Aerodynamic Heating Rate Evaluati on of Mach 5 Hypersonic Airplanes

Conceptual study of thermo protection structure of the hypersonic aircraft was carried out. Cruising speed of the reference aircraft is Mach 5 at the altitude of 24 km and liquid hydrogen is used as propellant of the engine and vehicle coolant. Precooled turbojet engines and ramjet engines are used as main propulsion system of the aircraft. Heating rate around HST which flies at Mach 5 was from 5kW/m 2 to 30kW/m 2 . For these heating rate vehicles, most suitable TPS was selected by 1-dimensional heating analysis. For heating rate of 5kW/m 2 , 10kW/m 2 and 20kW/m 2 , Titanium multiwall TPS become the lightest. For heating rate of 30kW/m 2 and 40kW/m 2 , SA honeycomb TPS became the lightest. To estimate the heating rate on lower and aft side of the vehicle where engine fuel rich combustion gas flows, engine combustion test was carried out. Heating rate on the vehicle was measured by two ways that is to estimate by history of wall thermocouples, and to estimate by flame temperature measured by radiation two-color method. Heating rates of both measurement agreed with accuracy of 15%. Assuming the TPS wall temperature of 1350K, heating rate on the vehicle is predicted from 350 kW/m 2 to 1190 kW/m 2 .