Heat Transfer Engineering, Vol.31, No.1, 70-82, 2010
Multimode Heat Transfer in a Near-Space Environment
A thermal circuit model has been used to examine the heat transfer characteristics of an idealized station-keeping near-space platform. Forced convection, natural convection, and thermal radiation heat transfer mechanisms have been included in the model. The contributions of forced and natural convection were incorporated using previously published correlations. Thermal radiation heat transfer was assumed to be the result of direct solar flux, planetary infrared, and planetary albedo thermal radiation contributions. Model closure was obtained by using data from the 1976 standard atmosphere model, an empirical model for wind speed and models for variable thermophysical properties. The results of the scaling analysis indicate that, as expected, natural convection may be neglected above certain altitudes. The results also show the relative importance of thermal radiation and forced convection as the dominant heat transfer mechanisms with respect to altitude. Results from parametric studies of albedo and surface material effects are also included.