Film Cooling of a Convex Surface with Coolant Supply Through Two Rows of Transverse Trenches

The results of computer simulation of the efficiency of film cooling on a convex cooled surface when supplying a coolant through inclined round holes in “shallow” trenches are presented. The calculations were performed using the commercial package ANSYS CFX in the range of change of the injection parameter from 0.55 to 1.93, with the SST model of turbulence being used in the calculations. On the convex surface, a symmetry of the adiabatic efficiency of film cooling with respect to the longitudinal axis is observed demonstrating the stability of the cooling air in the near-wall layer. At small injection parameters, a transverse nonuniformity is observed with maxima of the local cooling efficiency behind the film cooling holes, whereas with an increase in the injection parameter, the transverse unevenness is reduced behind both trenches. It is shown that for the configuration under study, the efficiency of film cooling on a convex surface is approximately the same as on a flat surface, which is due to the acceleration of the main flow and the positive pressure gradient along the channel height.