Transpiration cooling with phase change under extreme thermal environment: comparative analysis between numerical coupling simulations and high-temperature gas flow wind tunnel experiments

Transpiration cooling has become one of the most promising thermal protection approaches to overcome the extreme aerodynamic heat load for hypersonic flight. However, numerical coupling simulation method between the freestream gas flow and the porous flow considering phase change during transpiration cooling process using liquid coolant is still limited to accurately predict the cooling performance, especially further validating it by experimental method. In this work, a multi-region numerical coupling simulation strategy is firstly developed to investigate the phase-change transpiration cooling. To validate the numerical simulation method, an experimental platform using combustion gas flow is established to perform the transpiration cooling test using liquid coolant under the free-flow with Mach 1.36 and static temperature of 2800 K. Two typical porous structures are employed to investigate the transpiration cooling performance, and comparative analysis between the numerical simulation results and the combustion-gas flow experimental results are conducted. The results show that, the accuracy of the proposed coupled numerical method can be verified with the maximum deviation of stagnation temperature prediction less than 6%. The effect of nosecone curvature on cooling effectiveness is further revealed by numerical method, indicating that increasing curvature can enhance both stagnation-region cooling performance and coolant film coverage efficiency downstream. This work provides a quantitatively comparative analysis of the transpiration results between numerical simulations and combustion-gas flow experiments, offering a valuable reference for the future design of transpiration cooling system with phase change.