Experimental and Numerical Investigation of High Load Turbine Blade Tip Cavity Structures

Abstract

Leakage flow loss is an important factor affecting the aerodynamic efficiency of turbines. In this paper, experimental and numerical computational studies were used to investigate three different tips of a highly loaded turbine rotor. The single-cavity tip formed by squealers was considered as the original structure. Based on this, two improved structures were developed, namely, cavity winglet tip (CWT) and double-cavity combined winglet tip (DCWT). Five-hole probe and oil flow visualization were used for experimental studies, and numerical calculations were used to analyze vortex system structure and loss development. It was found that the double-cavity combined winglet tip structure can effectively change the vortex structure inside the cavity and reduce the leakage flowrate. At the same time, the aerodynamic performance was optimized by 4%.