Flame and combustion, 3rd Edition

Flame and combustion, 3rd Edition

Fire Safety Journal 28 (1997) 179-181 Published by Elsevier Science Limited Printed in Northern Ireland 0379-7112/97/$17-00 ELSEVIER PII: S0379-7112...

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Fire Safety Journal 28 (1997) 179-181 Published by Elsevier Science Limited Printed in Northern Ireland 0379-7112/97/$17-00 ELSEVIER

PII:

S0379-7112(97)00003-9

B o o k Review Flame and Combustion, 3rd Edition, by J. F. Griffiths and J. A. Barnard. Chapman and Hall, 2-6 Boundary Row, London SE1 8HN, UK, 1995. c. 288 pp., ISBN 0-7514-0199-4 paperback, £24.99. In the early 1990s, flesh from a degree in Physics, I undertook a doctoral study of the suppression of pre-mixed, gaseous hydrocarbon-air explosions with water sprays. A physics degree proved to be an excellent place to start for such a study as I had had a solid grounding in the disciplines, such as thermodynamics and fluid mechanics, which are invoked when we attempt to explore, describe and understand combustion processes. However, I needed a text book which could give a broad overview of the nature of combustion and how physical and chemical processes operated within flames. A colleague directed me to a copy of Flame and Combustion, then in its second edition. The book is an overview of the fields of flame and combustion, specifically aimed at final year undergraduate students and those new to the field. The bias is towards pre-mixed combustion with initially gaseous fuels, though diffusion flames are discussed too, as are the combustion of solids and liquids. Although this book does not contain such a great depth of information as, for example, Kuo's Combustion, it is far more likely to be read, rather than consulted, and thus the way that various aspects of combustion relate to each other become more obvious to the reader. For me, this book made a tremendously complex subject seem accessible. It was in great demand in my research group, which was primarily concerned with pre-mixed combustion, especially propagating flames and detonations. Postgraduates needing an overview of an unfamiliar aspect of combustion were told to "Look in Barnard and Bradley," as the first step in their investigations. When a new edition was advertised in 1995 I ordered a copy for myself, which I have now been using for over a year. This Third Edition retains the great strength of the Second Edition: it is very easily read, an especially important factor for people entering the field. It is clearly written and provides a good overview of combustion as a discipline. Unlike many text books, it manages to convey enthusiasm for the subject to the reader and to do so without losing rigour. It is short enough to be read from cover to cover. The authors display a good understanding of 179

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the needs of a newcomer: the topic is dissected into obvious areas; explanations are m o r e than adequate, though not exhaustive; nothing feels superfluous; a full bibliography is provided, as are suggestions for further reading. The preface of the Third Edition discusses a shift in emphasis of the book, away from explosives and propellants and towards efficiency, safety and the consideration of environmental impact. T h e r e are expanded sections on the chemistry and physics of flames, which are welcome. Particular instances stand out: I was pleased to see flame stretch given something m o r e than the cursory mention it was given in the Second Edition and paragraphs on laser diagnostics are included which will be useful starting points, though no m o r e that, for a researcher preparing to m a k e investigations in that area. In my view, the Preface to the First Edition should have been retained or incorporated into that of the Third. In the first Preface, J. N. Bradley explains that it was an explicit aim to m a k e the book short, and as such the selection of topics for inclusion or omission was necessarily arbitrary. This would, I think, better explain the purpose of the book and answer some facile criticisms: how can a book called Flame and Combustion say so little about propulsion and almost nothing about high explosives? Indeed whole chapters on high explosives and heating appliances have been omitted, but we can surmise that, as applications rather than aspects of combustion, these will be dealt with in other texts at the same level. R e a d e r s of the Fire Safety Journal will be interested to see the inclusion of a chapter on combustion hazards. The breadth of the subject, of course, precludes anything other than a brief overview in the short space abailable. Even within this context, however, there are deficiencies. Accidental gas explosions, in all their forms, are summarized, as are dust explosions. Mitigation of confined explosions by venting is discussed, though recent successes in using water sprays against vapour cloud explosions are not mentioned. This could have been achieved easily in a short paragraph. Spontaneous ignition is not discussed in the context of fire hazard, though smouldering combustion is: it seems surprising that one should be m e n t i o n e d without the other. The section on mitigating agents is especially disappointing. Water is discussed in a perfunctory m a n n e r , which is surprising given recent developments in the field of droplet size selection and the use of additives, though the role of halides in the quenching process is discussed. The section on fire spread is useful, though it would benefit from a greater emphasis on the role of heat release rate in flame spread, with a wider discussion of oxygen consumption calorimetry: as it stands, the cone calorimeter is m e n t i o n e d only briefly in a section on the role of polymers in fire.

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A f t e r using the Second Edition, this Third Edition has a notably different feel, both physically and with regard to its contents. The size of the book is a surprise: it is m u c h wider than the second edition and I find this slightly m o r e difficult to read without resting it on a surface. This m a y sound a trivial point, but the b o o k contains m a n y tables, t h r o u g h o u t the text, giving p a r a m e t e r s such as quenching distance, burning velocities and compositions of different gasolines. These are very useful, and I have often found it most convenient to be able to refer to one source for so m a n y disparate quantities. However, the change in format of the b o o k m a k e s it less easy to lift off the shelf and flick through to answer a quick query. A list of these tables would be m o r e convenient than having to use the main index, and the lack of units in the Glossary section is an uncharacteristic omission. I would also have liked to have seen the 'Useful Constants' page retained and expanded. The indexing is ample, though slightly clumsy at times. It seems slightly strange, even a little severe, that John Bradley is not credited as an author. It is simply m y conjecture, but as the originator of the work and s o m e o n e by w h o m Dr. Griffiths was once taught, it would seem strange if at no point in the present work is Bradley's original work used, or if no evidence of his hand should remain even in the structure of certain chapters. A l t h o u g h there are elements to the Third Edition which could be improved, this is largely due to fact that producing a lucid and comprehensive overview of combustion in some 280 pages is an extremely difficult task. It is a book which reflects the concerns and priorities current in the c o m m u n i t y and, as such, will be w e l c o m e d by students and inter-disciplinary researchers alike. In summary, the b o o k is the best introduction to the field that I have e n c o u n t e r e d and I doubt that there are m a n y old hands who would not gain anything at all by reading this. J. R. Brenton

Department of Civil and Environmental Engineering The University of Edinburgh Crew Building The King's Buildings Edinburgh EH9 3JN UK