Effect of film cooling/regenerative cooling on scramjet engine performances

A new film cooling model based on experimental results on the compressible mixing layer and on an analysis using the TBL is introduced. The model is applied to a quasi-1D simulation of a scramjet. In an engine employing a combination of film cooling and regenerative cooling, coolant flow rate of the engine slightly exceeded the stoichiometric flow rate, even at high flight Mach numbers, and had the best specific impulse and system pressure performances. These advantages were achieved by an increase in the volume flow rate and a decrease in the velocity difference between the main flow and the coolant, both due to an increase in the film coolant temperature. The effective cooling system with a combination of film cooling and regenerative cooling was also advantageous with regard to avoidance of excess cooling of the engine wall. (AIAA)