Variable geometry turbine with vortex elimination hole structures in front of movable blades

Abstract

The invention provides a variable geometry turbine with vortex elimination hole structures in the front of movable blades. The variable geometry turbine comprises a case and hubs, wherein adjustable static blades and the movable blades are uniformly installed between the case and the hubs in the circumferential direction, upper rotating shafts and lower rotating shafts are installed on the upper end faces and the lower end faces of the adjustable static blades respectively, the upper rotating shafts are embedded into the case, the lower rotating shafts are embedded into the correspondinghub, the movable blades are installed on the correspondinghub, the curved vortex elimination hole structures communicating with blade pressure surfaces and suction surfaces are formed in the front of the movable blades in the radial direction, and load distribution of blade profiles of the movable blades is of a rear-loading type. According to the variable geometry turbine, separation vortexes in the front of the blades can be reduced or even eliminated underthe off-design condition so that aerodynamic loss in channels of the movable blades can be obviously reduced, transverse differential pressure in front of the blades can be reduced underthe design condition, formation of secondary flow can be delayed, and then loss of the secondary flow can be reduced. The variable geometry turbine hasgood characteristic underall operating conditions on the whole.

Description

technical field [0001] The invention relates to a variable geometry turbine, in particular to a variable geometry turbine with a vortex elimination hole structure at the front of the moving blade. Background technique [0002] Gas turbines often operate at off-design conditions, where turbine efficiency is significantly reduced. The variable geometry turbine technology can effectively adjust and optimize the matching between various components of the gas turbine, and improve the acceleration and deceleration characteristics of the gas turbine and the performance of low working conditions. Adjusting the installation angle of the turbine vane is an effective variable geometry method. [0003] In the variable geometry turbine of the prior art, under low operating conditions, the adjustable vane is turned off to reduce the working fluid flow and output power, while the movable vane downstream of the adjustable vane tends to operate at a relatively large positive angle of attack...

AI Technical Summary

Problems solved by technology

[0003] In the variable geometry turbine of the prior art, under low operating conditions, the adjustable vane is turned off to reduce the working fluid flow and output power, while the movable vane downstream of the adjustable vane tends to operate at a relatively large positive angle of attack, causing dynamic The front side of the blade suction separates the flow; in the start-up and acceleration conditions, the adjustable vane is opened to increase the surge margin of the gas turbine compressor and the residual power of the gas generator, while the downstream moving vane tends to be at a relatively large negative angle of attack running, resulting in severe separation flow on the pressure surface of the rotor blade

According to the research, the three-dimensional separation vortex field on the rotor blade suction surface caused by the adjustable stator blade will lead to a more significant drop in the efficiency of the variable geometry turbine, and the drop rate is as high as 5%.

[0004] In order to reduce the adverse effects caused by the large angle of attack flow at the leading edge of the variable geometry turbine blade, domestic and foreign researchers have proposed that the variable geometry turbine blade should adopt the aerodynamic design principle of a large negative angle of attack, and then guide the design of the blade profile; However, up to now, there have been no related reports that can effectively reduce the adverse effects of high angle of attack flow at the leading edge of variable geometry turbine rotor blades.

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