A Slot Jet Film Cooling Structure for Turbine End Wall

Abstract

The invention relates to a slot jet air film cooling structure for the end wall of a turbine, which belongs to the cooling field of the end wall of the guide vane of a gas turbine; the cooling structure is provided with a jet air film hole on the step surface of the backward step upstream of the end wall made. The jet angle is parallel to and abuts against the end wall surface. In order to ensure the structural strength, the inlet diameter of the gas film hole is required to be D f Less than two-thirds of the step height. The slot jet holes parallel to the surface of the end wall only have a tangential jet velocity, which avoids the loss of cooling air caused by direct injection of a large amount of cooling air into the main flow; in addition, the high momentum slot jet cooling air greatly weakens the horseshoe vortex at the leading edge of the blade, making The jet flow better adheres to the wall. At the same time, the cold air jet flow through the slot also breaks through the gas backflow dead zone formed downstream of the step, avoiding a high temperature area downstream of the step, and forming a gas film to protect the surface of the turbine end wall.

Description

technical field [0001] The invention belongs to the cooling field of the turbine vane end wall of a gas turbine, and in particular relates to a slot jet air film cooling structure for the turbine end wall. Background technique [0002] With the improvement of gas turbine performance, the turbine inlet temperature continues to increase. Nowadays, the inlet temperature of some advanced engines has reached more than 2000K. Therefore, effective cooling measures must be used to protect the end wall of the turbine guide vane to avoid the end wall from being exposed to high temperature. corrosion and damage. Film cooling is one of the typical cooling methods used on end walls. Air film cooling is to inject a low-temperature airflow at a certain angle near the wall to isolate the high-temperature combustion body from the wall to achieve cooling protection for the heated wall. [0003] Arranging cylindrical air film holes on the surface of the end wall is a common cooling method, w...

AI Technical Summary

Problems solved by technology

Leakage cooling structures with different leak groove widths, jet angles, and distances from the leak groove to the leading edge of the blade have been proposed successively, but the jet tangential velocity has not been significantly improved due to the momentum loss caused by the lift of the jet gas.

The slot jet is tangent to the surface of the end wall, which solves the problem of jet gas elevation, but the relatively large slot gap reduces the jet flow of the cold air, and the improvement of the cooling efficiency of the turbine end wall is not obvious

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