Aero-engine turbine blade cold and hot fatigue test adapter segment structure

Abstract

A transition section structure for thermal fatigue testing of aero-engine turbine blades includes four pipe assemblies connected sequentially along the air intake to exhaust direction: a transition section, a stabilization section, a test section, and an exhaust section. Each pipe assembly includes an intake flange, an exhaust flange, an outer water jacket, and an inner water jacket. Annular bosses are respectively provided on the opposite end faces of the intake and exhaust flanges, and these annular bosses are arranged around the circumference of the vent holes of the intake and exhaust flanges. The two end faces of the inner water jacket are butt-welded to the annular bosses of the intake and exhaust flanges to form welds. The annular bosses serve both as welding surfaces and allow the outer circumference of the weld to lie within the cooling water channel formed by the outer and inner water jackets. The flowing cooling water in the channel cools the weld, preventing cracks and improving the temperature resistance and cycle life of the pipe assembly.

Description

Technical Field

[0001] This invention relates to testing technology for aero-engine components, and more particularly to a transition section structure for thermal fatigue testing of aero-engine turbine blades. Background Technology

[0002] With the continuous improvement of the thrust-to-weight ratio of aero-engines and the increasing turbine inlet temperature, more stringent requirements are being placed on the high-temperature performance of turbine blades. During engine operation, turbine blades not only bear significant aerodynamic loads but also the continuous impact of high-temperature combustion gases from the combustion chamber. Compared to mechanical vibration loads, the coupling effect of temperature and aerodynamic loads is the primary load form experienced by turbine blades during service. Engine start-up and shutdown cause rapid temperature changes on the inner and outer surfaces of the blades, creating a large temperature gradient along the blade thickness. Simultaneously, the blade generates uneven temperature distribution during flow splitting. This temperature imbalance leads to a large amount of heat exchange within a short period, resulting in significant thermal stress on the blade's interior and exterior, severely impacting its high-temperature performance and lifespan. Therefore, thermal fatigue tests are necessary to assess the turbine blade's resistance to thermal fatigue.

[0003] The principle of turbine blade thermal fatigue testing is to simulate the alternating temperature load experienced by turbine blades during engine start-up, operation, and shutdown using a certain cyclic load and time history. The gas temperature load is applied using a heating system. Compressed air is heated to the required test temperature via the main gas pipeline and then enters the test transition section. The main function of the test transition section is to transfer the high-temperature gas generated by the heating system to meet the required flow channel shape and size, provide installation space for gas parameter measuring devices, clamp and contain the test piece, and ensure the inlet and outlet angles of the test blades.

[0004] like Figure 1 The diagram shows the overall structure of an existing turbine blade thermal fatigue testing transition section. The entire transition section is divided into four parts: a transition section, a stabilization section, a testing section, and an exhaust section. During the test, high-temperature combustion gas exits the combustion chamber and passes sequentially through the transition section, stabilization section, testing section, and exhaust section before being discharged into the atmosphere. Each section is connected by flanges. To ensure normal operation of each section, each section is supplied with cooling water, which cools the internal flow channels in a direct-flow manner. However, in the existing turbine blade thermal fatigue testing transition section structure, the water jackets and flanges in each section are connected by lap welding (e.g.,...). Figure 2As shown at point A, the cooling water failed to effectively cool the weld. During the turbine blade thermal fatigue test, after multiple thermal cycles at high temperatures, cracks appeared at the weld seams where the water jacket and flange lap welded in each section of the existing test transition section, making it impossible to continue the test. Therefore, the existing test transition section has problems such as low temperature resistance and a small number of usable test cycles. Summary of the Invention

[0005] The main objective of this invention is to propose a transition section structure for thermal fatigue testing of aero-engine turbine blades, aiming to solve the problems of existing test transition sections having low temperature resistance and a limited number of usable test cycles, which are prone to cracking due to the inability to cool the weld.

[0006] To achieve the above objectives, this invention proposes a transition section structure for thermal fatigue testing of aero-engine turbine blades. Along the air intake to exhaust direction, it includes four pipe assembly segments connected sequentially: a transition segment, a stabilization segment, a test segment, and an exhaust segment. Each pipe assembly includes an intake side flange, an exhaust side flange, an outer water jacket, and an inner water jacket. Annular bosses are respectively provided on the opposite end faces of the intake and exhaust side flanges, and these annular bosses are arranged around the circumference of the ventilation holes of the intake and exhaust side flanges. The two ends of the inner water jacket are welded to the annular bosses of the air inlet flange and the exhaust flange, respectively, to form welds; the vent hole and the central through hole of the inner water jacket together form a gas flow channel; the outer water jacket is fitted outside the inner water jacket, and its two ends are connected to the air inlet flange and the exhaust flange, respectively; a cooling water flow channel is formed between the inner wall surface of the outer water jacket and the outer wall surface of the inner water jacket, and the circumferential surface of the weld is located on the cooling water flow channel; an inlet water interface pipe and an outlet water interface pipe are provided on the outer water jacket and connected to the cooling water flow channel.

[0007] Preferably, a first water storage groove is provided at one end of the outer water jacket, and a second water storage groove is provided at the other end; and both the first water storage groove and the second water storage groove are located near the weld.

[0008] Preferably, the first water storage groove is located at one end near the exhaust flange, and the water inlet pipe is connected to the first water storage groove; the second water storage groove is located at one end near the air inlet flange, and the water outlet pipe is connected to the second water storage groove; the water flow direction in the cooling water channel is opposite to the air flow direction in the gas channel.

[0009] Preferably, both the inlet and outlet water interface pipes are inclined, with the outlet end of the inlet water interface pipe facing the weld and the inlet end of the outlet water interface pipe facing the weld.

[0010] Preferably, the angle between the central axis of the inlet pipe and the outlet pipe and the central axis of the inner water jacket is 45 degrees.

[0011] Preferably, the radial depth h of the first water storage groove and the second water storage groove is ≥10mm.

[0012] Preferably, an annular groove is provided on the outer side of the annular boss on the air intake flange and the exhaust flange, and an annular retaining edge is provided on the end face of the outer water jacket, which is engaged with the side wall of the annular groove.

[0013] Preferably, an external thread is provided on the outer circumferential surface of the inlet end of the water inlet interface pipe, and an external thread is provided on the outer circumferential surface of the outlet end of the water outlet interface pipe.

[0014] Preferably, limit blocks are provided on the inlet and outlet water interface pipes respectively, and a sealing gasket is provided on the end face of the limit block near the external thread.

[0015] Preferably, the wall thickness of the annular boss is consistent with the wall thickness of the inner water jacket.

[0016] Due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows:

[0017] (1) In this invention, annular bosses are provided on the opposite end faces of the air inlet flange and the exhaust flange, and the end face of the annular bosses is butt-welded with the end face of the inner water jacket to form a weld. The annular bosses serve the purpose of welding and also allow the outer circumference of the weld to be located in the cooling water channel formed by the outer water jacket and the inner water jacket. When the cooling water in the cooling water channel flows, it can cool the weld. During the test, since the welds at both ends of the inner water jacket in each section of the pipe assembly are effectively cooled, cracks can be effectively avoided at the weld where the inner water jacket and the flange are lapped during the test, thus improving the temperature resistance and the number of cycles of the pipe assembly.

[0018] (2) In this invention, by providing a water storage groove structure at both ends of the outer water jacket near the weld, the heat exchange efficiency at the weld position is improved, the temperature at the weld position is further reduced, and the cooling effect is improved.

[0019] (3) In this invention, the direction of water flow in the cooling water channel is opposite to the direction of air flow in the gas channel, which can further enhance the cooling effect. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0021] Figure 1 A schematic diagram of the overall structure of the existing turbine blade thermal fatigue test transition section;

[0022] Figure 2 This is a schematic diagram of the existing structure where the inner water jacket and flange are lap-welded together.

[0023] Figure 3 This is a schematic diagram of the structure of each section of the tube assembly in this invention;

[0024] Figure 4 for Figure 3 The method diagram at point B in the middle.

[0025] Explanation of reference numerals: 1. Transition section; 2. Stabilization section; 3. Test section; 4. Exhaust section; 5. Air inlet flange; 6. Water outlet pipe; 7. Outer water jacket; 8. Inner water jacket; 9. Exhaust flange; 10. Water inlet pipe; 11. Annular boss; 12. Vent hole; 13. Weld; 14. First water storage groove; 15. Second water storage groove; 16. Annular groove; 17. Annular retaining edge; 18. Limiting block; 19. Sealing gasket. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0027] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0028] Furthermore, the use of terms such as "first" and "second" in this invention is for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. Additionally, the technical solutions of the various embodiments can be combined with each other, but only on the basis of being achievable by those skilled in the art. When the combination of technical solutions is contradictory or impossible to implement, such a combination of technical solutions should be considered non-existent and not within the scope of protection claimed by this invention.

[0029] Combination Figure 1 , Figure 3As shown, the present invention provides a transition section structure for thermal fatigue testing of aero-engine turbine blades. Along the air intake to exhaust direction, it comprises four pipe sections connected in sequence: a transition section 1, a stabilization section 2, a test section 3, and an exhaust section 4. During the experiment, the combustion gas flow enters from the transition section 1 and exits from the exhaust section 4. Each pipe section includes an intake flange 5, an exhaust flange 9, an outer water jacket 7, and an inner water jacket 8. Annular bosses 11 are respectively provided on the opposite end faces of the intake flange 5 and the exhaust flange 9, and these annular bosses 11 extend along the air passage of the intake flange 5 and the exhaust flange 9. The circumferential arrangement of the hole 12; the two end faces of the inner water jacket 8 are respectively butt-welded to the annular bosses 11 of the air inlet flange 5 and the exhaust flange 9 to form weld seams 13; the vent hole 12 and the central through hole of the inner water jacket 8 together form a gas flow channel; the outer water jacket 7 is sleeved on the outside of the inner water jacket 8, and its two ends are respectively connected to the air inlet flange 5 and the exhaust flange 9; the inner wall surface of the outer water jacket 7 and the outer wall surface of the inner water jacket 8 are spaced apart to form a cooling water flow channel, and the circumferential surface of the weld seam 13 is located on the cooling water flow channel; an inlet interface pipe 10 and an outlet interface pipe 6 are provided on the outer water jacket 7 and connected to the cooling water flow channel. By providing annular bosses 11 on the opposite end faces of the inlet flange 5 and the exhaust flange 9, and by butt-welding the end faces of these annular bosses 11 to the end faces of the inner water jacket 8 to form a weld 13, the annular bosses 11 serve both as welding surfaces and allow the outer circumference of the weld 13 to lie within the cooling water channel formed by the outer water jacket 7 and the inner water jacket 8. The flowing cooling water in this channel effectively cools the weld 13. During testing, because the welds at both ends of the inner water jacket 8 in each section of the pipe assembly are effectively cooled, cracks at the weld 13 where the inner water jacket and flange are lap-welded are effectively prevented, thus improving the temperature resistance and cycle life of the pipe assembly. Furthermore, butt-welding ensures consistent thermal deformation direction.

[0030] Combination Figure 3 As shown, a first water storage groove 14 is provided at one end of the outer water jacket 7, and a second water storage groove 15 is provided at the other end; and both the first water storage groove 14 and the second water storage groove 15 are located near the weld 13. The water storage groove structure provided at both ends of the outer water jacket 7 near the weld 11 improves the heat exchange efficiency at the weld 11, further reduces the temperature at the weld 11, and improves the cooling effect.

[0031] Combination Figure 1As shown, the first water storage groove 14 is located at one end near the exhaust flange 9, and the water inlet pipe 10 is connected to the first water storage groove 14; the second water storage groove 15 is located at one end near the air inlet flange 5, and the water outlet pipe 6 is connected to the second water storage groove 15; the aforementioned structure allows the water flow direction in the cooling water channel to be opposite to the air flow direction in the gas channel, thereby further enhancing the cooling effect.

[0032] Combination Figure 3 As shown, both the inlet pipe 10 and the outlet pipe 6 are inclined, with the outlet end of the inlet pipe 10 facing the weld 13 and the inlet end of the outlet pipe 6 facing the weld 13. Specifically, the angle between the central axis of the inlet pipe 10 and the outlet pipe 6 and the central axis of the inner water jacket 8 is 45 degrees. By adjusting the inflow and outflow angles of the cooling water, the weld 11 can be sufficiently cooled, reducing the working temperature of the weld and minimizing deformation, thus further solving the problem of low temperature resistance in the existing test transition section.

[0033] Combination Figure 4 As shown, in order to ensure the water storage capacity at the water storage groove and to ensure the cooling effect, the radial depth h of the first water storage groove 14 and the second water storage groove 15 is ≥10mm.

[0034] Combination Figure 4 As shown, annular grooves 16 are provided on the outer side of the annular boss 11 on the intake flange 5 and the exhaust flange 9. An annular retaining edge 17 is provided on the end face of the outer water jacket 7, and the annular retaining edge 17 is engaged with the side wall of the annular groove 16. The engaging structure formed by the annular retaining edge 17 and the annular groove 16 facilitates the installation of the outer water jacket 7. At the same time, when there is water pressure in the cooling water flow channel, the outer wall of the annular retaining edge 17 can be tightly attached to the side wall of the annular groove 16 to achieve a sealing effect, forming a self-sealing structure.

[0035] Combination Figure 3 As shown, external threads are provided on the outer circumferential surface of the inlet end of the water inlet pipe 10 and on the outer circumferential surface of the outlet end of the water outlet pipe 6. The external threads facilitate the connection of the cooling water pipes. Furthermore, limit blocks 18 are respectively provided on the water inlet pipe 10 and the water outlet pipe 6, and a sealing gasket 19 is provided on the end face of the limit block 18 near the external threads. The limit blocks 18 are used to restrict the connection position of the cooling water pipes. When the cooling water pipes are screwed onto the external threads, the end face of the cooling water pipes abuts against the sealing gasket 19 to form a sealing structure.

[0036] Combination Figure 3As shown, the wall thickness of the annular boss 11 is the same as the wall thickness of the inner water jacket 8. This consistent wall thickness structure effectively prevents a smooth transition between the cooling water and gas channels at their joints, improving the smoothness of both gas and cooling water flow.

[0037] Through comparative testing, the existing test transition section can withstand a maximum gas temperature of 1000℃. Furthermore, after approximately 200 thermal cycles at this maximum temperature, cracks appear in the weld of the test transition section, making further testing impossible. However, using the transition section structure provided by this invention, thermal fatigue testing of the low-pressure turbine guide vanes of a certain type of engine was conducted. During the test, the maximum gas temperature reached 1200℃, and the test transition section withstood 2400 test cycles without any weld cracking, saving testing time and costs. The tests also showed that this invention optimizes the cooling water flow path and weld position, adjusting the inflow and outflow angles of the cooling water to ensure sufficient cooling of the weld, reducing the working temperature at the weld and minimizing deformation, thus solving the problem of low temperature resistance in existing test transition sections.

[0038] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A transition section structure for thermal fatigue testing of aero-engine turbine blades, comprising a four-section tube assembly along the inlet to outlet direction, consisting of a transition section (1), a stabilization section (2), a test section (3), and an exhaust section (4) connected sequentially, characterized in that: Each pipe assembly includes an inlet flange (5), an exhaust flange (9), an outer water jacket (7), and an inner water jacket (8); annular bosses (11) are respectively provided on the opposite end faces of the inlet flange (5) and the exhaust flange (9), and the annular bosses (11) are arranged around the circumference of the air passage (12) of the inlet flange (5) and the exhaust flange (9); the two end faces of the inner water jacket (8) are respectively butt-welded to the annular bosses (11) of the inlet flange (5) and the exhaust flange (9) to form welds. 13); the ventilation hole (12) and the central through hole of the inner water jacket (8) together form a gas flow channel; the outer water jacket (7) is sleeved outside the inner water jacket (8), and its two ends are respectively connected to the air inlet flange (5) and the exhaust flange (9); the inner wall surface of the outer water jacket (7) and the outer wall surface of the inner water jacket (8) are spaced apart to form a cooling water flow channel, and the circumferential surface of the weld (13) is located on the cooling water flow channel; an inlet interface pipe (10) and an outlet interface pipe (6) are provided on the outer water jacket (7) and are connected to the cooling water flow channel; A first water storage groove (14) is provided at one end of the outer water jacket (7), and a second water storage groove (15) is provided at the other end; and the first water storage groove (14) and the second water storage groove (15) are both located near the weld (13); The first water storage groove (14) is located at one end near the exhaust flange (9), and the water inlet pipe (10) is connected to the first water storage groove (14); the second water storage groove (15) is located at one end near the air inlet flange (5), and the water outlet pipe (6) is connected to the second water storage groove (15); the water flow direction in the cooling water channel is opposite to the air flow direction in the gas channel; The inlet pipe (10) and outlet pipe (6) are both inclined, with the outlet end of the inlet pipe (10) facing the weld (13) and the inlet end of the outlet pipe (6) facing the weld.

2. The transition section structure for cold and hot fatigue testing of aero-engine turbine blades as described in claim 1, characterized in that: The angle between the central axis of the inlet pipe (10) and the outlet pipe (6) and the central axis of the inner water jacket (8) is 45 degrees.

3. The transition section structure for cold and hot fatigue testing of aero-engine turbine blades as described in claim 1, characterized in that: The radial depth h of the first water storage groove (14) and the second water storage groove (15) is ≥10mm.

4. The transition section structure for cold and hot fatigue testing of aero-engine turbine blades as described in claim 1, characterized in that: An annular groove (16) is provided on the outer side of the annular boss (11) on the air intake flange (5) and the exhaust flange (9). An annular retaining edge (17) is provided on the end face of the outer water jacket (7). The annular retaining edge (17) is engaged with the side wall of the annular groove (16).

5. The transition section structure for cold and hot fatigue testing of aero-engine turbine blades as described in claim 1, characterized in that: An external thread is provided on the outer circumferential surface of the inlet end of the water inlet pipe (10), and an external thread is provided on the outer circumferential surface of the outlet end of the water outlet pipe (6).

6. The transition section structure for cold and hot fatigue testing of aero-engine turbine blades as described in claim 1, characterized in that: Limiting blocks (18) are provided on the water inlet pipe (10) and the water outlet pipe (6), and a sealing gasket (19) is provided on the end face of the limiting block (18) near the external thread.

7. The transition section structure for cold and hot fatigue testing of aero-engine turbine blades as described in claim 1, characterized in that: The wall thickness of the annular boss (11) is consistent with the wall thickness of the inner water jacket (8).

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