Temperature Prediction Methodology for a Missile Flying at Low and High Altitudes

Missiles fly at supersonic and hypersonic speeds. Airframe forms the aerodynamic shape of the missile and houses several components essential for mission with suitable structural supports. The missile airframe is subjected to high rate of heating caused by kinetic heating due to very high vehicle speed. Heat transfer analysis of the missile airframe structure is required to be performed for wall temperature predictions to select the material of missile construction with suitable wall thickness and also to check design adequacy for ensuring the safe operation in the severe thermal environment experienced during flight. This paper describes the methodology of evaluation of heat flux distribution over missile wall, prediction of missile wall temperature distribution considering airframe as heat sink and validation of the methodology against flight data. Heat flux has been estimated using classical engineering methods for both stagnation as well as off-stagnation regions including the effect of angle of attack, rarified flow, thermal radiation and solar heating. Transient three dimensional heat transfer analysis with convective and radiative boundary conditions has been carried out for predicting the missile wall temperature profiles. Parametric study has been carried out, considering various parameters such as material of construction, thickness and time duration. The prediction methodology has been validated and a close match is observed between the predictions and flight data.