Computational Reacting Gas Dynamics
Computational Reacting Gas Dynamics

Author: National Aeronautics and Space Administration (NASA)

Publisher: Createspace Independent Publishing Platform

Published: 2018-07-17

Total Pages: 142

ISBN-13: 9781722973773

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In the study of high speed flows at high altitudes, such as that encountered by re-entry spacecrafts, the interaction of chemical reactions and other non-equilibrium processes in the flow field with the gas dynamics is crucial. Generally speaking, problems of this level of complexity must resort to numerical methods for solutions, using sophisticated computational fluid dynamics (CFD) codes. The difficulties introduced by reacting gas dynamics can be classified into three distinct headings: (1) the usually inadequate knowledge of the reaction rate coefficients in the non-equilibrium reaction system; (2) the vastly larger number of unknowns involved in the computation and the expected stiffness of the equations; and (3) the interpretation of the detailed reacting CFD numerical results. The research performed accepts the premise that reacting flows of practical interest in the future will in general be too complex or 'untractable' for traditional analytical developments. The power of modern computers must be exploited. However, instead of focusing solely on the construction of numerical solutions of full-model equations, attention is also directed to the 'derivation' of the simplified model from the given full-model. In other words, the present research aims to utilize computations to do tasks which have traditionally been done by skilled theoreticians: to reduce an originally complex full-model system into an approximate but otherwise equivalent simplified model system. The tacit assumption is that once the appropriate simplified model is derived, the interpretation of the detailed numerical reacting CFD numerical results will become much easier. The approach of the research is called computational singular perturbation (CSP). Lam, S. H. Unspecified Center CHEMICAL REACTIONS; COMPLEX SYSTEMS; COMPUTATIONAL FLUID DYNAMICS; GAS DYNAMICS; REACTING FLOW; SIMPLIFICATION; FLOW DISTRIBUTION; PERTURBATION; REACTION KINETICS...

Introduction to Reactive Gas Dynamics
Introduction to Reactive Gas Dynamics

Author: Raymond Brun

Publisher: OUP Oxford

Published: 2009-02-26

Total Pages: 430

ISBN-13: 0191567817

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In high energy gas flows, at high velocities and high temperatures, physical and chemical processes such as molecular vibrational excitation, dissociation, ionisation or various reactions take place and deeply influence the structure of the flows. The characteristic times of these processes have the same order of magnitude as aerodynamic characteristic times, so that these reactive media are generally in thermodynamic and chemical non-equilibrium. This book presents a general introductory study of these media. In the first part their fundamental statistical aspects are described, starting from their discrete structure and taking into account the interactions between elementary particles: transport phenomena, relaxation and kinetics as well as their coupling are analysed and illustrated by many examples. The second part deals with the macroscopic re-entry bodies. Finally, the experimental aspects of these flows, their simulations in shock tubes and shock tunnels are described, as well as their application, particularly in the aerospatial domain. This book is intended for students that have acquired a basic knowledge in thermodynamics, statistical physics and fluid mechanics. It will also be of interest to engineers in research and industry, in particular in the aerospace industry, and more generally to all researchers trying to simulate and calculate complex reactive flows.