Dynamics of Changes in the Rate and Mechanism of Destruction of a Composite Material Based on Carbon and Ceramics

The results of studying the destruction of composite materials are given, with the main attention being paid to the vicinity of the stagnation point, since the maximum heat flux develops in this vicinity. A strong dependence of the viscosity of the melt on the temperature is shown, which leads to the requirement that the film motion and energy-conservation equations need to be solved jointly. It is postulated that the consideration of heating unsteadiness is of fundamental importance for polymeric materials, mostly because it takes a longer time for melt coatings to establish a quasi-steady-state regime with the same mass-entrainment rates as for other heat-shield materials. With a change in the flow regime in the interface layer, shear forces (friction and pressure gradient) generally increase less than the heat-transfer coefficient. The main trends in the destruction of polymeric materials are analyzed. It is shown that the entrainment rate substantially depends on the stagnation enthalpy of the gas flow. The results of numerical calculations show that the process of nonequilibrium mass entrainment can be calculated by engineering methods.