Turbine moving blade of combined groove bottom discrete slit inclined air injection structure and winglet structure

Abstract

The invention discloses a turbine rotor blade combining a groove bottom discrete slit inclined air injection structure and a winglet structure, which comprises a blade body, a pressure side shoulder wall is arranged at the upper end of the pressure side of the blade body, a pressure side shoulder wall tangent plane is arranged on the inner side of the pressure side shoulder wall, and a suction side shoulder wall is arranged at the upper end of the suction side of the blade body. A suction side winglet is arranged on the inner side of the suction side shoulder wall; a groove bottom is arranged between the pressure side shoulder wall and the suction side shoulder wall, and the pressure side shoulder wall, the suction side shoulder wall and the groove bottom form a groove blade tip of the blade body; discrete slits are obliquely formed in the side, close to the pressure, of the groove bottom at acute angles, and cold air inlets of the discrete slits communicate with cold air outlets of the blade inner cooling cavities. The discrete air film holes in the bottom of the blade top of the groove are optimally designed into discrete slits for obliquely spraying cold air to the pressure side shoulder wall at a low angle, and the inner wall surface of the pressure side shoulder wall and the inner wall surface of the suction side shoulder wall are subjected to tangent plane modification and small wing structure process treatment, so that the blade top structure with high leakage suppression and low thermal load is obtained.

Description

Technical Field

[0001] The invention belongs to the field of aeroengines, and in particular relates to a turbine rotor blade suitable for an aeroengine. Background Art

[0002] As an important component of an aircraft engine, the turbine blades are closely related to the working efficiency of the turbine. In order to ensure the safe operation of the aircraft turbine, a certain radial gap must be provided between the blade tip and the stationary casing. The high-temperature combustion gas from the combustion chamber forms a leakage flow through this radial gap. On the one hand, the tip gap leakage increases the flow loss at the gap, resulting in a reduction in the aerodynamic performance of the turbine. On the other hand, the high-temperature combustion gas scours the blade tip, increasing the heat load on the blade tip and causing local overheating, which causes oxidation and ablation of the blade tip and reduces the safety and reliability of the turbine.

[0003] In view of the large leakage of the blade tip clearance and the phenomenon of blade tip ablation, there have been studies to improve it from the perspective of the groove shoulder wall shape and the structure and layout of the air film hole, such as patents CN204552835U and CN217176719U. There are also similar patents CN112240228A that use intermittent slots to improve it. The blade tip rib structure and the layout of the air film hole are optimized to improve the cooling effect and aerodynamic performance of the blade tip; Patent CN115169032A proposes a turbine blade design method with a blade tip groove and a winglet composite structure, and patent CN105179022B designs a turbine blade with a blade tip rib wing structure, which is also intended to reduce the tip clearance leakage, improve the heat transfer performance of the blade tip, and extend the working life of the turbine. Although the above patents are conducive to the improvement of the tip aero-thermal performance, when the turbine inlet temperature exceeds 2000K, the large tip heat load and easy ablation are still the problems that need to be solved urgently for turbine blades. It is still important to develop a high-efficiency cooling blade tip structure with high leakage suppression and low blade tip heat transfer.

[0004] The present invention takes the first-stage moving blade of the GE-E3 high-pressure turbine as the prototype. Under the same cold air outflow area and mass flow rate, the discrete air film holes at the bottom of the groove are optimized to be discrete slits with an inclined angle. The cold air outflow angle is changed from vertical 90° to 20° inclined to the pressure side. The inner wall edge of the pressure side shoulder wall is trimmed from the leading edge to the trailing edge to the outer side of the shoulder wall. The inner wall edge of the suction side shoulder wall is extended from the leading edge to the trailing edge to the inner side of the shoulder wall to form a winglet structure. The optimized blade tip cooling structure can significantly reduce the tip gap leakage and the heat load of the blade tip, and improve the gas-thermal performance and working reliability of the turbine. Summary of the invention

[0005] The purpose of the present invention is to provide a turbine blade with a combined slot bottom discrete slit inclined jet structure and a winglet structure to solve the problems of large blade tip heat load and easy ablation in existing turbine blades. The discrete slits at the slot bottom of the groove blade tip are inclined to jet cold air toward the inner wall of the pressure side shoulder wall, and the winglet on the inner side of the suction side shoulder wall is combined to improve the gas thermal performance of the turbine.

[0006] To achieve the above object, the present invention adopts the following technical solution:

[0007] A turbine rotor blade with a combined slot bottom discrete slit inclined jet structure and a winglet structure comprises a blade body, one side of the blade body is a pressure side, and the other side is a suction side, an inner blade cold cavity is arranged in the blade body, and a cold air outlet is arranged in the inner blade cold cavity; a pressure side shoulder wall is arranged at the upper end of the pressure side of the blade body, a pressure side shoulder wall section is arranged on the inner side of the pressure side shoulder wall, a suction side shoulder wall is arranged at the upper end of the suction side of the blade body, and a suction side winglet is arranged on the inner side of the suction side shoulder wall; a slot bottom is arranged between the pressure side shoulder wall and the suction side shoulder wall, and the pressure side shoulder wall, the suction side shoulder wall and the slot bottom constitute the groove tip of the blade body; a discrete slit is inclined at an acute angle near the pressure side of the slot bottom, and the cold air inlet of the discrete slit is connected to the cold air outlet of the inner blade cold cavity.

[0008] The height S of the blade body is 41.0 mm, and the chord length C x The axial chord length is 38.2mm. ax It is 28.7mm.

[0009] The height h of the pressure side shoulder wall and the suction side shoulder wall is 1.0% to 5.0% of the blade body height S, and the value range is 0.41 to 2.05 mm; the width w of the pressure side shoulder wall and the suction side shoulder wall is 1.0% to 2.0% of the blade body height S, and the value range is 0.41 to 0.82 mm.

[0010] The inner wall surface of the pressure side shoulder wall is smoothly cut from the leading edge to the trailing edge at an inclination angle a of 80° to 85° to form a pressure side shoulder wall section.

[0011] The suction side winglet is located on the inner side of the suction side shoulder wall, with a height m being 1 / 2 of the shoulder wall height h, a width n being 1.0% to 2.0% of the blade body height S, and a value range of 0.41 to 0.82 mm. The suction side winglet is obtained by linearly scanning from the leading edge to the trailing edge of the suction side shoulder wall.

[0012] The distance δ from the discrete slit to the inner edge of the pressure side shoulder wall is 1.0% to 3.0% of the blade height S, with a value range of 0.41 to 1.23 mm. The distance l from the starting point of the discrete slit to the starting point of the leading edge of the blade is 5.0% of the axial chord length C of the blade. ax , the value is 1.435mm.

[0013] The number of segments of the discrete slits is 3, 4 or 5. If there are 3 segments, the length p of each discrete slit is 6.20 mm, if there are 4 segments, the length p of each discrete slit is 4.65 mm, if there are 5 segments, the length p of each discrete slit is 3.72 mm, and the interval between adjacent discrete slits is 1.0 mm; the width d of the discrete slits ranges from 0.1 to 0.3 mm, the cold air outflow angle, i.e., the angle β between the discrete slits and the bottom of the groove, ranges from 10° to 20°, and the depth f of the discrete slits along the cold air outflow direction ranges from 2.0 to 3.0 mm.

[0014] The depth g of the discrete slit in the vertical direction to the cold cavity in the blade ranges from 2.0 to 5.0 mm.

[0015] The pressure side shoulder wall section and the discrete slits are obtained by cutting using laser cutting technology.

[0016] The suction side winglet and the suction side shoulder wall are obtained by integral casting.

[0017] The principle of the present invention is as follows: the present invention arranges discrete slits on the pressure side of the groove bottom of the groove blade tip, and the cold air obliquely flows out of the slit and hits the inner wall of the pressure side shoulder wall. The pressure side corner vortex in the groove is lifted, and part of the cold air is drawn into the pressure side corner vortex to increase the vortex size. The pressure side corner vortex develops to the casing and reduces the effective flow area of ​​the leakage flow. The cold air that is not drawn into the pressure side corner vortex flows up the wall to the casing, hindering the high-temperature combustion gas from entering the tip gap and producing the effect of reversely flowing out of the pressure side shoulder wall. The inclined section obtained by shaping the inner wall edge of the pressure side shoulder wall promotes the flow of cold air to the pressure side shoulder wall, enhancing the cold air coverage effect. The high-temperature combustion gas produces flow separation on the pressure side shoulder wall, further hindering the inflow of high-temperature combustion gas. The small wing on the inner side of the suction side shoulder wall increases the flow resistance of the leakage flow, and the leakage flow forms flow separation on the suction side shoulder wall surface, inhibiting the leakage of the tip gap, and reducing the heat transfer coefficient and heat load of the blade tip. Compared with the groove blade top, the discrete slit inclined jet structure at the groove bottom combined with the winglet structure on the inner side of the suction side shoulder wall can effectively cool the blade tip, inhibit tip gap leakage, and solve the problem of blade tip ablation.

[0018] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0019] 1. The groove bottom air film hole of the present invention is designed as a discrete slit. It is found that under the same cold air flow rate, the cold air ejected from the discrete slit at a low angle acts on the groove flow field to prevent the high-temperature combustion gas from entering the blade tip gap. The tip gap leakage is reduced by nearly 12.5%, and the total pressure loss is reduced to nearly 5.0%.

[0020] 2. The present invention has the effect of effectively suppressing the leakage of the blade tip clearance, reducing the distribution area of ​​the high heat transfer coefficient on the blade tip, reducing the average heat transfer coefficient on the blade tip by 10.17% to 16.46%, and reducing the average heat transfer coefficient on the groove shoulder wall surface by 29.38%. The heat transfer of the shoulder wall is weakened, and the problem of blade tip ablation is effectively solved.

[0021] 3. In the present invention, the cold air ejected from the discrete slits will block the high-temperature combustion gas from entering the tip gap and will have the effect of flowing back out of the pressure side shoulder wall; the suction side winglet will increase the flow resistance of the gap leakage, and the flow separation on the suction side shoulder wall surface will weaken the heat exchange of the suction side shoulder wall and inhibit the gap leakage, thereby improving the gas-thermal performance of the moving blades and ensuring safety and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the model structure of the present invention;

[0023] Figure 2 It is a schematic cross-sectional view of the model of the present invention;

[0024] Figure 3 This is a schematic diagram of the axial cross-sectional streamline distribution of an embodiment of the present invention;

[0025] Figure 4 The heat transfer coefficient distribution diagram of the blade tip and the groove in the embodiment of the present invention;

[0026] In the figure: 1 is the blade body, 2 is the pressure side shoulder wall, 3 is the suction side shoulder wall, 4 is the pressure side shoulder wall section, 5 is the suction side winglet, 6 is the groove bottom, 7 is the discrete slit, and 8 is the cold cavity in the blade. DETAILED DESCRIPTION

[0027] The present invention will be further explained below in conjunction with the accompanying drawings.

[0028] like Figure 1 and Figure 2 As shown, a turbine rotor blade of the present invention, which combines a groove bottom discrete slit inclined jet structure and a winglet structure, comprises a blade body 1, one side of the blade body 1 is a pressure side, and the other side is a suction side, a blade inner cold cavity 8 is arranged in the blade body 1, and the blade inner cold cavity 8 is provided with a cold air outlet; a pressure side shoulder wall 2 is arranged at the upper end of the pressure side of the blade body 1, and a pressure side shoulder wall section 4 is arranged on the inner side of the pressure side shoulder wall 2, a suction side shoulder wall 3 is arranged on the upper end of the suction side of the blade body 1, and a suction side winglet 5 is arranged on the inner side of the suction side shoulder wall 3; a groove bottom 6 is arranged between the pressure side shoulder wall 2 and the suction side shoulder wall 3, and the pressure side shoulder wall 2, the suction side shoulder wall 3 and the groove bottom 6 constitute the groove tip of the blade body 1; a discrete slit 7 is inclined at an acute angle near the pressure side of the groove bottom 6, and the cold air inlet of the discrete slit 7 is connected with the cold air outlet of the blade inner cold cavity 8.

[0029] The height S of the blade body 1 is 41.0 mm, and the chord length C x The axial chord length is 38.2mm. ax It is 28.7mm.

[0030] The height h of the pressure side shoulder wall 2 and the suction side shoulder wall 3 is 1.0% to 5.0% of the height S of the blade body 1, and the value range is 0.41 to 2.05 mm; the width w of the pressure side shoulder wall 2 and the suction side shoulder wall 3 is 1.0% to 2.0% of the height S of the blade body 1, and the value range is 0.41 to 0.82 mm.

[0031] The inner wall surface of the pressure side shoulder wall 2 is smoothly cut from the leading edge to the trailing edge at an inclination angle a of 80° to 85° to form a pressure side shoulder wall section 4.

[0032] The suction side winglet 5 is located on the inner side of the suction side shoulder wall 3, with a height m being 1 / 2 of the shoulder wall height h, and a width n being 1.0% to 2.0% of the blade body 1 height S, with a value range of 0.41 to 0.82 mm. The suction side winglet 5 is obtained by linearly scanning from the leading edge to the trailing edge of the suction side shoulder wall 3.

[0033] The distance δ from the discrete slit 7 to the inner wall edge of the pressure side shoulder wall 2 is 1.0% to 3.0% of the blade body 1 height S, with a value range of 0.41 to 1.23 mm. The distance l from the starting point of the discrete slit 7 to the starting point of the leading edge of the blade body 1 is 5.0% of the axial chord length C of the blade body 1. ax , and the value is 1.435mm. The number of discrete slits 7 is 3, 4 or 5. If there are 3 sections, the length p of each discrete slit 7 is 6.20mm, if there are 4 sections, the length p of each discrete slit 5 is 4.65mm, if there are 5 sections, the length p of each discrete slit 5 is 3.72mm, and the interval between adjacent discrete slits 7 is 1.0mm; the width d of the discrete slit 7 is in the range of 0.1 to 0.3mm, the cold air outflow angle, that is, the angle β between the discrete slit 7 and the groove bottom 6 is in the range of 10° to 20°, and the depth f of the discrete slit 7 along the cold air outflow direction is in the range of 2.0 to 3.0mm. The depth g of the vertical direction between the discrete slit 7 and the cold cavity 8 in the blade is in the range of 2.0 to 5.0mm.

[0034] The pressure side shoulder wall section 4 and the discrete slits 7 are obtained by cutting using laser cutting technology, and the connection form with the meandering internal cooling structure is designed according to actual conditions.

[0035] The suction side winglet 5 and the suction side shoulder wall 3 are integrally cast and processed.

[0036] Figure 3 is a schematic diagram of axial cross-sectional streamline distribution in an embodiment of the present invention, Figure 4The heat transfer coefficient distribution diagram of the blade tip and the heat transfer coefficient of the groove of the embodiment of the present invention. The present invention optimizes the discrete air film holes at the bottom of the groove blade tip to be discrete slits that spray cold air at a low angle to the pressure side shoulder wall, and performs surface shaping and winglet structure processing on the inner wall surface of the pressure side shoulder wall and the inner wall surface of the suction side shoulder wall, respectively, to obtain a blade tip structure with high leakage suppression and low heat load. Compared with the prototype blade tip, the tip clearance leakage of the present invention is reduced by nearly 12.5%, the total pressure loss is reduced to nearly 5.0%, and the aerodynamic performance of the blade tip is improved; the distribution area of ​​high heat transfer coefficient of the blade tip is reduced, the average heat transfer coefficient of the blade tip is reduced by 10.17% to 16.46%, the average heat transfer coefficient of the shoulder wall surface is reduced by 29.38%, the heat exchange of the shoulder wall is weakened, and the problem of blade tip ablation is effectively solved.

[0037] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A turbine rotor blade with a combined slot bottom discrete slit inclined jet structure and a winglet structure, characterized in that: The invention comprises a blade body (1), one side of the blade body (1) is a pressure side, and the other side is a suction side. The blade body (1) is provided with an inner blade cold cavity (8), and the inner blade cold cavity (8) is provided with a cold air outlet. A pressure side shoulder wall (2) is provided at the upper end of the pressure side of the blade body (1), and a pressure side shoulder wall section (4) is provided on the inner side of the pressure side shoulder wall (2). A suction side shoulder wall (3) is provided at the upper end of the suction side of the blade body (1), and a suction side winglet (5) is provided on the inner side of the suction side shoulder wall (3). A groove bottom (6) is provided between the pressure side shoulder wall (2) and the suction side shoulder wall (3), and the pressure side shoulder wall (2), the suction side shoulder wall (3) and the groove bottom (6) form a groove blade tip of the blade body (1). A discrete slit (7) is provided at an acute angle near the pressure side of the groove bottom (6), and the cold air inlet of the discrete slit (7) is connected to the cold air outlet of the inner blade cold cavity (8).

2. The turbine rotor blade with a combined slot bottom discrete slit inclined jet structure and a winglet structure according to claim 1, characterized in that: The height S of the blade body (1) is 41.0 mm, and the chord length C x The axial chord length is 38.2mm. ax It is 28.7mm.

3. The turbine rotor blade with a combined slot bottom discrete slit inclined jet structure and a winglet structure according to claim 1, characterized in that: The height h of the pressure side shoulder wall (2) and the suction side shoulder wall (3) is 1.0% to 5.0% of the height S of the blade body (1), and the value range is 0.41 to 2.05 mm; the width w of the pressure side shoulder wall (2) and the suction side shoulder wall (3) is 1.0% to 2.0% of the height S of the blade body (1), and the value range is 0.41 to 0.82 mm.

4. The turbine rotor blade with a combined slot bottom discrete slit inclined jet structure and a winglet structure according to claim 1, characterized in that: The inner wall surface of the pressure side shoulder wall (2) is smoothly cut from the leading edge to the trailing edge at an inclination angle a of 80° to 85° to form a pressure side shoulder wall section (4).

5. The turbine rotor blade with a combined slot bottom discrete slit inclined jet structure and a winglet structure according to claim 1, characterized in that: The suction side winglet (5) is located on the inner side of the suction side shoulder wall (3), has a height m that is 1 / 2 of the shoulder wall height h, and a width n that is 1.0% to 2.0% of the blade body (1) height S, with a value range of 0.41 to 0.82 mm, and is obtained by linearly scanning from the leading edge to the trailing edge of the suction side shoulder wall (3).

6. The turbine rotor blade with a combined slot bottom discrete slit inclined jet structure and a winglet structure according to claim 1, characterized in that: The distance δ from the discrete slit (7) to the inner wall edge of the pressure side shoulder wall (2) is 1.0% to 3.0% of the height S of the blade body (1), and the value range is 0.41 to 1.23 mm. The distance l from the starting point of the discrete slit (7) to the starting point of the leading edge of the blade body (1) is 5.0% of the axial chord length C of the blade body (1). ax , the value is 1.435mm.

7. The turbine rotor blade with a combined slot bottom discrete slit inclined jet structure and a winglet structure according to claim 1, characterized in that: The number of the discrete slits (7) is 3, 4 or 5. If there are 3 sections, the length p of each discrete slit (7) is 6.20 mm. If there are 4 sections, the length p of each discrete slit (5) is 4.65 mm. If there are 5 sections, the length p of each discrete slit (5) is 3.72 mm. The interval between adjacent discrete slits (7) is 1.0 mm. The width d of the discrete slits (7) is in the range of 0.1 to 0.3 mm. The cold air outflow angle, i.e., the angle β between the discrete slits (7) and the groove bottom (6), is in the range of 10° to 20°. The depth f of the discrete slits (7) along the cold air outflow direction is in the range of 2.0 to 3.0 mm.

8. The turbine rotor blade with a combined slot bottom discrete slit inclined jet structure and a winglet structure according to claim 1, characterized in that: The depth g in the vertical direction between the discrete slit (7) and the cold cavity (8) in the blade is in the range of 2.0 to 5.0 mm.

9. The turbine impeller with a combined slot bottom discrete slit inclined jet structure and a winglet structure according to claim 1, characterized in that: The pressure side shoulder wall section (4) and the discrete slits (7) are obtained by cutting using laser cutting technology.

10. The turbine rotor blade with a combined slot bottom discrete slit inclined jet structure and a winglet structure according to claim 1, characterized in that: The suction side winglet (5) and the suction side shoulder wall (3) are obtained by integral casting.

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