Database Driven Computational Investigation of Aerothermodynamics And Automatic Grid Generation of Atmospheric Entry Vehicles

The kinetic energy of a space vehicle as it enters the atmosphere is converted into heat. How much of the heat goes into the vehicle depends on the trajectory flown, size and shape of the vehicle. The choice of the trajectory is actually limited by the realities of vehicle dimensions - lift, drag and the mass. The purpose of this research was to investigate the aerothermodynamics of atmospheric vehicles and to provide a computational database framework for trajectory information for such vehicle. Grids can be generated automatically for reentry vehicles given the geometry of the vehicles and a CFD tool can be employed to demonstrate the automatic capability of predicting the flow field around the vehicle. A platform independent GUI based tool HyperSphere has been developed and integrated to a planetary probe database to study aerodynamic heating and to do trajectory analysis. A comprehensive database of different atmospheric entry vehicles has been developed from the Planetary Mission Entry Vehicles Manual and also from other web sources. The database comprises vehicle dimensions, trajectory data, and aero-thermal data for many different ballistic entry vehicles. Comparative data analysis capability is achieved through a Relational Database Management System. HyperSphere GUI provides capabilities to choose from a list of flight vehicles or enter trajectory and geometry information of a vehicle in design such that Geometry centered grids can be generated automatically. An empirical model of the standard atmosphere GAME: General Atmospheric Model for Earth to calculate pressure, density, temperature, Reynolds number and speed of sound as a function of altitude has been developed. GRAM models have been used for MARS, Venus, Titan and Neptune atmospheres. The vehicular Flight path angle as a function of velocity and altitude to compute the trajectory of the vehicle as it traverses through the atmosphere has been modeled. A fourth order Runge-Kutta integration is employed for trajectory calculations. Transport properties such as coefficient of viscosity, thermal conductivity have been modeled using the Sutherland’s law. Empirical correlations for stagnation point heat transfer have been modeled using Fay-Riddell and Sutton-Grave correlations.