Flow and heat transfer characteristics of porous plate in combustion chamber

Abstract

Transpiration cooling is an important active thermal protection technology in advanced spacecraft. This work aims to study the flow and heat transfer mechanisms to accurately predict the transpiration cooling performance. Consequently, this work employs a real gas model coupled with a combustion model to establish a model for transpiration cooling of porous plates in the combustion chamber. The flow and heat transfer mechanism of porous plate transpiration cooling is thoroughly discussed, and the impact of the Joule-Thomson effect on the temperature of porous transpiration is considered. The evolution pattern of transpiration cooling characteristics under trans-critical conditions is studied. The results demonstrated that heating and cooling coexist in the porous plate. The lowest temperature is 8 K less than the inlet temperature of the coolant, and along the axial direction, the temperature declines first and then rises. When the porosity is 0.12 and the pore diameter is 60 μm, the temperature non-uniformity of the porous plate reaches its peak. The cooling effectiveness of CO₂ coolant is 20% higher than the other four coolants, while the blowing ratio of CO₂ coolant is 36.62% higher than the minimum blowing ratio of CO. The research outcomes can help guide the choice of porous plate parameters, coolant types, and coolant inlet temperature, thereby improving the cooling performance and thermal stability of transpiration plates.