Consistent kinetic-continuum dissociation model. II. Continuum formulation and verification

Abstract

In this article, we implement a recently developed non-equilibrium chemical kinetics model 1 based on ab initio simulation data and perform verification studies. Direct molecular simulation data is used to verify the predictive capabilities of the model. Using the model, dominant physics such as need for a rotational energy equation, and the quantitative role of non-Boltzmann effects are identified. Based on the analysis and reasonable assumptions, a simplified model for implementation into large-scale CFD simulations is proposed. Without incurring additional computational cost, the model can be used in existing flow solvers to analyze hypersonic flows.

Consistent Kinetic-Continuum Recombination Model for High Temperature Reacting Flows

“…3-5 with Direct Molecular Simulation (equivalent to full master equation) results have been carried out in Ref. 27 . However, these studies do not model recombination processes.…”

“…Specifically, recombination terms (written in bold face in Eqs. [3][4][5] have not been considered in the earlier work 1,27 . The focus of this article, therefore, is to derive the recombination rate constant (k r AB−C ), as well as the average vibrational ( ε rec v ) and average rotational energy ( ε rec rot ) of molecules formed in recombination reactions.…”

“…The dissociation model is analytically consistent between the kinetic-scale and continuum scale 1 . The continuum model incorporates the non-Boltzmann vibrational energy distribution model 26 for dissociating gas and is shown to reproduce ab initio data at continuum scale 27 . The model can be implemented in largescale CFD solvers and direct simulation Monte Carlo (DSMC) solvers 1,27 .…”

“…The continuum model incorporates the non-Boltzmann vibrational energy distribution model 26 for dissociating gas and is shown to reproduce ab initio data at continuum scale 27 . The model can be implemented in largescale CFD solvers and direct simulation Monte Carlo (DSMC) solvers 1,27 . Other recent efforts of developing a continuum nonequilibrium dissociation model based on recent ab initio data can be found in Refs.…”

“…Based on the obtained ab initio data, a nonequilibrium dissociation model has been derived using first principles by the authors in Refs. 1,[26][27][28][29][30] . The dissociation model is analytically consistent between the kinetic-scale and continuum scale 1 .…”