Rapid prediction method for wall heat flux within gap induced by supersonic flow based on log-linear distribution law

Rapid and precise prediction of the thermal environment within the surface gaps of supersonic vehicles can be used to assess localized high heat flux and thermal intrusion, ensuring the thermal stability and safety. In this study, the log-linear distribution law of wall heat flux within gap induced by supersonic flow is theoretically deduced. Based on this characteristic, the heat flux distribution within the gap can be divided into two regions: the nonlinear region and the log-linear region. The nonlinear region is located at the top of the gap, influenced by the strong shear of the mainstream, where vortex velocities are high, and heat transfer is jointly dominated by convection and conduction. The log-linear region corresponds to the deep-seated stokes flow area within the gap, approaching a quasi-stagnation state, and can be approximated as a pure conduction process. Subsequently, the impact of Mach number, angle of attack, and aspect ratio on the dividing positions of the two regions and local heat flux are investigated by numerical simulation. The results indicate that the dividing positions between the two regions under different conditions are primarily influenced by the shear strength of the mainstream. Meanwhile, local heat flux is simultaneously influenced by both the dividing position and stagnation heat flux. With a clear understanding of the mechanism of parameters affecting heat flux, a rapid prediction model for log-linear region heat flux was established. The model exhibits exceptionally high fitting accuracy and can be employed to guide the thermal sealing design of gaps on supersonic vehicles.