Bridging the Gray and Yang, Sal'nikov and one-step, non-isothermal reaction schemes for oscillatory and explosive behaviour

Explosions may occur as a result of thermal and branching effects in combustion processes. The aim of this work is to study the effects of chain branching and termination in a "Gray and Yang" three-step, chain-thermal reaction scheme, and the role of thermal diffusion and convection in det...

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Bibliographic Details
Published in:Physical chemistry chemical physics : PCCP 2013-10, Vol.15 (39), p.16713-16724
Main Authors: Gonçalves de Azevedo, Filipa, Griffiths, John F, Cardoso, Silvana S. S
Format: Article
Language:English
Subjects:
Chain branching
Chemistry
Combustion
Exact sciences and technology
Exothermic reactions
Explosions
General and physical chemistry
Mathematical analysis
Mathematical models
Three dimensional
Transport
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Summary:Explosions may occur as a result of thermal and branching effects in combustion processes. The aim of this work is to study the effects of chain branching and termination in a "Gray and Yang" three-step, chain-thermal reaction scheme, and the role of thermal diffusion and convection in determining the global behaviour. The response includes steady, exothermic combustion, oscillatory reaction and explosion. This was done by solving numerically the governing equations for the underlying kinetics and the heat transport, and analysing solutions for the limits at which each transport phenomenon dominates. Using scales to describe the different transport mechanisms, a 3D regime diagram is used to characterise the behaviour of the system. The results show how branching and heating by reaction enhance the oscillatory and explosive behaviour. The integration of a two-step Sal'nikov reaction scheme and a one-step reaction model in the Gray and Yang scheme is presented and the Frank-Kamenteskii and Semenov limits are identified on the regime diagram. Comparison is made with some experimental, numerical and analytical results. Natural convection promotes large amplitude oscillations of temperature in a Gray and Yang three-step branching reaction, occurring in a closed, spherical vessel.
ISSN:1463-9076
1463-9084
DOI:10.1039/c3cp52241e