Convective Heat Transfer In Planetary Gases

Equilibrium convective heat transfer in several real gases was investigated. The gases considered were air, nitrogen, hydrogen, carbon dioxide, and argon. Solutions to the similar form of the boundary-layer equations were obtained for flight velocities to 30,000 ft/sec for a range of parameters sufficient to define the effects of pressure level, pressure gradient, boundary-layer-edge velocity, and wall temperature. Results are presented for stagnation-point heating and for the heating-rate distribution. For the range of parameters investigated the wall heat transfer depended on the transport properties near the wall and precise evaluation of properties in the high-energy portions of the boundary layer was not needed. A correlation of the solutions to the boundary-layer equations was obtained which depended only on the low temperature properties of the gases. This result can be used to evaluate the heat transfer in gases other than those considered. The largest stagnation-point heat transfer at a constant flight velocity was obtained for argon followed successively by carbon dioxide, air, nitrogen, and hydrogen. The blunt-body heating-rate distribution was found to depend mainly on the inviscid flow field. For each gas, correlation equations of boundary-layer thermodynamic and transport properties as a function of enthalpy are given for a wide range of pressures to a maximum enthalpy of 18,000 Btu/lb.