer wall, 6- afterburner inner wall

In Figure 2: 1-afterburner outer wall, 2-afterburner inner wall, 3-swirler, 4-the first row of air inlets, 5-swirler center gradually expanding air inlets, 6-the first row Second row air intake

detailed description

The present invention will be further described now in conjunction with accompanying drawing:

With reference to Fig. 1, Fig. 2 and Fig. 3, the present invention provides a belt that can change the air flow state inside the afterburner chamber, increase the size of the recirculation zone of the afterburner chamber, improve the atomization fineness of the fuel oil, and improve the flame stability. Afterburner structure of swirler. Figure 1 is the overall view of the afterburner, Figure 2 is the layout of the swirler, Figure 3 is a schematic diagram of the swirler, and Figure 4 is a cross-sectional view of the swirler blades.

After entering the afterburner, the airflow passes through the inlet rectifying strut plate (1 in Figure 1), the airflow is initially decelerated, and then passes through the diffuser section (7 in Figure 1), the airflow is further decelerated, and then the airflow passes through the swirler (Figure 1 1, 3), the airflow produces a local swirl, and a recirculation zone is generated at the rear of the afterburner, and the fuel is mixed more uniformly through the effect of the swirl, which can provide conditions for good combustion of the afterburner. At the same time, the airflow can enter the airflow through the two rows of air intake holes (4 in Figure 2, 6 in Figure 2) of the central annular baffle (4 in Figure 1) to provide sufficient air for combustion. When the airflow passes through the diffuser section, it is divided into two streams. Most of the airflow passes through the central passage and decelerates to participate in combustion. Infrared radiation, which can improve the stealth performance of the aircraft.

Claims (5)

1. An afterburner structure with a swirler, characterized in that: the inlet of the afterburner adopts a layer of rectifying struts, a diffuser inlet section is arranged in the middle of the afterburner tail cone, and the tail of the afterburner tail cone An annular baffle is arranged, and a cyclone is arranged on the baffle. 2. An afterburner structure with a swirler according to claim 1, characterized in that: the length of the straightening strut at the inlet position is 35-40 mm, the thickness is 5-8 mm, and the airfoil head of the straightening strut The inner part adopts a circular arc with a radius of 1-3mm, the blade body adopts a circular arc with a radius of 1600-2000mm, and the entire blade shape adopts a streamlined shape. 3. The afterburner structure with a swirler according to claim 1, characterized in that: the diffuser intake section is arranged in the middle of the afterburner tail cone, wherein the expansion angle of the diffuser section is 10°～ 20°, the expansion angle should be smaller than the wall angle of the augmented caudal vertebra corresponding to this position, so as to ensure that the diffuser inlet section is the expansion inlet. The diffuser section is connected with the inner wall of the afterburner, and the distance between the inner and outer walls of the afterburner is 2-6 mm. 4. A kind of afterburner structure with a swirler according to claim 1, characterized in that: the annular baffle at the afterburner tail vertebra of the afterburner is set as a fully enclosed shape, which is compatible with the afterburner The indoor wall is connected to the wall of the afterburner tail cone, and two rows of air inlets are opened on the annular baffle, each with 6 holes. The first row of air inlets is located at the upper 1/5 of the annular baffle, and the diameter of the opening is 15mm. ~20mm; the second row of air intake holes is located at the lower 1/3 of the annular baffle, and the opening diameter is 20~25mm. 5. The afterburner structure with a swirler according to claim 1 or 4, characterized in that the afterburner is provided with six single-stage swirlers on the annular baffle. The center height of the swirler is 1/5~1/4 of the channel height of the afterburner, the height of the primary blade can be set slightly higher than the center height of the swirler, and the total length of the swirler is 20mm~50mm, which can be adjusted according to the The size of the combustion chamber should be adjusted appropriately. The deflection angle of the swirler blades is 15° to 30°, and the center of the swirler is provided with a gradually expanding circular inlet with a gradually expanding angle of 5° to 10°.