A Large Meridian Expansion Variable Geometry Turbine with Orthogonal Adjustable Vanes

Abstract

The invention aims to provide a large meridional expansion variable-geometry turbine with orthogonal adjustable stator blades. The large meridional expansion variable-geometry turbine comprises a large meridional expansion endwall case and a hub. Adjustable stator blades in the front and rotor blades in the rear are evenly mounted in the peripheral direction between the large meridional expansion endwall case and the hub. Upper and lower rotating shafts are disposed on upper and lower end faces of each adjustable stator blade, respectively; the axes of the upper and lower rotating shafts are coaxial and have different axial diameters; the upper rotating shaft is embedded in the large meridional expansion endwall case; the lower rotating shaft is embedded in the hub. The rotor blades are mounted on the hub. The adjustable stator blades are orthogonal blades, each having a blade body orthogonal to an endwall. The hub comprises a convex-concave joint segment matching with the adjustable stator blades. The large meridional expansion variable-geometry turbine has the advantages that gap endwall flow can be reconstructed, gap endwall loss can be reduced, endwall gap height can be slowly changed with changes in working condition, and the characteristic of variable working conditions can be improved further.

Description

technical field [0001] The invention relates to a turbine of a gas turbine. Background technique [0002] Gas turbines often operate at off-design conditions, where turbine efficiency is significantly reduced. Variable geometry turbine technology can effectively improve the efficiency of gas turbines in variable working conditions, and adjusting the installation angle of turbine vanes is an effective variable geometry method. In the adjustable vane structure of the prior art, in order to ensure that the turbine vane can rotate, there must be a gap between the upper and lower end walls of the vane, which causes the leakage loss of the vane and seriously affects the turbine efficiency; and for large meridian expansion variable geometry turbine , the large meridional expansion angle tends to decelerate the flow near the end wall, thicken the boundary layer, weaken the ability of the fluid to resist the lateral pressure gradient, and make it easier to form secondary flow, which...

AI Technical Summary

Problems solved by technology

So far, for the unfavorable problems of large meridian expansion variable geometry turbines, the existing technology has not considered combining the control of blade tip clearance leakage with the reorganization of the flow at the end area of ​​large meridian expansion, let alone improving the large meridian expansion. Variable working condition characteristics of expanding variable geometry turbine

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