Double-walled cooling device and application

Abstract

This invention discloses a double-walled cooling device and its application, belonging to the field of aero-engines. It includes a cold-side flat plate, a hot-side corrugated plate, and hollow baffle columns. The cold-side flat plate is located on one side of the cold air passage, and the hot-side corrugated plate is located on the other side of the high-temperature gas passage. A periodically varying inverted hill-shaped intermediate passage is formed between the two wall plates. Several hollow baffle columns are arranged between the cold-side flat plate and the hot-side corrugated plate, connecting the cold air passage and the high-temperature gas passage. The connection between the hollow baffle columns and the hot-side corrugated plate is located on the crest of the hot-side corrugated plate. This invention combines hollow column baffle cooling with external film cooling, achieving high cooling efficiency with less cold air while reducing internal thermal stress and flow resistance. It also avoids the drawback of high flow resistance in traditional corrugated plate cold air passages, effectively solving the problem of insufficient total cold air pressure preventing flow from downstream heat shields and nozzle heat shields.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of aero-engines, and particularly relates to a double-wall cooling device and application. BACKGROUND

[0002] The working environment of the afterburner and the high-temperature components behind the afterburner is harsh. The gas temperature in the afterburner after ignition and re-combustion can be as high as 2050K-2100K, or even higher. Afterburning is usually turned on and off in a short time, and the thermal stress and thermal deformation caused by temperature distribution and changes need to be considered. In addition, the occurrence of oscillating combustion in the afterburner cylinder will also seriously affect its service life, and must also be considered in the design of the cooling structure.

[0003] The longitudinal corrugated heat shield is one of the commonly used heat shields for afterburners, which has the advantages of reducing thermal stress and high cold gas residence cold efficiency. In order to improve the cooling effect, gas film holes are usually opened on the gas leeward surface. Although the cold gas can reside at the cold gas side of the wave peak concave surface, which has the characteristics of high cold efficiency, due to the characteristics of high cold gas speed and low pressure in the cold gas channel wave peak area, it is not suitable to open gas film holes in the 1 / 6 area of the cold gas wave peak, which can easily cause gas backflow. See "Research on Flow Characteristics of Sinusoidal Longitudinal Corrugated Heat Shield[D]. Nanjing University of Aeronautics and Astronautics, 2010", author Chang Guoqiang.

[0004] Impingement + effusion double-wall gas film cooling technology is one of the advanced cooling methods for high-temperature components of modern engines. Before the formation of the gas film, it can fully utilize the high impingement heat exchange coefficient to achieve the effect of local heat exchange enhancement. The cooling structure of the combustion chamber flame tube of the aircraft engine in the invention patent CN105042640B is composed of an outer wall plate, an inner wall plate and a spoiler column, and a composite cooling double-wall structure formed by impingement + effusion + spoiler column is adopted to ensure high cooling effect with less cooling gas consumption. Liu Youhong et al. compared the cooling performance of the new impingement / effusion cooling panel heat shield in "Impingement / Effusion Cooling Panel Heat Shield Cooling Performance and Comparison [J]. Journal of Aerospace Power, 2014, 29(006): 1272-1278", demonstrating its feasibility for application in afterburner. The same working conditions were compared and analyzed with corrugated panel heat shield and single-layer flat panel heat shield, and the results showed that the impingement / effusion cooling panel heat shield had good cooling effect. The double-wall structure has structural strengthening effect, and the gas film hole outflow also has a certain anti-vibration effect, which can improve the life and reliability of the afterburner. The double-wall for aircraft engines and aircraft engine blades in patent CN205225464U disclose a double-wall for aircraft engines and aircraft engine blades, which utilizes impingement + gas film cooling structure and utilizes the columnar gas film hole penetrating through the two wall surfaces to enhance heat exchange effect. Although the impingement + effusion double-wall structure can achieve good heat exchange effect, the internal flow resistance is large, and it is greatly affected by the change of the primary and secondary flow total pressure ratio, and it is not easy to outflow under small pressure ratio. In addition, since the double-wall structure is a flat plate structure, the thermal stress is not easy to release, and under the action of frequent heating-cooling, it is easy to appear the rupture condition.

[0005] The corrugated hole plate cooling technology is another widely used cooling method for engine high-temperature components, which utilizes the residence of cold gas in the corrugated groove and has good cooling effect, and utilizes the corrugated structure to release the thermal stress in the structure. The patent "Gas Turbine Engine Multi-Hole Film Cooled Combustor Liner and Method of Manufacture" of Wakeman: US Patent, 5181379, proposes a sinusoidal thin-walled corrugated plate with dense gas film holes, and the hole diameter is recommended to be about 0.5 mm, and the inclination angle of the hole to the flow direction is 20°. This structure has a uniform wall thickness, which can reduce the radial temperature gradient.

[0006] Patent CN112178692A proposes a longitudinal corrugated cooling structure with an L-shaped impact orifice plate, which adds an L-shaped impact orifice plate to the corrugated plate structure to enhance the cooling effect by impact heat exchange. However, the corrugated structure and its improved structure undoubtedly improve the cooling effect, but there are still problems such as excessive consumption of cold gas and large thermal stress caused by uneven surface temperature of high-temperature components. Therefore, deeply tapping the cooling capacity of cold gas and reducing the flow resistance inside the cooling structure are the biggest challenges of existing cooling technology.

[0007] For the heat shield of the afterburner and nozzle of an aero-engine, on the one hand, it has to withstand the convective heating of the high-temperature gas on the wall surface, and on the other hand, it is subjected to the radiation heating of the high-temperature flame, therefore, the heat shield is prone to high-temperature ablation and thermal stress damage, the traditional corrugated plate structure has large cold gas consumption and large flow resistance in the cold gas channel, which is not conducive to the outflow of cold gas downstream of the corrugated plate structure. SUMMARY

[0008] The technical problem to be solved is:

[0009] In order to avoid the shortcomings of the prior art, the present application provides a double-wall cooling device, which communicates the cold side flat plate and the hot side corrugated plate through a hollow spoiler column, solving the problem of large cold gas consumption and large flow resistance in the cold gas channel of the traditional corrugated plate structure, which is not conducive to the outflow of cold gas downstream of the corrugated plate structure.

[0010] The technical solution of the present application is: a double-wall cooling device, comprising a cold side flat plate, a hot side corrugated plate and a hollow spoiler column, the cold side flat plate is located on one side of the cold gas channel, the hot side corrugated plate is located on one side of the high-temperature gas channel, and the two wall plates form an inverted hilly-shaped intermediate channel with periodically varying cross-sectional area therebetween;

[0011] A plurality of hollow spoiler columns are arranged between the cold side flat plate and the hot side corrugated plate, the cold gas channel and the high-temperature gas channel are communicated through the hollow holes in the hollow spoiler columns, and the connection between the hollow spoiler column and the hot side corrugated plate is located on the wave crest of the hot side corrugated plate.

[0012] The further technical solution of the present application is: the hot side corrugated plate is a symmetric sinusoidal corrugated plate or an asymmetric corrugated plate, and the corrugated track is perpendicular and parallel to the direction of the high-temperature main flow.

[0013] The further technical solution of the present application is: the wavelength of the hot side corrugated plate is 10-60mm, and the corrugated amplitude M is 1-10mm.

[0014] The further technical solution of the present application is: the average height H of the channel formed by the hot side corrugated plate and the cold side flat plate is 1-5 times the corrugated amplitude M.

[0015] The hollow hole section of the hollow spoiler column is circular, and the hollow hole diameter D of the hollow spoiler column is 0.5-5 mm i The hollow hole is inclined at an angle of 30-90°, and the wall thickness of the hollow spoiler column is 0.25-2 mm.

[0016] The spanwise spacing P of the hollow holes of adjacent hollow spoiler columns is 4-8D i The streamwise spacing S of the hollow holes of adjacent hollow spoiler columns is 0.33-1 times the wavelength λ of the corrugation, and the wavelength is an integer multiple of the streamwise through-hole spacing.

[0017] The radial section shape of the hollow spoiler column is circular, elliptical, water-drop-shaped or hyperbolic.

[0018] The hollow hole section of the hollow spoiler column is consistent with the radial section shape of the hollow spoiler column.

[0019] The application of a double-wall cooling device, which is applied to a thrust chamber, the cold side plate and the outer wall of the thrust chamber form a cold gas passage, and the hot side corrugated plate forms an inner wall surface of the thrust chamber; part of the cooling gas flow in the cold gas passage flows backward along the axial direction, and part of the cooling gas flow flows out through the hollow holes of the hollow spoiler column to form an outflow gas film on the inner side of the hot side corrugated plate.

[0020] Advantages

[0021] The application provides a flat plate plus corrugated plate cooling device with a hollow spoiler column, which combines hollow column spoiler cooling and external gas film cooling, uses less cooling gas to achieve high cooling efficiency, reduces internal thermal stress of the structure, and reduces flow resistance of the structure. Figure 2 As shown in the figure, part of the cooling gas flow B passes through the hollow holes 3 to form a standing cooling gas vortex E on the high-temperature gas side of the corrugated plate, thereby forming a cooling gas film on the hot side corrugated surface, reducing the heat transfer of the main flow gas A to the heat shield; another part of the cooling gas C flows through the hollow column spoiler 3 in the passage formed by the cold side plate 1 and the corrugated plate 2 to cool the hot side corrugated plate 2; the hot side corrugated plate 2 can allow certain deformation under uneven heat flow conditions, passively changes the amplitude M of the corrugation, eliminates thermal stress, and thereby prolongs the service life of the heat shield; the hollow spoiler column 4 is inclined at an angle of 30-90° with the intermediate passage gas flow C, on the one hand, the flow cross section is elliptical, reducing the internal flow resistance, and on the other hand, the cooling gas flow D1 has a small included angle with the main flow A, ensuring the adhesion of the cooling gas to the wall surface, thereby achieving higher cooling effect and reducing the mixing loss of the nozzle. Figure 5As shown, the outer cold air passage 8 is composed of the cold side flat plate 1 and the flat outer wall 7, avoiding the large flow resistance of the traditional corrugated plate cold air passage, effectively solving the problem that the downstream heat shield and the nozzle heat shield cannot flow out due to insufficient total pressure of the cold air. Figure 6 As shown, the cylindrical shape of the ellipse 13, the water droplet 14, and the hyperbolic shape 15 not only makes the gas film better adhere to the surface of the gas, enhances the heat exchange effect, but also reduces the flow resistance of the internal column row.

[0022] After numerical verification, as Figure 7 and 8 The comparative distribution cloud diagram and line diagram of the comprehensive cooling efficiency of an embodiment of the present application and the traditional single-layer corrugated plate structure model with the same position opening are shown, and under the condition of using the same amount of gas film cooling air, the comprehensive cooling efficiency is improved from 0.267 to 0.742, with an increase of 2.78 times. As can be seen from the figure, the cooling efficiency distribution of the embodiment is more uniform, so the internal thermal stress of the structure is smaller. The flow resistance of the structure is measured by the total pressure loss coefficient, which decreases from 1.29 to 1.1, which is 85.3% of the original structure, so the structure can be cooled by lower pressure cold air.

[0023] In summary, the advantages of the present application are: (1) less cooling air, high cooling efficiency; (2) the corrugated structure effectively reduces the thermal stress; (3) the flow resistance of the structure is small, which ensures the outflow of the downstream cooling structure. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The figure is a schematic diagram of a double-layer wall cooling device of the present application;

[0025] Figure 2 The figure is a flow schematic diagram of a double-layer wall cooling device of the present application;

[0026] Figure 3 The figure is a schematic diagram of the feature size of a double-layer wall cooling device of the present application;

[0027] Figure 4 The figure is a schematic diagram of the hole arrangement of a double-layer wall cooling device of the present application;

[0028] Figure 5 The figure is a schematic diagram of the application scenario of the present application in the afterburner;

[0029] Figure 6 The figure is a schematic diagram of the structure of the hollow spoiler column in the present application;

[0030] Figure 7 The figure is a comparative cloud diagram of the comprehensive cooling efficiency of an embodiment of the present application and a single-layer corrugated plate model;

[0031] Figure 8 The figure is a comparative line diagram of the spanwise average comprehensive cooling efficiency of an embodiment of the present application and a single-layer corrugated plate model.

[0032] Reference numerals: 1, cold side flat plate; 2, hot side corrugated plate; 3, hollow hole; 4, hollow spoiler column; 5, trough of hot side corrugated plate; 6, crest of hot side corrugated plate; 7, outer wall; 8, cold gas channel; 9, main combustion gas duct; 10, adjustable nozzle; 11, circular hollow spoiler column; 12, elliptical hollow spoiler column; 13, water droplet-shaped hollow spoiler column; 14, hyperbolic hollow spoiler column; A, main flow combustion gas; B, cooling gas flow; C, inter-plate cooling gas flow; D1, hollow hole outflow; D2, outflow gas film; D i hollow spoiler column inner diameter; D o hollow spoiler column outer diameter; E, cold gas vortex residing in the concave part of the crest of hot side corrugated plate; H, average height of inter-plate channel; M, corrugation amplitude; P, spanwise spacing of hollow spoiler column row; S, streamwise spacing of hollow spoiler column row; λ, corrugation length. DETAILED DESCRIPTION

[0033] The embodiments described below with reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application.

[0034] In the description of the present application, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0035] The present embodiment is a specific embodiment of a flat plate plus corrugated plate cooling device with hollow spoiler columns in a thrust chamber.

[0036] The high-temperature low-pressure combustion gas discharged from the turbine enters the main combustion gas duct 9 after being expanded, mixes with the fuel sprayed by the fuel nozzle, and then burns to form high-temperature gas. The temperature of the main flow high-temperature gas A can be as high as 2200K, far exceeding the melting point of the material, so the heat shield needs to be cooled.

[0037] Referring to Figure 1 , Figure 2 , Figure 3 , Figure 4The flat plate and corrugated plate cooling device for the afterburner in this embodiment includes a cold-side flat plate 1, a hot-side corrugated plate 2, and a hollow turbulence column 4 connecting the cold-side flat plate and the hot-side corrugated plate. The cold-side flat plate 1 and the outer wall 7 form a cold air passage 8, forming an inverted hill-shaped intermediate passage with a periodically changing cross-sectional area between the cold-side flat plate and the hot-side corrugated plate. The hot-side corrugated plate 2 forms the inner wall of the afterburner.

[0038] Figure 2 and Figure 5 The diagram illustrates the operation of a flat-plate and corrugated-plate cooling device with a hollow baffle column in the afterburner. This device is fixedly mounted on the outer wall 7 of the afterburner via a bracket, and the adjustable exhaust nozzle 10 is also fixedly connected to the outer wall 7. Cooling airflow B flows axially backward in the cold air passage 8, with a pressure higher than the combustion gas pressure in the main combustion duct 9. A portion of the cooling airflow B passes through the hollow column to form an outflow D1 and forms an outflow film D2 on the hot-side corrugated plate 2. An intermediate channel is formed between the cold-side flat plate and the hot-side corrugated plate, through which airflow C passes, cooling the hot-side corrugated plate through convective heat transfer.

[0039] In this implementation case, the corrugation length λ is 12mm, the average channel height H between the two corrugated plates is 6mm, the corrugation amplitude M is 2mm, and the inner diameter D of the hollow column is... i The outer diameter D of the hollow column is 2mm. o The spacing between the hollow baffle columns is 4mm, the longitudinal spacing P is 12mm, and the lateral spacing S is 12mm. Because the cold air vortex E resides in the concave part of the hot-side corrugated plate crest, a film layer is formed to effectively cover the hot-side corrugated plate, thus significantly reducing the heat transfer from the combustion gas to the hot-side corrugated plate. Furthermore, the cooling airflow C passes through the middle channel between the two corrugated plates, cooling the hot-side corrugated plate through convection heat transfer, carrying away the heat from the hot-side corrugated plate, further reducing its temperature, and thus providing good protection for the entire afterburner. The straight cold air channel significantly reduces flow resistance compared to the traditional corrugated cold air channel. Numerical calculations were performed to compare this implementation case with a single-layer corrugated plate structure with the same opening ratio and opening position. Specific calculation settings are shown in Table 1. A comparison of the cooling efficiency of the implementation case with single-layer and multi-layer corrugated plate structures is shown in Table 1. Figure 7 and Figure 8 Under the same cooling air consumption, the overall cooling efficiency of this embodiment is 2.78 times that of a single-layer corrugated plate, and the total pressure loss coefficient of the cooling air is reduced by 85.3%.

[0040] Table 1. Implementation Cases and Numerical Calculation Methods for Single-Layer Corrugated Plate Models

[0041]

[0042] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and are not to be construed as limiting the present application, and that changes, modifications, substitutions and variations can be made by those skilled in the art without departing from the spirit and scope of the present application.

Claims

1. A double-walled cooling device, characterized by: The double-layer wall cooling device comprises a cold-side flat plate, a hot-side corrugated plate and hollow turbulence columns, the cold-side flat plate is located on one side of a cold gas passage, the hot-side corrugated plate is located on one side of a high-temperature gas passage, and an inverted hilly intermediate passage with periodically changed cross-sectional area is formed between the two wall plates; A plurality of hollow turbulence columns are arranged between the cold-side flat plate and the hot-side corrugated plate, the cold gas passage and the high-temperature gas passage are communicated through hollow holes in the hollow turbulence columns, and the connection between the hollow turbulence columns and the hot-side corrugated plate is located on the wave crest of the hot-side corrugated plate; The hot-side corrugated plate is a symmetric sinusoidal corrugated plate or an asymmetric corrugated plate, and the corrugated track is perpendicular and parallel to the high-temperature main flow direction; The wavelength λ of the hot-side corrugated plate is 10-60 mm, and the corrugated amplitude M is 1-10 mm; The average height H of the passage formed by the hot-side corrugated plate and the cold-side flat plate is 1-5 times the corrugated amplitude M; The hollow hole section of the hollow spoiler column is circular, and the hollow hole diameter D i The hollow hole is between 0.5-5mm, and the inclination angle is 30°-90°; the wall thickness of the hollow spoiler column is between 0.25-2mm; The spanwise distance P between the hollow holes of the adjacent hollow spoiler columns is 4-8D i The streamwise distance S between the hollow holes of the adjacent hollow spoiler columns is 0.33-1 times the corrugation wavelength λ, and the wavelength is an integer multiple of the streamwise hole distance. The radial cross-sectional shape of the hollow turbulence column is circular, elliptical, water-drop-shaped or hyperbolic.

2. The double-walled cooling device according to claim 1, characterized in that: The cross-sectional shape of the hollow hole of the hollow turbulence column is consistent with the radial cross-sectional shape of the hollow turbulence column.

3. Use of the double-walled cooling device according to claim 1, characterized in that: The double-layer wall cooling device is applied to a thrust combustion chamber, the cold-side flat plate and the outer wall of the thrust combustion chamber constitute a cold gas passage, and the hot-side corrugated plate constitutes the inner wall surface of the thrust combustion chamber; part of the cooling gas flow in the cold gas passage flows axially rearward, and part of the cooling gas flow flows out through the hollow holes of the hollow turbulence columns to form an outflow gas film on the inner side of the hot-side corrugated plate.

Images