Branching and converging transition section structure of interstage combustion chamber engine

Abstract

The invention provides a flow dividing and converging transition section structure for an interstage combustion chamber engine. The flow dividing and converging transition section structure comprises a flow dividing ring, inner and outer side flow channels, rectifying blades, an interstage combustion chamber, a lobe mixer and the like. The flow dividing ring is used for dividing gas into two streams, one stream enters the inner side flow channel, the other stream enters the outer side flow channel and flows into the interstage combustion chamber to be mixed with fuel oil to be combusted again, then the two streams of gas flow are efficiently mixed at the lobe mixer, and the mixed gas enters the follow-up process. Integrated design is adopted, the number of parts is reduced, the part mounting steps are simplified, and the weight of an engine is reduced while the requirement for combustion organization of an interstage combustion chamber, the requirement for temperature uniformity of a low-pressure turbine inlet and the requirement for pressure loss are met.

Description

Technical Field

[0001] The present invention relates to the technical field of aviation engines, and in particular to a flow-dividing and converging transition section structure for an interstage combustion chamber engine. Background Art

[0002] Interstage combustion technology in aircraft engines achieves the goal of increasing cycle work and thrust by injecting fuel between turbine stages to reheat the gases. Due to internal engine size limitations and temperature restrictions on the low-pressure turbine inlet, reburning a portion of the gases at the high-pressure turbine outlet rather than reheating the entire flow is a preferred approach.

[0003] However, the application of this interstage combustion scheme presents many new challenges, including structurally implementing the diversion of the high-pressure turbine outlet gas, addressing the high velocity and swirl of the diverted gas entering the interstage combustor, and addressing the uneven temperature at the low-pressure turbine inlet caused by partial gas reheating. Conventional engines connect the high-pressure and low-pressure turbines through a gradually expanding transition section, necessitating an integrated design of the diversion and transition sections. The interstage combustor also requires low-velocity, uniform, and swirl-free inlet airflow, necessitating simultaneous diversion and rectification of the high-pressure turbine outlet gas. Furthermore, the use of partial reburning heating introduces temperature unevenness, necessitating mixing of the reheated gas with the cooler gas to achieve the required temperature uniformity at the low-pressure turbine inlet. These requirements must be addressed through a unified approach, encompassing both the engine layout and the design of related components, with the goal of achieving the simplest and most compact structural solution possible. This is crucial for the practical application of interstage combustor engines. Summary of the Invention

[0004] In view of this, the present invention provides a diverging and converging flow transition section structure for an interstage combustion chamber engine to meet the requirement of mixing reheated gas and lower temperature gas to achieve temperature uniformity at the low-pressure turbine inlet.

[0005] The present invention employs the following technical solution: a flow-dividing and converging transition section structure for an interstage combustion chamber engine, comprising a high-pressure turbine, a low-pressure turbine, and an interstage combustion chamber. A diverter ring is disposed at the rear end of the high-pressure turbine, an outer flow channel is disposed on the outer ring of the diverter ring and communicates with the interstage combustion chamber, an inner flow channel is disposed on the inner ring of the diverter ring, and a lobe blender is connected to both the inner flow channel and the interstage combustion chamber. The blended gas in the lobe blender enters the low-pressure turbine.

[0006] Preferably, a discrete rectifying blade structure for adjusting the circumferential flow angle of the airflow is provided in the outer flow channel.

[0007] Preferably, the outer flow channel is an expansion channel.

[0008] Preferably, the inner flow passage is provided with a discrete straightening blade structure for adjusting the circumferential flow angle of the airflow.

[0009] Preferably, the inner flow channel is of an expansion type or a convergence type.

[0010] Preferably, the diverter ring is a position-adjustable structure, so as to control the flow ratio of the inner flow channel and the outer flow channel.

[0011] Preferably, an air film cooling hole structure is provided on the wall surface of the lobe mixer.

[0012] Compared with the prior art, the beneficial effects that can be achieved by at least one of the above-mentioned technical solutions adopted in the present invention include at least: a diverter and converging flow transition section structure, which can reheat part of the airflow at the high-pressure turbine outlet to increase the temperature of the working airflow entering the low-pressure turbine, thereby achieving the goal of increasing cycle work and thrust without increasing the outer diameter and length of the engine; the diverter and converging flow transition section structure integrates the diverter ring, inner and outer flow channels, straightening blades, and mixing lobe structure, and adopts an integrated design, which reduces the number of parts, simplifies the parts installation steps, and reduces the engine weight while ensuring that the combustion organization requirements of the inter-stage combustion chamber, the temperature uniformity requirements of the low-pressure turbine inlet, and the pressure loss requirements are met. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0014] Figure 1 It is a structural diagram of an embodiment of the present invention.

[0015] Reference numerals in the figure: 1. high-pressure turbine; 2. low-pressure turbine; 3. splitter ring; 4. outer flow channel; 5. inner flow channel; 6. interstage combustion chamber; 7. lobe mixer; 8. mixing flow channel. DETAILED DESCRIPTION

[0016] The embodiments of the present application are described in detail below with reference to the accompanying drawings.

[0017] It should be noted that, in the absence of conflict, the embodiments and features of the embodiments in this application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0018] like Figure 1As shown, the gas that expands and produces work in the engine's high-pressure turbine passes through the inlet of the transition section structure and is then split into two streams by the diverter ring 3. One stream flows from the outer flow channel 4 into the interstage combustion chamber 6 to mix with the fuel and burn again. The other stream continues to flow backward through the inner flow channel 5 and is mixed with the gas flowing out of the interstage combustion chamber 6 in the lobe blender 7. The evenly mixed air then passes through the blending flow channel 8 and enters the engine's low-pressure turbine 2 to continue expanding and producing work.

[0019] It should be noted that in the present invention, the position of the diverter ring 3 can be adjusted to control the flow ratio entering the inner flow channel 5 and the outer flow channel 4. This allows the amount of gas flowing into different flow channels to break through the traditional fixed geometric limitations. By adjusting the flow channel position, continuous and precise flow distribution can be achieved, which can synergistically optimize aerodynamic performance and thermodynamic cycle, and reduce fuel consumption, etc.

[0020] In the present invention, both the outer flow channel 4 and the inner flow channel have discrete straightening blade structures, and the discrete straightening blade structures can be used to adjust the circumferential airflow angle of the airflow; among them, the straightening blades of the outer flow channel 4 serve to connect the inner and outer flow channels and provide support, and the straightening blades of the inner flow channel 5 also serve to connect the flow channel and the lobe mixer 7.

[0021] It should be noted that the outer flow channel 4 is an expansion channel to achieve deceleration and pressure increase, thereby meeting the intake air swirl and velocity requirements of the combustion organization of the interstage combustor. The inner flow channel 5 can be expansion or convergence, depending on the mixing requirements of the rear-end lobe blender 7. The expansion or convergence design of the inner flow channel 5 essentially creates optimal gas inlet conditions for the rear-end blender, achieving efficient mixing and system stability by regulating velocity and pressure.

[0022] In the present invention, the airflow passing through the interstage combustion chamber and the airflow passing through the inner flow channel 5 are efficiently mixed in the lobe mixer 7, wherein the shape of the lobe mixer resembles a periodic wave crest and trough. The airflow in the inner flow channel 5 flows into the crest, and the airflow at the interstage combustion chamber outlet flows into the trough, thereby strengthening the circumferential mixing of the two airflows. Under the dual effects of velocity difference and direction difference, the gas in the inner flow channel and the airflow at the interstage combustion chamber outlet can stimulate surface shear layer instability, generate high-intensity turbulence, and greatly improve the mixing efficiency. At the same time, an air film cooling hole structure can be designed on the wall of the lobe mixer 7. Because when the low-temperature cold air in the inner flow channel intersects the high-temperature combustion gas in the interstage combustion chamber, the high-speed shear and flow impact will cause metal fatigue and erosion. The air film cooling hole injects the cooling airflow at a controllable angle / speed to form a "flexible air film layer" on the wall surface. This not only isolates the direct thermal impact of the high-temperature combustion gas on the metal, but also buffers the mechanical load through momentum exchange between the air film and the mainstream, while optimizing the uniformity of the flow field. This design suppresses thermal stress and extends service life while avoiding loss of mixing efficiency. It can effectively protect the metal material of the lobe and avoid cracks caused by thermal deformation.

[0023] In the present invention, the evenly mixed airflow enters the engine low-pressure turbine 2 and continues to expand and do work. Since part of the airflow is burned and heated in the interstage combustion chamber, the temperature of the airflow entering the low-pressure turbine 2 is increased, achieving the goal of increasing cycle work and increasing thrust.

[0024] The above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the invention. Therefore, substitutions of equivalent components, or equivalent changes and modifications made within the scope of patent protection, should still fall within the scope of this patent. Furthermore, the technical features of the present invention may be freely combined with one another, with other technical solutions, and with other technical solutions.

Claims

1. A flow-dividing and converging transition section structure for an interstage combustion chamber engine, comprising a high-pressure turbine (1), a low-pressure turbine (2), and an interstage combustion chamber (6), characterized in that: The branch and merge flow transition section structure also includes: A splitter ring (3) is provided at the rear end of the high-pressure turbine (1); An outer flow channel (4) is provided on the outer ring of the diverter ring (3) and is in communication with the interstage combustion chamber (6); An inner flow channel (5) is provided on the inner ring of the diverter ring (3); The lobe mixer (7) is connected to both the inner flow channel (5) and the interstage combustion chamber (6), and the mixed gas of the lobe mixer (7) enters the low-pressure turbine (2).

2. The flow-dividing and converging transition section structure for an interstage combustion chamber engine according to claim 1, characterized in that: A discrete rectifying blade structure for adjusting the circumferential flow angle of the airflow is provided in the outer flow channel (4).

3. The flow-dividing and converging transition section structure for an interstage combustion chamber engine according to claim 2, characterized in that: The outer flow channel (4) is an expansion channel.

4. The flow-dividing and converging transition section structure for an interstage combustion chamber engine according to claim 1, characterized in that: The inner flow channel (5) is provided with a discrete rectifying blade structure for adjusting the circumferential flow angle of the airflow.

5. The flow-dividing and converging transition section structure for an interstage combustion chamber engine according to claim 4, characterized in that: The inner flow channel (5) is of expansion type or convergence type.

6. The flow-dividing and converging transition section structure for an interstage combustion chamber engine according to claim 2, characterized in that: The flow dividing ring (3) is a position-adjustable structure, thereby controlling the flow ratio of the fluid entering the inner flow channel (5) and the fluid entering the outer flow channel (4).

7. The flow-dividing and converging transition section structure for an interstage combustion chamber engine according to claim 5, characterized in that: An air film cooling hole structure is provided on the wall surface of the lobe mixer (7).

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