One-Dimensional Aerodynamic Heating and Ablation Prediction

Abstract

A simplified method is developed to calculate aerodynamic heating, ablation, and structural temperature response for a body traveling at high speeds. Mach number, altitude, and angle of attack are used as a function of time. Compressibility effects are considered by using Eckert's reference temperature approach. Convective aerodynamic heating is calculated using external flow relations. Local pressure values are found through modified Newtonian theory. An approximate recession method that uses the heat of ablation is coupled to the aerodynamic heating. An in-depth solution accounts for material decomposition; however, it does not include the energy absorption of pyrolysis gases through the material. Reduction in the heat transfer coefficient caused by the transpiring gases is estimated. An Arrhenius equation is used to model the density of the ablative material. The method is examined for the validation of six different cases, and predictions are found to be in good agreement with experimental and analytical results. The verification studies indicate that the methodology is well suited for predicting the ablation and thermal response of a thermal protection system. (c) 2019 American Society of Civil Engineers.