Prediction of Heatshield Material Performance in an Arcjet
During hypersonic re-entry into the Earth’s atmosphere, a vehicle is likely to experience a severe aero-thermal environment with regards to temperature, pressure and shear stress. The extreme temperatures behind the bow shock may cause the air to dissociate and undergo ionisation. Thermal energy is transferred to the vehicle surface from this hot gas in the form of heat. To manage the vehicles heatshield thermal loading, one method is to use a charring, ablating heatshield. This choice of thermal protection system typically uses a composite material comprising a fibre matrix impregnated with a resin. This type of high performance charring ablator is comprised of carbon fibres and a phenolic resin. Due to the extreme thermal environment seen during re-entry, this carbon phenolic material may ablate at the surface, char in depth and outgas. These three mechanisms reduce the transfer of thermal energy from the flow into the surface by mass removal, internal chemical decomposition and transpiration cooling and thus reduce the thermal energy through to the load bearing structure and interior of the vehicle.
KeywordsRarefaction Wave Wall Condition Sweet Spot Thermal Protection System Transpiration Cool
Unable to display preview. Download preview PDF.