Investigation of Unsteady Film Cooling Characteristics on the Hot Streak Migration Path

The migration of heat streaks in the turbine stage will cause high local temperature of the blade, which will affect the service life of the blade. In present paper, the unsteady gas film cooling characteristics on the migration path of the heat streaks are studied by numerical simulation of the entire turbine cascade. The results show that: The periodic change of the flow and temperature field near the film cooling hole is the same as the main stream, and the time of the hot streak pass through leading edge is about 1/4 of the whole period. The gas cooling jet of the leading edge can break up the high temperature fluid of hot streak, due to of which the temperature of hot streak fluid decreases. The cooling efficiency of cooling gas film with pressure pulsation is lower than that of conventional film cooling, and the cooling efficiency increases with the increase of pulse frequency.