LAUSR

High-temperature-induced chemical non-equilibrium effects critically influence the prediction of aerodynamic performance, assessment of thermal environments, and optimization of hypersonic vehicle designs. The local Damköhler number (DaL) is proposed as a dimensionless parameter for quantifying the degree of chemical non-equilibrium in flow fields. Based on this parameter, a derived zoning criterion DaL1 is further established to segment the flow field into chemical equilibrium, non-equilibrium, and freezing zones, with corresponding zone-specific chemical kinetics models implemented through a zoning algorithm. Numerical simulations of cylindrical and blunt flat plate flows validate the algorithm and assess the effects of freestream conditions on zoning outcomes. Results indicate that chemical equilibrium zones predominantly form near the upstream stagnation points, while extensive chemical freezing zones develop in the downstream region. Furthermore, a simplified method based on zoning criteria for simulating chemical non-equilibrium flow fields has been proposed. This method has been validated to enhance computational efficiency while ensuring accuracy in calculations.