Viscous flow of silica and its effects on ablation of carbon/silicon carbide composites as a liquid-fueled rocket engine nozzle

Viscous flow behavior of silica melts on an uncooled carbon/silicon carbide composite nozzle was investigated in the combustion environment of a liquid-fueled rocket engine simulated by an ethanol/oxygen combustion gas generator. The results showed that severe ablation of the nozzle throat were attributed to flow downstream and blow-off of the silica scales derived from vigorous oxidation of the silicon carbide matrix. The viscous flow behavior of the silica was determined by both the intrinsic viscosity of silica melts and the external aerodynamic forces of the combustion gas.