Effects of Squealer Width and Height on Aerodynamic Performance of Tip-Leakage Flow of Cavity Tips

Abstract

The scraping vortex (SV) is the dominant flow structure in the cavity tip gap. As the basic geometric parameters, it is of great significance to explore the influence mechanism of the squealer width and height on the evolution of SV. In this study, the influence mechanism of the squealer width and height on the SV evolution and aerodynamic performance in a typical transonic high-pressure turbine stage is investigated numerically, which is obtained by analyzing the influences of squealer width and height on the pressure distribution in the tip region, SV characteristics, and tip-leakage performance. The results show that decreasing squealer width or increasing squealer height reduces the transverse pressure gradient (TPG) in the cavity gap, which draws SV to the suction side squealer (SSS) and makes it easier to flow out of the cavity. Moreover, a thinner or a higher squealer leads to a smaller streamwise pressure gradient (SPG) in the cavity, and then the SV intensity enhances and size reduces accordingly. Extensive analysis reveals that there are optimum values of squealer width and height producing the most aerodynamic performance benefits.