Heat Transfer Measurements over Large Angle Blunt Cones Entering Martian Atmosphere

摘要

In continuation of the efforts to generate experimental data on heat transfer rates for a generic blunt sphere cone used in Mars exploration missions, flying at hypersonic Mach numbers with varying freestream flow enthalpies, we have measured the heat transfer data for a 120 deg blunt sphere cone configuration. Measurements are carried out in the free piston-driven shock tunnel HST3 at a flow Mach number of 5.8 and freestream enthalpy of 3.55 MJ/kg, with carbon dioxide as the test gas. The flow properties in the shock tube are predicted using CHEMKIN and polynomial curve fits (Shomate equation) for the specific heat of the gas species behind the reflected shock wave. Measured heat transfer rates are found to be higher around the geometric stagnation point at 0 angle of attack, and they gradually decreased toward the corner. With the increase in angle of attack, heat transfer rates increased on windward side and decreased on leeward side. The heat transfer rates for a flow enthalpy of 3.55 MJ are found to be higher when compared with data from two lower enthalpies of 0.68 and 1.2 MJ/kg. The percentage of increase of the heat transfer rates around the stagnation point is found to be influenced by the real gas effects at higher freestream enthalpy.