PRELIMINARY ANALYSIS OF THE CAPABILITIES OF A COMPOSITE SLAB FOR AN ADVANCED HEAT-SINK DESIGN

摘要

Presented here are the results of a numerical analysis of the capability of a composite slab of beryllium oxide (BeO) and beryllium (Be) to absorb the heating associated with the reentry of a high performance ballistic missile. The trajectory considered corresponds to a ballistic factor (W/CDA) equal to 2, 000 psf, to a reentry velocity of 20, 000 fps, and to a reentry angle of 20°. The thermal properties of the metals were considered temperature dependent; surface radiation was included. An implicit system of numerical integration was applied.nThe numerical results indicate that the maximum permissible heat transfer rates for the trajectory are obtained with a relatively thin slab of beryllium oxide. The addition of beryllium to this slab may be required for structural and thermal shock considerations but does not greatly improve the heat-sink capabilities.nThe permissible values of the heat transfer parameter are applied to a slender cone with a 20° half angle and with a spherical cap of 0. 25 ft. nose radius. The laminar and turbulent heat transfer data for such a cone were available. It is shown that for laminar flow no heat transfer reduction is required on the cone while for turbulent flow a reduction to l/2 is required. The possibility of utilizing a mass transfer system in ord.er to reduce the heat transfer on the spherical cap and on the cone in the case of turbulent flow is briefly discussed.