ESTIMATION OF AEROTHERMAL ENVIRONMENT AT THE BASE REGION OF A LAUNCH VEHICLE
Interaction of jets during the ascent phase of the launch vehicle pose a serious heat transfer problem at the base region of the vehicle. The jets coming out from two or more sources at the base of the vehicle leads to a complex flow field, especially when they are interacting with each other. The complexity of the flow develops from shock-shock interactions, shear layer interactions of the jet stream and atmospheric air, the reverse flow from jets, turbulent flow mixing and inherent unsteadiness of the flow at the base region. Due to jet interaction, reverse flow occurs,
which increases the base pressure and temperature resulting in severe thermal environment. Numerical simulations were carried out over a typical launch vehicle having two boosters and a core to understand the flow existing at the base region. The study is focused on the interaction of jets from the boosters and the thermal environments prevailing at the base region of the vehicle.
Analysis show that due to jet interaction, especially at
higher altitudes, the base thermal environments become severe. Using the flow field data the base heat flux has been computed and subsequently compared with flight measured data. This paper gives in detail the jet simulation of a typical launch vehicle, its interaction, the severe thermal environment prevailing at the base region and the methodology for the estimation of heat flux at the base region and the validation with flight measurements.