Coupled heat transfer characteristics on gas-solid reacting interface in carbon-oxygen dissociating environment for spacecraft entry flow

Abstract

High-enthalpy dissociating aerodynamic environment during high-speed spacecraft entries brings new challenges to the prediction of heat transfer characteristics on the surface of thermal protection system. This study numerically dealt with the coupling modeling of chemically reacting interface in carbon-oxygen dissociating environment in order to accurately and reliably predict the Mars entry heating load. Computational fluid dynamics, computational heat transfer and interface balance with proper coupling strategy were involved in the coupling algorithm to take into account the surface catalysis, material ablation and structural thermal response. Numerical simulation shows that the interfacial reaction model has influences on coupling evolution by exchanging various patterns of heat transfer on the interface, including that from temperature gradient, that caused by chemical reaction, and that carried by the injection kinetic energy. The types and energy barriers of interfacial reaction were found to change the aerodynamic heating enhancement and its evolution over coupling time, which is the most remarkable difference from the perfect gas result. Gas-solid interaction involving interfacial reaction exhibits three distinct temporal intervals: the initial, developing and fully developed stages, and the chemical dynamics and heat transfer characteristics vary at different temporal scales. Related research provides important technical support for the design of thermal protection system for space vehicles.

Keywords

• heat transfer
• reacting flow
• numerical simulation
• hypersonic
• carbon-oxygen dissociation
• coupling
• surface catalysis
• material ablation