A turbine moving blade tip with combined truss structure

Abstract

The invention provides a blade tip with a combined prismatic frustum structure for a turbine moving blade. A plurality of prism type concave cavities are formed in the blade tip of the turbine movingblade from the leading edge to the tailing edge of the turbine moving blade in an array manner; an inverted prismatic frustum structure with a heeling angle is combined on the bottom surface of each prism type concave cavity; a prism and prismatic frustum combined concave cavity is formed; the specific value of the maximum depths of the prism type concave cavities to the height of the turbine moving blade is 0.5 to 4 percent; the specific value of the depth of the prismatic frustum structure to the depths of the prism type concave cavities is in the range of 0.5 to 3. According to the blade tip, as the side wall surfaces of the bottom prismatic frustum have the heeling angel consistent with the directions of vortexes, the development of the vortexes in the prism type concave cavities are promoted; the scales and intensities of the vortexes are increased. On one hand, the intrinsic dissipation effects, on clearance energy, of the vortexes are enhanced; on the other hand, the parts, extending into upper clearances, of the vortexes in the concave cavities are increased; the more effective pneumatic interception effect is generated to the flow in the upper clearances, and the obstruction effect on the leakage flow in the clearances is enhanced.

Description

technical field [0001] The invention belongs to the technical field of turbines, and in particular relates to a turbine moving blade top with a combined truss structure. Background technique [0002] There must be a certain tip clearance between the rotating blades and the casing inside the turbine. Due to the existence of the tip clearance, the tip clearance leakage flow must be formed under the action of the lateral pressure gradient on both sides of the blade pressure surface and suction surface. On the one hand, separation flow will be generated inside the gap due to wall shearing; on the other hand, the leakage flow out of the gap forms a leakage vortex on the suction side, which is mixed with the mainstream fluid such as the upper channel vortex and blade radial fluid, and finally leads to the flow in the blade end region. Complicated, the cascade loss increases, which has a great impact on the efficiency and overall performance of the turbine. Especially in recent ye...

AI Technical Summary

Problems solved by technology

On the one hand, due to the high fluid velocity in the gap, the vortex formed by part of the prismatic cavity is suppressed in the cavity to form a dead zone of air flow, which weakens the inhibition effect of the prismatic cavity tip structure on the leakage flow; on the other hand, the prismatic cavity The bottom surface is directly impacted by the leaking fluid and will bear a large thermal load

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