Numerical study of spallation phenomenon in an arc-jet environment

Abstract

The spallation phenomenon might affect the aerodynamic heating rates of re-entry vehicles. To investigate spallation effects, a code is developed to compute the dynamics of spalled particles. The code uses a finite-rate chemistry model to study the chemical interactions of the particles with the flow field. The spallation code is one-way coupled to a CFD solver that models the hypersonic flow field around an ablative sample. Spalled particles behavior is numerically studied for argon and air flow field. The chemistry model is compared with that of Park's model which complies with oxidation and sublimation and shows disagreement for nitridation.

A drag coefficient model for Lagrangian particle dynamics relevant to high-speed flows

“…The particle model simulates the dynamics of a particle by employing a Lagrangian formulation [28] and includes the chemical interaction of the particle with the flow field [27]. The model assumes the particle to be spherical in shape.…”

“…The flow fields used in this study are determined using converged solutions of the aerothermodynamic computational fluid dynamics (CFD) code KATS. KATS is a laminar aerothermodynamics Navier-Stokes solver that uses a finite-volume approach with various modules [30,31,32,33] for simulating complex phenomena in ablation-related problems, including spallation studies [27,28,26,24]. The module KATS-CFD is used for computing compressible viscous flows including thermo-chemical nonequilibrium flows by solving the corresponding governing equations in the form…”

“…[39]. The coupling of the Lagrangian particle code and the hypersonic aerothermodynamic CFD code was developed in previous works, and used to study the effects of the flow field on the particles, and vice-versa [26,27,28].…”

Application of A New Thermal-Mechanical Coupling Solver for Ablation

“…However, another ablation phenomenon, spallation, occurs when low density ablative materials are subjected to high enthalpy flows. 1,2 This phenomenon can be described as the ejection of material particles into the flow field. The particle ejection can lead to the formation of grooves which escalates aerodynamic heating and accelerates material recession.…”

Emission Spectroscopic Boundary Layer Investigation during Ablative Material Testing in Plasmatron

“…Furthermore, the absence of internal material oxidation argues against the inflow or diffusion of hot boundary layer gases into the porous test sample. Such internal oxidation, as studied numerically by Weng et al for PICA 47 , could lead to a weaker fiber structure, causing mechanical failure of the material, for example, in the form of spallation 48,49 . Therefore, we highly suggest a general microscale analysis along with high-enthalpy testing of porous carbon-composite materials for heat shield applications.…”