Heat transfer to a flat plate with arbitrary surface catalysis under partially dissociated nitrogen freestream.

The article focuses on investigating the effects of chemical nonequilibrium and finite-rate catalytic wall reactions on heat flux to a flat plate in high-enthalpy shock tunnel experiments simulating partially dissociated hypersonic nitrogen flows. Using computational fluid dynamics (CFD) with the HyFLOW solver developed by the China Aerodynamics Research and Development Center, the study introduces a Damköhler number (Da_c) to characterize the nonequilibrium degree of catalytic surface reactions and derives a predictive formula for catalytic heating distinct from classical calorically perfect gas models. Theoretical results are validated against numerical simulations across varying Mach numbers, Reynolds numbers, and dissociation degrees, showing good agreement and highlighting the importance of accounting for viscous interaction effects near the leading edge of the flat plate. These findings provide a framework for more accurate aeroheating predictions in shock tunnel experiments and support ground-to-flight extrapolation methodologies for chemical nonequilibrium hypersonic flows.