Analysis on the mechanism of evolutionary process of counter-rotating vortex pair in film cooling based on hybrid thermal lattice Boltzmann method

Massively parallel simulation applying multiple graphic processing units (multi-GPUs) is carried out to perform a deep going investigation on the counter-rotating vortex pair (CVP) in single-jet film cooling based on hybrid thermal lattice Boltzmann method (HTLBM) and large eddy simulation (LES). The mechanism of evolutionary process of CVP and its influence on the Reynolds shear stress and cooling performance are studied in detail. In the simulation, the blowing ratio of coolant jet is kept to BR = 0.5 and the inclined angle is α = 30°. The Reynolds number based on the crossflow velocity and diameter of the jet hole is Re = 4000. The secondary anti-kidney vortices, tertiary kidney vortices and quaternary anti-kidney vortices are captured, which increase the spanwise coolant-film coverage on the surface of the bottom wall. The size of the primary CVP significantly influences the distribution of Reynolds shear stress Ruv and Ruw. The vortex strength of the primary CVP and the characteristics of minor counter-rotating vortices mainly impact on the streamwise and spanwise distribution of film cooling effectiveness, respectively.