CN113048513B - A multi-stage fuel injection hole center cone integrated afterburner - Google Patents

Abstract

The invention provides an integrated afterburner with a central cone of multi-stage oil injection holes. The central cone is provided with multi-stage oil injection holes, the central cone is hollow and stepped, and the stepped central cone structure increases The surface area of the high-temperature gas and fuel oil heat exchange in the fuel oil channel forms impact heat exchange at the steps, which strengthens the heat exchange. Due to the multi-stage central cone structure, the high-temperature gas will form an angular vortex between each two-stage sudden expansion when it flows through. A more pronounced recirculation zone is created downstream. The preheated fuel in the center cone fuel passage is sprayed out through the fuel injection holes arranged on the multi-stage center cone, and burns downstream. When fuel is injected from the fuel injection hole, the liquid film will be broken to form secondary atomization, which further improves the atomization effect and the uniformity of oil and gas mixing, thereby improving the combustion efficiency. A recirculation zone is formed in the center of the chamber for stable combustion.

Description

A multi-stage fuel injection hole center cone integrated afterburner

technical field

The invention belongs to the field of gas turbine engines, and in particular relates to a multi-stage fuel injection hole central cone integrated afterburner.

Background technique

Certain aero-engines cannot perform well over the entire thrust range. For example, when the aircraft takes off, it needs much more thrust than when cruising. If the engine is designed according to the take-off thrust, the mass of the engine will be too large, and the performance of the engine will be poor during cruise due to the non-design point state; The thrust design of the engine will cause the aircraft to not take off normally. One of the measures to solve the above problems is to add an afterburner between the gas turbine and the nozzle of the engine, which can greatly increase the thrust of the engine in a short period of time. Although the mass of the afterburner is only about 1/5 of the engine, the thrust can be increased by more than 60%. At present, the new generation of military engines all over the world basically adopts the structure with afterburner.

Afterburner is an important part of aeroengine. Although its mass only accounts for about 20% of the total mass of the engine, it can greatly increase the thrust of the engine. The afterburner is installed between the turbine and the tail nozzle, and uses the residual oxygen in the exhaust gas of the combustion chamber to re-inject fuel for reburning, thereby providing the possibility to increase the thrust of the aircraft engine. However, since the afterburner uses the fuel gas from the main combustion chamber for fuel injection and reburning, the oxygen content in the gas flow is only about 2/3 to 3/4 of the normal air, so its combustion efficiency is low. In addition, because the afterburner mostly uses direct injection nozzles, the fuel is directly injected into the air flow, the fuel atomization effect is poor, and the mixing with the air flow is not uniform, which further reduces the combustion efficiency.

The working environment of the afterburner is poor, and the gas discharged from the turbine outlet has high temperature, low pressure and high speed, which is not conducive to the ignition and organization of the combustion of the gas in the afterburner. Usually, a bluff body structure is used as a flame stabilizer in a traditional afterburner, and the stable low-speed recirculation zone behind the bluff body is used to ignite the air-fuel mixture and organize combustion. With the continuous increase of the total temperature at the inlet of the afterburner of the engine, the working environment in the afterburner is more severe, and the problems of self-ignition of fuel, high temperature resistance and structural reliability of components such as fuel injection rod and bluff flame stabilizer are more obvious.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to propose a multi-stage fuel injection hole center cone integrated afterburner. Compared with the existing technology, the advantage of this solution is that the diffuser-center cone-fuel injection hole is integrated It is designed with multi-stage direct injection nozzles on the center cone. The center cone is hollow and stepped. When the fuel enters the fuel channel in the center cone, it can be preheated by the high-temperature gas that has been burned upstream. The central cone structure increases the heat exchange surface area of the high-temperature gas and fuel oil in the fuel channel, forming impact heat exchange at the steps, which strengthens the heat exchange, and the fuel channel inside the central cone of the multi-stage fuel injection hole is shrunk, and the fuel channel flows through it. The cross-sectional area gradually decreases, the pressure gradually increases, and the size of the sprayed droplets decreases, which is helpful for fuel atomization. The preheated fuel is ejected through the fuel injection holes arranged on the multi-stage central cone, and burns downstream. Due to the multi-stage central cone structure, the high-temperature gas will form an angular vortex between each two-stage sudden expansion when it flows through. The downstream produces a more obvious recirculation area and an area with greater turbulence intensity. The inclined surface between each two stages causes the fuel to form a pre-film on it. When the fuel is injected from the fuel injection hole of the next stage, the liquid film will be broken. , forming secondary atomization, further improving the atomization effect and the uniformity of oil and gas mixing, thereby improving the combustion efficiency.

Technical solutions

The purpose of the present invention is to provide a multi-stage fuel injection hole center cone integrated afterburner.

The technical scheme of the present invention is as follows:

A multi-stage fuel injection hole central cone integrated afterburner is characterized in that: the multi-stage fuel injection hole central cone integrated afterburner comprises an inner and outer casing, a rectifying support plate structure, a multi-stage The center cone, the multi-stage fuel injection holes on the center cone, the graded and tapered fuel passages inside the center cone, the sudden expansion structure between each stage of the center cone and the inclined surface between each two stages; the inner and outer casings of this structure are The casing structure of the conventional afterburner, the rectifying support plate is located between the inner casing and the center cone and connects them, and is distributed circumferentially, the number is 10-20, and the interior is arranged with fuel passages to connect into the combustion chamber. Fuel oil; the multi-stage central cone connected with the rectifying support plate is stepped, and the number of stages is 3-5. It is located in the circumferential center of the entire afterburner, and the axial direction is upstream of the combustion chamber. Due to the difference in height, a sudden expansion structure will be formed. There is an inclined surface between each two-stage center cone, the length of which is 30-80mm, and the angle between the inclined angle and the axial direction is 30°-60°. The graded and tapered fuel channel has fuel injection holes on the surface of the center cone of each level, so that the surface of the center cone forms a multi-level fuel injection hole structure, and the diameter of the injection holes is 1-4mm; Inside the center cone, under the action of the graded and tapered fuel passages inside the center cone, the particle size of the fuel sprayed from the injection holes of each stage becomes smaller, and is pre-filmed on the inclined surface between each two stages. The membrane is further broken under the action of the fuel injected from the next stage to form secondary atomization, and the sudden expansion structure between each stage is beneficial to the formation of angular vortex to achieve flame stability.

The multi-stage fuel injection hole central cone integrated afterburner is characterized in that: the central cone is in a stepped form in the downstream part, and the number is 3-5 stages. A sudden-expansion structure is formed. The described multi-level injection hole center cone integrated afterburner is characterized in that: multi-level injection holes are divided on the multi-level center cone, and the multi-level injection hole center cone structure oil injection hole diameter is 1~4mm, the length of the inclined surface between each two stages is 30~80mm, and the angle between the inclined angle and the axial direction is 30°~60°. The injection holes are evenly arranged in the circumferential direction on each stage, and the stages are staggered, and a single row or multiple rows of injection holes can be set on each stage. In addition, the fuel channel inside the central cone of the multi-stage fuel injection hole is in a constricted shape, and the cross-sectional area through which the fuel channel flows decreases step by step.

The present invention has the following beneficial effects:

The advantage of the integrated afterburner designed in this scheme is that there are multi-stage fuel injection holes on the front side of the traditional central cone to form a hollow and stepped multi-stage central cone, so that the fuel can be in contact with more high-temperature gas. , to achieve better atomization effect. At the same time, this multi-stage central cone structure is conducive to the formation of the central recirculation zone, and there is a sudden expansion structure between every two stages, which is helpful for the deceleration and boosting of high-temperature gas. The fuel injection holes are arranged on the top, which can strengthen the disturbance of the central airflow, so that the fuel mixture in this area stays longer and the mixing is more uniform. The inclined surface between each two stages makes the fuel form a pre-film on it. When the first-level fuel injection hole sprays fuel, the liquid film will be broken to form secondary atomization, which further improves the atomization effect and the uniformity of oil and gas mixing, thereby improving the combustion efficiency.

Description of drawings

Figure 1: Schematic diagram of the overall structure of a multi-stage fuel injection hole center cone integrated afterburner

Figure 2: Schematic diagram of the structure of the center cone of the multi-stage fuel injection hole and the rectifier support plate

Figure 3: Enlarged view of part A of the central cone of the multi-stage fuel injection hole in Figure 2

Figure 4: Left view of the center cone of the multi-stage fuel injection hole and the structure of the rectifier support plate

Figure 5: Right side view of the overall structure of a multi-stage fuel injection hole center cone integrated afterburner

Figure 6: Right view of the structure of the center cone of the multi-stage fuel injection hole and the rectifier support plate

Figure 7: Enlarged view of part B in Figure 6

In the figure: 1- rectifier support plate, 2- multi-stage center cone, 3- fuel injection hole, 4- sudden expansion structure, 5- inclined surface

Detailed ways

Now in conjunction with the accompanying drawings, the present invention will be further described:

Figure 1 is a schematic diagram of the overall structure of a multi-stage fuel injection hole central cone integrated afterburner, Figure 2 is a schematic structural diagram of the multi-stage fuel injection hole central cone and a rectifier support plate, Figures 3 and 4 are the multi-stage fuel injection holes in Figure 2. The enlarged view of part A of the central cone of the stage injection hole and the left view of the central cone of the multi-stage injection hole and the structure of the rectifier support plate. From this, we can see the layout of the central cone structure, which is used to determine the size, distribution and distribution of the injection holes. Its relative position, Figure 5 is a right side view of the overall structure of a multi-stage fuel injection hole center cone integrated afterburner, Figure 6 and Figure 7 are the right side view of the multi-stage fuel injection hole center cone and the rectifier support plate structure and Figure 7. Enlarged view of part B in 6.

The air flow from the internal and external ducts is mixed between the rectifying support plate flame stabilizer blades, and the high-temperature gas is decelerated and pressurized through the sudden expansion structure 4 between each two stages of the center cone in Fig. 2. The fuel injection holes 3 are evenly arranged on the stage. The fuel preheated by the high temperature gas is sprayed out through the fuel injection holes 3 and forms a pre-film on the inclined surface 5 below. Under the action of crushing to form secondary atomization. Due to the hierarchical structure of the center cone, the mixed air in the inner and outer ducts will be entrained into the central area after flowing through the rectifying support plate, forming a strong return area, and the presence of the fuel injection holes can further increase the disturbance of the airflow. The oil and gas atomization effect is better, and the combustion efficiency and stability are improved.

Claims (3)

1. The utility model provides a multistage nozzle opening center awl integration afterburner which characterized in that: the multistage oil spray hole and center cone integrated afterburner comprises an inner casing, an outer casing, a rectifying support plate structure and a multistage center cone, wherein the multistage center cone is provided with a multistage oil spray hole, a graded tapered fuel oil channel inside the multistage center cone, a sudden expansion structure between each stage of the multistage center cone and an inclined plane between each two stages; the inner casing and the outer casing of the structure are of a casing structure of a conventional afterburner, the rectifying support plates are positioned between and connected with the inner casing and the multi-stage central cone and are circumferentially distributed, the number of the rectifying support plates is 10-20, and fuel oil channels are arranged in the rectifying support plates and connected with fuel oil entering the combustor; the multistage central cone connected with the rectifying support plate is in a step shape, the number of stages is 3-5, the multistage central cone is located at the circumferential center of the whole afterburner, the axial direction is at the upstream position of the combustor, a sudden expansion structure can be formed between each two stages of the multistage central cone due to different heights, an inclined plane is arranged between each two stages of the multistage central cone, the length of the inclined plane is 30-80 mm, the included angle between the inclined plane and the axial direction is 30-60 degrees, a graded tapered fuel oil channel is arranged in the multistage central cone, each stage surface of the multistage central cone is provided with an oil injection hole, so that a multistage oil injection hole structure is formed on the surface of the multistage central cone, and the diameter of the oil injection hole is 1-4 mm; the fuel oil enters the multi-stage central cone from the fuel oil channel in the rectifying support plate, under the action of the graded tapered fuel oil channel in the multi-stage central cone, the particle size of the fuel oil sprayed from each stage of fuel oil spray holes is reduced, a film is pre-formed on the inclined surface between each two stages, the film is further broken under the action of the fuel oil sprayed from the next stage to form secondary atomization, and the sudden expansion structure between each stage is beneficial to forming angular vortex to realize flame stabilization.

2. The integrated afterburner with the multi-stage oil injection hole and the central cone is characterized in that: the oil spout hole is evenly arranged along circumference on every level, and crisscross distribution between the level sets up single row or multirow jet orifice on every level.

3. The integrated afterburner with the multi-stage oil injection hole and the central cone is characterized in that: the fuel oil channel inside the center cone of the multi-stage fuel spray hole is in a contraction shape, and the cross-sectional area through which the fuel oil channel flows is gradually reduced.

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