Numerical investigation of transpiration cooling with microchannels for aerospace vehicles' leading edge

Abstract

Transpiration cooling is a promising active thermal protection strategy for hypersonic vehicles; however, its application to sharp leading edges remains challenging due to extreme heat flux, structural fragility, and inefficient coolant distribution. To address these limitations, this study proposes an innovative transpiration cooling configuration incorporating precisely designed microchannels, thereby enhancing both cooling uniformity and mechanical strength. A coupled 1D–3D computational framework is developed to capture the interactions between aerodynamic heating, internal coolant transport, and phase change, balancing numerical efficiency with accuracy. The cooling architecture is divided into two functional channel types: primary control channels that transport and pre-cool the coolant, and distribution channels that enable efficient effusion and protective film formation. Results show that the proposed system substantially reduces peak wall temperature and achieves high cooling efficiency even at Mach 8 flight conditions. Parametric analyses reveal that increasing the coolant mass flow rate from 4.0×10⁻⁶ to 5.0×10⁻⁶ kg/s improves cooling efficiency by nearly 10%, while raising the altitude from 34 km to 38 km further enhances efficiency by more than 13% due to reduced heat flux. An optimal blowing ratio of 6.83% is identified, balancing effective thermal protection with structural reliability. The findings demonstrate that transpiration cooling with microchannels offers a practical and robust solution for sharp leading-edge protection, providing valuable guidance for future reusable hypersonic vehicle design.