Method for Correlating Discharge Coefficients of Film-Cooling Holes

A method for correlating the discharge coefficient of a 30-deg inclined, cylindrical film-cooling hole over a broad range of engine-like conditions is presented. The flow conditions considered are the pressure ratio across the hole (up to 2.25), the crossflow Mach number at the hole entry side (up to 0.6), and the crossflow Mach number at the hole exit side (up to 1.2). The effects of baseline hole flow as well as hole entry and exit crossflows on discharge coefficient were correlated independently of each other. Therefore, the discharge coefficient of any combination of pressure ratio, external Mach number, and internal Mach number flow case can be predicted. A comparison of predicted and measured discharge coefficients reveals the capability of the method proposed