Numerical investigation of particle deposition in film-cooled blade leading edge

Abstract

This study numerically investigates film-cooling performance and particle trajectories in AGTB (two rows of cylindrical holes equipped on suction side (SS) and pressure side (PS) of the leading edge, respectively) turbine cascade. Particle deposition on a turbine blade is analyzed by calculations of capture efficiency and impact efficiency. The turbulent flow is modeled by the Realizable k-ε turbulence model, and the discrete phase model (DPM) with user-defined functions (UDFs) is used to simulate the particle motions. An invasion efficiency is proposed to analyze the possibility of particle invasion into the film hole. Comparisons of various particles with diameters of 1 µm, 5 µm, 10 µm, 20 µm, and 50 µm, respectively, are conducted for four blowing ratios (0.53, 0.93, 1.31, 1.63) and three inlet flow angles (123°, 133°, and 143°). It is observed that with a small inlet flow angle and a large blowing ratio, the capture efficiency on the PS decreases. It is found that smaller particle size results in lower invasion efficiency, and larger particles are more likely to invade into the film-cooling hole especially at a low blowing ratio.