An air bleed flow path structure for controlling a seal rib gap

Abstract

The application belongs to the field of labyrinth seal of an aero-engine, and discloses an air bleed flow path structure for controlling the gap of a labyrinth seal, which comprises a last stage rotor of a compressor, a diffuser, a labyrinth seal at the outlet of the compressor and a labyrinth seal honeycomb. The diffuser is provided with a stator wall surface away from the last stage rotor of the compressor, the stator wall surface is connected with the labyrinth seal honeycomb, the side wall of the stator wall surface is provided with air bleed holes, and the air bleed holes can guide two air flows. The gap between the diffuser and the last stage rotor of the compressor can guide root air bleed. The end of the rotor wall surface of the last stage rotor of the compressor is provided with a flow guide ring, and the flow guide ring has a gap with the diffuser. The introduction of the two air flows can significantly reduce the flow of the root air bleed. The root air bleed is replaced by the two air flows, so that the temperature of the labyrinth seal front cavity can be effectively reduced. The flow of the root air bleed is guided away from the rotor wall surface by the flow guide ring, the work temperature rising effect of the rotor wall surface on the flow is reduced, and the temperature rise of the root air bleed after entering the disc cavity is inhibited.

Description

An airflow path structure for controlling the gap between sealing teeth Technical Field

[0001] This application belongs to the field of aero-engine tooth sealing, and specifically relates to an airflow path structure for controlling the gap of sealing teeth. Background Technology

[0002] Grate seals are the most commonly used non-contact rotary-stationary seal type for aero-engines and a crucial throttling unit in air system design. For critical grate seals, excessive grate clearance increases bleed air volume, impacting engine performance; insufficient clearance leads to rotor jamming and excessive wear of the honeycomb bushings, affecting engine safety. Therefore, maintaining appropriate critical grate clearance during engine operation is essential for ensuring proper air system function and controlling its impact on engine performance.

[0003] A sealing grate structure is typically installed at the compressor outlet to control the amount of bleed air from the compressor system. The grate clearance at this location has a significant impact on the compressor outlet bleed air volume, making it a critical grate position in the air system. This airflow itself is already hot, and the temperature is further increased by the work done by the rotor wall. This causes the temperature of the honeycomb ring fixed to the combustion chamber casing to rise, resulting in significant thermal deformation. This leads to the grate clearance deviating from the design expectation, increasing the bleed air volume and affecting engine performance. To control the compressor outlet grate clearance, it is necessary to consider controlling the airflow temperature to reduce its impact on the grate clearance.

[0004] The compressor outlet induced flow path typically uses an annular gap between the end face of the compressor rotor's last-stage blade root and the front face of the combustion chamber diffuser to guide the main flow path near the compressor rotor root to the compressor outlet grate inlet chamber (see Figure 1). This method of induced flow can increase the grate clearance, deviating from the design range. The main reasons include:

[0005] 1) The research results show that the air temperature distribution in the main channel of the compressor is characterized by "low temperature in the middle and high temperature on both sides". The air temperature drawn from the root of the main channel will be higher than the average temperature of the main channel cross section.

[0006] 2) As the airflow passes over the compressor rotor wall, the airflow temperature increases further due to the work done by the rotor wall on the airflow.

[0007] 3) The honeycomb rings fixed on the combustion chamber casing are usually cantilever structures. The high-temperature airflow has a significant effect on their thermal deformation. The honeycomb rings undergo large radial deformation when heated, which leads to an increase in the gap between the grates and deviates from the design expectation.

[0008] Therefore, how to prevent the gap between the ferrules from deviating from the design range is a problem that needs to be solved. Summary of the Invention

[0009] The purpose of this application is to provide an airflow path structure for controlling the gap between sealing grates, so as to solve the problem that existing grates are prone to deviation due to the influence of temperature, position and structure.

[0010] The technical solution of this application is: an airflow path structure for controlling the gap of the sealing grates, including a compressor final-stage rotor, a diffuser, compressor outlet grates, and a grating honeycomb; the grating honeycomb is arranged opposite to the compressor outlet grates, a rotor wall is provided between the compressor final-stage rotor and the compressor outlet grates, the rotor wall is connected to the compressor outlet grates, the diffuser is arranged side by side with the compressor final-stage rotor, and a stator wall is provided on the side of the diffuser away from the compressor final-stage rotor. The stator wall is connected to the honeycomb structure. An air intake hole is provided on the side wall of the stator wall. The air intake hole can receive two streams of air. The diffuser can receive root air between the diffuser and the last stage rotor of the compressor. A guide ring is provided at one end of the last stage rotor of the compressor on the rotor wall. There is a gap between the guide ring and the diffuser. The root air flows out from the gap between the guide ring and the diffuser, and then mixes with the two streams of air flowing out through the air intake hole before flowing into the space between the compressor outlet grate and the honeycomb structure.

[0011] Preferably, a pressure plate is provided on the outer side of the honeycomb, and the two airflows are drawn out from the air inlet holes, pass through the outer surface of the pressure plate, and then mix with the root airflow.

[0012] Preferably, a flow-guiding ring is provided on the inner side wall of the stator wall, the flow-guiding ring protruding outward towards the side close to the rotor wall and concave inward towards the side of the air intake hole.

[0013] This application discloses an airflow path structure for controlling the gap of the sealing grates, comprising a compressor final-stage rotor, a diffuser, compressor outlet grates, and a grating honeycomb. The diffuser has a stator wall on the side away from the compressor final-stage rotor, which is connected to the grating honeycomb. Air ducts are formed on the sidewall of the stator wall, allowing for the intake of two airflow streams. Root airflow can be introduced between the diffuser and the compressor final-stage rotor. A guide ring is provided at one end of the compressor final-stage rotor on the rotor wall, with a gap between the guide ring and the diffuser. Introducing two airflow streams can significantly reduce the flow rate of the root airflow. Replacing the root airflow with two airflow streams can effectively reduce the airflow temperature in the front cavity of the grates. By setting the guide ring, the root airflow is kept away from the rotor wall, reducing the work done by the rotor wall on the airflow and thus suppressing the temperature rise after the root airflow enters the cavity. Attached Figure Description

[0014] To more clearly illustrate the technical solutions provided in this application, the accompanying drawings will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application.

[0015] Figure 1 is a schematic diagram of the background technology structure;

[0016] Figure 2 is a schematic diagram of the overall structure of this application;

[0017] Figure 3 is a structural schematic diagram of another embodiment of this application.

[0018] 1. Compressor final stage rotor; 2. Diffuser; 3. Compressor outlet grate; 4. Grate honeycomb; 5. Rotor wall; 6. Stator wall; 7. Air duct; 8. Guide ring; 9. Pressure plate; 10. Guide ring. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] A flow path structure for controlling the gap between sealing grates, as shown in Figure 2, includes a compressor final stage rotor 1, a diffuser 2, compressor outlet grates 3, and grating honeycomb 4.

[0021] The honeycomb 4 is positioned opposite the compressor outlet honeycomb 3. A rotor wall 5 is provided between the compressor final stage rotor 1 and the compressor outlet honeycomb 3. The rotor wall 5 is connected to the compressor outlet honeycomb 3. The diffuser 2 is arranged side by side with the compressor final stage rotor 1. A stator wall 6 is provided on the side of the diffuser 2 away from the compressor final stage rotor 1. The stator wall 6 is connected to the honeycomb 4. An air intake hole 7 is provided on the side wall of the stator wall 6. The air intake hole 7 can draw in two streams of air.

[0022] The diffuser 2 can receive root bleed air between itself and the compressor's last stage rotor 1. The rotor wall 5 has a guide ring 8 at one end of the compressor's last stage rotor 1. There is a gap between the guide ring 8 and the diffuser 2. The root bleed air flows out from the gap between the guide ring 8 and the diffuser 2, and then mixes with the two streams of bleed air flowing out through the bleed hole 7 before flowing into the space between the compressor outlet grate 3 and the grate honeycomb 4.

[0023] This airflow path structure introduces relatively low-temperature airflow and organizes the airflow direction. On the one hand, it reduces the airflow temperature and flow rate at the compressor outlet root, and on the other hand, it controls the thermal deformation of the honeycomb ring, thereby controlling the working clearance of the compressor outlet grate 3.

[0024] Since the temperatures of the two airflow streams are closer to the average cross-sectional temperature of the compressor outlet mainstream flow channel, and are lower than the root bleed air temperature (research results show that the air temperature distribution of the compressor mainstream channel exhibits a "low in the middle, high on both sides" characteristic, with the airflow temperature at the root of the mainstream channel being higher than the average cross-sectional temperature), and the pressures of the two airflow streams are essentially equivalent, introducing the two airflow streams can significantly reduce the flow rate of the root bleed air. Replacing the root bleed air with the two airflow streams can effectively reduce the airflow temperature in the front cavity of the grate. Simultaneously, after passing through the bleed hole 7, the two airflow streams first impact-cool the upper end of the honeycomb ring, controlling the thermal deformation of the honeycomb ring caused by airflow heat conduction, thus achieving the function of controlling the working clearance of the compressor outlet grate 3.

[0025] By setting the guide ring 8, the airflow from the root is kept away from the rotor wall 5, reducing the temperature rise effect of the rotor wall 5 on the airflow, thereby suppressing the temperature rise after the root airflow enters the disk cavity.

[0026] Action relationship description: The air intake path draws air from the compressor outlet root and two air streams simultaneously. By designing the flow area of ​​the air intake hole 7, it is ensured that the total air intake is mainly drawn from the two air streams, minimizing the proportion of air intake from the root. The axial position of the air intake hole 7 needs to be determined after comparative analysis of the cooling effect of the air intake on the 4 rings of the comb tooth honeycomb. When designing the rotor outlet guide structure, factors such as guide effect, structural design, strength, and rotor-stator clearance need to be considered.

[0027] Preferably, a pressure plate 9 is provided on the outer side of the comb honeycomb 4. After the two airflows are drawn out from the air inlet 7, they pass through the outer surface of the pressure plate 9 and then mix with the air at the root. By setting the pressure plate 9, the two airflows will exert pressure on the pressure plate 9 after flowing into the air inlet 7, making the gap between the compressor outlet comb 3 and the comb honeycomb 4 more stable.

[0028] As a specific implementation, as shown in Figure 3, a flow-guiding ring 10 is provided on the inner sidewall of the stator wall 6. The flow-guiding ring 10 protrudes outward towards the side near the rotor wall 5 and is simultaneously recessed towards the side of the air intake hole 7. Since the two airflows and the root airflow have different directions after contact, in order to prevent turbine generation, the flow-guiding ring 10 is provided to simultaneously guide the two airflows and the root airflow, so that the two airflows and the root airflow flow more smoothly into the space between the grate honeycomb 4 and the compressor outlet grate 3, ensuring air intake efficiency.

[0029] Finally, the following points should be noted: First, in the description of this application, it should be noted that, unless otherwise specified and limited, the terms "installation", "connection", and "linkage" should be interpreted broadly, and can be mechanical or electrical connections, or internal connections between two components, or direct connections. "Up", "down", "left", "right", etc. are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may change.

[0030] Secondly: The accompanying drawings of the embodiments disclosed in this invention only involve the structures involved in the embodiments disclosed in this invention. Other structures can refer to the general design. In the absence of conflict, the same embodiment and different embodiments of this invention can be combined with each other.

[0031] In conclusion, the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A flow path structure for controlling the gap between sealing teeth, characterized in that: The compressor includes a final stage rotor (1), a diffuser (2), a compressor outlet grate (3), and a grate honeycomb (4). The grate honeycomb (4) is positioned opposite the compressor outlet grate (3). A rotor wall (5) is provided between the final stage rotor (1) and the compressor outlet grate (3), and the rotor wall (5) is connected to the compressor outlet grate (3). The diffuser (2) is arranged side by side with the final stage rotor (1). A stator wall (6) is provided on the side of the diffuser (2) away from the final stage rotor (1), and the stator wall (6) is connected to the grate honeycomb (4). An air intake hole (7) is provided on the side wall of the stator wall (6), which can draw in two streams of air. The diffuser (2) and the final stage rotor (1) can draw in the root of the air intake. The rotor wall (5) of the compressor's last stage rotor (1) is provided with a guide ring (8). There is a gap between the guide ring (8) and the diffuser (2). The root induced air flows out from the gap between the guide ring (8) and the diffuser (2), and then mixes with the two streams of induced air flowing out through the induced air hole (7) before flowing into the space between the compressor outlet grate (3) and the grate honeycomb (4). The inner wall of the stator wall (6) is provided with a guide ring (10). The guide ring (10) protrudes outward toward the side close to the rotor wall (5) and is concave inward toward the side of the induced air hole (7). By setting the guide ring (10), the two streams of induced air and the root induced air are simultaneously guided, so that the two streams of induced air and the root induced air flow more smoothly into the space between the grate honeycomb (4) and the compressor outlet grate (3).

2. The airflow path structure for controlling the gap between the sealing teeth as described in claim 1, characterized in that: The outer side of the honeycomb (4) is provided with a pressure plate (9). The two streams of air are drawn out from the air inlet (7), pass through the outer surface of the pressure plate (9), and then mix with the root air.

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