Combustion chamber with ceramic-based heat shield and aircraft engine

Abstract

The application discloses a combustion chamber adopting a ceramic-based heat shield and an aero-engine. The combustion chamber adopting the ceramic-based heat shield comprises a casing, a diffuser, a flame tube and a turbine guide vane. The flame tube comprises a head, an outer ring, an inner ring and an elbow pipe. A plurality of first mounting holes are uniformly arranged on the head in the circumferential direction. The head is further provided with heat insulation assemblies corresponding to the first mounting holes. The heat insulation assemblies comprise heat shields and fixing seats. The fixing seats are inserted into the first mounting holes and fixedly connected with the head. The fixing seats are in clearance fit with the heat shields. The fixing seats are used for mounting the heat shields on the head and limiting the heat shields in the axial direction and in the circumferential direction relative to the head. Ribs for supporting the heat shields are formed on the head so that the heat shields are arranged in a spaced manner with the head. Adjacent two heat shields are arranged in a clearance. The head and the fixing seat are made of a metal-based material. The heat shield is made of a ceramic-based material.

Description

Technical Field

[0001] This invention relates to the field of aero-engine technology, and in particular to a combustion chamber employing a ceramic-based heat shield. Furthermore, this invention also relates to an aero-engine including the aforementioned combustion chamber employing a ceramic-based heat shield. Background Technology

[0002] With the development of engine technology, the operating temperature of the combustion chamber flame tube is gradually increasing. This necessitates that flame tube materials, in addition to meeting requirements such as light weight, high reliability, and long service life, also possess improved temperature resistance. Replacing traditional high-temperature alloy materials with ceramic matrix composites is the best way to improve the temperature resistance of engine combustion chamber components and engine efficiency.

[0003] Currently, the flame tube head of high-temperature rise, high power-to-weight ratio combustion chambers is often designed with a double-wall structure due to the high temperature. Generally, the outer wall is a complete ring of rotating material, i.e., the flame tube head; the inner wall is a fan-shaped structure, i.e., a heat shield. The heat shield mainly serves to insulate and guide airflow, while also reducing the flame tube head wall temperature and improving the flame tube's lifespan. Existing designs for the flame tube head and heat shield mainly use two material schemes: one is to use metal-based materials for both the flame tube head and the heat shield, and the other is to use ceramic-based composite materials for the flame tube head and metal-based materials for the heat shield. However, since the heat shield wall temperature is often higher than the flame tube head wall temperature, materials with better temperature resistance are needed. Current designs have not actually improved the overall temperature resistance of the flame tube.

[0004] The use of metal materials for the heat shield limits the improvement of the temperature resistance of the flame tube head wall, thus affecting the overall temperature resistance of the flame tube. Due to the huge difference in thermal expansion properties between ceramic matrix composites and metal materials, and the fact that ceramic matrix and metal matrix cannot be connected by traditional welding methods, while riveting methods have extremely strict requirements for the manufacturing process of ceramic matrix parts, making it difficult to achieve. This makes it difficult for existing structural solutions to achieve the positioning and connection of ceramic matrix composite heat shield and metal flame tube head, resulting in difficulty in improving the heat resistance of the combustion chamber flame tube head. Summary of the Invention

[0005] This invention provides a combustion chamber using a ceramic-based heat insulation cover to solve the technical problem of how to improve the temperature resistance of the flame tube head and enhance the performance requirements of the flame tube in high-temperature, high-power-to-weight-ratio combustion chambers.

[0006] The present invention also provides an aircraft engine employing the combustion chamber with the ceramic-based heat shield described above.

[0007] According to one aspect of the present invention, a combustion chamber employing a ceramic-based heat shield is provided, comprising a casing, a diffuser disposed at the casing inlet, a flame tube disposed within the casing, and a turbine guide connected to the flame tube. The flame tube includes a head, an outer ring, an inner ring, and a bend. A plurality of first mounting holes are uniformly formed along the circumference of the head. A heat insulation component is also disposed on the head, corresponding to each of the first mounting holes. The heat insulation component includes a heat shield and a fixing seat. The fixing seat extends into the first mounting holes and is fixedly connected to the head. The fixing seat and the heat shield are clearance-fitted. The fixing seat is used to mount the heat shield on the head and to limit the heat shield axially and circumferentially relative to the head. Ribs are provided on the head at intervals relative to the fixing seat. The ribs are used to support the heat shield so that the heat shield is spaced apart from the head. A gap is provided between adjacent heat shields. The head and the fixing seat are both made of a metal-based material, and the heat shield is made of a ceramic-based composite material.

[0008] Furthermore, the heat insulation cover has a second mounting hole and a mounting conical surface inclined toward the second mounting hole. The fixing seat includes a mounting ring that is clearance-fitted with the second mounting hole and a retaining ring connected to the mounting ring. The mounting ring passes through the second mounting hole and extends into the first mounting hole to cooperate and fix with the head. The retaining ring has an outer conical surface, which is used to cooperate with the mounting conical surface to limit the heat insulation cover relative to the head along the axial direction.

[0009] Furthermore, the mounting cone surface is provided with an anti-rotation groove extending axially along the second mounting hole, and the fixing seat is provided with an anti-rotation protrusion. The anti-rotation protrusion is clearance-fitted with the anti-rotation groove and the heat insulation cover is circumferentially limited relative to the head. The anti-rotation protrusion is clearance-set with the head.

[0010] Furthermore, the head, the ribs, the heat shield, and the fixing base are arranged to form an impact cavity. The head is provided with a plurality of impact holes that are respectively connected to the impact cavity. The impact holes are used to introduce cold air into the impact cavity to cool the side of the heat shield facing the head.

[0011] Furthermore, the ribs are provided with multiple ventilation slots, which are used to guide the cold air in the impact chamber into the flame tube so as to cool the side of the heat shield away from the head.

[0012] Furthermore, the wall of the ventilation groove is inclined, and the ventilation groove is inclined in the direction from the impact chamber toward the inside of the flame tube to the direction toward the heat shield.

[0013] Furthermore, a number of ventilation slots are spaced apart on the outer conical surface. These ventilation slots are used to guide the cold air in the impact chamber into the flame tube so as to cool the side of the heat shield away from the head through the cold air.

[0014] Furthermore, a bend is formed on the heat insulation cover, which is used to form a guide channel with the head to guide the cold airflow to the outer ring.

[0015] Furthermore, a third mounting hole is provided on the fixed base, and a vortex generator is provided in the third mounting hole. A nozzle for injecting fuel into the flame tube is installed on the vortex generator, and the vortex generator is used to atomize the injected fuel.

[0016] According to another aspect of the invention, an aircraft engine is also provided, which includes the combustion chamber with the ceramic-based heat shield described above.

[0017] The present invention has the following beneficial effects:

[0018] In the combustion chamber of this invention, which employs a ceramic-based heat shield, the ceramic-based heat shield is connected to the head of the metal-based flame tube via a metal-based mounting base. The mounting base installs the heat shield on the head and, with the assistance of ribs, axially positions the heat shield relative to the head. The mounting base also prevents the heat shield from rotating, thus limiting its circumferential position relative to the head. Due to the gap design between the heat shield and the mounting base during installation, the heat shield has sufficient circumferential and radial movement space through precise gap design. This solves the problem of interference and excessive local stress caused by the inconsistent thermal expansion coefficients of the metal and ceramic substrates under hot conditions. This allows the ceramic-based heat shield to be used on the flame tube. Since the wall temperature of the heat shield is often higher than the wall temperature of the flame tube head in actual use, the heat resistance of the flame tube after using a ceramic-based heat shield with better heat resistance is significantly improved, thereby enhancing the flame tube's performance in high-temperature, high-power-to-weight-ratio combustion chambers.

[0019] In summary, the combustion chamber of this invention, employing a ceramic-based heat shield, provides a positioning and connection structure for the ceramic-based composite heat shield and the metal-based flame tube head. A fixing base is used to position the ceramic-based heat shield axially and circumferentially, with a clearance fit between the fixing base and the heat shield to ensure sufficient thermal expansion space in both the circumferential and radial directions. This allows for stable positioning and connection of the ceramic-based composite heat shield and the metal-based flame tube head even under high-temperature conditions, eliminating the influence of the significant difference in thermal expansion properties between ceramic-based composite materials and metal materials. This enables the use of ceramic-based heat shields in flame tubes. Since the heat shield wall temperature is often higher than the flame tube head wall temperature in actual use, the heat resistance of the flame tube is significantly improved by using a ceramic-based heat shield with better heat resistance, thereby enhancing the flame tube's performance in high-temperature rise, high power-to-weight ratio combustion chambers. It can meet the needs of higher temperature rise combustion chambers.

[0020] In addition to the objectives, features, and advantages described above, the present invention has other objectives, features, and advantages. The invention will now be described in further detail with reference to the figures. Attached Figure Description

[0021] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0022] Figure 1 This is a schematic diagram of the combustion chamber using a ceramic-based heat shield according to a preferred embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the installation structure of the heat insulation cover according to a preferred embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the structure of the heat insulation cover according to a preferred embodiment of the present invention;

[0025] Figure 4 This is a schematic diagram of the structure of the fixing base according to a preferred embodiment of the present invention;

[0026] Figure 5 This is a schematic diagram of the head structure according to a preferred embodiment of the present invention;

[0027] Figure 6 This is a schematic diagram of the structure of the heat insulation cover and the head in a preferred embodiment of the present invention.

[0028] Legend:

[0029] 1. Diffuser;

[0030] 2. Casing;

[0031] 3. Flame tube; 31. Vortex generator; 32. Head; 321. First mounting hole; 322. Rib; 323. Impact hole; 324. Ventilation groove; 325. Impact chamber;

[0032] 33. Heat shield; 331. Mounting cone surface; 332. Anti-rotation groove; 333. Second mounting hole;

[0033] 34. Fixing base; 341. Third mounting hole; 342. Vent slot; 343. Anti-rotation protrusion; 344. Outer conical surface; 345. Mounting ring; 346. Retaining ring; 347. Bending part;

[0034] 35. Outer ring; 36. Inner ring; 37. Bend;

[0035] 4. Nozzle; 5. Turbine guide. Detailed Implementation

[0036] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways as defined and covered below.

[0037] like Figures 1-6 As shown, this embodiment provides a combustion chamber employing a ceramic-based heat shield 33, including a casing 2, a diffuser 1 disposed at the inlet of the casing 2, a flame tube 3 disposed within the casing 2, and a turbine guide 5 connected to the flame tube 3. The flame tube 3 includes a head 32, an outer ring 35, an inner ring 36, and a bend 37. The head 32 has a plurality of first mounting holes 321 evenly distributed circumferentially. The head 32 is also provided with heat insulation components corresponding to the first mounting holes 321 one by one. The heat insulation components include a heat shield 33 and a fixing seat 34. The fixing seat 34 extends into the first mounting holes 321 and is connected to the heat shield 33. The head 32 is fixedly connected, and the fixing seat 34 is clearance-fitted with the heat insulation cover 33. The fixing seat 34 is used to install the heat insulation cover 33 on the head 32 and to limit the heat insulation cover 33 axially and circumferentially relative to the head 32. The head 32 is provided with ribs 322 spaced apart from the fixing seat 34. The ribs 322 are used to support the heat insulation cover 33 so that the heat insulation cover 33 is spaced apart from the head 32 and there is a gap between two adjacent heat insulation covers 33. The head 32 and the fixing seat 34 are both made of metal-based materials, and the heat insulation cover 33 is made of ceramic-based composite material.

[0038] In this embodiment, the head 32, outer ring 35, inner ring 36, and bend 37 are all integral ring structures, forming a complete flame tube 3. The ribs 322 provided on the head 32 are used to support the heat insulation cover 33 and to create a certain gap between the heat insulation cover 33 and the head 32 body. Specifically, the heat insulation cover 33 is fan-shaped, and the arrangement of the ribs 322 is consistent with the shape of the heat insulation cover 33, also fan-shaped and proportionally contracted, so that the ribs 322 can all contact the heat insulation cover 33, thereby supporting the heat insulation cover 33.

[0039] Specifically, the ceramic-based heat shield 33 is connected to the head 32 of the metal-based flame tube 3 via a metal-based mounting base 34. The mounting base 34 mounts the heat shield 33 onto the head 32, and with the cooperation of the ribs 322, axially positions the heat shield 33 relative to the head 32. The mounting base 34 also prevents the heat shield 33 from rotating, thus circumferentially limiting its position relative to the head 32. Due to the gap between the heat shield 33 and the mounting base 34 during installation, the precise design of these gaps ensures that the heat shield 33... 3. With a certain amount of room for movement in both the circumferential and radial directions, it can solve the problem of interference and excessive local stress caused by the inconsistency of the thermal expansion coefficients of the metal matrix and the ceramic matrix under hot conditions. This allows the ceramic matrix heat shield 33 to be used on the flame tube 3. Since the wall temperature of the heat shield 33 is often higher than the wall temperature of the head 32 of the flame tube 3 in actual use, the heat resistance of the flame tube 3 after adopting the ceramic matrix heat shield 33 with better heat resistance can be significantly improved, thereby improving the requirements of the flame tube 3 in high temperature rise and high power-to-weight ratio combustion chambers.

[0040] In summary, the combustion chamber of this invention, employing a ceramic-based heat shield 33, provides a positioning and connection structure for the ceramic-based composite heat shield 33 and the metal-based flame tube 3 head 32. A fixing seat 34 is used to position the ceramic-based heat shield 33 axially and circumferentially, with a clearance fit between the fixing seat 34 and the heat shield 33 to ensure sufficient thermal expansion space in both the circumferential and radial directions. This allows for stable positioning and connection of the ceramic-based composite heat shield 33 and the metal-based flame tube 3 head 32 even under high-temperature conditions, eliminating the significant difference in thermal expansion properties between the ceramic-based composite material and the metal material. This enables the ceramic-based heat shield 33 to be used on the flame tube 3. Since the wall temperature of the heat shield 33 is often higher than the wall temperature of the flame tube 3 head 32 in actual use, the heat resistance of the flame tube 3 is significantly improved by using the ceramic-based heat shield 33, which has better heat resistance. This enhances the flame tube 3's performance in high-temperature rise, high power-to-weight ratio combustion chambers, meeting the requirements for higher temperature rise combustion chambers.

[0041] Furthermore, the heat insulation cover 33 is provided with a second mounting hole 333, and the heat insulation cover 33 is provided with a mounting cone surface 331 inclined toward the second mounting hole 333. The fixing seat 34 includes a mounting ring 345 that is clearance-fitted with the second mounting hole 333 and a retaining ring 346 connected to the mounting ring 345. The mounting ring 345 passes through the second mounting hole 333 and extends into the first mounting hole 321 to cooperate and fix with the head 32. The retaining ring 346 is provided with an outer cone surface 344, and the outer cone surface 344 cooperates with the mounting cone surface 331 to limit the heat insulation cover 33 axially relative to the head 32.

[0042] In this embodiment, due to the significant difference in thermal expansion coefficients between the ceramic substrate and the metal substrate, a clearance fit is required between the mounting ring 345 and the second mounting hole 333. Specifically, a certain gap t3 is maintained between the outer diameter of the mounting ring 345 and the second mounting hole 333. The mounting ring 345 is attached to the first mounting hole 321 and fixed to the head 32 by argon arc welding. The outer conical surface 344 on the retaining ring 346 mates with the mounting conical surface 331, allowing the heat insulation cover 33 to be installed between the head 32 and the fixing seat 34. At this time, the side of the heat insulation cover 33 facing the head 32 abuts against the rib 322, thereby limiting the axial position of the heat insulation cover 33 relative to the head 32. The use of the outer conical surface 344 mates with the mounting conical surface 331 increases the contact area during connection, making the installation more stable. On the other hand, the fit between the inclined surfaces has a guiding effect, facilitating quick positioning of the fixing seat 34 and the heat insulation cover 33 during assembly, thereby improving installation efficiency. In practice, the angle between the mounting cone surface 331 and its center line is 30 to 50°, and the corresponding angle between the outer cone surface 344 and the mounting cone surface 331 is set accordingly.

[0043] Furthermore, the mounting cone surface 331 is provided with an anti-rotation groove 332 extending axially along the second mounting hole 333, and the fixing seat 34 is provided with an anti-rotation protrusion 343. The anti-rotation protrusion 343 is clearance-fitted with the anti-rotation groove 332 and limits the heat insulation cover 33 relative to the head 32 in the circumferential direction. The anti-rotation protrusion 343 is clearance-set with the head 32.

[0044] In this embodiment, the heat insulation cover 33 has two anti-rotation grooves 332 of different sizes in the circumferential design. These grooves are engaged with two anti-rotation protrusions 343 of different sizes on the fixing base 34 to prevent circumferential misalignment. The anti-rotation protrusions 343 and the anti-rotation grooves 332 are fitted together with a gap to limit the heat insulation cover 33 relative to the head 32 in the circumferential direction. Since the coefficient of thermal expansion of the ceramic substrate is significantly different from that of the metal substrate, the anti-rotation protrusions 343 maintain a certain radial gap t2 with the anti-rotation grooves on the heat insulation cover 33. At the same time, there needs to be a gap t1 between the anti-rotation protrusions 343 and the head 32. The design of the gap t1 should prevent the ribs 322 of the head 32 from contacting the heat insulation cover 33 before the head 32 ribs 322 in any state.

[0045] Furthermore, the head 32, the ribs 322, the heat shield 33, and the fixing base 34 form an impact cavity 325. The head 32 is provided with a plurality of impact holes 323 that communicate with the impact cavity 325. The impact holes 323 are used to introduce cold air into the impact cavity 325 so as to cool the side of the heat shield 33 facing the head 32.

[0046] In this embodiment, the impact cavity 325, supported by ribs 322, is formed by the head 32, ribs 322, heat shield 33, and fixing base 34. The thickness of the impact cavity 325 is the distance between the inner plane of the head 32 and the outer plane of the heat shield 33, i.e., the thickness of the ribs 322. The distance of the impact cavity 325 is usually maintained between 1mm and 5mm to ensure that the impact cavity 325 has sufficient space to accommodate the cold air entering the impact cavity 325 through the cold air impact hole 323, thereby ensuring the cooling effect of the cold air on the heat shield 33. When the distance of the impact cavity 325 is less than 1mm, the space accommodated by the impact cavity 325 is too small, which is not conducive to the residence and cooling of the cold air, resulting in a decrease in the cooling effect of the heat shield 33. When the distance of the impact cavity 325 is greater than 5mm, the space accommodated by the impact cavity 325 is too large, which is not conducive to the rapid filling of the cold air, resulting in a decrease in the initial cooling efficiency of the heat shield 33, and the heat shield 33 cannot be cooled in time.

[0047] Furthermore, the rib 322 is provided with a plurality of ventilation slots 324, which are used to guide the cold air in the impact chamber 325 into the flame tube 3 so as to cool the side of the heat shield 33 away from the head 32 through the cold air.

[0048] In this embodiment, the ventilation groove 324 is a U-shaped ventilation groove, and multiple grooves can be provided at intervals on the rib 322 so that the cooling in the impact chamber 325 can flow quickly into the flame tube 3 and cool the side of the heat shield 33 away from the head 32.

[0049] Furthermore, the wall of the ventilation groove 324 is inclined, and the ventilation groove 324 is inclined in the direction of the impact chamber 325 toward the inside of the flame tube 3 and in the direction toward the heat insulation cover 33.

[0050] In this embodiment, by rationally designing the cooling structure, multiple inclined U-shaped ventilation slots 324 with gradually decreasing areas are designed on the head 32 ribs 322, which can ensure that the air film is closer to the wall of the ceramic-based heat insulation cover 33, thus achieving a good cooling effect. Specifically, the inclination angle b of the ventilation slots 324 is 20 to 40 degrees, the depth L2 is 0.5 to 1.5 mm, the width is 2 to 5 mm, and the interval between adjacent slots is 2 to 4 mm.

[0051] Furthermore, a plurality of ventilation slots 342 are spaced apart on the outer conical surface 344. These ventilation slots 342 guide the cold air from the impact chamber 325 into the flame tube 3 to cool the side of the heat shield 33 away from the head 32. In this embodiment, by rationally designing the cooling structure, multiple inclined U-shaped ventilation grooves 324 with gradually decreasing areas are designed on the ribs 322 of the head 32. This ensures that the air film adheres better to the wall of the ceramic-based heat shield 33, achieving a good cooling effect. Simultaneously, ventilation slots 342 are designed on the metal base fixing seat 34, ensuring that the air film flows out from the narrower gaps, forming an air film with good wall adhesion to protect the ceramic-based heat shield 33 and further improve the temperature resistance of the heat shield 33. Specifically, the depth L1 of the ventilation slots 342 is 0.1–0.3 mm, and the number is 4–20.

[0052] This invention provides a positioning and connection structure for a ceramic-based composite heat shield 33 and a metal-based flame tube 3 head 32. The structure allows for axial positioning of the ceramic-based heat shield 33, ensuring sufficient thermal expansion space in both the circumferential and radial directions. Simultaneously, a reasonable cooling structure is designed. Through impact cooling and a finely designed ventilation groove 324 and ventilation slit 342 structure, the ceramic-based heat shield 33 can be well protected, improving the overall temperature resistance of both the heat shield 33 and the flame tube 3, thus meeting the requirements for higher temperature rise combustion chambers.

[0053] Furthermore, a third mounting hole 341 is provided on the fixed base 34, and a vortex generator 31 is provided in the third mounting hole 341. A nozzle 4 for injecting fuel into the flame tube 3 is installed on the vortex generator 31, and the vortex generator 31 is used to atomize the injected fuel.

[0054] In this embodiment, there are two connection schemes for the fixing base 34, the vortex generator 31, and the flame tube 3 head 32. One connection scheme is that the fixing base 34 and the vortex generator 31 only mate but are not connected, and are welded to the flame tube 3 head 32 respectively, but the welding positions are different; the other connection scheme is that the fixing base 34 and the vortex generator 31 are connected by threads, and the vortex generator 31 is spot welded to the flame tube 3 head 32, and the fixing base 34 and the flame tube 3 head 32 only mate but are not connected.

[0055] In practice, part of the high-temperature, high-pressure air entering from the diffuser 1 passes through two channels between the casing 2 and the flame tube 3 before entering the flame tube 3, while the other part enters the head 32 of the flame tube 3 from the vortex generator 31. Under the action of the swirling channels, multi-stage swirling air with different directions is formed. The swirling air atomizes the fuel injected from the nozzle 4 and, due to the generation of a central negative pressure, forms a stable recirculation zone in the main combustion zone to ensure stable combustion under different intake conditions. The resulting high-temperature combustion gas enters the turbine components after passing through the turbine guide vane 5.

[0056] Furthermore, a bend 347 is formed on the heat insulation cover 33, which, together with the head 32, forms a flow channel guiding the cold airflow towards the outer ring. In this embodiment, the bend 347 is formed on the heat insulation cover 33, and the bend 347, together with the head 32, forms a flow channel guiding the cold airflow towards the outer ring 35. The cold air is directed towards the outer ring 35 for cooling, thereby cooling the initial section of the outer ring 35.

[0057] According to another aspect of the invention, an aircraft engine is also provided, which includes the combustion chamber with the ceramic-based heat shield 33 described above. Therefore, this engine protects the combustion chamber with the ceramic-based heat shield 33 from all the beneficial effects described above.

[0058] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A combustion chamber with ceramic-based heat shield, comprising a casing (2), a diffuser (1) arranged at the inlet of the casing (2), a flame tube (3) arranged in the casing (2), and a turbine guide vane (5) connected to the flame tube (3), the flame tube (3) comprising a head (32), an outer ring (35), an inner ring (36), and a bend (37), characterized in that, The head (32) is provided with a plurality of first mounting holes (321) evenly distributed along its circumference. The head (32) is also provided with heat insulation components that correspond one-to-one with the first mounting holes (321). Each heat insulation component includes a heat insulation cover (33) and a fixing seat (34). The fixing seat (34) extends into the first mounting hole (321) and is fixedly connected to the head (32). The fixing seat (34) is clearance-fitted with the heat insulation cover (33). The fixing seat (34) is used to mount the heat insulation cover (33) onto the head (32). 2) and make the heat insulation cover (33) axially and circumferentially limited relative to the head (32). The head (32) is provided with ribs (322) spaced apart from the fixed seat (34). The ribs (322) are used to support the heat insulation cover (33) so that the heat insulation cover (33) and the head (32) are spaced apart. There is a gap between two adjacent heat insulation covers (33). The head (32) and the fixed seat (34) are both made of metal-based materials. The heat insulation cover (33) is made of ceramic-based composite material. The heat insulation cover (33) has a second mounting hole (333) and a mounting cone surface (331) inclined toward the second mounting hole (333). The fixing seat (34) includes a mounting ring (345) that is clearance-fitted with the second mounting hole (333) and a retaining ring (346) connected to the mounting ring (345). The mounting ring (345) passes through the second mounting hole (333) and extends into the first mounting hole (321) to cooperate and fix with the head (32). The retaining ring (346) has an outer cone surface (344) that cooperates with the mounting cone surface (331) to limit the heat insulation cover (33) relative to the head (32) axially.

2. The combustion chamber employing a ceramic-based heat shield according to claim 1, characterized in that, The mounting cone surface (331) is provided with an anti-rotation groove (332) extending axially along the second mounting hole (333), and the fixing seat (34) is provided with an anti-rotation protrusion (343). The anti-rotation protrusion (343) is clearance-fitted with the anti-rotation groove (332) and limits the heat insulation cover (33) relative to the head (32) in the circumferential direction. The anti-rotation protrusion (343) is clearance-fitted with the head (32).

3. The combustion chamber employing a ceramic-based heat shield according to claim 1, characterized in that, The head (32), the ribs (322), the heat shield (33), and the fixing base (34) enclose an impact cavity (325). The head (32) has a plurality of impact holes (323) that communicate with the impact cavity (325). The impact holes (323) are used to introduce cold air into the impact cavity (325) to cool the side of the heat shield (33) facing the head (32).

4. The combustion chamber employing a ceramic-based heat shield according to claim 3, characterized in that, The rib (322) is provided with a plurality of ventilation slots (324), which are used to guide the cold air in the impact chamber (325) into the flame tube (3) so as to cool the side of the heat shield (33) away from the head (32) by means of the cold air.

5. The combustion chamber employing a ceramic-based heat shield according to claim 4, characterized in that, The ventilation groove (324) is inclined, and the ventilation groove (324) is inclined in the direction of the impact chamber (325) toward the inside of the flame tube (3) and toward the heat shield (33).

6. The combustion chamber employing a ceramic-based heat shield according to claim 3, characterized in that, The outer conical surface (344) is provided with a plurality of ventilation slots (342) spaced apart. The ventilation slots (342) are used to guide the cold air in the impact chamber (325) into the flame tube (3) so as to cool the side of the heat shield (33) away from the head (32) by means of the cold air.

7. The combustion chamber employing a ceramic-based heat shield according to claim 3, characterized in that, The heat shield (33) has a bend (347) formed thereon, which is used to form a guide channel with the head (32) to guide the cold airflow to the outer ring (35).

8. The combustion chamber employing a ceramic-based heat shield according to any one of claims 1 to 7, characterized in that, The mounting base (34) has a third mounting hole (341), and a vortex generator (31) is provided in the third mounting hole (341). A nozzle (4) for injecting fuel into the flame tube (3) is installed on the vortex generator (31), and the vortex generator (31) is used to atomize the injected fuel.

9. An aircraft engine, characterized in that, This includes a combustion chamber employing a ceramic-based heat shield (33) as described in any one of claims 1 to 8.

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