A combustion chamber having an adaptive anti-speed distortion diffuser

Abstract

The application discloses a combustion chamber with a self-adaptive anti-speed distortion diffuser, which comprises a combustion chamber outer shell, a flame tube and a diffuser, the diffuser is arranged at the front end of the combustion chamber outer shell and is connected with the combustion chamber outer shell, the flow passage section of the diffuser gradually increases along the air inlet direction, the end of the diffuser is provided with a rotatable swirler, the swirler rotates under the air inlet blowing, and the projection of the swirler on the flow passage section of the diffuser occupies a part of the flow passage section. The swirler is arranged, the rotating speed can be self-adaptively changed according to the inlet airflow speed, the blocking ratio is changed, the gradually expanding diffuser is matched, the combustion chamber can adapt to different inlet speed conditions, the speed distortion is resisted, the pressure loss is reduced, the flow field is stabilized, and the combustion is stabilized.

Description

TECHNICAL FIELD

[0001] The present application relates to a combustion chamber, in particular to a combustion chamber with self-adaptive anti-speed distortion diffuser. BACKGROUND

[0002] The main components of an aero-engine include a compressor, a combustion chamber and a turbine. Since the Mach number of the airflow from the outlet of the compressor is generally between 0.2 and 0.3, the high-speed airflow is difficult to be fully combusted after directly entering the flame tube of the combustion chamber, and meanwhile, the total pressure loss is caused, which brings bad effects on the economic benefit and power of the engine.

[0003] The diffuser, as an important component of the combustion chamber, is arranged at the connection between the compressor and the inlet of the flame tube for reducing the influence of the high-speed airflow. The dynamic pressure of the head of the combustion chamber is effectively converted into static pressure, so as to reduce the speed of the airflow entering the flame tube, increase the static pressure of the flame tube, and play a role in reducing the total pressure loss of the combustion chamber. The flow rate is reduced while the pressure is increased, so as to realize the full combustion in the combustion chamber. In the design process of the combustion chamber, the specific requirements of the diffuser of the combustion chamber are as follows: 1) the total pressure loss is reduced as much as possible, and the thrust is further improved; 2) the diffuser has the ability of anti-distortion and is not sensitive to the change of the flow field at the outlet of the compressor; 3) the size of the diffuser is reduced as much as possible, so as to reduce the overall size and weight of the engine; 4) the airflow at the outlet of the diffuser is uniform and stable in the circumferential and radial directions.

[0004] The diffuser of the prior art has a straight wall diffuser, which gradually increases the flow passage section along the direction of fluid flow, so that the airflow speed is gradually reduced, and the static pressure slowly rises. The short and sudden diffuser diffuser can further reduce the airflow speed, but it also has the disadvantages of large total pressure loss and airflow separation consuming most of the energy. SUMMARY

[0005] In view of the defects of the prior art, the task of the present application is to provide a combustion chamber with a self-adaptive anti-speed distortion diffuser, so as to realize anti-speed distortion, reduce total pressure loss and stabilize combustion in the combustion chamber.

[0006] The technical scheme of the present application is as follows: a combustion chamber with a self-adaptive anti-speed distortion diffuser, comprising a combustion chamber outer shell, a flame tube and a diffuser, the diffuser is arranged at the front end of the combustion chamber outer shell and connected with the combustion chamber outer shell, the flow passage section of the diffuser gradually increases along the air inlet direction, the end of the diffuser is provided with a rotatable swirler, the swirler rotates under the blowing of the air inlet, and the projection of the swirler on the flow passage section of the diffuser occupies a part of the flow passage section.

[0007] Further, the expansion angle of the diffuser is 6-12 degrees. In order to ensure the effect of deceleration and pressure increase, if the expansion angle is too small, the diffuser must be lengthened, the wall friction of the diffuser leads to high total pressure loss and significant increase in structure mass, and if the expansion angle is increased, the boundary layer separation leads to large stall loss.

[0008] Further, the projection of the swirler on the flow passage section of the diffuser occupies 15-50% of the area of the flow passage section.

[0009] Further, the end of the diffuser is provided with a plurality of extended baffles for blocking the airflow at the outer periphery of the swirler.

[0010] Further, the projection of the swirler and the extended baffles on the flow passage section of the diffuser occupies 15-50% of the area of the flow passage section.

[0011] Further, the rotation plane of the swirler is arranged in parallel with the flow passage section of the diffuser.

[0012] Further, the extended baffles are arranged in parallel with the flow passage section of the diffuser.

[0013] Further, the swirler comprises a rotating shaft and swirler blades, and the inclination angle of the swirler blades is 15-60 degrees.

[0014] Further, the swirler blades are 5-8 pieces.

[0015] Further, the diffuser is a straight-wall diffuser.

[0016] Compared with the prior art, the present application has the following advantages:

[0017] The present application sets a rotatable swirler at the end of the diffuser connected with the combustion chamber shell, after the high-speed airflow left from the outlet of the compressor enters the diffuser, the airflow rotates the swirler when flowing through the swirler in the diffuser, the swirler is rapidly rotated, the blockage ratio is increased, the airflow is decelerated and pressurized, the static pressure at the inlet of the flame tube is increased, the flow field at the outlet behind the diffuser is stable, the effect of reducing the total pressure loss is achieved, the distortion degree of the airflow at the outlet of the compressor is improved, and the flame combustion in the combustion chamber is stabilized.

[0018] The beneficial effects of this invention are specifically as follows: Firstly, the diffuser, similar to a pneumatic diffuser, is a straight-walled diffuser channel that gradually increases its cross-section along the direction of airflow, causing the airflow velocity to gradually decrease and the static pressure to rise slowly, resulting in effective deceleration and pressurization. Secondly, the rotatable swirler, when facing a large inlet airflow velocity, will rotate rapidly accordingly, increasing its blockage ratio and reducing the outlet airflow of the diffuser. When facing a small inlet airflow velocity, the swirler will rotate slowly, decreasing its blockage ratio and reducing the reduction in the outlet airflow of the diffuser, maintaining a large flow rate. This allows the flow rate through the swirler to remain stable within a certain range, enabling the combustion chamber to adapt to different inlet velocity conditions, effectively reducing pressure loss, stabilizing the flow field, and stabilizing combustion. Furthermore, by adding a swirler to the diffuser, since the deceleration and pressurization effect is mainly achieved through the swirler, the length of the diffuser can be minimized to reduce the length and mass of the engine. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the combustion chamber with an adaptive anti-velocity distortion diffuser, as shown in the embodiment.

[0020] Figure 2 for Figure 1 A partial schematic diagram of point A.

[0021] Figure 3 This is a schematic diagram of the projection of the hydrocyclone and the extended baffle onto the flow section of the diffuser.

[0022] Figure 4 This is a schematic diagram illustrating the working principle of an adaptive anti-velocity distortion diffuser. Detailed Implementation

[0023] The present invention will be further described below with reference to embodiments, but these are not intended to limit the scope of the invention.

[0024] Please combine Figures 1 to 3 As shown, the combustion chamber with an adaptive anti-velocity distortion diffuser involved in this embodiment includes an outer casing 1, a flame tube 2, and a diffuser 3, with the flame tube 2 located inside the outer casing 1. The diffuser 3 is disposed at the front end of the outer casing 1, corresponding to the front inlet of the flame tube 2.

[0025] The straight wall diffuser 3 is surrounded by four walls to form an air inlet channel, and the flow cross section of the air inlet channel is substantially rectangular. The flow cross section of the air inlet channel gradually increases along the air flow direction, in other words, the diffuser 3 is in a flared structure. An angle is formed between the upper and lower walls 3a of the diffuser 3, and the angle is an expansion angle. Based on the length of the diffuser 3 and the influence of the air flow pressure loss, the expansion angle can be set to 6°-12°.

[0026] A rotatable swirler 4 is arranged at the end of the diffuser 3, that is, the connection position of the diffuser 3 and the combustion chamber shell 1. A support can be arranged behind the swirler 4 for connecting the rotating shaft 4a of the swirler 4, and the support is not shown in the figure. It should be pointed out that, similar to a general axial flow fan, the support is connected to the wall of the diffuser 1 and is mainly used to support the swirler 4. The rotating shaft 4a of the swirler 4 is rotatably connected to the support.

[0027] Generally, 5-8 swirler vanes 4b are arranged on the circumferential side of the rotating shaft 4a of the swirler 4. The inclination angle of the swirler vane 4b can be set to 15°-60° according to the different blockage ratios to be controlled. In this embodiment, six swirler vanes 4b with an inclination angle of 45° are arranged. In addition, in this embodiment, the rotating shaft 4a of the swirler 4 is arranged parallel to the axis of the diffuser 3, that is, the rotating plane of the swirler 4 is arranged parallel to the flow cross section of the diffuser 3. The projection of the swirler 4 on the flow cross section of the diffuser 3 occupies a part of the flow cross section. In this way, when the swirler 4 rotates under the action of the inlet air, the swirler 4 rotates rapidly when the air flow passes through the swirler 4 in the diffuser 3, thereby increasing the blockage ratio, thereby decelerating and pressurizing the incoming flow, ensuring the stability of the flow field at the outlet of the diffuser 3, and stabilizing the flame combustion in the combustion chamber.

[0028] As a preferred embodiment, a plurality of extended baffles 5 for blocking the air flow are arranged at the end of the diffuser 3 and outside the swirler 4, that is, the extended baffles 5 are arranged at the corner positions of the flow cross section of the diffuser 3 which are not obviously affected by the swirler 4. The extended baffles 5 are also arranged parallel to the flow cross section of the diffuser 3, and the projections of the swirler 4 and the extended baffles 5 on the flow cross section of the diffuser 3 occupy 15%-50% of the area of the flow cross section. Through the blocking effects of the swirler 4 and the extended baffles 5 on the air flow, the blockage ratio is 15%-50%.

[0029] Please refer to Figure 4 As shown in the figure, after the high-speed air flow from the outlet of the compressor enters the diffuser 3, most of the dynamic pressure is converted into static pressure, so that the diffuser 3 is effectively decelerated and pressurized. After the air flow flows to the tail end of the diffuser 3 and contacts the swirler 4, a part of the air is blocked by the extended baffles 5, greatly reducing the air flow speed, and another part of the air is rotated after passing through the swirler vane 4b, thereby increasing the blockage ratio, and forming a uniform and stable flow at the outlet of the diffuser 3.

[0030] When facing the high speed airflow at the compressor outlet, the swirler 4 can adaptively rotate fast to form a corresponding blockage ratio, so as to reduce the total pressure loss. This design can improve the distortion degree of the airflow at the compressor outlet and stably operate under all working conditions. In addition, the swirler can form a uniform and stable flow at the outlet of the diffuser 3, enhance the anti-distortion ability of the outlet flow field, greatly improve the combustion stability and efficiency in the combustion chamber, and greatly shorten the length of the diffuser 3 to reduce the length and mass of the engine.

Claims

1. A combustion chamber having an adaptive anti-speed distortion diffuser, characterized by, The combustor comprises a combustor outer shell, a flame tube and a diffuser, the diffuser is arranged at the front end of the combustor outer shell and connected with the combustor outer shell, the flow passage cross section of the diffuser gradually increases along the air intake direction, the end of the diffuser is provided with a rotatable swirler, the swirler rotates under the air intake blowing, the projection of the swirler on the flow passage cross section of the diffuser occupies a part of the flow passage cross section, the end of the diffuser is provided with a plurality of extended baffles for blocking air flow at the outer periphery of the swirler, the projection of the swirler and the extended baffles on the flow passage cross section of the diffuser occupies 15% to 50% of the area of the flow passage cross section.

2. The combustion chamber with adaptive anti-speed-distortion diffuser of claim 1, characterized by, The expansion angle of the diffuser is 6° to 12°.

3. The combustion chamber with adaptive anti-speed-distortion diffuser of claim 1, characterized by that, The rotation plane of the swirler is arranged in parallel with the flow passage cross section of the diffuser.

4. The combustion chamber with adaptive anti-speed-distortion diffuser of claim 1, characterized by that, The extended baffles are arranged in parallel with the flow passage cross section of the diffuser.

5. The combustion chamber with adaptive anti-speed-distortion diffuser of claim 1, characterized by that, The swirler comprises a rotating shaft and swirler blades, the inclination angle of the swirler blades is 15° to 60°.

6. The combustion chamber with adaptive anti-speed-distortion diffuser of claim 5, characterized by that, The swirler blades are 5 to 8.

7. The combustion chamber with adaptive anti-speed-distortion diffuser of claim 1, characterized by that, The diffuser is a straight wall diffuser.

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