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...

Fast Chemical Reactions in Turbulent Flows
Fast Chemical Reactions in Turbulent Flows

Author: Rustam Ya Deberdeev

Publisher: Smithers Rapra

Published: 2013-09-02

Total Pages: 334

ISBN-13: 1909030287

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This book describes the fundamentals of fast liquid-phase chemical reactions and the principles of their scientific foundation, technical implementation and industrial application of new technologies. In addition, the equipment required to perform these reactions, in a turbulent mode in the chemical, petrochemical and petroleum industries, is also discussed. The macrokinetic approach has been developed with consideration of the diffusion, hydrodynamics, and heat transfer processes. Due to the advancement of fundamental knowledge, equations of practical engineering importance have been obtained for the calculations of mass and heat transfer processes carried out in conditions of high turbulence, and developed for the implementation in fast chemical reactions involving the synthesis of low molecular weight products and polymers. New methods for controlling the molecular characteristics of polymers have been developed based on the tailored regulation of the hydrodynamics of the reactive mixture flow. Typical processes have been used as model examples to reveal the influence of turbulence on the behaviour of fast chemical reactions used for the synthesis of low molecular weight products, in single-phase and two-phase reactive systems. Brand new tubular devices have been developed with the following characteristics: compact size, high productivity, and a quasi-perfect mixing operation mode in turbulent flows. These devices are subdivided into cylindrical, shell-and-tube, 'zone', and diffuser-confusor designs. Original solutions are proposed for the instrumental implementation of fast liquid-phase processes and development of continuous energy- and resource-efficient technologies for the synthesis of some large-scale compounds.