Numerical study of pin-fin cooling on gas turbine blades

Abstract

This paper describes a numerical study of internal pin-fin cooling performance of a trailing-edge cutback configuration for gas turbine blade. The study was performed at two steps: first, to validate simulation results from an existing TE cutback cooling with staggered pin-fin arrays inside the cooling passage against experimental measurements. Three structured meshes were used for grid convergence and to evaluate film-cooling effectiveness and discharge coefficient; second, to investigate the pin-fin cooling performance with various blowing ratios. Simulations were performed by keeping the same initial and boundary conditions as the corresponding experiment. The results show that validation can be considered acceptable by keeping quality grid and its resolution in near wall regions. Both computational data of the adiabatic film-cooling effectiveness and the discharge coefficient are in fairly good agreement with the test data. The pin-fin array has important roles to promote flow turbulence activity inside the cooling passage, in addition to increase surface areas for heat transfer. Hence the turbulence intensity is more pronounced due to the existence of the pin-fin and it is concomitant with the coolant flow inside the wedge-shaped duct.