Blade tip structure with improved cooling efficiency and blade

Abstract

The application discloses a blade tip structure and blade with improved cooling efficiency, comprising a groove formed in a tip clearance leakage flow area, the inner wall of the groove is inclined to the mean camber line of the blade, the outlet of the cooling hole of the blade is located on the inner wall of the groove, the flow direction of the cooling working medium output by the cooling hole is the same as the flow direction of the leakage flow, the dovetail groove and the cooling hole are combined, the dovetail groove suppresses the formation of the pressure side corner vortex and reduces the heat exchange coefficient on the near pressure surface side; the cooling hole directly blows out the cooling gas to the blade tip high heat exchange area for impact cooling, the cooling gas flows to the suction surface side under the action of the pressure difference after the impact cooling, the blade tip temperature distribution is improved, the cooling gas utilization rate is improved, and the blade tip temperature distribution is uniform; on the other hand, the high-speed cooling jet forms an approximate circumferential rib structure, plays a role of aerodynamic sealing, suppresses the development of the leakage flow to the downstream, reduces the blade tip leakage amount, improves the gas-thermal characteristics of the blade tip area, prolongs the service life of the high-pressure turbine blade, and guarantees the safe and effective operation of the gas turbine.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of gas turbine blade cooling technology, in particular to a turbine rotor blade tip structure and a blade. BACKGROUND

[0002] In recent years, with the rapid development of the aviation industry, the performance of the aircraft engine is facing higher requirements. In order to improve the thrust-to-weight ratio and reduce fuel consumption, the turbine inlet temperature must be increased to improve the thermal efficiency. However, this also brings a series of serious problems to the normal operation of the engine. The increase speed of turbine inlet temperature is much higher than the development speed of blade material temperature resistance, especially for the first stage blade of high pressure turbine. The blade tip is in a high temperature environment for a long time, which will cause oxidation and corrosion, and then affect the performance and service life of the blade.

[0003] The groove tip structure can effectively reduce the leakage loss. At present, it is widely used on the turbine rotor blade tip. Compared with the flat tip, the existing tip groove structure can significantly inhibit the leakage flow at the top of the rotor blade. However, the leakage flow will cause high temperature and heat load on the wall surface of the tip end area, which will threaten the reliability and service life of the turbine tip area. In order to prevent the turbine blade tip area from being corroded by high temperature gas and reduce the heat load of the tip, effective cooling measures must be used to protect the turbine blade. SUMMARY

[0004] In view of the problems in the prior art, the present application provides a blade tip structure with improved cooling efficiency and a blade. By modeling the turbine rotor blade tip structure, the aerodynamic loss caused by the tip leakage can be effectively reduced, the heat exchange characteristics of the tip area can be improved, the service life of the blade can be prolonged, and the working efficiency of the turbine blade can be improved.

[0005] The present application is realized by the following technical solutions:

[0006] A blade tip structure with improved cooling efficiency, comprising a groove formed in the tip gap leakage flow area, the groove extending from the tip to the tail, the inner wall of the groove being inclined from bottom to top to the middle arc line of the blade, the outlet of the cooling hole of the blade being located on the inner wall of the groove, the flow direction of the cooling medium output by the cooling hole being the same as the flow direction of the leakage flow, and the cooling hole being used for impact cooling of the bottom surface of the groove.

[0007] Preferably, the front end and the rear end of the groove are flat and perpendicular to the middle arc line of the blade.

[0008] Preferably, the inner wall of the pressure side or / and the suction side of the groove is inclined from bottom to top to the middle arc line of the blade.

[0009] Preferably, the outlet of the cooling hole 5 is located on the inner wall of the pressure side or / and the suction side of the groove.

[0010] Preferably, the pressure side inner wall of the groove is inclined upward from the bottom to the middle camber line of the blade, and the suction side inner wall of the groove is perpendicular to the bottom of the groove.

[0011] Preferably, the cooling hole is arranged on the pressure side inner wall.

[0012] Preferably, the included angle between the bottom of the groove and the side wall is 15-75°.

[0013] Preferably, the width of the upper shoulder wall of the groove is 2-4G, and the width of the lower shoulder wall of the groove is 0.5-1.5G, where G is the tip gap height.

[0014] 9. A blade, characterized in that the top of the blade is provided with the above-mentioned tip structure with improved cooling efficiency.

[0015] A turbine engine, wherein the rotor blade of the turbine engine is provided with the above-mentioned tip structure with improved cooling efficiency.

[0016] Compared with the prior art, the present application has the following beneficial technical effects:

[0017] The present application provides a tip structure with improved cooling efficiency, wherein a groove is designed in the tip gap leakage flow area of a blade, the upper end of the inner wall of the groove is inclined to the middle camber line, and the outlet of a cooling hole is arranged on the inner wall of the groove, so that the flow direction of the cooling working medium is the same as the leakage flow direction. The tip structure combines the dovetail groove and the cooling hole, the inner wall of the groove suppresses the formation of the pressure side corner vortex, reduces the heat exchange coefficient on the near pressure surface side, the cooling hole can directly output the cooling working medium to the tip high heat exchange area for impingement cooling, the cooling working medium flows to the suction surface side under the action of pressure difference after impingement cooling, the utilization rate of the cooling working medium is improved, the tip temperature distribution is uniform, the tip heat exchange coefficient is reduced, at the same time, the high-speed cooling jet forms an approximate circumferential rib structure, plays a role of aerodynamic sealing, suppresses the development of the leakage flow to the downstream, reduces the tip leakage amount, and improves the aerothermodynamic characteristics of the tip area; the tip structure can suppress the tip gap leakage flow and reduce the leakage flow, and realizes effective cooling effect by impinging the groove bottom surface with the cooling jet, prolongs the service life of the high-pressure turbine blade, and ensures the safe and effective operation of the gas turbine.

[0018] Secondly, the front end and the rear end of the groove are perpendicular to the middle camber line of the tip, so that the groove as a whole forms an approximate rectangular structure, blocks the development of the groove cavity vortex, and improves the heat exchange characteristics from the tip chord to the trailing edge. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 FIG. 1 is a schematic diagram of a turbine rotor tip structure according to Embodiment 1 of the present application;

[0020] Figure 2Fig. 1 is a top view of the turbine rotor blade tip structure of the embodiment 1 of the present application;

[0021] Figure 3 Fig. 2 is a right view of the turbine rotor blade tip structure of the embodiment 1 of the present application;

[0022] Figure 4 Fig. 3 is a sectional view of the turbine rotor blade tip structure of the embodiment 1 of the present application along the line A-A.

[0023] Figure 5 Fig. 4 is a comparison of the three-dimensional streamline of the turbine rotor blade tip structure of the prior art and the present application; (a) is the three-dimensional streamline of the conventional film-cooling blade tip, (b) is the three-dimensional streamline of the blade tip of the present application.

[0024] Figure 6 Fig. 5 is a comparison of the film-cooling effect distribution of the turbine rotor blade tip structure of the prior art and the present application; (a) is the film-cooling effect distribution of the conventional film-cooling blade tip, (b) is the film-cooling effect distribution of the blade tip of the present application.

[0025] In the figure: 1-blade, 2-blade tip, 3-groove bottom surface, 4-pressure side shoulder wall, 5-cooling hole, 6-suction side shoulder wall, 7-groove front end, 8-groove rear end, 9-turbine casing. DETAILED DESCRIPTION

[0026] The present application will be further described in detail below with reference to the accompanying drawings, which are provided to explain the present application rather than to limit the present application.

[0027] A blade tip structure with improved cooling efficiency, comprising a cooling hole formed in the blade 1, and a groove formed in the blade tip 2, the groove extending from the tip to the trailing edge of the blade, the pressure side and / or suction side inner wall of the groove being inclined upwardly from the bottom to the camber line of the blade, the outlet of the cooling hole 5 being located on the pressure side and / or suction side inner wall of the groove, the cooling medium output by the cooling hole 5 flowing in the same direction as the leakage flow, for impingement cooling of the groove bottom surface 3.

[0028] The groove front end 7 and the groove rear end 8 are flat and perpendicular to the camber line of the blade, the groove front end 7 being close to the leading edge of the blade, the groove rear end 8 being close to the trailing edge of the blade, the groove extending from the leading edge to the trailing edge of the blade, the length L of the groove being 0.2-0.8C, the top shoulder wall width of the groove being 2-4G, the bottom shoulder wall width of the groove being 0.5-1.5G, the groove depth d1 being 0.5-1.5G, the included angle a1 between the inner wall of the groove and the groove bottom surface being 15°-75°, and the diameter D1 of the cooling hole being 0.8-1.5G.

[0029] Wherein, the shoulder wall is the distance from the groove side wall to the suction surface or pressure surface of the blade, and G is the tip clearance height, i.e. the distance between the blade tip 2 and the turbine casing.

[0030] The turbine rotor tip structure has a groove designed in the tip clearance leakage flow area of the blade, the groove extends from the leading edge of the blade to the trailing edge along the flow direction, the upper end of the inner wall of the groove is inclined to the mean camber line, the cross section of the groove forms a dovetail groove structure, the outlet of the cooling hole is arranged on the inner wall of the groove, the flow direction of the cooling working medium is the same as the leakage flow direction, the cooling working medium impacts and cools the bottom surface of the groove, the dovetail groove and the cooling hole are combined, the inner wall of the groove inhibits the formation of the pressure side corner vortex, reduces the heat exchange coefficient on the near pressure surface side, the cooling hole can directly output the cooling working medium to the tip high heat exchange area for impact cooling, the cooling working medium flows to the suction surface side under the action of the pressure difference after impact cooling, the utilization rate of the cooling working medium is improved, the tip temperature distribution is uniform, the tip heat exchange coefficient is reduced, and the gas-thermal characteristics of the tip area are improved; secondly, the front end and the rear end of the groove are perpendicular to the tip mean camber line, the groove as a whole forms an approximately rectangular structure, the development of the groove cavity vortex is blocked, and the heat exchange characteristics of the tip chord to the trailing edge are improved; in addition, the reasonable layout and geometric structure of the cooling hole can change the gas-thermal characteristics of the tip of the groove, effectively improve the working efficiency of the turbine rotor, and improve the overall performance of the aero-engine.

[0031] Referring to Figures 1-2 A tip structure with improved cooling efficiency comprises a groove arranged in the tip clearance leakage flow area of the tip 2, the groove extends from the leading edge of the blade to the trailing edge along the flow direction of the blade, the pressure side inner wall of the groove is inclined from bottom to top to the mean camber line of the blade, the suction side of the groove is perpendicular to the bottom surface 3 of the groove, the front end 7 and the rear end 8 of the groove are planes, and the planes are perpendicular to the mean camber line of the blade.

[0032] Referring to Figure 3 The blade is internally provided with a plurality of cooling holes 5, the inlet of the cooling hole is located at the blade root, the outlet of the cooling hole is arranged on the pressure side inner wall of the groove, the flow direction of the cooling working medium output by the cooling hole 5 is the same as the leakage flow direction, and the cooling working medium is used for impact cooling of the bottom surface 3 of the groove.

[0033] The number of the cooling holes is 1-8, and the cooling holes are arranged at intervals along the pressure side inner wall of the groove.

[0034] Referring to Figure 4 The length of the groove is L, which is 0.2-0.8C, the top width w1 of the pressure side shoulder wall 4 of the groove is 2-4G, the bottom width w2 of the pressure side shoulder wall 4 of the groove is 0.5-1.5G, the width w3 of the suction side shoulder wall 5 of the groove is 0.5-1.5G, the depth d1 of the groove is 0.5-2G, the included angle alpha1 between the pressure side inner wall of the groove and the bottom surface of the groove is 15-75 DEG, and the diameter D1 of the cooling hole is 0.8-1.5G.

[0035] Example 1

[0036] A blade tip structure with improved cooling efficiency, comprising a groove arranged at the blade tip, the pressure side inner wall of the groove is inclined from bottom to top to the camber line of the blade, the suction side of the groove is perpendicular to the groove bottom surface 3, the front end 7 and the rear end 8 of the groove are planes, and the planes are perpendicular to the camber line of the blade; the inside of the blade is provided with three cooling holes 5, the inlet of the cooling hole is located at the blade root, and the outlet of the cooling hole is arranged on the pressure side inner wall of the groove; the flow direction of the cooling working medium output by the cooling hole 5 is the same as the flow direction of the leakage flow, and is used for impact cooling of the groove bottom surface 3.

[0037] The length of the groove L is 0.7C, the ratio of the upper shoulder wall and the lower shoulder wall of the pressure side is w1 / w2=3 / 2, the top width w1 of the pressure side shoulder wall 4 of the groove is 3.0mm, the bottom width w2 of the pressure side shoulder wall 4 of the groove is 2mm, the width w3 of the suction side shoulder wall 5 of the groove is 1mm, the depth d1 of the groove is 1.5mm, the included angle α1 between the pressure side inner wall of the groove and the groove bottom surface is 30°, the diameter D1 of the cooling hole is 1mm, the blade tip gap height G is 1mm, and the blade chord length C is 57mm.

[0038] In the embodiment, the width ratio of the upper and lower shoulder walls of the pressure side dovetail groove is w1 / w2=3 / 2, and the angle between the cooling hole and the groove bottom is 30°. The dovetail groove with impact cooling structure formed by different settings of the width ratio of the upper and lower shoulder walls of the pressure side and the angle of the cooling hole suppresses the formation of the pressure side corner vortex, reduces the heat transfer coefficient on the near pressure side, and reduces the thermal load. The cooling hole on the pressure side shoulder wall sprays cold air to the groove bottom surface for impact cooling, and suppresses the flow of the blade tip leading edge leakage flow, changes the formation of the cavity vortex, not only cools the blade tip wall surface, but also suppresses the leakage flow, improves the cold air utilization rate, and improves the gas-thermal characteristics of the blade tip area.

[0039] Referring to Figure 5 In the embodiment, the inner wall of the groove pressure side is inclined to form a dovetail groove structure, and a cooling hole is arranged on the side wall. The inclined inner wall suppresses the formation of the pressure side corner vortex and reduces the heat transfer coefficient on the near pressure side. The cooling hole on the pressure side dovetail shoulder wall can directly blow cold air to the blade tip high heat transfer area for impact cooling. After impact cooling, the cold air flows to the suction side wall surface under the action of pressure difference for cooling, and the high-speed cold air jet forms an approximate circumferential rib structure to suppress the development of the leakage flow downstream, effectively control the aerodynamic loss caused by the blade tip leakage, improve the heat transfer characteristics of the blade tip area, prolong the service life of the blade, and improve the working efficiency of the turbine blade.

[0040] Numerical simulation results have preliminarily proved that the blade tip structure of the present application can significantly reduce the thermal load of the blade tip (as shown in Figure 6 ).

[0041] Example 2

[0042] A blade tip structure with improved cooling efficiency, comprising a cooling hole formed inside a blade 1, and a groove formed in a blade tip 2, the groove extending from a blade tip to a blade tail, the pressure side and suction side inner walls of the groove being inclined from bottom to top to the camber line of the blade; 8 cooling holes are evenly arranged on the pressure side and suction side of the blade, and the outlets of the cooling holes are located on the pressure side and suction side inner walls of the groove, the cooling holes on the pressure side and suction side inner walls are staggered, the flow direction of the cooling working medium output by the cooling holes 5 is the same as the flow direction of the leakage flow, for impact cooling of the groove bottom surface 3.

[0043] In the present embodiment, the pressure side and suction side inner walls of the groove are inclined from bottom to top to the camber line of the blade, and cooling holes are arranged on the inner walls, the inclined inner walls inhibit the formation of pressure side corner vortex and suction side corner vortex, and the wall surface heat transfer coefficient on the near pressure side and suction side of the groove is reduced; the cooling holes staggered on the pressure side and suction side inner walls can directly blow out cold air to the blade tip groove wall surface for impact cooling, the cold air covers a large area of the blade tip groove wall surface and reduces the wall surface heat load, and the high-speed cold air jet forms an approximate circumferential rib structure to inhibit the development of leakage flow downstream, effectively control the aerodynamic loss caused by blade tip leakage, improve the heat transfer characteristics of the blade tip region, prolong the service life of the blade, and improve the working efficiency of the turbine blade.

[0044] Embodiment 3

[0045] A blade, the top of the blade being provided with the above blade tip structure.

[0046] Embodiment 4

[0047] A turbine engine, the rotor blade of the turbine engine being provided with the above blade tip structure.

[0048] The above is only to illustrate the technical idea of the present application, and cannot limit the protection scope of the present application, any modification made according to the technical idea of the present application on the basis of the technical scheme, falls within the protection scope of the claims of the present application.

Claims

1. A blade tip structure having improved cooling efficiency, characterized by, The groove is formed in the tip clearance leakage flow area, extends from the tip to the tail of the blade, the pressure side inner wall of the groove is inclined to the mean camber line of the blade from bottom to top, the suction side inner wall of the groove is perpendicular to the bottom surface of the groove, the outlet of the cooling hole of the blade is arranged on the pressure side inner wall, the flow direction of the cooling working medium output by the cooling hole is the same as the flow direction of the leakage flow, and the cooling working medium is used for impact cooling of the bottom surface of the groove. The front end and the rear end of the groove are planes and are perpendicular to the mean camber line of the blade. The included angle between the bottom surface of the groove and the pressure side inner wall is 15°-75°. The inclined inner wall inhibits the formation of the pressure side corner vortex and reduces the heat exchange coefficient on the near pressure side; the cooling hole on the dovetail groove shoulder wall blows out the cold air directly to the tip high heat exchange area for impact cooling, the cold air flows to the suction side for wall cooling under the action of the pressure difference after the impact cooling, and the high-speed cold air jet forms an approximate circumferential rib structure to inhibit the development of the leakage flow to the downstream.

2. The blade tip structure with improved cooling efficiency according to claim 1, wherein The top width of the pressure side shoulder wall of the groove is 2-4G, the bottom width of the pressure side shoulder wall of the groove is 0.5-1.5G, and G is the tip clearance height.

3. A blade, characterized in that The top of the blade is provided with the tip structure with improved cooling efficiency according to any one of claims 1-2.

4. A turbine engine characterized by, The rotor blade of the turbine engine is provided with the tip structure with improved cooling efficiency according to any one of claims 1-2.

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