Thermal protection structure and method for aero-engine afterburner test

Abstract

The invention discloses an aero-engine afterburner test thermal protection structure and method, the structure comprises a cooling cover, a test piece, a water jacket and a casing, the water jacket wraps the outer wall of the test piece, the casing is arranged at the bottom of the inner cavity of the test piece, and the cooling cover is arranged in the casing. The multiple sets of cooling holes distributed in the circumferential direction are formed in the cooling cover in the cartridge receiver, more heat is taken away through impact of sprayed water flow to strengthen cooling, the hole diameter of the holes in the fan-shaped face can be selected according to the water flow pressure, the distance from the cartridge receiver and the like, and the inclined holes are formed in the corresponding flowing dead zone direction; the aperture ratio and the aperture d are adjusted according to the size of the flow dead zone. Water flow sprayed out of the cooling cover scatters large air in the flowing dead zone, and a large-area high-temperature dead zone is avoided. The casing is divided into multiple cavities by arranging the reinforcing ribs, so that the situation that a single flowing dead zone is too large is avoided.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine technology, and particularly relates to a thermal protection structure and method for testing afterburners in aero-engines. Background Technology

[0002] During testing of the fan-shaped test specimen of an aero-engine, the two side casings are located in the combustion zone, requiring forced cooling of the casing walls using cooling water jackets. The cooling water removes heat, keeping the entire outer casing at a low temperature to ensure long-term operation under high-temperature conditions. However, a fan-shaped arc-shaped flow structure is formed at the lower edge water inlet to accommodate a temperature measuring device. During testing, this arc-shaped structure easily creates a high-pressure airflow dead zone at its top, resulting in poor heat exchange at the bottom of the casing. This can lead to high-temperature deformation of the test specimen, and in severe cases, even casing cracks, causing test failure.

[0003] The existing cooling water inlet is basically a parallel casing structure. This structure is simple and easy to form, and will not cause high temperature deformation of the test piece. However, it will affect the installation of the rotating temperature measuring device, leading to deviations in the measurement results and affecting the accuracy of the measurement results.

[0004] Patent application document CN115508094A discloses a combustion chamber test device and its casing test piece. The U-shaped guide plate set at the flow channel opening makes the water flow smoother, reduces flow loss, and avoids the occurrence of flow dead zones, which would cause the water-cooled inner jacket to overheat and burn. However, this method is not suitable for areas that do not contact the flow channel or areas that need to be cooled by spraying cooling water. Summary of the Invention

[0005] To solve the above-mentioned technical problems, the present invention provides a thermal protection structure and method for testing afterburners in aero-engines.

[0006] The present invention is achieved through the following technical solutions.

[0007] The present invention provides a test thermal protection structure for an afterburner chamber of an aero-engine, comprising a cooling shroud, a test piece, a water jacket, and a housing. The test piece is provided with a water jacket on its outer wall, the housing is located at the bottom of the inner cavity of the test piece, and the cooling shroud is located inside the housing.

[0008] Preferably, the top surface of the cooling cover is fan-shaped, and impact holes are provided on the sides and top surface of the cooling cover, while oblique holes are provided on the top surface of the cooling cover.

[0009] Preferably, the distance between the top of the cooling cover and the top surface of the inner cavity of the arc-shaped casing is not less than 5d, where d is the diameter of the impact hole.

[0010] Preferably, the top of the casing is fan-shaped, and a reinforcing rib is provided at the top of the inner cavity of the casing.

[0011] Preferably, the water jacket has an inlet pipe at the bottom, which extends into the casing and communicates with the cooling cover, and an outlet pipe at the top.

[0012] Preferably, the casing is located at the bottom of the inner cavity of the test piece.

[0013] Preferably, the test piece has a first mounting edge on one side and a second mounting edge on the other side.

[0014] A design method for a test thermal protection structure of an afterburner chamber for an aero-engine includes the following steps: Step 1: Use 3D modeling software to construct a 3D model of the water jacket. The target includes the outlet pipe, the fluid domain formed by the casing and the water jacket, the reinforcing ribs in the fluid domain, and the inlet pipe. Step 2: Set the boundary conditions for the inlet and outlet pipes of the model. At this time, the inlet pipe is not connected to the cooling shroud. The velocity distribution in the fluid domain of the model is obtained through numerical simulation. The boundary conditions of the inlet pipe include backflow pressure and temperature, and the boundary conditions of the outlet pipe include backflow pressure and temperature. The pressure of the outlet pipe is adjusted by monitoring the mass flow rate. Step 3: Based on the velocity distribution within the fluid domain, obtain the flow dead zone. Determine the position and angle of the oblique holes on the cooling shroud based on the location of the flow dead zone. For other areas, the cooling shroud achieves the purpose of air cooling at the inner wall of the fan-shaped top of the casing by spraying cooling water from the impact holes and oblique holes to impact the casing wall and form splash. Step 4: After completing the impact holes and oblique holes of the cooling cover, replace the water inlet pipe on the water jacket that is not connected to the cooling cover with a water inlet pipe with the cooling cover. Perform flow field simulation as in Step 2. Check whether there is a flow dead zone based on the velocity distribution in the fluid domain. The impact holes can be iterated according to the velocity.

[0015] Preferably, the formula for calculating the inclination angle of the oblique hole is: φ=arctan(X / L)+1 Where: X is the horizontal distance from the inclined hole to the flow dead zone, and L is the vertical distance from the inclined hole to the flow dead zone.

[0016] The flow dead zone is the region within the fluid domain where the velocity distribution is below 0.1 m / s.

[0017] The beneficial effects of this invention are as follows: This invention features multiple sets of circumferentially distributed cooling holes on the cooling shroud inside the casing. The sprayed water jets remove more heat, enhancing cooling. The hole diameter on the fan-shaped surface can be selected based on water pressure, distance from the casing, etc. Angled holes should be provided in the direction corresponding to the flow dead zone. The aperture ratio and hole diameter d are adjusted according to the volume of the flow dead zone. The water jets from the cooling shroud disperse large clumps of air within the flow dead zone, preventing large-area high-temperature dead zones. Reinforcing ribs divide the casing into multiple cavities to prevent any single flow dead zone from becoming excessively large. Attached Figure Description

[0018] Figure 1 This is the front view of the present invention; Figure 2 This is a schematic diagram of the structure of the water jacket of the present invention; Figure 3 This is a schematic diagram of the cooling shroud of the present invention; Figure 4 This is a front view of the cooling shroud of the present invention; Figure 5 This is a schematic diagram of the operation of the cooling shroud of the present invention; In the figure: 1-cooling cover, 2-test piece, 3-water jacket, 4-casing, 5-reinforcing rib, 6-first mounting edge, 7-second mounting edge, 8-impact hole, 9-inlet pipe, 10-slanted hole, 11-flow dead zone, 12-outlet pipe. Detailed Implementation

[0019] The technical solution of the present invention is further described below, but the scope of protection is not limited to what is described.

[0020] Example: like Figures 1 to 5 As shown, a test thermal protection structure for an afterburner chamber of an aero-engine includes a cooling shroud 1, a test piece 2, a water jacket 3, and a casing 4. The water jacket 3 is installed on the outer wall of the test piece 2, and the water jacket 3 covers the outer wall of the test piece 2. The casing 4 is located at the bottom of the inner cavity of the test piece 2, and the cooling shroud 1 is located inside the casing 4.

[0021] The top surface of the cooling cover 1 is fan-shaped, and impact holes 8 are provided on the side and top surfaces of the cooling cover 1. The impact holes 8 are perpendicular to the wall surface of the cooling cover 1, and oblique holes 10 are provided on the top surface of the cooling cover 1. The impact holes 8 and oblique holes 10 constitute a cooling hole. The cooling hole can be designed as a circular hole structure that is wider on the inside and narrower on the outside to increase the initial velocity of the water jet.

[0022] The distance between the top of the cooling cover 1 and the top surface of the inner cavity of the casing 4 is not less than 5d, where d is the diameter of the impact hole 8.

[0023] The top of the casing 4 is fan-shaped, and a reinforcing rib 5 is provided on the top of the inner cavity of the casing 4 to strengthen the casing 4 and divide the casing 4 into multiple cavities.

[0024] The bottom of the water jacket 3 is provided with a water inlet pipe 9, which extends into the casing 4 and communicates with the cooling cover 1. The top of the water jacket 3 is provided with a water outlet pipe 12. During the test, the water in the water jacket 3 carries away the heat of the test piece 2, and the water sprayed out by the cooling cover 1 disperses the large mass of air in the flow dead zone 11, thus avoiding the formation of a large area of ​​high temperature dead zone.

[0025] The casing 4 is located at the bottom of the inner cavity of the test piece 2.

[0026] The test piece 2 has a first mounting edge 6 on one side and a second mounting edge 7 on the other side for connecting the test piece 2 to the test bench.

[0027] A design method for a test thermal protection structure of an afterburner chamber for an aero-engine, comprising the following steps: Step 1: Use the 3D modeling software Unigraphics NX to construct a 3D model of the water jacket 3. The target includes the water outlet pipe 12, the fluid domain formed by the casing 4 and the water jacket 3, the reinforcing ribs 5 in the fluid domain, and the water inlet pipe 9. Step 2: Set the boundary conditions for the model's inlet pipe 9 and outlet pipe 12. At this time, the inlet pipe 9 is not connected to the cooling cover 1. Numerical simulation is performed using Ansys software to obtain the velocity distribution in the model's fluid domain. The boundary conditions for the inlet pipe 9 include backflow pressure and temperature, and the boundary conditions for the outlet pipe 12 include backflow pressure and temperature. The pressure of the outlet pipe 12 is adjusted by monitoring the mass flow rate. Step 3: Based on the velocity distribution within the fluid domain, obtain the flow dead zone 11 with a velocity lower than 0.1 m / s. Determine the position and angle of the oblique hole 10 on the cooling cover 1 based on the position of the flow dead zone 11. For other areas, the cooling cover 1 achieves the purpose of air cooling at the inner wall of the fan-shaped top of the casing 4 by spraying cooling water from the impact hole 8 and oblique hole 10 to impact the wall of the casing 4 and form splash. Step 4: After completing the opening of the impact hole 8 and the oblique hole 10 of the cooling cover 1, replace the water inlet pipe 9 on the water jacket 3 that is not connected to the cooling cover 1 with the water inlet pipe 9 connected to the cooling cover 1. Conduct flow field simulation according to Step 2. Based on the velocity distribution in the fluid domain, check whether there is a flow dead zone 11 with a velocity lower than 0.1m / s. The impact hole 8 can be iterated according to the velocity.

[0028] The formula for calculating the inclination angle of the inclined hole 10 is as follows: φ = arctan(X / L) + 1 Where: X is the horizontal distance from the oblique hole 10 to the flow dead zone 11, and L is the vertical distance from the oblique hole 10 to the flow dead zone 11. The casing 4 can be evaluated. If the inclined surface should not affect the flow field in the combustion zone, the fan-shaped surface on the top surface of the casing 4 can be set as an inclined surface to ensure that the flow dead zone 11 is at the junction of the reinforcing rib 5 and the casing 4, which facilitates the setting of the oblique hole 10 of the cooling shroud 1. The inclination angle of the inclined 10 should be less than 1°.

Claims

1. A test thermal protection structure for an afterburner chamber of an aero-engine, characterized in that: It includes a cooling cover (1), a test piece (2), a water jacket (3) and a casing (4). The test piece (2) has a water jacket (3) on its outer wall, the casing (4) is located at the bottom of the inner cavity of the test piece (2), and the cooling cover (1) is located inside the casing (4).

2. The thermal protection structure for an afterburner test of an aero-engine as described in claim 1, characterized in that: The top surface of the cooling cover (1) is fan-shaped, and impact holes (8) are provided on the side and top surface of the cooling cover (1). An oblique hole (10) is provided on the top surface of the cooling cover (1).

3. The thermal protection structure for an afterburner test of an aero-engine as described in claim 2, characterized in that: The distance between the top of the cooling cover (1) and the top surface of the inner cavity of the arc-shaped casing 4 is not less than 5d, where d is the diameter of the impact hole (8).

4. The thermal protection structure for an afterburner test of an aero-engine as described in claim 1, characterized in that: The top of the casing (4) is fan-shaped, and a reinforcing rib (5) is provided on the top of the inner cavity of the casing (4).

5. The thermal protection structure for an afterburner test of an aero-engine as described in claim 1, characterized in that: The bottom of the water jacket (3) is provided with a water inlet pipe (9), which extends into the casing (4) and communicates with the cooling cover (1). The top of the water jacket (3) is provided with a water outlet pipe (12).

6. The thermal protection structure for an afterburner test of an aero-engine as described in claim 1, characterized in that: The casing (4) is located at the bottom of the inner cavity of the test piece (2).

7. The thermal protection structure for an afterburner test of an aero-engine as described in claim 1, characterized in that: The test piece (2) has a first mounting edge (6) on one side and a second mounting edge (7) on the other side.

8. A design method for a test thermal protection structure for an afterburner of an aero-engine as described in any one of claims 1-9, characterized in that, Includes the following steps: Step 1: Use 3D modeling software to construct a 3D model of the water jacket (3). The target includes the water outlet pipe (12), the fluid domain formed by the casing (4) and the water jacket (3), the reinforcing ribs (5) in the fluid domain, and the water inlet pipe (9). Step 2: Set the boundary conditions for the model's inlet pipe (9) and outlet pipe (12). At this time, the inlet pipe (9) is not connected to the cooling cover (1). The velocity distribution in the model's fluid domain is obtained through numerical simulation. The boundary conditions for the inlet pipe (9) include backflow pressure and temperature, and the boundary conditions for the outlet pipe (12) include backflow pressure and temperature. The pressure of the outlet pipe (12) is adjusted by monitoring the mass flow rate. Step 3: Based on the velocity distribution within the fluid domain, obtain the flow dead zone (11). Determine the position and angle of the oblique hole (10) on the cooling cover (1) based on the position of the flow dead zone (11). For other areas, the cooling cover (1) achieves the purpose of air cooling at the inner wall of the fan-shaped top of the casing (4) by spraying cooling water from the impact hole (8) and oblique hole (10) to impact the wall of the casing (4) and forming splash. Step 4: After completing the opening of the impact hole (8) and oblique hole (10) of the cooling cover (1), replace the water inlet pipe (9) on the water jacket (3) that is not connected to the cooling cover (1) with the water inlet pipe (9) with the cooling cover (1). Perform flow field simulation according to step 2. Check whether there is a flow dead zone (11) based on the velocity distribution in the fluid domain. The impact hole (8) can be iterated according to the velocity.

9. The design method of a test thermal protection structure for an afterburner of an aero-engine as described in claim 8, characterized in that: The formula for calculating the inclination angle of the inclined hole (10) is as follows: φ = arctan(X / L) + 1 Where: X is the horizontal distance from the inclined hole (10) to the flow dead zone (11); L is the vertical distance from the inclined hole (10) to the flow dead zone (11).

10. The design method of a test thermal protection structure for an afterburner of an aero-engine as described in claim 8, characterized in that: The flow dead zone (11) is the region within the fluid domain where the velocity distribution is less than 0.1 m / s.

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