Turbine moving blade with discrete slit inclined cold air injection structure

Abstract

The invention discloses a turbine moving blade with a discrete slit inclined cold air injection structure, which comprises a blade body, one side of the blade body is a pressure side, the other side of the blade body is a suction side, a blade inner cooling cavity is arranged in the blade body, and the blade inner cooling cavity is provided with a cold air outlet; a pressure side shoulder wall is arranged at the upper end of the pressure side of the blade body; a suction side shoulder wall is arranged at the upper end of the suction side of the blade body; 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 in an acute angle mode and provided with cold air inlets, and the cold air inlets communicate with cold air outlets of the blade inner cooling cavities. According to the invention, the discrete air film holes at the blade top of the groove are optimally designed into the discrete slits for obliquely spraying cold air to the pressure side at a low angle, and the blade top cooling structure with high leakage suppression and low thermal load is innovatively developed.

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] In order to ensure the safe operation of aviation turbines, there must be a certain radial gap between the blade tip and the stationary casing, and the high-temperature combustion gas from the combustion chamber forms a leaky flow through this 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 prominent local overheating, causing blade tip ablation and reducing the safety and reliability of the turbine.

[0003] In response to the problem of turbine tip clearance leakage and tip ablation, some studies have been conducted to improve the structure and layout of the air film holes, such as patents CN204552835U and CN217176719U. There are also similar patents CN112240228A that use intermittent slots to improve the blade tip cooling effect and aerodynamic performance. However, when the turbine inlet temperature exceeds 2000K, the high heat load and easy ablation of the blade tip are still the problems that need to be solved for turbine moving blades. It is still important to develop an efficient cooling blade tip structure with high leakage suppression and low blade tip heat exchange.

[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 cold air flow rate, the discrete air film holes on the groove blade top are optimized to be discrete slits with an inclination angle. The cold air outflow angle is changed from 90° to 20° inclined toward the pressure side. The optimized blade tip cooling structure can effectively reduce the leakage loss of the blade tip clearance and the heat load of the blade tip, thereby improving 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 discrete slit inclined cooling air injection structure to solve the problems of large tip gap leakage and tip ablation of existing turbine blades. Discrete slits are arranged at the bottom of the groove tip to inject cooling air obliquely toward the inner wall surface of the pressure side shoulder wall, thereby improving the turbine gas thermal performance.

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

[0007] A turbine rotor blade with a discrete slit inclined cold air injection 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 the inner blade cold cavity is arranged with a cold air outlet; a pressure side shoulder wall is arranged at the upper end of the pressure side of the blade body, and a suction side shoulder wall is arranged at the upper end of the suction side of the blade body; 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 constitute the groove tip of the blade body; a discrete slit is inclined at an acute angle near the pressure side of the groove bottom, and the discrete slit is provided with a cold air inlet, and the cold air inlet is connected with 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 38.2 mm, and the axial chord length is C ax It is 28.7mm.

[0009] The height h of the pressure side shoulder wall and the suction side shoulder wall is 1% to 5% of the height S of the blade body (1), and the value range is 0.41 to 2.05 mm.

[0010] The width w of the pressure side shoulder wall and the suction side shoulder wall is 1% to 2% of the height S of the blade body (1), and the value range is 0.41 to 0.82 mm.

[0011] The distance δ from the discrete slit to the inner edge of the pressure side shoulder wall is 1% to 3% of the height S of the blade body, and the value range is 0.41 to 1.23 mm.

[0012] The distance l from the starting point of the discrete slit to the starting point of the leading edge of the blade body is 5% of the axial chord length C of the blade body. ax , the value is 1.435mm.

[0013] The number of discrete slit sections is 3, 4 or 5. If there are 3 sections, the slit length L is 6.20 mm, if there are 4 sections, the slit length L is 4.65 mm, if there are 5 sections, the slit length L is 3.72 mm, each discrete slit is spaced 1.0 mm apart, the width d of the discrete slit ranges from 0.1 to 0.3 mm, the cold air outflow angle, i.e., the angle a between the discrete slit and the bottom of the groove ranges from 10° to 20°, and the depth f of the discrete slit 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 discrete slits are obtained by cutting using laser cutting technology.

[0016] 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 flows out of the slit obliquely to hit the inner wall of the pressure side shoulder wall, the pressure side angular vortex in the groove is lifted, and part of the cold air is drawn into the pressure side angular vortex to increase the vortex size, and the pressure side angular vortex develops to the casing to reduce the effective flow area of ​​the leakage flow; the cold air that is not drawn into the pressure side angular vortex flows up to the casing along the wall, preventing the high-temperature combustion gas from entering the tip gap and flowing out of the pressure side shoulder wall in the opposite direction, and the shoulder wall is effectively cooled, and the high-temperature combustion gas forms flow separation above the pressure side shoulder wall to produce a better flow resistance effect. The discrete slits at the bottom of the groove spray cold air obliquely toward the pressure side, which can effectively cool the blade tip and inhibit gap leakage, greatly reduce the blade tip heat transfer coefficient and heat load, and avoid blade tip ablation.

[0017] Beneficial effects: Compared with the prior art, the present invention has the following advantages:

[0018] 1. The present invention designs the air film holes as discrete slits. Experimental verification combined with numerical research shows that under the same cold air flow rate, the cold air ejected from the discrete slits at a low angle acts on the groove flow field to hinder the high-temperature combustion gas from entering the tip gap, reducing the tip gap leakage by 4.51% to 12.33% and the total pressure loss of the blade cascade by 7.12% to 8.40%.

[0019] 2. Compared with the grooved blade tip, the present invention reduces the distribution area of ​​high heat transfer coefficient on the blade tip, reduces the average heat transfer coefficient on the blade tip by 9.86% to 15.95%, and reduces the average heat transfer coefficient on the shoulder wall surface by 18.28%, thus solving the problem of blade tip ablation.

[0020] 3. In the present invention, the cold air ejected from the discrete slits prevents the high-temperature combustion gas from entering the tip gap and flows out of the pressure side shoulder wall in the opposite direction. The cold air coverage effect of the shoulder wall is improved, the cooling efficiency of the blade tip is improved, the heat load is reduced, the thermal performance of the turbine is improved, and the working reliability is guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the model structure of the present invention;

[0022] Figure 2 It is a schematic cross-sectional view of the model of the present invention;

[0023] Figure 3 This is a schematic diagram of the axial cross-sectional streamline distribution of an embodiment of the present invention;

[0024] Figure 4 The heat transfer coefficient distribution diagram of the blade tip and the groove blade tip of the embodiment of the present invention;

[0025] 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 groove bottom, 5 is the discrete slit, and 6 is the cold cavity in the blade. DETAILED DESCRIPTION

[0026] The present invention will be further explained below in conjunction with the accompanying drawings.

[0027] like Figure 1 and Figure 2 As shown, a turbine rotor blade with a discrete slit inclined cold air injection structure of the present 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, a blade inner cold cavity 6 is arranged in the blade body 1, and the blade inner cold cavity 6 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 suction side shoulder wall 3 is arranged at the upper end of the suction side of the blade body 1; a groove bottom 4 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 4 constitute the groove tip of the blade body 1; a discrete slit 5 is inclined at an acute angle near the pressure side of the groove bottom 4, and the discrete slit 5 is provided with a cold air inlet, and the cold air inlet is connected to the cold air outlet of the blade inner cold cavity 6.

[0028] The height S of the blade body 1 is 41.0 mm, and the chord length C x The axial chord length is 38.2 mm, and the axial chord length is C ax It is 28.7mm. The height h of the pressure side shoulder wall 2 and the suction side shoulder wall 3 is 1% to 5% of the height S of the blade body 1, and the value range is 0.41 to 2.05mm. The width w of the pressure side shoulder wall 2 and the suction side shoulder wall 3 is 1% to 2% of the height S of the blade body 1, and the value range is 0.41 to 0.82mm. The distance δ from the discrete slit 5 to the inner wall edge of the pressure side shoulder wall 2 is 1% to 3% of the height S of the blade body 1, and the value range is 0.41 to 1.23mm. The distance l from the starting point of the discrete slit 5 to the starting point of the leading edge of the blade body 1 is 5% of the axial chord length C of the blade body. ax , and the value is 1.435mm. The number of discrete slits 5 is 3, 4 or 5. If there are 3 sections, the length L of each discrete slit 5 is 6.20mm, if there are 4 sections, the length L of each discrete slit 5 is 4.65mm, if there are 5 sections, the length L of each discrete slit 5 is 3.72mm, and each discrete slit 5 is 1.0mm apart. The width d of the discrete slit 5 ranges from 0.1 to 0.3mm, the cold air outflow angle, i.e., the angle a between the discrete slit 5 and the groove bottom 4 ranges from 10° to 20°, and the depth f of the discrete slit 5 along the cold air outflow direction ranges from 2.0 to 3.0mm. The vertical depth g of the discrete slit 5 and the cold cavity 6 in the blade ranges from 2.0 to 5.0mm, and the connection form with the meandering inner cooling structure is designed according to the actual situation.

[0029] The discrete slits 5 are cut by laser cutting technology.

[0030] 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 groove blade tip of the embodiment of the present invention. Compared with the groove blade tip, the tip clearance leakage of the present invention is reduced by 4.51% to 12.33%, and the total pressure loss of the blade cascade is reduced by 7.12% to 8.40%; the high heat transfer coefficient distribution area of ​​the blade tip is reduced, the average heat transfer coefficient of the blade tip is reduced by 9.86% to 15.95%, and the average heat transfer coefficient of the shoulder wall surface is reduced by 18.28%, the heat transfer of the shoulder wall is weakened, and the tip ablation problem is solved. After the discrete slit inclined injection cooling structure is applied to the groove blade tip, the turbine gas thermal performance is improved, and the working life and safety reliability of the blade are guaranteed.

[0031] 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 discrete slit inclined cooling air injection structure, characterized in that: The blade body (1) comprises a blade body (1), one side of the blade body (1) being a pressure side and the other side being a suction side, a blade inner cold cavity (6) being arranged in the blade body (1), and a cold air outlet being arranged in the blade inner cold cavity (6); a pressure side shoulder wall (2) being arranged at the upper end of the pressure side of the blade body (1), and a suction side shoulder wall (3) being arranged at the upper end of the suction side of the blade body (1); a groove bottom (4) being 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 (4) forming a groove blade tip of the blade body (1); and a discrete slit (5) being inclined at an acute angle near the pressure side of the groove bottom (4), and the discrete slit (5) being provided with a cold air inlet, and the cold air inlet being connected to the cold air outlet of the blade inner cold cavity (6).

2. The turbine rotor blade with a discrete slit inclined cooling air injection 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 38.2 mm, and the axial chord length is C ax It is 28.7mm.

3. The turbine rotor blade with a discrete slit inclined cold air injection 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% to 5% of the height S of the blade body (1), and the value range is 0.41 to 2.05 mm.

4. The turbine impeller with a discrete slit inclined cooling air injection structure according to claim 1, characterized in that: The width w of the pressure-side shoulder wall (2) and the suction-side shoulder wall (3) is 1% to 2% of the height S of the blade body (1), and the value range is 0.41 to 0.82 mm.

5. The turbine impeller with a discrete slit inclined cooling air injection structure according to claim 1, characterized in that: The distance δ from the discrete slit (5) to the inner wall edge of the pressure side shoulder wall (2) is 1% to 3% of the height S of the blade body (1), and the value range is 0.41 to 1.23 mm.

6. The turbine impeller with a discrete slit inclined cooling air injection structure according to claim 1, characterized in that: The distance l from the starting point of the discrete slit (5) to the starting point of the leading edge of the blade body (1) is 5% of the axial chord length C of the blade body. ax , the value is 1.435mm.

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

8. The turbine impeller with a discrete slit inclined cooling air injection structure according to claim 1, characterized in that: The depth g in the vertical direction between the discrete slit (5) and the cooling cavity (6) in the blade is in the range of 2.0 to 5.0 mm.

9. The turbine impeller with a discrete slit inclined cooling air injection structure according to claim 1, characterized in that: The discrete slits (5) are obtained by cutting using laser cutting technology.

Images