Numerical Study on Effects of Jet Nozzle Angle and Number on Vortex Cooling Behavior for Gas Turbine Blade Leading Edge

Abstract

Vortex cooling is a promising blade cooling technique for its excellent heat transfer and pressure loss control behavior. In this paper, the proper vortex chamber model is utilized for vortex cooling mechanism analysis. Three dimensional viscous steady Reynolds Averaged Navier-Stokes (RANS) equations are adopted to explore the influences of jet nozzle angle and number on vortex cooling flow and thermal performance. Turbulence model verification and grid independence analysis are conducted to determine the suitable turbulence model and mesh number for calculations. Results show that due to obvious mass flux enhancement downstream, stronger axial impact effect will generate, leading to the high Nusselt number region downstream deflection towards outlet. As jet nozzle angle increases from α=60° to α=120°, the static pressure ratio increases for the upstream region and decreases for the downstream region, and the total pressure loss ratio increases. The rotation movement and heat transfer intensity will decrease when jet nozzle angle changes away from α=90°. The air jetting velocity decreases and the static pressure ratio increases with the increasing jet nozzle number. When jet nozzle angle increases from 1 to 11, the total pressure loss ratio decreases and the heat transfer intensity increases at first and then decreases.