A long-time thermal test support structure for an RBCC composite engine

Abstract

The application discloses a long-time thermal test support structure for RBCC composite engine, a plurality of support structures are arranged along the length direction of the engine, and the support structures are divided into fixed support structures and hanging support structures; each support structure comprises a horizontal tool plate, clamps for clamping the combustion chamber of the engine are arranged above the horizontal tool plate, and gradient heat insulation materials are filled between each clamp and the contact surface of the outer wall of the engine; wherein the clamps of the fixed support structures are screw-connected with the tool plate through long screw rod assemblies on both sides of the clamps, and the outer wall of each screw rod in the long screw rod assembly is wrapped with aerogel heat insulation felt. The long-time ground direct-connection thermal test under the extreme force-thermal environment is realized.

Description

Technical Field

[0001] This invention belongs to the field of combined engine testing technology, specifically relating to a support structure for long-term thermal testing of an RBCC composite engine. Background Technology

[0002] Stamped engines or combined engines made of metal materials generally use a fixed arc-shaped bracket to accommodate test benches of different sizes. The bracket is usually fastened to the engine housing. However, due to thermal expansion and deformation caused by long-term testing, the metal engine usually releases displacement by sliding between the bracket and the test bench.

[0003] Composite material engines are characterized by low weight and high temperature resistance. However, after approximately 100 seconds of prolonged testing, the outer surface temperature of a passively cooled composite material engine will reach over 1000°C. Further testing will cause the outer surface temperature to reach the melting point of the metal support frame. Therefore, thermal protection is necessary for the engine or test frame, commonly achieved by wrapping the engine with heat-insulating materials. However, while heat insulation solutions using materials such as ceramic fibers can slow down heat transfer, they can affect the vibration modal characteristics of the engine during direct-drive testing.

[0004] Meanwhile, compared to the isotropic nature of metallic materials, composite materials exhibit highly non-uniform mechanical responses in different directions due to the anisotropy of fiber orientation and layup design. In the manufacturing of composite engine systems, the radial and axial thermal expansion coefficients differ by more than tenfold. The sliding release mechanism used in metallic engines is ill-suited to the anisotropic thermal deformation characteristics of composite materials. Because of the significant difference in radial and axial thermal expansion coefficients between composite engine components, traditional uniform support structures are prone to asymmetric stress concentration at high temperatures, leading to localized high stress in the composite shell. More importantly, the radial expansion of composite materials at temperatures above 1500℃ can cause compressive interference with rigid tooling, and a single axial sliding design cannot coordinate multi-directional deformation, easily leading to structural fracture. Therefore, there is an urgent need for a composite engine test support system that combines efficient heat insulation, adaptive adjustment of multi-directional thermal deformation, and high-temperature structural stability to overcome the technical bottleneck of thermo-mechanical coupling failure in long-term direct-drive tests. Summary of the Invention

[0005] The purpose of this invention is to provide a support structure for long-term thermal testing of RBCC composite engine, which is used for long-term direct ground-based thermal testing under extreme force and heat conditions.

[0006] The present invention adopts the following technical solution: a support structure for long-term thermal testing of an RBCC composite material engine, wherein multiple support structures are arranged along the length of the engine, and the support structures are divided into fixed support structures and suspended support structures; Each support structure includes a horizontal tooling plate with a clamp above it for clamping the engine combustion chamber, and a gradient heat insulation material is filled between the contact surface between each clamp and the outer wall of the engine. The fixture with fixed support structure is connected to the tooling plate by long screw assemblies on both sides, and the outer wall of each screw in the long screw assembly is wrapped with aerogel insulation felt.

[0007] Furthermore, the clamp for fixing the support structure is a circular combustion chamber clamp, which has an upper arc-shaped clamp and a lower arc-shaped clamp that are arranged opposite each other and form a circular clamping space. The lower arc-shaped clamping plate includes an arc-shaped steel plate. The bottom of the arc-shaped steel plate is connected to a horizontally set intermediate crossbeam via a flat plate. The bottom of the intermediate crossbeam is connected to a tooling plate via a height adjustment device. When the outer surface diameter of the engine housing is ≤400mm, the parts of the upper arc-shaped clamping plate and the lower arc-shaped clamping plate that contact the engine surface are both 150° arc-shaped structures. A top crossbeam is set parallel above the middle crossbeam. The upper arc-shaped clamping plate includes an arc-shaped steel plate, and the upper part of the arc-shaped steel plate is connected to the top crossbeam through a flat plate. The two sides of the two arc-shaped steel plates are connected by a first long screw thread; multiple second long screws are provided on both sides of the two arc-shaped steel plates and through the top crossbeam and the middle crossbeam, and each second long screw extends to the tooling plate; When the outer surface diameter of the engine housing is greater than 400mm, the parts of the upper and lower arc-shaped clamps that contact the engine surface are both 120° arc-shaped structures; the upper arc-shaped clamp is an arc-shaped steel plate, and the two sides of the upper and lower arc-shaped steel plates are connected by a third long screw thread, which passes through the middle crossbeam and extends to the tooling plate.

[0008] Furthermore, the fixture for fixing the support structure is a square combustion chamber fixture. The square combustion chamber fixture has an upper clamping plate and a lower clamping plate arranged side by side with adjustable spacing. A middle crossbeam and a top crossbeam are arranged in parallel and spaced apart above the tooling plate. The upper clamping plate is connected to the bottom of the top crossbeam, and the lower clamping plate is connected to the top of the middle crossbeam. Multiple fourth long screws are threadedly connected to both sides of the upper and lower clamping plates, through the top crossbeam, the middle crossbeam, and the tooling plate. The lower clamping plate is used to adjust the engine height, and the upper clamping plate is used to press the engine housing.

[0009] Furthermore, the clamp of the suspension support structure includes a water-cooled clamp ring, which is divided into two half-clamp rings, left and right. The contact surfaces of the two half-clamp rings are filled with aerogel insulation felt, and each half-clamp ring is an arc of 179°. A hanging rod is horizontally installed at the midpoint of both the left and right sides of the water-cooled ring. A middle crossbeam is horizontally installed at the bottom of the water-cooled ring. A bracket is vertically installed on both sides of the water-cooled ring above the middle crossbeam. Each bracket is perpendicular to its extension direction and has a groove at its top. The hanging rod is used to push the hanging rod horizontally into the groove.

[0010] Furthermore, the bottom of the intermediate crossbeam is connected to the tooling plate via a height adjustment device, which includes several telescopic rods disposed between the intermediate crossbeam and the tooling plate.

[0011] Furthermore, the bottom of the tooling plate is provided with a tooling base, which includes two inverted T-shaped legs. Each leg includes a horizontal plate and a vertical plate that are perpendicular to each other. The horizontal plate is provided with a waist-shaped groove, and the vertical plate is used to move within the waist-shaped groove.

[0012] The beneficial effects of this invention are as follows: By employing a passive heat insulation scheme of "gradient heat insulation material + stainless steel bracket" and an active cooling scheme of "aerogel heat insulation pad + water-cooled retainer," this invention achieves efficient heat insulation in extreme thermal environments above 1500℃ through the synergistic effect of these two approaches. Furthermore, this invention releases the axial elongation deformation of the composite material under high temperatures by designing an axial movement gap, and adjusts the height by setting up a bracket structure with adjustable height and direction. In summary, this invention, through heat insulation design and a horizontal and height-adjustable structure, employing gradient heat insulation materials and a water-cooled thermal protection structure, and a multi-degree-of-freedom adjustment device, realizes a testing fixture scenario for composite material engines under extreme thermal and mechanical conditions. Attached Figure Description

[0013] Figure 1 A schematic diagram of the service status of a support structure for a long-term thermal testing of an RBCC composite engine, provided in an embodiment of the present invention; Figure 2 This is a test support structure for a circular combustion chamber fixture; Figure 3 This is a test support structure for another type of circular combustion chamber fixture; Figure 4 This is a test support structure for a square combustion chamber fixture; Figure 5 This is a test support structure for a hanging support structure clamp; Figure 6 This is a schematic diagram showing the final temperature of the thermal insulation material in an embodiment of the present invention.

[0014] The components are: 1. Tooling plate, 2. Lower clamping plate, 3. Upper clamping plate, 4. Semi-clamping ring, 5. Curved steel plate, 6. Flat plate, 7. Middle crossbeam, 8. Top crossbeam, 9. First long screw, 10. Second long bolt, 11. Third long screw, 12. Bracket, 13. Hanging rod, 14. Groove, 15. Telescopic rod, 16. Fourth long screw, 17. Tooling base, 18. Waist-shaped groove. Detailed Implementation

[0015] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0016] This invention provides a support structure for long-term thermal testing of RBCC composite engine, such as... Figure 1 As shown, multiple support structures are arranged along the length of the engine. These support structures are divided into fixed support structures and suspended support structures. The type of support structure is selected based on the engine's shape characteristics. Under flight conditions, suspended support structures are used at the connection between the engine and the aircraft, while fixed support structures are used in other auxiliary support areas. In practical use, this invention can provide various combinations to accommodate engines of different sizes and engine casing shapes, while also taking into account different fixing methods.

[0017] Each support structure includes a horizontal tooling plate 1, on which a clamp for clamping the engine combustion chamber is mounted. The contact surface between each clamp and the engine outer wall is filled with a gradient thermal insulation material, which is made of a laminate of flexible graphite sheets and alumina fiber cotton. The flexible graphite has an in-plane thermal conductivity of approximately 750 W / (m·K), enabling it to rapidly diffuse and homogenize the concentrated heat from the engine outer wall along the planar direction. The alumina fiber layer, with its extremely low thermal conductivity, effectively blocks heat transfer into the depth of the metal support. This "draining then blocking" gradient design also provides flexible compression margin for the radial thermal expansion of the composite material shell. By employing a flexible transition, the contact surface between the engine shell and the tooling clamp is filled with gradient thermal insulation material and an aerogel thermal pad, preventing rigid collisions and avoiding the problem of flange breakage due to pressure between the flange and the tooling caused by radial expansion of the composite engine at high temperatures.

[0018] The fixture of the fixed support structure is threaded to the tooling plate 1 on both sides via long screw assemblies. The outer wall of each screw in the long screw assembly is wrapped with aerogel heat insulation felt. The bracket is wrapped with heat insulation material to prevent the bracket from softening due to high temperature caused by the radiation temperature of the engine's outer wall surface during long-term experiments.

[0019] In some embodiments, the clamp for fixing the support structure is a circular combustion chamber clamp, which has an upper arc-shaped clamp and a lower arc-shaped clamp that are arranged opposite each other and form a circular clamping space. like Figure 2 and Figure 3 As shown, the lower arc-shaped clamping plate includes an arc-shaped steel plate 5. The bottom of the arc-shaped steel plate 5 is connected to a horizontally arranged intermediate crossbeam 7 via a flat plate 6. The bottom of the intermediate crossbeam 7 is connected to the tooling plate 1 via a height adjustment device. Among them, such as Figure 2 As shown, when the diameter of the outer surface of the engine housing is ≤400mm, the parts of the upper arc-shaped clamp and the lower arc-shaped clamp that contact the engine surface are both 150° arc-shaped structures. A top crossbeam 6 is arranged parallel above the middle crossbeam 7. The upper arc-shaped clamp includes an arc-shaped steel plate 5. The upper part of the arc-shaped steel plate 5 is connected to the top crossbeam 8 through a flat plate 6. The two sides of the two arc-shaped steel plates 5 are connected by the first long screw 9; multiple second long screws 10 are provided on both sides of the two arc-shaped steel plates 5 and through the top crossbeam 8 and the middle crossbeam 7, and each second long screw 10 extends to the tooling plate 1. like Figure 3 As shown, when the diameter of the outer surface of the engine housing is >400mm, the parts of the upper arc-shaped clamping plate and the lower arc-shaped clamping plate that contact the engine surface are both 120° arc-shaped structures; the upper arc-shaped clamping plate is an arc-shaped steel plate 5, and the two sides of the upper and lower arc-shaped steel plates 5 are threaded together by a third long screw 11. The third long screw 11 passes through the middle crossbeam 7 and extends to the tooling plate 1.

[0020] In some embodiments, such as Figure 4 As shown, the fixture for fixing the support structure is a square combustion chamber fixture. The square combustion chamber fixture has an upper clamping plate 3 and a lower clamping plate 2 arranged side by side with adjustable spacing. A middle crossbeam 7 and a top crossbeam 8 are arranged in parallel and spaced apart above the tooling plate 1. The upper clamping plate 3 is connected to the bottom of the top crossbeam 8, and the lower clamping plate 2 is connected to the top of the middle crossbeam 7. Multiple fourth long screws 16 are threadedly connected to both sides of the upper clamping plate 3 and the lower clamping plate 2, through the top crossbeam 8, the middle crossbeam 7 and the tooling plate 1. The lower clamping plate 2 is used to adjust the engine height, and the upper clamping plate 3 is used to press the engine housing.

[0021] In some embodiments, such as Figure 5 As shown, the clamp of the hanging support structure includes a water-cooled ring, which is divided into two half-rings 4, left and right. The contact surfaces of the two half-rings 4 are filled with aerogel insulation felt, and each half-ring 4 is an arc of 179°. A hanging rod 13 is horizontally installed at the midpoint of both the left and right sides of the water-cooled ring. A middle crossbeam 7 is horizontally installed at the bottom of the water-cooled ring. A bracket 12 is vertically installed on both sides of the water-cooled ring above the middle crossbeam 7. Each bracket 12 is perpendicular to the extension direction of its extension direction and has a groove 14 at its top. The hanging rod 13 is used to be pushed horizontally into the groove 14.

[0022] The water-cooled retainer has an internal circulating cooling water channel that uses forced convection to continuously remove heat. The aerogel insulation pad filling the space between the retainer and the engine casing plays a crucial role in heat insulation—the aerogel's nanoscale porosity of over 95% results in a thermal conductivity as low as 0.02~0.1 W / (m·K) at room temperature, significantly reducing heat conduction and radiation. Simulation results show that in a 300-second transient thermal test, when the engine outer wall temperature approaches 1500℃, a mere 20 mm thick aerogel insulation pad can control the contact temperature between the water-cooled retainer and the bracket below 250℃.

[0023] In some embodiments, the bottom of the intermediate crossbeam 7 is connected to the tooling plate 1 via a height adjustment device, which includes a plurality of telescopic rods 15 disposed between the intermediate crossbeam 7 and the tooling plate 1. The telescopic rods 15 are typically double-ended studs. Height adjustment is mainly performed through the height adjustment device, by rotating the double-ended studs to adjust the overall height of the engine clamp.

[0024] In some embodiments, a tooling base 17 is provided at the bottom of the tooling plate 1. The tooling base 17 includes two inverted T-shaped legs, each leg including a horizontal plate and a vertical plate that are perpendicular to each other. A waist-shaped groove 18 is provided on the horizontal plate, and the vertical plate is used to move within the waist-shaped groove 18. A plurality of elongated holes are provided on the tooling plate 1 for connecting with a long screw assembly, and the lateral position of the engine is adjusted through these elongated holes.

[0025] Addressing the bottleneck of thermo-mechanical coupling failure in long-term direct-heat testing of composite engine technologies, this invention provides a systematic solution in its implementation. For efficient heat insulation, a combined active and passive thermal protection strategy is adopted: the passive insulation solution involves laying a gradient insulation material made of flexible graphite sheets and alumina fiber cotton laminates on the outer side of the engine casing; the active cooling solution employs a water-cooled ring structure with built-in water-cooling channels, with aerogel insulation felt filling the space between the two halves of the ring to balance heat insulation and vibration reduction. Simulation calculations show that when the engine outer wall temperature approaches 1500℃ after 300 seconds, a 20mm thick aerogel insulation pad can control the support temperature below 250℃. Regarding the adaptive adjustment of multi-directional thermal deformation, considering the anisotropic characteristics of composite materials where the radial thermal expansion coefficient can reach more than 10 times that of the axial coefficient, two release mechanisms were designed: axial sliding gap and radial flexible transition. Axial displacement is released through three pathways: the sliding between the flexible graphite sheet on the surface of the gradient insulation material and the metal support, and the axial movement of the hanging point along the groove. Radial expansion is absorbed by the compression margin provided by the gradient insulation material and the flexible transition interface, avoiding direct compression between the composite shell and the rigid clamp. For high-temperature structural stability, the support clamp is made of 304 stainless steel to ensure high-temperature strength. The screw is wrapped with aerogel insulation felt to prevent strength attenuation caused by high-temperature radiation. Simultaneously, a height adjustment device and multi-degree-of-freedom installation adjustment ensure a reasonable layout of each support position. Static and dynamic simulations verified the safety and reliability of the structure under the combined action of thermal and vibration loads.

[0026] like Figure 2 As shown, this is a circular combustion chamber fixture used when the diameter is ≤400mm. It includes a horizontal tooling plate 1 mounted on the test bench, and a combustion chamber fixture for fixing the engine, which consists of an upper arc-shaped clamping plate and a lower arc-shaped clamping plate. These three parts are connected by M30 long screws around the perimeter. Nuts are used to secure the long screws on both sides of the horizontal tooling plate and on both sides of the combustion chamber fixture. The nut on the lower arc-shaped clamping plate is used to adjust the engine height, and the nut on the upper arc-shaped clamping plate is used to press the engine housing. An engine height adjustment device is used to further enhance the stability of the combustion chamber fixture, and three more stable screws are used to fix the upper and lower arc-shaped clamping plates. The circular combustion chamber fixture is not only connected to the tooling base 17 mounted on the ground by four M30 screws, but also has two additional M30 screws to connect the upper and lower arc-shaped clamping plates.

[0027] like Figure 3 As shown, it is a circular combustion chamber clamp used when the diameter is >400mm, and... Figure 2In contrast, to prevent deformation of the M30 bolt connecting the lower arc-shaped clamp and the tooling base 17 due to insufficient rigidity during large-diameter engine testing, two telescopic rods 15 are added to the tooling base 17 to ensure structural rigidity. Simultaneously, the arc-shaped clamp on the combustion chamber support is modified, eliminating the original horizontal plate structure and using only one arc-shaped clamp, i.e., the arc-shaped steel plate 5. This reduces the weight of the upper part of the engine support, lowers the center of gravity, increases the overall rigidity of the support, and prevents excessive amplitude vibration that could damage the connection points.

[0028] like Figure 5 As shown, this is a clamp for a suspended support structure, a heat testing suspended support structure fixed to the ground. It includes a tooling base 17 installed on the ground, a height adjustment device, a bracket 12 supporting the suspension points, and a water-cooled retaining ring divided into two parts. During installation, the ground tooling base 17 is first fully secured to the ground using anchor bolts. Then, the height adjustment device and tooling plate 1 are installed. The height and horizontal position of the tooling plate 1 need to be determined based on the suspension point position on the water-cooled retaining ring. The height adjustment device needs to be adjusted after installing the water-cooled retaining ring. Then, the suspension rod 13 is fully inserted into the groove 14 from one side. Finally, all bolts on the entire support are tightened.

[0029] This fixture is used for long-term ground-based direct-connection thermal testing of composite engine casings. Through different structural combinations, it can secure engine casings of varying sizes and shapes. The fixture plate 1 mounted on the test bench and the fixture base 17 mounted on the ground can be selected based on the ground fixing method for different engine locations. When considering the need to increase the overall rigidity of the support fixture, a height adjustment device or a screw connection can be used. Figure 1 As shown, depending on the shape of the engine casing, either a square or round combustion chamber clamp can be used. To simulate the method used when installing an engine on an aircraft, a suspension support structure clamp can be selected.

[0030] Example: For the long-term ground-based direct thermal testing fixture for composite material engines, structural simulation calculations under thermal insulation and mechanical vibration conditions are required. A long-term ground-based direct thermal testing of a 4000mm long composite material engine will be conducted. Six sets of fixture supports will be designed according to... Figure 1 The arrangement is shown. When designing the corresponding tooling bracket, the first consideration is the actual connection method between the engine and the aircraft. In this embodiment, the connection method used is a mounting point connection. Therefore, the support structure at the mounting point connection is arranged first, such as... Figure 1The third and fifth support structures from left to right are shown in the middle. The design of other support structures follows. Key design considerations include that, except for the hanging point supports, the structures must be designed according to the actual shape of the engine. The support spacing is generally less than four times the engine diameter. Modal analysis is performed after the design is complete to prevent resonance in the support structures. The maximum span between each set of fixtures is approximately 800mm. A 20mm thick layer of alumina fiber aerogel is used for insulation between the fixtures and the composite engine.

[0031] Specifically, the engine's thermal environment and heat transfer were first calculated. Under Mach 6 operating conditions, the temperature of the support structure (i.e., the insulation layer) was calculated after a 300-second transient test. Convective heat transfer boundaries were used on the inner wall surface, while thermal radiation was considered between the outer wall surface of the composite material and the support structure and insulation. The ambient temperature was 80℃, and the surface emissivity of all materials was 0.8, allowing for structural thermal radiation to the external environment. Anisotropic materials were used for the composite material. The final insulation material temperature was as follows: Figure 6 As shown, the temperature is highest on the outer wall of the concave section of the engine combustion chamber. After 300 seconds, the temperature of the outer wall of the engine approaches 1500℃. The 20mm silica aerogel heat insulation pad here can ensure that the temperature of the outer wall is less than 300℃ after heat insulation, while the highest temperature of the bracket is 250℃.

[0032] Then, static and modal calculations and corresponding harmonic response analyses were performed on the engine bracket at high temperatures. The static analysis mainly verifies the strength and stiffness of the structure under steady-state loads, while the modal calculations and harmonic response analyses mainly predict the resonance risk of the structure under periodic excitation.

[0033] Specifically, static calculations were first performed. After applying a transient heat transfer load for 300 seconds, structural strength calculations were conducted. In addition to the fixed constraints on the ground and tooling plate, fixed constraints were also added to the engine front flange, and a downward force of 3000N due to engine thrust eccentricity was also added. The overall calculation results showed a maximum deformation of approximately 13mm, exhibiting a backward tensile state. The bolts used were grade 12.9 bolts with a yield stress of 900MPa. The actual stress of the bolts was less than 400MPa, and the strain was approximately 0.2%. The support structure met safety requirements.

[0034] Dynamic analysis was then conducted. The calculation results for the first three modes were 75.6Hz, 93.2Hz, and 96.9Hz. Frequency sweep calculations were performed within the range of 10~200Hz, with a transverse 5.5G acceleration as the excitation. The results showed that the overall structure would resonate at 76Hz and 93.6Hz. At 76Hz, the entire test structure would resonate transversely with a displacement of 2.8mm. The calculation results for the metal support and long screw showed that at 93.6Hz, the maximum stress of the support was located on the rear support of the tail nozzle. Under the 5.5g acceleration excitation, the maximum equivalent stress reached 255MPa, which was less than the yield stress of the 12.9 grade screw (900MPa), indicating that the support structure was safe.

Claims

1. A support structure for long-term thermal testing of an RBCC composite engine, characterized in that, Multiple support structures are arranged along the length of the engine, and the support structures are divided into fixed support structures and suspended support structures. Each of the support structures includes a horizontal tooling plate (1) with a clamp for clamping the engine combustion chamber above it, and a gradient heat insulation material is filled between the contact surface between each clamp and the outer wall of the engine. The fixture of the fixed support structure is connected to the tooling plate (1) by a long screw assembly on both sides. The outer wall of each screw in the long screw assembly is wrapped with aerogel heat insulation felt.

2. The support structure for long-term thermal testing of an RBCC composite engine as described in claim 1, characterized in that, The clamp of the fixed support structure is a circular combustion chamber clamp, which has an upper arc-shaped clamp and a lower arc-shaped clamp that are arranged opposite each other to form a circular clamping space. The lower arc-shaped clamping plate includes an arc-shaped steel plate (5), the bottom of which is connected to a horizontally arranged intermediate crossbeam (7) via a flat plate (6), and the bottom of the intermediate crossbeam (7) is connected to the tooling plate (1) via a height adjustment device. When the outer surface diameter of the engine housing is ≤400mm, the upper arc-shaped clamp and the lower arc-shaped clamp are both arc-shaped structures with a 150° angle in contact with the engine surface. A top crossbeam (6) is arranged parallel above the middle crossbeam (7). The upper arc-shaped clamp includes an arc-shaped steel plate (5). The upper part of the arc-shaped steel plate (5) is connected to the top crossbeam (8) through a flat plate (6). The two sides of the two arc-shaped steel plates (5) are connected by a first long screw (9); multiple second long screws (10) are provided on both sides of the two arc-shaped steel plates (5) and through the top crossbeam (8) and the middle crossbeam (7), and each second long screw (10) extends to the tooling plate (1). When the outer surface diameter of the engine housing is >400mm, the parts of the upper arc-shaped clamp and the lower arc-shaped clamp that contact the engine surface are both 120° arc-shaped structures; the upper arc-shaped clamp is an arc-shaped steel plate (5), and the two sides of the upper and lower arc-shaped steel plates (5) are threaded together by a third long screw (11), and the third long screw (11) passes through the intermediate crossbeam (7) and extends to the tooling plate (1).

3. The support structure for long-term thermal testing of an RBCC composite engine as described in claim 1, characterized in that, The fixture of the fixed support structure is a square combustion chamber fixture. The square combustion chamber fixture has an upper clamping plate (3) and a lower clamping plate (2) arranged side by side with adjustable spacing. A middle crossbeam (7) and a top crossbeam (8) are arranged in parallel above the tooling plate (1) with intervals. The upper clamping plate (3) is connected below the top crossbeam (8), and the lower clamping plate (2) is connected above the middle crossbeam (7). Multiple fourth long screws (16) are threaded through the upper clamping plate (3) and the lower clamping plate (2) on both sides and through the top crossbeam (8), the middle crossbeam (7) and the tooling plate (1). The lower clamping plate (2) is used to adjust the engine height, and the upper clamping plate (3) is used to press the engine housing.

4. The support structure for long-term thermal testing of an RBCC composite engine as described in claim 1, characterized in that, The clamp of the hanging support structure includes a water-cooled ring, which is divided into two half rings (4) on the left and right sides. The surfaces of the two half rings (4) that are in contact are filled with aerogel insulation felt. Each half ring (4) is an arc of 179°. A hanging rod (13) is horizontally installed at the midpoint of the left and right sides of the water-cooled ring. A middle crossbeam (7) is horizontally installed at the bottom of the water-cooled ring. A bracket (12) is vertically installed above the middle crossbeam (7) on both sides of the water-cooled ring. Each bracket (12) is perpendicular to the extension direction of its extension direction and has a groove (14) at its top. The hanging rod (13) is used to be pushed horizontally into the groove (14).

5. A support structure for long-term thermal testing of an RBCC composite engine as described in claim 2 or 4, characterized in that, The bottom of the intermediate crossbeam (7) is connected to the tooling plate (1) via a height adjustment device, which includes a plurality of telescopic rods (15) disposed between the intermediate crossbeam (7) and the tooling plate (1).

6. The support structure for long-term thermal testing of an RBCC composite engine as described in claim 5, characterized in that, The tooling plate (1) is provided with a tooling base (17) at its bottom. The tooling base (17) includes two inverted T-shaped legs. Each leg includes a horizontal plate and a vertical plate that are perpendicular to each other. The horizontal plate is provided with a waist-shaped groove (18). The vertical plate is used to move within the waist-shaped groove (18).

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