Film cooling characteristics with sunk or lifted upstream wall

Film cooling characteristics has been investigated numerically with the aid of FLUENT software for the sunk or the lifted upstream wall from the slot injection exit. In this study, with the fixed blowing ratio of 1 and the fixed coolant injection angle of 30 .deg., the downstream flow field and the downstream temperature field were examined in terms of velocity vector, turbulent kinetic energy, temperature contours, and downstream wall temperature. Upstream wall was sunk or lifted from 1d to 5d(d=slot width). The result shows that the up-1d upstream wall has the best film cooling performance. This is due to the fact that the up-1d upstream wall configuration reduces velocity gradient just enough to minimize the turbulent mixing between the mainstream and the coolant just off the slot exit