A backflow combustion chamber with adjustable circumferential timing position of guide vanes and a turbine coupling experimental device

Abstract

The application provides a backflow combustion chamber and turbine coupling experimental device with adjustable circumferential timing position of guide vane, and relates to the technical field of aero-engine testing. The device comprises a combustion chamber outer casing, a flame tube and a turbine guide vane module arranged in the combustion chamber outer casing. The turbine guide vane module is composed of multiple intermediate guide vanes and two replaceable edge accompanying guide vanes. By replacing the edge accompanying guide vanes with different profiles or assembling the edge accompanying guide vanes, the circumferential relative position of the swirler outlet and the guide vane channel can be directly changed, so that the timing position of the guide vane can be flexibly adjusted. The design does not need to change the combustion chamber main body and inlet conditions, and the adjustment is convenient and has good repeatability. The device integrates the functions of embedded measuring points, uniform cooling and optical observation, can accurately obtain the influence law of different heat spot timing positions on the gas thermal load of the guide vane in the real combustion environment, and provides key experimental data for the thermal protection design of the turbine blade.

Description

Technical Field

[0001] This invention relates to the field of aero-engine testing technology, and more specifically, to an experimental apparatus for studying the interaction between combustion chamber outlet temperature distortion (hot spot) and high-pressure turbine guide vanes, and particularly to an experimental apparatus for coupling a recirculating combustion chamber and a turbine with adjustable guide vane circumferential timing position. Background Technology

[0002] In aero-engines, the recirculating combustion chamber, due to its strong swirling combustion and recirculation structure, typically exhibits significant temperature non-uniformity in its high-temperature exhaust gas flow field at the outlet, forming localized strip-shaped regions with temperatures far exceeding the average, known as "hot spots." When these hot spots enter the downstream high-pressure turbine guide vane, their migration and diffusion behavior within the blade passage, as well as their relative circumferential position (time-sequence relationship) with the guide vane, directly determine the local thermal load distribution on the guide vane surface. This is a key factor leading to overheating or even ablation of the blade leading edge, suction surface, or tip region.

[0003] Currently, experimental research methods for this problem suffer from two main shortcomings: First, single-component test benches based on the combustion chamber or turbine lack a realistic integrated flow and thermal coupling environment, resulting in boundary conditions that differ significantly from actual operating conditions. Second, the few existing combustion chamber-turbine coupling experimental devices are mostly complex in structure and expensive, and the circumferential relative position between the combustion chamber outlet and the turbine blade ring is fixed after assembly, making it difficult to flexibly adjust and systematically study the influence of changes in the circumferential position of hot spots on the thermal load of the guide vanes. Furthermore, some simplified devices using cold flow or low-calorific-value gases as simulations cannot accurately reflect the physical property changes and chemical reaction effects of high-temperature combustion products.

[0004] Therefore, there is an urgent need for an integrated experimental device that can simulate the real high-temperature combustion environment and conveniently and accurately adjust the circumferential timing position of the turbine guide vane relative to the hot spot at the combustion chamber outlet, so as to reveal the hot spot migration mechanism and its interaction with blade cooling, and provide reliable experimental data and theoretical support for the thermal protection design of turbine blades. Summary of the Invention

[0005] This invention aims to overcome the shortcomings of existing technologies and provide an experimental device for coupling a recirculating combustion chamber and a turbine with adjustable circumferential timing position of the guide vanes. This device is compact and easy to adjust, enabling repeated and precise adjustment of the circumferential timing position of the turbine guide vane module by simply replacing local components, while maintaining the main structure of the combustion chamber and the inlet boundary conditions. This allows for the systematic study of the influence of different hot spot circumferential positions on the temperature field and pressure distribution on the guide vane surface under real combustion conditions.

[0006] To achieve the above-mentioned objectives, the present invention adopts the following technical solution: An experimental device for coupling a recirculating combustion chamber and a turbine with adjustable guide vane circumferential timing position includes: an outer casing of the combustion chamber, a flame tube and turbine guide vane module disposed in the outer casing of the combustion chamber, and a vortex generator installed at the head of the flame tube. The turbine guide vane module includes multiple intermediate guide vanes and at least two replaceable edge accompanying guide vanes; By replacing the edge-accompanying guide vanes with different profiles or using different assembly combinations, the circumferential position of the outlet centerline of the cyclone separator relative to the turbine guide vane module is changed, thereby achieving adjustment of the circumferential timing position of the guide vanes.

[0007] Furthermore, the turbine guide vane module is detachably connected to the combustion chamber outside the casing; the device also includes a tenon and mortise joint, which is disposed on the upstream side of the turbine guide vane module to achieve axial limiting and circumferential positioning between the flame tube and the turbine guide vane module.

[0008] Furthermore, the combustion chamber is provided with a cooling gas collection chamber and a displacement mechanism guide vane cooling gas chamber connected thereto. The displacement mechanism guide vane cooling gas chamber is provided with a rectifier structure. After the cooling gas is rectified by the displacement mechanism guide vane cooling gas chamber, it enters the cooling gas collection chamber and is then distributed to each guide vane of the turbine guide vane module.

[0009] Furthermore, among the multiple intermediate guide vanes, at least one intermediate guide vane is embedded with a thermocouple for measuring surface temperature, and / or at least one intermediate guide vane is embedded with a static pressure tube for static pressure on the side surface.

[0010] Furthermore, the flame tube is a multi-head recirculation combustion chamber structure, with each head equipped with an independent swirler and fuel nozzle.

[0011] Furthermore, observation windows for observation are provided on the walls of both the combustion chamber and the flame tube.

[0012] Furthermore, it also includes a displacement scanning measurement system, which includes a displacement mechanism, a drive unit, and a multi-point temperature probe. The drive unit drives the displacement mechanism to move the multi-point temperature probe in a circumferential scanning motion to measure the temperature field distribution of the section before the inlet and / or after the outlet of the turbine guide vane module.

[0013] Furthermore, the exhaust section of the combustion chamber is equipped with a water-cooled rectifier blade.

[0014] Compared with the prior art, the beneficial technical effects of the present invention are as follows: Flexible and adjustable timing position: By replacing or adjusting the two accompanying guide vanes in the turbine guide vane module, the circumferential timing position of the guide vanes can be easily and quickly changed without disassembling the combustion chamber body or altering core boundary conditions such as inlet flow, pressure, and temperature. This greatly improves experimental efficiency and ensures consistency of experimental conditions under different timing conditions.

[0015] Compact structure and reliable sealing: The flame tube and turbine guide vane module are integrated into a compact layout and are precisely positioned and connected by mortise and tenon joints, ensuring the integrity, rigidity and sealing performance of the structure under high temperature and high pressure test environment.

[0016] High integration of measurement functions: The turbine guide vane module integrates temperature and pressure measurement functions (embedded thermocouple and static pressure tube), combined with external circumferential scanning multi-point temperature probe and multiple optical observation windows, which can realize synchronous and multi-dimensional measurement of local heat load, pressure distribution and the entire flow field structure on the guide vane surface, and acquire comprehensive data.

[0017] The simulated environment is realistic: It adopts a realistic multi-head recirculation combustion chamber structure, which can conduct actual fuel combustion experiments and generate high-temperature gas with realistic swirling and temperature distortion characteristics. This makes the generation, migration and interaction of hot spots with turbine guide vanes closer to the actual working conditions of the engine.

[0018] Uniform and controllable cooling supply: The design of the cooling air chamber and rectifier grid of the displacement mechanism guide vane ensures that the cooling airflow supplied to the turbine guide vane module is uniform and stable, which is conducive to separating and focusing the study of the influence of the single variable of the circumferential position of the hot spot on the cooling effect of the guide vane. Attached Figure Description

[0019] The present invention will be further described below with reference to the accompanying drawings.

[0020] Figure 1 This is a schematic diagram of the structure of the intermediate guide vane with an embedded thermocouple in an embodiment of the present invention. Figure 1 ; Figure 2 This is a schematic diagram of the structure of the intermediate guide vane with an embedded thermocouple in an embodiment of the present invention. Figure 2 ; Figure 3 This is a schematic diagram of the structure of the intermediate guide vane with an embedded static pressure tube in an embodiment of the present invention. Figure 1 ; Figure 4 This is a schematic diagram of the structure of the intermediate guide vane with an embedded static pressure tube in an embodiment of the present invention. Figure 2 ; Figure 5 This diagram illustrates the edge-accompanying guide vane assembly used to achieve the timing position of "cyclone separator directly opposite the center of the guide vane passage". Figure 1 ; Figure 6 This diagram illustrates the edge-accompanying guide vane assembly used to achieve the timing position of "cyclone separator directly opposite the center of the guide vane passage". Figure 2 ; Figure 7 This diagram illustrates the edge-accompanying guide vane assembly used to achieve the timing position of "cyclone separator directly opposite the leading edge of the guide vane". Figure 1 ; Figure 8 This diagram illustrates the edge-accompanying guide vane assembly used to achieve the timing position of "cyclone separator directly opposite the leading edge of the guide vane". Figure 2 ; Figure 9 This is a schematic diagram of the mortise and tenon joint used for connection and positioning in this invention; Figure 10 This is a vertical cross-sectional view of a specific embodiment of the experimental apparatus of the present invention.

[0021] Explanation of reference numerals in the attached drawings: 1. Combustion chamber outer casing; 2. Flame tube; 3. Swirl head; 4. Ignition needle; 5. Flame tube outer ring mixing hole assembly; 6. Flame tube inner ring mixing hole assembly; 7. Fuel nozzle; 8. Fuel pipe mounting bracket; 9. Turbine guide vane module; 10. Displacement mechanism guide vane cooling chamber; 11. Displacement mechanism; 12. Multi-point temperature probe; 13. Servo; 14. Water-cooled rectifier blade cascade; 15. Flame tube large bend optical observation window; 16. Guide vane exhaust section optical observation window; 17. Tongue and tenon joint; 18. Shaft flange; 19. Star-shaped gasket; 20. Shaft. Detailed Implementation

[0022] To make the technical problems to be solved, the technical solutions, and the beneficial effects of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention.

[0023] Reference Figure 10 The present invention provides an experimental device for coupling a recirculating combustion chamber and a turbine with adjustable guide vane circumferential timing position. The main body of the device is a cylindrical outer casing 1 of the combustion chamber. Inside the outer casing 1, a flame tube 2 and a turbine guide vane module 9 are installed sequentially from front to back.

[0024] The flame tube 2 adopts a three-head recirculation design, with three swirlers 3 installed at its head. Fuel is introduced through a fuel pipe mounting bracket 8 fixed to the outside of the casing and delivered to the fuel nozzles 7 at each head via fuel lines. Air and fuel mix downstream of the swirlers 3 and are ignited by the ignition needle 4, forming high-temperature combustion products. Replaceable flame tube outer ring mixing hole kits 5 and inner ring mixing hole kits 6 are threadedly connected to the inner and outer ring walls of the flame tube 2 to introduce dilution air and regulate the temperature distribution at the combustion chamber outlet. The flame tube 2 is installed by tenons on its outer wall engaging with corresponding tenons on the inner wall of the outer casing 1 of the combustion chamber, and is secured by pressure plate bolts.

[0025] The turbine guide vane module 9 is located after the bend at the exit of the flame tube 2. The turbine guide vane module 9 consists of four geometrically identical intermediate guide vanes and two edge guide vanes mounted on either side of the module, forming a partial fan-shaped guide vane grid. Among the four intermediate guide vanes, such as... Figure 1 , 2 As shown, two of the blades have multiple thermocouples embedded inside the blade body to measure the temperature at key locations on the blade surface (such as the leading edge, pressure surface, and suction surface); Figure 3 , 4 As shown, the other two blades have embedded small static pressure tubes to obtain the static pressure distribution on the blade surface. The entire turbine guide vane module 9 is connected and fixed to the corresponding threaded holes on the inner wall of the combustion chamber outer casing 1 through bolt holes on its mounting side.

[0026] To achieve the adjustment of the circumferential timing position of the guide vanes, this invention designs two sets of edge-accompanying guide vanes with different profiles. For example... Figure 5 , 6 As shown, when the first set of edge guide vanes is installed, the outlet centerline of the cyclone separator 3 is roughly aligned with the central region of the flow channel formed by the intermediate guide vanes. Figure 7 , 8 As shown, when the second set of edge-accompanying guide vanes is replaced, the outlet centerline of the cyclone separator 3 is roughly aligned with the leading edge of one of the middle guide vanes. This replacement operation changes the initial circumferential position of the high-temperature combustion gas (hot spot) impacting the turbine guide vanes at the combustion chamber outlet.

[0027] like Figure 9 As shown, a tenon-and-mortise joint 17 is provided between the upstream end face of the turbine guide vane module 9 and the outlet end face of the flame tube 2. One end of the tenon-and-mortise joint 17 is embedded in the circumferential groove of the inner wall of the combustion chamber 1, and the other end is precisely connected to the corresponding structure of the turbine guide vane module 9 and the flame tube 2, which plays the role of axial thrust prevention, circumferential anti-rotation and sealing of gas, ensuring the rigidity and airtightness of the connection part.

[0028] To provide cooling air to the turbine guide vane module 9, an annular cooling air collection chamber is provided at the bottom of the outer combustion chamber casing 1. Below this collection chamber, the guide vane cooling air chamber 10 of the displacement mechanism is connected via a flange or threaded connection. Cooling gas enters from the air inlets on both sides of the guide vane cooling air chamber 10, and after being homogenized by a perforated plate or grid-type rectifier inside, flows upward into the cooling air collection chamber at the bottom of the outer combustion chamber casing 1. It then enters the cooling flow path inside each guide vane through the air supply channels at the root of the guide vane, providing a uniform and controllable cooling airflow to the guide vane.

[0029] An optical observation window 15 for the large bend of the flame tube and an optical observation window 16 for the guide vane exhaust section are respectively installed on the side wall (corresponding to the bend section of the flame tube) and the outlet section of the combustion chamber 1. The optical observation window 15 of the large curved tube of the flame tube and the optical observation window 16 of the guide vane exhaust section adopt a high-temperature resistant and pressure-bearing double-layer quartz glass structure to facilitate the visualization observation of the combustion flow field and turbine channel flow field using optical diagnostic technologies such as particle image velocimetry (PIV) and planar laser-induced fluorescence (PLIF). A displacement mechanism 11 is installed below the outer casing 1 of the combustion chamber. The displacement mechanism 11 is located on the outside of the outer casing 1 of the combustion chamber and is detachably connected to the outer casing 1 of the combustion chamber by threads. It is used to support and position the rotating shaft 20 and its internal multi-point temperature probes 12, and to provide axial compression sealing and cooling conditions for the circumferential scanning measurement process. The displacement mechanism 11 consists of a main body and a base plate; the main body has a double-wall structure, and a water-cooling channel is formed in its interlayer to suppress overheating of the device under high-temperature conditions; the upper middle part of the main body is provided with a guide vane cooling air chamber 10 of the displacement mechanism. The cooling air enters the internal channel of the turbine guide vane module 9 through the rectifier grid from the air collection chamber to achieve individual air supply and cooling of the guide vane. The rotating shaft 20 is arranged on both sides of the displacement mechanism 11. The star-shaped washer 19 is sleeved on the rotating shaft 20 to form a shaft seal. The rotating shaft flange 18 is fixed and pressed to the rotating shaft 20 and the star-shaped washer 19 through a threaded connection with the displacement mechanism 11, so that the rotating shaft 20 can still rotate under the shaft seal condition. The servo motor 13 is connected to the rotating shaft 20 through a spline, thereby driving the multi-point temperature probe 12 to perform circumferential scanning temperature measurement with the rotating shaft 20. The multi-point temperature probe 12 passes through the internal through hole of the rotating shaft 20 and is fixed by the rotating shaft set screw thread. Its lead wire is led out through the granite head on the base plate to achieve an air seal.

[0030] The exhaust end of the experimental device is equipped with a water-cooled rectifier blade 14, which is used to regulate the flow field and provide preliminary cooling for the high-temperature gas.

[0031] During the experiment, the corresponding edge-accompanying guide vanes were first selected and installed according to the research objectives, and the initial timing position was determined. The experimental system was started, air and fuel were introduced, and stable combustion was established through ignition. After the operating conditions stabilized, the cooling gas supply was turned on. Temperature and pressure data of the blade body were collected through thermocouples and static pressure tubes embedded in the middle guide vane. The multi-point temperature probe 12 was driven by the displacement mechanism 11 to scan and obtain the temperature field of the inlet and outlet sections. The flow field could be observed through the optical observation window 15 of the large curved tube of the flame tube and the optical observation window 16 of the guide vane exhaust section using high-speed photography, infrared thermal imagers, or laser diagnostic equipment. After completing a set of data acquisitions, the system could be stopped and another set of edge-accompanying guide vanes replaced to repeat the experiment, thereby obtaining comparative data at different circumferential timing positions of hot spots.

[0032] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0033] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. An experimental device for coupling a recirculating combustion chamber and a turbine with adjustable guide vane circumferential timing position, characterized in that, include: Combustion outdoor unit casing, flame tube and turbine guide vane module disposed in the combustion outdoor unit casing, and vortex generator installed at the head of the flame tube; The turbine guide vane module includes multiple intermediate guide vanes and at least two replaceable edge accompanying guide vanes; By replacing the edge-accompanying guide vanes with different profiles or using different assembly combinations, the circumferential position of the outlet centerline of the cyclone separator relative to the turbine guide vane module is changed, thereby achieving adjustment of the circumferential timing position of the guide vanes.

2. The experimental apparatus for coupling a recirculating combustion chamber and a turbine with adjustable guide vane circumferential timing position according to claim 1, characterized in that: The turbine guide vane module is detachably connected to the combustion chamber outside the casing; the device also includes a tenon and mortise joint, which is disposed on the upstream side of the turbine guide vane module to realize axial limiting and circumferential positioning between the flame tube and the turbine guide vane module.

3. The experimental apparatus for coupling a recirculating combustion chamber and a turbine with adjustable guide vane circumferential timing position according to claim 2, characterized in that: The outer casing of the combustion chamber is provided with a cooling gas collection chamber and a displacement mechanism guide vane cooling gas chamber connected thereto. The displacement mechanism guide vane cooling gas chamber is provided with a rectification structure. After the cooling gas is rectified by the displacement mechanism guide vane cooling gas chamber, it enters the cooling gas collection chamber and is then distributed to each guide vane of the turbine guide vane module.

4. The experimental apparatus for coupling a recirculating combustion chamber and a turbine with adjustable guide vane circumferential timing position according to claim 1, characterized in that: Among the multiple intermediate guide vanes, at least one intermediate guide vane has a thermocouple embedded inside for measuring surface temperature, and / or at least one intermediate guide vane has a static pressure tube embedded inside for static pressure on the side surface.

5. The experimental apparatus for coupling a recirculating combustion chamber and a turbine with adjustable guide vane circumferential timing position according to claim 1, characterized in that: The flame tube is a multi-head recirculation combustion chamber structure, with each head equipped with an independent swirler and fuel nozzle.

6. The experimental apparatus for coupling a recirculating combustion chamber and a turbine with adjustable guide vane circumferential timing position according to claim 1, characterized in that: Both the outer casing of the combustion chamber and the flame tube have observation windows for observation.

7. The experimental apparatus for coupling a recirculating combustion chamber and a turbine with adjustable guide vane circumferential timing position according to claim 1, characterized in that: It also includes a displacement scanning measurement system, which includes a displacement mechanism, a drive unit, and a multi-point temperature probe. The drive unit drives the displacement mechanism to move the multi-point temperature probe in a circumferential scanning motion to measure the temperature field distribution of the section before the inlet and / or after the outlet of the turbine guide vane module.

8. The experimental apparatus for coupling a recirculating combustion chamber and a turbine with adjustable guide vane circumferential timing position according to claim 1, characterized in that: The exhaust section of the outdoor combustion chamber is equipped with a water-cooled rectifier blade.

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