Multidimensional Aerothermodynamic Analysis For Planetary Probes using OLAP Cubes

Abstract

SPARTA is an Aerothermodynamic, two dimensional, Structured, Compressible, Navier-Stokes flow-solver which is platform independent, JAVA based and Graphical User Interface driven. A Trajectory framework has been developed to study the aerodynamic heating and to do preliminary trajectory analysis. This framework is linked to a planetary probe Online Analytical Processing (OLAP) Database Management System for comparative data analysis capability. The database contains a comprehensive list of atmospheric entry vehicles and comprises vehicle dimensions, trajectory and aero-thermal data. SPARTA provides capabilities to choose from a list of flight vehicles or enter trajectory and geometry information of a vehicle in design such that grids can be generated automatically for entry vehicles given the geometry of the vehicles from the user configuration. A Newtonian flow solver is developed for two and three dimensional geometries that computes the aerodynamic forces and moments for hypersonic freestream conditions. A fourth order Runge-Kutta integration is employed for trajectory calculations. Fay-Riddell and Tauber-Sutton empirical correlations have been modeled for the stagnation point convective and radiative heat transfer computations. An approach is presented for dynamic TPS design. Materials properties like Carbon, Silicon and Carbon-Phenolic based Ablators have been obtained from the NASA Ames Thermal Protection Materials and System Branch TPSX Internet Database and modeled into the local OLAP database and integrated with the user interface. The purpose of this research is to investigate the aerothermodynamics environment of atmospheric entry probes and to generate an automatic computational trajectory database populated by OLAP cubes and to provide flow field analysis for such probes. In addition, the OLAP database (DB) provides dynamic links to compressible flow solvers (CFD++, GASP, CFD-RC, LAURA, SPARTA) and allows for aerothermodynamic CFD modeling. CFD solutions computed at select points along the trajectory are then populated into the OLAP database. SPARTA is benchmarked against the industry standard tools and the results are tabulated. Nomenclature Greek Cp Specific heat at constant pressure (kJ/kg.K) α Angle of attack, Material absorptivity Cv Specific heat at constant volume ρ Freestream density (kg/m) h Enthalpy (J/kg) β Ballistic Coefficient (kg/m) Kn Knudsen number Υ Ratio of specific heats Le Lewis number e Surface emissivity of the material m Entry mass (Kg) σ Stefan-Boltzmann’s constant M Mach number γ Flight path angle (°) P Pressure (N/m) θ Surface area inclination angle Pr Prandtl’s number &conv q Convective heat transfer rate W/cm 2 Subscripts &rad q Radiative heat transfer rate W/cm 2 &tot q Total heat transfer rate W/cm 2 b forebody * Q Heat of ablation c corner Rb Fore body radius (m) conv convective Rc Corner radius e entry Re Reynolds number n nose Reff Effective radius rad radiative Rn Nose radius tot total Rs Shoulder radius w wall S Base area of the capsule (m) ∞ freestream & S Recession rate t Time (sec) T Temperature (K) ∞ V Freestream flight velocity (m/s) § Graduate Researcher and Aerospace Engineer, AIAA Member AIAA Atmospheric Flight Mechanics Conference and Exhibit 21-24 August 2006, Keystone, Colorado, USA AIAA-2006-3787 Page 3 of 27