Leakage groove air film cooling structure used for turbine end wall and provided with protrusions and application of leakage groove air film cooling structure

Abstract

The invention discloses a leakage groove air film cooling structure used for a turbine end wall and provided with protrusions and application, and belongs to the technical field of cooling of turbine guide vane end walls of gas turbines. A leakage groove structure and a leakage groove air supply cavity are arranged on the upstream portion of the turbine end wall, and the leakage groove structure is located at an outlet of the leakage groove air supply cavity and serves as a cooling airflow channel. A plurality of protruding structures are evenly distributed on the inner wall of the side, away from the turbine blade, of the leakage groove structure in the spanwise direction, the protruding structures correspond to the front edge of the suction face of the turbine blade 4 in a one-to-one mode, so that most cooling airflow flows out of a channel between the adjacent protruding structures, and an air film is formed on the cooling wall face. Cooling airflow B flowing out of a leakage groove flows in the main flow direction under driving of main flow airflow A, and an air film is formed in a cooling wall face area; the structure can greatly weaken the influence of the pressure gradient C on the leaked cold air jet on the cooling wall surface, and secondly, the coverage area of the cold air of the leaked groove on the cooling wall surface is further uniformized.

Description

technical field [0001] The invention belongs to the technical field of cooling the end wall of the guide vane of a gas turbine, and in particular relates to a gas film cooling structure and application of a leakage groove with protrusions on the end wall of a turbine. 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] The cooling method of the end wall...

AI Technical Summary

Problems solved by technology

However, in subsequent studies, it was found that the air film formed by the cylindrical hole cannot provide cooling protection for the area between the holes.

With the development of end wall film cooling technology, it is found that the extension of the fan-shaped film holes in the span direction can significantly improve the cooling effect of the wall in the region between the holes, but the film holes in the upstream region of the leading edge of the guide vane produce poor cooling characteristics , so many scholars improve the film cooling effect upstream of the end wall by using the thermal gap structure between the end wall and the combustion chamber, that is, the leakage flow. However, in the cascade channel due to the geometric structure of the pressure surface and the suction surface The spanwise pressure gradient has a greater impact on the leaked cold air, which makes the cold air more inclined to flow out from the suction side slot of the leakage groove and gather to the area near the suction surface, such as figure 2 shown [1]

Subsequently, scholars at home and abroad have successively proposed leakage cooling structures with different leak groove broadband, jet angle, and distance from the leak groove to the leading edge of the blade. [2-4] , but affected by the spanwise pressure gradient at the inlet of the cascade, a large amount of leaked cold air is still pushed to the suction side area, which reduces the cooling efficiency of the pressure side end wall area, resulting in supercooled and uncooled air on the end wall surface. distribution phenomenon, which is extremely detrimental to the thermal protection of the turbine end wall

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