Entry Spacecraft Research Articles

Aerodynamic and aerothermodynamic analysis of high-speed earth re-entry capsule

This paper deals with the computational fluid dynamics analysis of a capsule entering the earth atmosphere at the end of a sample return mission. Several numerical simulations have been carried out to assess the flowfield environment past a sphere-cone capsule, by using non-equilibrium reacting gas approximations. Heat shield ablation and effects of flow plasma radiation on capsule aeroheating are also accounted for in the flowfield analysis. The issue of aerodynamic and aerothermodynamic performance of the entry spacecraft in the framework of a super-orbital re-entry scenario is addressed.

A Study of Thermal Response and Flow Field Coupling Simulation around Hayabusa Capsule Loaded with Light-Weight Ablator

The numerical simulation of flow field around Hayabusa capsule loaded with light-weight ablator thermal response coupled with pyrolysis gas flow inside the ablator was carried out. In addition, the radiation from high temperature gas around the capsule was coupled with flow field. Hayabusa capsule reentered the atmosphere about 12 km/sec in velocity and Mach number about 30. During such an atmospheric entry, space vehicle is exposed to very savior aerodynamic heating due to convection and radiation. In this study, Hayabusa capsule was treated as a typical model of the atmospheric entry spacecraft. The light-weight ablator had porous structure, and permeability was an important parameter to analyze flow inside ablator. In this study, permeability was a variable parameter dependent on density of ablator. It is found that the effect of permeability of light-weight ablator was important with this analysis.

Elemental Demixing in Inductively Coupled Air Plasma Torches at High Pressures

We present and analyze detailed numerical simulations of high-pressure inductively coupled air plasma flows using two different mathematical formulations: an extended chemical non-equilibrium formalism including finite-rate chemistry and a form of the equations valid in the limit of local thermodynamic equilibrium and accounting for the demixing of chemical elements. Simulations at various operating pressures indicate that significant demixing of oxygen and nitrogen occurs, regardless of the degree of nonequilibrium in the plasma. Ideally, this effect should therefore be taken into account when the results of tests of thermal protection materials for (re-)entry spacecraft in inductively coupled plasma wind tunnels are processed. As the operating pressure is increased, chemistry becomes increasingly fast and the nonequilibrium results correctly approach the results obtained assuming local thermodynamic equilibrium, supporting the validity of the proposed local equilibrium formulation.