Thermal loading of spent rocket stage structure during ballistic descent

Abstract

The results of a numerical calculation of the aerodynamic heating of a spent rocket stage structural elements during
its controlled descent along a ballistic trajectory are presented. The influence of the initial trajectory parameters on the
specific convective and radiant heat fluxes is determined. To assess the thermal loading of the spent rocket stage
structure, the parameter of the total specific energy flux is introduced. It has been established that in the range of initial
speeds of the spent rocket stage from 1800 m/s to 2600 m/s, an increase in the initial speed by 200 m/s leads to an
increase in the specific convective flow by an average of 11 % for the tail compartment and the fuel tank and by 5 % for
the oxidizer tank. The share of the specific radiant energy flux withdrawn from the surface in relation to the specific
convective energy flux is from 0,15 to 0,19 for the tail compartment, from 0,12 to 0,15 for the fuel tank and not more
than 0,009 for the oxidizer tank. Empirical dependencies are proposed for the preliminary stage of assessing the
temperature state of the spent rocket stage structure when moving on a ballistic trajectory. The error of the calculation
results according to the proposed dependencies does not exceed 12 %.