Flame tube cooling structure, flame tube and combustion chamber

Abstract

The flame tube cooling structure arranged on the double-layer wall structure is provided, the double-layer wall structure comprises an outer-layer impact wall, an inner-layer diffusion wall and a crack located between the outer-layer impact wall and the inner-layer diffusion wall, and the cooling structure comprises a first impact hole and a second impact hole; one end of the convex ring rib is connected with the inner-layer diverging wall, and the other end of the convex ring rib is not connected with the outer-layer impact wall; and the second impact holes comprise forward-inclined diverging holes and backward-inclined diverging holes, the forward-inclined diverging holes are located at the axial front end of the inner-layer diverging wall and used for guiding the cooling airflow to flow out towards the axial front side, and the backward-inclined diverging holes are used for guiding the cooling airflow to flow out towards the axial rear side. The invention further provides a flame tube and a combustion chamber. The cooling structure can effectively prevent the problem of inharmonious radial thermal deformation of the double-layer wall of the flame tube, and has a better cooling effect.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of aero-engine combustion chamber, in particular to the field of cooling of flame tube. BACKGROUND

[0002] With the development of aero-engine and gas turbine technology, the temperature before the engine turbine is continuously increased, and the thermal load of the working environment of the flame tube is also increased. In order to realize the long-term reliable thermal protection of the flame tube in a high-temperature harsh environment, the flame tube needs to adopt a reliable cooling design.

[0003] The impingement-divergent film composite cooling structure is a double-wall cooling structure. For example, Chinese patent CN103629697 discloses an impingement-multiple inclined hole flame tube wall plate structure. The impingement hole flame tube wall plate is provided with impingement holes, and the multiple inclined hole flame tube wall plate is provided with inclined holes. The impingement holes and the inclined holes are arranged in multiple along the streamline direction. The outside of the impingement hole flame tube wall plate as a low-temperature wall is a cooling gas flow, and the inside of the multiple inclined hole flame tube wall plate as a high-temperature wall is a high-temperature main gas flow. The cooling gas flow passes through the impingement hole flame tube wall plate through multiple impingement holes to form multiple cooling gas flows, which have an impingement cooling effect on the multiple inclined hole flame tube wall plate, and preliminarily cool the multiple inclined hole flame tube wall plate. Then, the cooling gas flow enters the flame tube in the form of a cooling gas flow along the multiple inclined holes on the multiple inclined hole flame tube wall plate, forms a continuous and uniform gas film protection on the hot side of the flame tube wall plate, separates the multiple inclined hole flame tube wall plate from the high-temperature main gas flow in the flame tube, and forms a convection cooling on the hot side of the multiple inclined hole flame tube wall plate, thereby reducing the temperature of the flame tube wall.

[0004] However, the inventors have found that the impingement-divergent film composite cooling structure has the problem that the first few rows of gas films in the axial direction are difficult to form a better gas film superposition covering effect, and the large-size flame tube double-wall thin-wall part is prone to have an incoordination of axial and radial thermal deformation during service, which further leads to the failure of the double-wall cooling structure form. SUMMARY

[0005] An object of the present application is to provide a flame tube cooling structure which can effectively prevent the incoordination of radial thermal deformation of the flame tube double wall and has a better cooling effect.

[0006] The flame tube cooling structure is arranged on a double-wall structure, the double-wall structure comprises an outer impact wall, an inner divergent wall, and a gap between the outer impact wall and the inner divergent wall, the cooling structure comprises: first impact holes arranged on the outer impact wall; second impact holes arranged on the inner divergent wall; the cooling structure further comprises a raised ring rib arranged in the gap, one end of the raised ring rib is connected with the inner divergent wall, and the other end of the raised ring rib is not connected with the outer impact wall; wherein the second impact holes comprise forwardly-inclined divergent holes and rearwardly-inclined divergent holes, the forwardly-inclined divergent holes are located at an axial front end of the inner divergent wall, and are used to guide cooling airflow to flow out to an axial front side, and the rearwardly-inclined divergent holes are used to guide cooling airflow to flow out to an axial rear side.

[0007] In one or more embodiments, the raised ring rib comprises a plurality of rows of raised ring ribs, and each row of raised ring ribs is staggered with the first impact holes and the second impact holes.

[0008] In one or more embodiments, the first impact holes and the second impact holes comprise a plurality of rows of holes distributed in a circumferential direction, and an inlet of the second impact holes and an outlet of the first impact holes are staggered.

[0009] In one or more embodiments, the forwardly-inclined divergent holes are located at an axial front side of the first impact holes.

[0010] In one or more embodiments, the forwardly-inclined divergent holes are the first row of holes or the first few rows of holes of the second impact holes in an axial direction, and form a staggered distribution with the first impact holes.

[0011] In one or more embodiments, an inclination angle of the forwardly-inclined divergent holes and / or the rearwardly-inclined divergent holes ranges from 0° to 75°.

[0012] In one or more embodiments, a spacing between the raised ring rib and the outer impact wall ranges from 0 to 1 mm.

[0013] In one or more embodiments, the raised ring rib is a discontinuously-distributed ring-shaped raised rib.

[0014] Another object of the present application is to provide a flame tube comprising a double-wall structure and the above-mentioned flame tube cooling structure.

[0015] Still another object of the present application is to provide a combustion chamber comprising an outer casing, a flame tube, a head, and a nozzle, the flame tube being the above-mentioned flame tube.

[0016] The flame tube cooling structure adopts the raised ring rib to ensure that a radial gap always exists between the outer layer impact wall and the inner layer divergent wall, the raised ring rib can also increase the strength of the inner layer divergent wall structure, thereby avoiding the problem of uncoordinated radial thermal deformation of the double-layer wall thin-wall part of the flame tube during service; meanwhile, the combination of the front-inclined divergent hole and the rear-inclined divergent hole of the inner layer divergent wall makes the overall wall temperature of the flame tube lower and more uniform, and has a better cooling effect. BRIEF DESCRIPTION OF DRAWINGS

[0017] The above and other features, properties and advantages of the present application will become more apparent by reference to the following description of the embodiments wherein:

[0018] Figure 1 is a structural schematic diagram of an aero-engine combustion chamber;

[0019] Figure 2 is a cross-sectional view of a flame tube cooling structure;

[0020] Figure 3 is an enlarged view of the flame tube cooling structure;

[0021] Figure 4 is a schematic diagram of a cooling gas flow path;

[0022] Figure 5 is a partial top view of the inner layer divergent wall of the flame tube.

[0023] SYMBOL EXPLANATION

[0024] 1 outer ring cavity air

[0025] 2 head air inlet

[0026] 3 inner ring cavity air

[0027] 4 flame tube

[0028] 5 outer casing

[0029] 6 head

[0030] 11 first gas flow

[0031] 12 second gas flow

[0032] 31 third gas flow

[0033] 32 fourth gas flow

[0034] 41 outer layer impact wall

[0035] 42 inner layer divergent wall

[0036] 43 front end

[0037] 44 tail end

[0038] 45. Gap

[0039] 101 Flame tube cooling gas

[0040] 102 Forward airflow

[0041] 103 Backflow airflow

[0042] 104 Crossflow Gas

[0043] 411 First Impact Hole

[0044] 420 Second Impact Hole

[0045] 421 Forward-tilting diverging hole

[0046] 422 Backward tilting divergence hole

[0047] 423 Raised ring rib Detailed Implementation

[0048] The present invention will be further described below with reference to specific embodiments and accompanying drawings. More details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention can obviously be implemented in many other ways different from those described herein. Those skilled in the art can make similar extensions and derivations based on actual application situations without departing from the spirit of the present invention. Therefore, the scope of protection of the present invention should not be limited by the content of this specific embodiment.

[0049] It should be noted that these and other accompanying drawings are merely examples and are not drawn to scale, and should not be construed as limiting the scope of protection of the present invention.

[0050] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components in the following content is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this application.

[0051] Figure 1 The structure of the gas turbine combustor is shown, including a flame tube 4, an outer casing 5, a nozzle, and a head 6. The airflow entering the combustor is divided into three streams, as shown by dashed lines: outer annular air 1, head intake air 2, and inner annular air 3. The outer annular air 1 is divided into two streams: a first airflow 11 for cooling the flame tube and a second airflow 12 flowing out of the outer annular cavity. The inner annular air 3 is divided into two streams: a third airflow 31 for cooling the flame tube and a fourth airflow 32 flowing out of the inner annular cavity. The head intake air 2 mixes with fuel in the head 6 and then burns in the flame tube 4. The resulting high-temperature combustion gas flows backward, driving the turbine to perform work.

[0052] Figure 2 Further show the structure of the flame tube, the flame tube 4 is a double-walled structure, the outer layer is called the outer impact wall 41, and the impact wall is distributed with impact holes perpendicular to the inner wall surface; the inner layer is called the inner divergent wall 42, which is in contact with hot combustion gas, and the divergent wall is densely distributed with gas film micro-holes having an angle with the wall surface. The front end 43 of the outer impact wall 41 is fixedly connected to the inner divergent wall 42, and the rear side of the outer impact wall 41 relative to the front end 43 forms a circumferential gap 45 with the inner divergent wall 42. The end 44 of the outer impact wall 41 is overlapped with the boss 424 on the inner divergent wall 42, which ensures that the outer impact wall 41 and the inner divergent wall 42 can freely expand in the axial direction.

[0053] In general cooling structure, the outer impact wall 41 and the inner divergent wall 42 are both provided with cooling holes, and the cooling gas flow enters the impact wall holes and impinges on the cooling holes of the divergent wall, and is injected into the main flow from the gas film holes.

[0054] However, under this cooling mode, the cooling effect of several rows of gas films located on the front side in the axial direction is not good, and for a double-walled structure with large size, thermal deformation is not coordinated during service, which leads to the failure of the cooling mode of the double-layer cooling holes.

[0055] Therefore, the present application provides a flame tube cooling structure, further provided with a raised ring rib 423, and the distribution structure of the cooling holes provided on the inner divergent wall 42 is adjusted.

[0056] Specifically, referring to Figures 2 to 4 As shown in the figure, the outer impact wall 41 is provided with first impact holes 411, and the inner divergent wall 42 is provided with second impact holes 420. The first impact holes and the second impact holes both include multiple rows of holes distributed in the circumferential direction, and the inlets of the second impact holes and the outlets of the first impact holes are staggered.

[0057] Further, the second impact holes 420 include front inclined divergent holes 421 and rear inclined divergent holes 422.

[0058] The front inclined divergent holes 421 are located at the axial front end of the inner divergent wall 42, and are used to guide the cooling gas flow to flow out to the front side in the axial direction. The rear inclined divergent holes 422 are used to cool the cooling gas flow to flow out to the rear side in the axial direction. In Figure 2 In the embodiment shown in the figure, x represents the axial direction, +x represents the rear side in the axial direction, and -x represents the front side in the axial direction; y represents the radial direction, +y represents the outer side in the radial direction, and -y represents the inner side in the radial direction.

[0059] In some embodiments, the inclination angle of the front inclined divergent holes 421 and / or the rear inclined divergent holes 422 relative to the y-axis ranges from 0 to 75 degrees.

[0060] The convex ring rib 423 is arranged in the gap 45, one end of which is connected with the inner layer divergent wall 42, and the other end is not connected with the outer layer impact wall 41, but forms a radial gap of 0-1 mm with the outer layer impact wall 41. Because the temperature of the inner layer divergent wall 42 close to the high-temperature gas side is higher than that of the outer layer impact wall 41, the inner layer divergent wall 42 expands radially outward relative to the outer layer impact wall 41 during service, and the existence of the convex ring rib 423 can make it abut against the outer layer impact wall 41 in the deformed state, thereby ensuring that a radial gap is always maintained between the outer layer impact wall 41 and the inner layer divergent wall 42, limiting further deformation of the wall body, thereby avoiding the problem of failure of the double-layer wall cooling structure form due to the uncoordinated radial thermal deformation of the double-layer wall thin-walled part during service.

[0061] Further, the existence of the convex ring rib 423 also plays the role of a reinforcing rib, enhancing the strength of the structure of the inner layer divergent wall 42, and reducing the risk of cracks or even structural damage of the inner layer divergent wall 42 of the flame tube under high heat load.

[0062] As shown in Figure 4 The flame tube cooling gas 101 flows from the discrete impact holes 411 in the outer layer impact wall 41, impinges on the inner layer divergent wall 42 to play an impact cooling effect, a part of the cross-flow gas 104 flows in the gap between the outer layer impact wall 41 and the inner layer divergent wall 42 to form a convection cooling effect, another part flows out through the forward divergent holes 421 to form a forward flow gas stream 102, and another part flows out through the backward divergent holes 422 to form a backward flow gas stream 103, forming a gas film cooling effect.

[0063] Further, the existence of the convex ring rib 423 enhances the convection cooling in the gap between the outer layer impact wall 41 and the inner layer divergent wall 42, and strengthens the convection cooling effect of the inner layer divergent wall 42, which is beneficial to reducing the wall temperature of the inner layer divergent wall 42.

[0064] Due to the influence of the swirl of the head 6, the thermal load of the front end of the inner layer divergent wall 42 is high, and although the overall average gas film cooling effect of the backward divergent holes 422 is high, it is difficult to form an effective gas film cooling superposition coverage effect in the front rows of the flame tube. Therefore, the flame tube cooling structure is provided with forward divergent holes 421 at the axial front end of the inner layer divergent wall, and the existence of the forward divergent holes 421 forms a reverse penetration effect to the main flow, significantly improving the gas film cooling effect of the front rows of the flame tube, which is beneficial to reducing the wall temperature of the front end of the flame tube.

[0065] Preferably, the forward divergent holes 421 are the first row or the first few rows of holes of the second impact holes in the axial direction, which are located on the axial front side of the first impact holes 411 and form a staggered structure with the first impact holes 411, as shown in Figure 3As shown, the front inclined divergent hole 421 solves the problem of insufficient cooling at the front end of the inner layer divergent wall 42, and the rear inclined divergent hole 422 has excellent average film cooling effect overall except for the front rows. The combination of the front inclined divergent hole 421 and the rear inclined divergent hole 422 makes the overall wall temperature of the flame tube lower and more uniform, which is beneficial to reduce the thermal stress of the flame tube and improve the service life.

[0066] In some embodiments, the raised ring ribs include a plurality of circumferentially continuous rows of raised ring ribs 423, as shown, and each row of raised ring ribs is staggered with the first impact hole 411 and the second impact hole 420. Figure 5

[0067] In other embodiments, the raised ring ribs can also be discontinuous annular raised ribs circumferentially distributed on the radial outer surface of the inner layer divergent wall 42.

[0068] The above flame tube cooling structure avoids the problem of uncoordinated radial thermal deformation of the thin-walled double-layer wall of the flame tube during service by adding raised ring ribs, while enhancing the strength of the inner layer divergent wall structure and reducing the risk of cracks or even structural damage of the inner layer divergent wall of the flame tube under high thermal load. The use of raised ring ribs can also strengthen the convective cooling effect of the inner layer divergent wall, which is beneficial to reduce the wall temperature of the inner layer divergent wall. The combination of front inclined divergent holes and rear inclined divergent holes in the inner wall divergent wall makes the overall wall temperature of the flame tube lower and more uniform, which is beneficial to reduce the thermal stress of the flame tube and improve the service life.

[0069] In combination with the introduction of the above flame tube cooling structure, it can also be understood that a flame tube including the flame tube cooling structure has a better cooling effect.

[0070] It can also be further understood that a combustion chamber includes an outer casing, a nozzle, and a head, and also includes a flame tube having the above structure.

[0071] Meanwhile, specific words are used in the present application to describe the embodiments of the present application. As "one embodiment", "an embodiment", and / or "some embodiments" mean a certain feature, structure or characteristic related to at least one embodiment of the present application. Therefore, it should be emphasized and noted that the "one embodiment" or "one embodiment" or "one alternative embodiment" mentioned in different places in the specification does not necessarily refer to the same embodiment. In addition, some features, structures or characteristics in one or more embodiments of the present application can be properly combined.

[0072] ​Although the present application is disclosed with reference to the preferred embodiments above, it is not intended to limit the present application, and any person skilled in the art can make possible changes and modifications without departing from the spirit and scope of the present application. Therefore, any modification, equivalent change and modification made to the above embodiments according to the technical essence of the present application without departing from the technical solutions of the present application, all fall within the protection scope defined by the claims of the present application.

Claims

1. A cooling structure of a flame tube, arranged on a double-wall structure, the double-wall structure comprising an outer impact wall, an inner divergent wall, and a gap between the outer impact wall and the inner divergent wall, the cooling structure comprising: first impact holes arranged on the outer impact wall; and second impact holes arranged on the inner divergent wall; characterized in that the cooling structure further comprises: a raised annular rib arranged in the gap, one end of the raised annular rib being connected to the inner divergent wall and the other end of the raised annular rib being not connected to the outer impact wall; wherein the second impact holes comprise forwardly inclined divergent holes and rearwardly inclined divergent holes, the forwardly inclined divergent holes being located at an axial front end of the inner divergent wall and used for guiding a cooling airflow to flow out to an axial front side, and the rearwardly inclined divergent holes being used for guiding the cooling airflow to flow out to an axial rear side. The raised annular rib comprises a plurality of rows of raised annular ribs, each row of raised annular ribs being staggered with the first impact holes and the second impact holes. The first impact holes and the second impact holes comprise a plurality of rows of holes distributed in a circumferential direction, and an inlet of the second impact holes and an outlet of the first impact holes are staggered. The forwardly inclined divergent holes are located at an axial front side of the first impact holes. The forwardly inclined divergent holes are the first row or the front several rows of holes of the second impact holes in an axial direction, and the forwardly inclined divergent holes and the first impact holes form a staggered distribution. An inclination angle of the forwardly inclined divergent holes and / or the rearwardly inclined divergent holes ranges from 0° to 75°.

2. The flame tube cooling structure of claim 1, wherein A distance between the raised annular rib and the outer impact wall ranges from 0 to 1 mm.

3. The flame tube cooling structure of claim 2, wherein The raised annular rib is a discontinuously distributed annular raised rib.

4. The flame tube cooling structure of claim 1, wherein The cooling structure of the flame tube according to any one of claims 1-8.

5. The flame tube cooling structure of claim 1, wherein The flame tube according to claim 9.

6. The flame tube cooling structure of claim 1, wherein ​ 7. The flame tube cooling structure of claim 1, wherein ​ 8. The flame tube cooling structure of claim 1, wherein ​ 9. A flame tube comprising a double-walled structure, characterized in that ​ 10. A combustion chamber comprising an outer casing, a flame tube, a head and a nozzle, characterised in that, ​

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