Aerothermodynamic Analysis of a Reentry Brazilian Satellite

TL;DR

This study uses DSMC simulations to analyze the aerothermodynamics of the Brazilian reentry satellite SARA at high altitudes, comparing flow properties and configurations, and validating results with experimental data.

Contribution

It provides detailed DSMC-based insights into the flowfield and thermally stressed regions of SARA during reentry, including geometry effects and validation against experiments.

Findings

Flow disturbances vary along the stagnation streamline.

Stagnation region is highly thermally stressed and compressed.

Good agreement with experimental wall pressure data.

Abstract

This work deals with a computational investigation on the small ballistic reentry Brazilian vehicle SARA (acronyms for SAt\'elite de Reentrada Atmosf\'erica). Hypersonic flows over the vehicle SARA at zero-degree angle of attack in a chemical equilibrium and thermal non-equilibrium are modeled by the Direct Simulation Monte Carlo (DSMC) method, which has become the main technique for studying complex multidimensional rarefied flows, and that properly accounts for the non-equilibrium aspects of the flows. The emphasis of this paper is to examine the behavior of the primary properties during the high altitude portion of SARA reentry. In this way, velocity, density, pressure and temperature field are investigated for altitudes of 100, 95, 90, 85 and 80 km. In addition, comparisons based on geometry are made between axisymmetric and planar two-dimensional configurations. Some significant differences between these configurations were noted on the flowfield structure in the reentry trajectory. The analysis showed that the flow disturbances have different influence on velocity, density, pressure and temperature along the stagnation streamline ahead of the capsule nose. It was found that the stagnation region is a thermally stressed zone. It was also found that the stagnation region is a zone of strong compression, high wall pressure. Wall pressure distributions are compared with those of available experimental data and good agreement is found along the spherical nose for the altitude range investigated.