Squealer Geometry Effects on Aerothermal Performance of Tip-Leakage Flow of Cavity Tips

摘要

In a high-pressure turbine, the tip-leakage flow reduces the efficiency of the turbine and results in high metal temperatures on the blade tip. Quite a few studies showed that cavity tips produced lower loss than a flat tip. Also, cavity tips are widely used in industrial gas turbines. This paper focuses on cavity-tip geometries. Both experimental and numerical methods are used to study the aerothermal performance of the tip-leakage flow of cavity tips. The effects of the squealer height and thickness are investigated. The current research aims to understand the change of the flow physics and its impact on the loss mechanism and heat transfer as the squealer geometry changes. The flow pattern over the tip, the tip-leakage loss, and the heat transfer of the tip are investigated. Reducing the squealer thickness reduces the tip-leakage loss. The squealer height has a complex effect on the tip-leakage loss. Reducing the thickness of the squealers reduces the average heat transfer coefficient and the heat load of the tip. Increasing the height of the squealer also reduces the heat transfer coefficient of the tip. However, due to the increase in the surface area of the tip, the increase of the squealer height increases the heat load of the tip.