Ball bottom prism and recessed cavity blade tip capable of inhibiting turbine tip leakage flow

Abstract

The invention provides a ball bottom prism and recessed cavity blade tip capable of inhibiting a turbine tip leakage flow. A plurality of prism type recessed cavities are formed in a blade tip of a turbine moving blade from the front edge to the rear edge of the turbine moving blade; a ball bottom structure of which the circular section is internally tangent with the lower bottom surface of the corresponding prism type recessed cavity is assembled at the bottom surface of each prism type recessed cavity; and a ratio of the maximum height of the prism type recessed cavity to the blade height is0.5-4%. A vortex structure is formed in each single recessed cavity and develops to a gap in the single recessed cavity, so that gap kinetic energy is dissipated, at the same time small-size pneumatic barriers are formed, and the leakage flow resistance is increased. Ball bottom prism and recessed cavity assembled structures allow fluid in recessed cavities to act on the ball bottom wall surfacesalong tangent lines basically, and due to smooth arc-shaped transition of the ball bottom structures, the vortex development resistance is reduced, so that vortexes formed in the cavities develop more completely and have larger sizes, the inhibition effect on the flow in the gaps is improved, and a better effect of controlling the tip leakage flow can be further achieved.

Description

technical field [0001] The invention belongs to the technical field of turbines, and in particular relates to a spherical-bottom prismatic concave-cavity blade top for suppressing leakage flow at the top of a turbine. Background technique [0002] The turbine is one of the three core components of the gas turbine engine. Its function is to convert the gas enthalpy of high-temperature and high-pressure gas into gas kinetic energy to do work on the turbine blades, and then output mechanical work. With the increase of the high-performance turbine load, another problem that cannot be ignored: with the increase of the turbine load, the lateral pressure gradient in the cascade channel increases, and the gap between the turbine blade tip and the casing Existence makes the gap leakage flow from the pressure surface to the suction surface of the rotor blade tip more obvious, which brings more complex flow in the top end zone and increases the aerodynamic loss of the turbine. Especia...

AI Technical Summary

Problems solved by technology

With the increase of the high-performance turbine load, another problem that cannot be ignored: with the increase of the turbine load, the lateral pressure gradient in the cascade channel increases, and the gap between the turbine blade tip and the casing Existence, leading to more obvious gap leakage flow from the pressure surface to the suction surface of the moving blade tip, resulting in more complex flow in the top end zone and increasing the aerodynamic loss of the turbine

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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