A turbine rotor blade having a discrete slot inclined jet cooling structure

Abstract

The application discloses a turbine moving blade with a discrete slot inclined jet cold air structure, which comprises a blade body, one side of the blade body is a pressure side, the other side is a suction side, an inner cooling cavity is arranged in the blade body, and a cold air outlet is arranged in the inner cooling cavity; 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; a discrete slot is arranged on the groove bottom near the pressure side in an acute angle, a cold air inlet is arranged in the discrete slot, and the cold air inlet is communicated with the cold air outlet of the inner cooling cavity. The discrete gas film hole of the groove blade tip is optimally designed as the discrete slot for the low-angle inclined jet of the cold air to the pressure side, and the blade tip cooling structure with high leakage suppression and low heat load is innovatively developed.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of aero-engines, and particularly relates to a turbine moving blade suitable for an aero-engine. BACKGROUND

[0002] To ensure the safe operation of the turbine, a certain radial gap is required between the moving blade tip and the stationary casing, and the high-temperature gas from the combustion chamber forms a leakage flow through the gap. The tip clearance leakage increases the flow loss at the gap, resulting in a decrease in the aerodynamic performance of the turbine. On the other hand, the high-temperature gas washes the tip, the tip heat load increases, and the local overheating phenomenon is prominent, causing tip ablation and reducing the safety and reliability of the turbine.

[0003] In view of the turbine tip clearance leakage problem and tip ablation phenomenon, existing research has improved the structure and layout of the film hole, such as patents CN204552835U and CN217176719U. Similarly, patent CN112240228A uses an intermittent slot hole to improve the tip cooling effect and aerodynamic performance to a certain extent. However, in the case where the turbine inlet temperature exceeds 2000K, the tip heat load is large and easy to ablate, which is still a difficult problem to be solved for the turbine moving blade. Therefore, it is still important to develop a high-efficiency cooling tip structure with high leakage suppression and low tip heat exchange.

[0004] The present application takes GE-E3 high-pressure turbine first-stage moving blade as a prototype, and optimizes the discrete film hole of the groove tip to a discrete slit with an inclination angle under the same cold gas outflow area and cold gas flow. The cold gas outflow angle changes from 90° to 20° to the pressure side. The optimized tip cooling structure can effectively reduce the leakage loss of the tip clearance and the heat load of the tip, and improve the aerothermal performance and working reliability of the turbine. SUMMARY

[0005] The present application aims to provide a turbine moving blade with a discrete slit inclined cold gas injection structure to solve the problems of large tip clearance leakage and tip ablation in existing turbine moving blades. By arranging discrete slits on the groove bottom of the groove tip to inject cold gas obliquely to the pressure side shoulder wall inner wall surface, the aerothermal performance of the turbine is improved.

[0006] To achieve the above-mentioned purpose, the present application adopts the following technical solutions:

[0007] A turbine blade with a discrete slit inclined injection cooling gas structure includes a blade body, one side of which is a pressure side and the other side is a suction side. An internal cooling cavity is provided inside the blade body, and a cooling gas outlet is provided in the internal cooling cavity. A pressure side shoulder wall is provided at the upper end of the pressure side of the blade body, and a suction side shoulder wall is provided at the upper end of the suction side of the blade body. A groove bottom is provided 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 the groove tip of the blade body. A discrete slit is opened at an acute angle near the pressure side of the groove bottom, and a cooling gas inlet is provided in the discrete slit. The cooling gas inlet is connected to the cooling gas outlet of the internal cooling cavity of the blade.

[0008] The blade body has a height S of 41.0 mm and a chord length C. x The axial chord length is 38.2 mm, and the value of C is... 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 blade body (1) height S, with a value range of 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 ranges from 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 blade height S, with a value range of 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 discrete slits are 3, 4, or 5 segments. If there are 3 segments, the slit length L is 6.20 mm; if there are 4 segments, the slit length L is 4.65 mm; and if there are 5 segments, the slit length L is 3.72 mm. The discrete slits are spaced 1.0 mm apart. The width d of the discrete slits ranges from 0.1 to 0.3 mm. The cold air outflow angle, i.e., the angle α between the discrete slits and the bottom of the tank, ranges from 10° to 20°. 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 perpendicular to the internal cooling cavity of the blade ranges from 2.0 to 5.0 mm.

[0015] The discrete slits are obtained by laser cutting technology.

[0016] The principle of this invention is as follows: Discrete slits are arranged at the bottom pressure side of the grooved blade tip. Cold air flows obliquely out of the slits and impacts the inner wall of the pressure-side shoulder wall. The pressure-side vortex within the groove is lifted, and some cold air is entrained into the vortex, increasing its size. The pressure-side vortex develops to the casing, reducing the effective flow area for leakage. The cold air not entrained in the vortex flows upwards along the wall to the casing, hindering the high-temperature combustion gas from entering the blade tip gap and flowing out of the pressure-side shoulder wall in the opposite direction. The shoulder wall is effectively cooled, and the high-temperature combustion gas forms flow separation above the pressure-side shoulder wall, producing a good flow obstruction effect. The discreet slits at the bottom of the groove, which spray cold air obliquely towards the pressure side, effectively cool the blade tip, suppress gap leakage, and significantly reduce the blade tip heat transfer coefficient and heat load, thus preventing blade tip ablation.

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

[0018] 1. In this invention, the air film orifice is designed as a discrete slit. Experimental verification combined with numerical research shows that, under the same cold air flow rate, the cold air ejected at a low angle from the discrete slit acts on the groove flow field to hinder the entry of high-temperature combustion gas into the blade tip gap. The leakage of the blade tip gap 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%.

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

[0020] 3. In this invention, the cold air ejected from the discrete slits not only prevents the high-temperature combustion gas from entering the blade tip gap, but also flows out of the pressure side shoulder wall in the opposite direction. This improves the cold air coverage effect on the shoulder wall, increases the blade tip cooling efficiency, reduces the heat load, and improves the turbine's thermal performance while ensuring its operational reliability. Attached Figure Description

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

[0022] Figure 2 This 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 according to an embodiment of the present invention;

[0024] Figure 4 This is a distribution diagram of the heat transfer coefficient at the blade tip and the heat transfer coefficient at the grooved blade tip according to an 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 bottom of the slot, 5 is the discrete slit, and 6 is the internal cooling cavity of the blade. Detailed Implementation

[0026] The application will be further explained in connection with the accompanying drawings.

[0027] As shown in Figure 1 and Figure 2 , a turbine moving blade with discrete slot inclined jet cold air structure of the application comprises a blade body 1, one side of the blade body 1 is a pressure side, the other side is a suction side, the blade body 1 is provided with an internal blade cooling cavity 6, and the internal blade cooling cavity 6 is provided with a cold air outlet; the upper end of the pressure side of the blade body 1 is provided with a pressure side shoulder wall 2, and the upper end of the suction side of the blade body 1 is provided with a suction side shoulder wall 3; 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 form a groove blade tip of the blade body 1; the groove bottom 4 is provided with a discrete slot 5 which is obliquely arranged near the pressure side at an acute angle, and the discrete slot 5 is provided with a cold air inlet which is communicated with the cold air outlet of the internal blade cooling cavity 6.

[0028] The height S of the blade body 1 is 41.0 mm, the chord value C x of the blade body 1 is 38.2 mm, and the axial chord value C ax of the blade body 1 is 28.7 mm. 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. 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. The distance δ from the discrete slot 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. The distance l from the starting point of the discrete slot 5 to the starting point of the leading edge of the blade body 1 is 5% of the axial chord value C ax of the blade body, and the value is 1.435 mm. The number of the discrete slot 5 is 3, 4 or 5, if the number is 3, the length L of each discrete slot 5 is 6.20 mm, if the number is 4, the length L of each discrete slot 5 is 4.65 mm, and if the number is 5, the length L of each discrete slot 5 is 3.72 mm. The discrete slot 5 is spaced by 1.0 mm, the width d of the discrete slot 5 is 0.1 to 0.3 mm, the cold air outflow angle, that is, the included angle a between the discrete slot 5 and the groove bottom 4 is 10° to 20°, and the depth f of the discrete slot 5 along the cold air outflow direction is 2.0 to 3.0 mm. The depth g of the discrete slot 5 in the vertical direction of the internal blade cooling cavity 6 is 2.0 to 5.0 mm, and the communication form of the meandering internal cooling structure is designed according to the actual situation.

[0029] The discrete slot 5 is cut and processed by laser cutting technology.

[0030] Figure 3 is a schematic diagram of the axial cross-sectional streamline distribution of the embodiment of the application, Figure 4The heat exchange coefficient distribution diagram of the blade tip of the embodiment of the present application and the heat exchange coefficient distribution diagram of the concave blade tip. Compared with the concave blade tip, the tip clearance leakage of the present application is reduced by 4.51% to 12.33%, the total pressure loss of the blade cascade is reduced by 7.12% to 8.40%; the distribution area of the high heat exchange coefficient of the blade tip is reduced, the average heat exchange coefficient of the blade tip is reduced by 9.86% to 15.95%, the average heat exchange coefficient of the shoulder wall surface is reduced by 18.28%, the heat exchange of the shoulder wall is weakened, and the blade tip ablation problem is solved. After the discrete narrow slit inclined cold gas injection structure is applied to the concave blade tip, the turbine gas thermal performance is improved, the working life and safety reliability of the blade are guaranteed.

[0031] The above only describes the preferred embodiments of the present application, and it should be noted that, for those skilled in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered within the protection scope of the present application.

Claims

1. A turbine rotor blade having a discrete slot inclined jet cooling air structure, characterized by: The application relates to a blade body (1), one side of the blade body (1) is a pressure side, the other side is a suction side, an inner cooling cavity (6) is arranged in the blade body (1), the inner cooling 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), 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), the pressure side shoulder wall (2), the suction side shoulder wall (3) and the groove bottom (4) form a concave groove tip of the blade body (1); a discrete slit (5) is arranged on the groove bottom (4) near the pressure side and is obliquely arranged at an acute angle, the discrete slit (5) is provided with a cold air inlet, and the cold air inlet is communicated with the cold air outlet of the inner cooling cavity (6). the height of the vane body (1) S is 41.0 mm, the chord value C x is 38.2 mm, the axial chord value C ax is 28.7 mm; The height of the pressure side shoulder wall (2) and the suction side shoulder wall (3) h 1%~5% of the height of the blade body (1) S The value range is 0.41~2.05mm; The width of the pressure side shoulder wall (2) and the suction side shoulder wall (3) w 1%~2% of the height of the blade body (1) S The value range is 0.41~0.82mm; The distance of the discrete slit (5) to the inner edge of the pressure side shoulder wall (2) The discrete slit (5) is obtained by laser cutting technology. 1%~3% of the height of the blade body (1) S The value range is 0.41~1.23mm; The distance from the start of the discrete slit (5) to the start of the leading edge of the blade body (1) l is 5% of the axial chord length value of the blade body C ax and is 1.435 mm. The number of the discrete slits (5) is 3, 4 or 5, if 3, the length of each discrete slit (5) is 6.20mm L , if 4, the length of each discrete slit (5) is 4.65mm L , if 5, the length of each discrete slit (5) is 3.72mm L , the interval between each discrete slit (5) is 1.0mm, and the width of the discrete slit (5) is 0.2mm d , the value range of the outflow angle of the cold air, i.e. the angle between the discrete slit (5) and the groove bottom (4) is 0.1-0.3mm a , the value range of the depth of the discrete slit (5) along the outflow direction of the cold air is 10°-20° f , and the value range of the depth of the discrete slit (5) along the outflow direction of the cold air is 2.0-3.0mm The discrete slit (5) is perpendicular to the depth of the inner cooling cavity (6) of the blade g The value range is 2.0-5.0 mm.

2. The turbine rotor blade having a discrete slot skew injection cooling air structure of claim 1, wherein: ​

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