Heat and mass transfer characterization of gap and sealed porous media under hypersonic airflow

Due to structural and functional requirements, the surfaces of hypersonic vehicles often incorporate gaps. External hypersonic flow environments facilitate heat and mass transfer through these gap structures and into the cabin interior. Porous sealing components are typically employed to seal the gap structures, yet current thermal sealing designs lack theoretical guidance. This study investigates the heat and mass transfer processes at hypersonic vehicle gap structures. Numerical simulations analyse the fluid-structure interaction heat transfer within the gap structure over 1200 s. Compared to scenarios that ignore structural deformation, deformation has a significant impact on heat and mass ingress, increasing them by 47.3% and 17.8%, respectively. Thus, deformation cannot be neglected for small-scale gap structures. By varying structural and operating parameters, this study elucidates the influence mechanisms of flow pressure, flow static temperature, Mach number, angle of attack, and initial gap width on heat and mass transfer within the gap flow. A porous medium seal component filled to a specific depth within the gap achieves thermal insulation efficiency of up to 88.3% and mass sealing efficiency of up to 92%. Building upon this, the study further investigates the effects of porosity and permeability on sealing performance. This research provides theoretical guidance for the design and optimization of gap thermal sealing structures for long-endurance hypersonic vehicles.