Comparison of aerodynamic heating models and optimization of radius for launch vehicle fairing

This study systematically investigates the aerodynamic heating characteristics of payload fairings in launch vehicles using a domestically developed computational fluid dynamics (CFD) platform. Through configuration optimization, we achieve a reduction in thermal loads and an enhancement of thermal protection performance. Based on a representative rocket configuration, we conduct a comparative analysis between calorically perfect gas (laminar/turbulent) and thermally perfect gas (turbulent) models to assess differences in thermal environment predictions, elucidating the coupling mechanism between real gas effects and turbulent transport. The results indicate that the thermally perfect turbulent model provides higher accuracy under high-temperature and high-Mach-number conditions. Simulations across six hemispherical nose radii (0.05–4.5m) reveal a nonlinear relationship between stagnation point heat flux, total heat load, and curvature, identifying 2.5m as the optimal nose radius for minimizing thermal loads.