Analytical Transient Heat Transfer Model for Active Cooling Channels

Transient heat transfer analysis on a scramjet inlet with convective cooling channels is presented. To accurately model heat transfer transiency while saving computational time, lumped-capacitance resistor-capacitor circuit elements are developed. Temperature dependent superalloys such as Inconel 718, C103, and GRX-810 are compared in transient response along with other active cooling materials. Parametric studies reveal that thermal response scales nonlinearly with channel length and skin thickness, while decreasing nonlinearly with increased land thickness and coolant mass flow. Additionally, the model is validated against two-dimensional finite element analysis. This comparison highlights a critical limitation in one-dimensional modeling: the omission of thermal constriction resistance at the skin-land boundary. Consequently, the one-dimensional model is found to over-predict temperatures during an increase in heat flux and under-predict during a decrease in heat flux at the cost of computational time.