Physico-Mathematical Modeling of the Advanced Active Thermal Protection Method for High-Speed Aerospace Vehicle Structures
V. F. Formalev, S. A. Kolesnik, B. A. Garibyan
Abstract
Abstract A new method is proposed for thermal protection of high-speed aircraft (HSA) nose cones, which is based on injection of a coolant with a strong temperature dependence of its dynamic viscosity (changing by 3‒5 orders of magnitude upon temperatures variation from 300 to 500 K) into the gas-dynamic boundary layer. This dependence allows the design of an automatic system for coolant delivery through channels formed in the structure onto the blunt cone surface, since, as the temperature of the structure increases, the coolant viscosity drops sharply, its fluidity increases, and, at a constant pressure differential between the coolant reservoir and the surface, its delivery to the boundary layer increases, forming a protective liquid film that flows and evaporates, injecting vapor into the boundary layer. As the structural temperature drops, the coolant delivery decreases. The efficiency of this thermal protection method is related to the fact that, first, the HSA surface temperature does not exceed the coolant evaporation temperature and, second, the HSA structure operates without mass loss and maintains its geometry. Numerical results have been obtained for the mass flow rate, mass evaporation rate of the liquid coolant film, its temperature, and the HSA structure temperature.