Gaseous Detonations: Their Nature, Effects and Control

ISBN-13: 9789401079150 / Angielski / Miękka / 2011 / 256 str.

M. a. Nettleton

Opis

My introduction to the fascinating phenomena associated with detonation waves came through appointments as an external fellow at the Department of Physics, University College of Wales, and at the Department of Mechanical Engineering, University of Leeds. Very special thanks for his accurate guidance through the large body of information on gaseous detonations are due to Professor D. H. Edwards of University College of Wales. Indeed, the onerous task of concisely enumerating the key features of unidimensional theories of detonations was undertaken by him, and Chapter 2 is based on his initial draft. When the text strays to the use of we, it is a deserved acknow- ledgement of his contribution. Again, I should like to thank Professor D. Bradley of Leeds University for his enthusiastic encouragement of my efforts at developing a model of the composition limits of detonability through a relationship between run-up distance and composition of the mixture. The text has been prepared in the context of these fellowships, and I am grateful to the Central Electricity Generating Board for its permission to accept these appointments.

Spis treści

1 Introduction.- 1.1 General remarks.- 1.2 Definitions of commonly-used terms.- 1.3 Unidimensional models of detonations.- 1.4 Structure of a detonation wave.- 1.5 Philosophy of presentation.- 2 Unidimensional models.- 2.1 Introductory remarks.- 2.2 Properties of unidimensional shock waves.- 2.3 Properties of unidimensional shock waves with energy addition.- 2.4 Properties of the Chapman-Jouguet state.- 2.5 Comparison of C–J predictions and experiment.- 2.6 The Zel’dovich, von Neumann, Doring model.- 2.7 Comparison of the ZND model and experiment.- 2.8 The Taylor expansion wave.- 2.9 Concluding remarks.- 3 Structure of detonation fronts.- 3.1 General remarks.- 3.2 ‘Spinning’ detonation fronts.- 3.3 ‘Galloping’ fronts.- 3.4 Experimental studies of multi-headed fronts.- 3.5 Theoretical treatments of multi-headed fronts.- 3.6 Concluding remarks.- 4 Detonable media.- 4.1 General remarks.- 4.2 Confined and unconfined detonations.- 4.3 Gases and vapours which are detonable in the absence of an oxidant.- 4.4 Comparison of detonation limits for confined and unconfined detonations with flammability limits for mixtures of hydrocarbons with oxygen and air.- 4.5 Homology hypothesis for predicting detonation limits.- 4.6 Detonations with oxidants other than oxygen.- 4.7 Influence of initial pressure and temperature on detonability.- 4.8 Influence of additives on detonability.- 4.9 Detonations in suspensions of dusts and droplet mists in oxidizing atmospheres.- 5 Initiation of a detonation wave.- 5.1 General remarks.- 5.2 Initiation of confined detonations by shock waves.- 5.3 Initiation by blast waves from electrical and laser sparks and charges of conventional explosives.- 5.4 Detonations in large unconfined clouds of vapour.- 5.5 Minimum ignition energies.- 5.6 Laminar burning velocities.- 5.7 Expansion ratios.- 5.8 Detonations arising from accelerating flames.- 5.9 Influence of initial temperature and pressure of the medium on run-up distances.- 5.10 Influence of diameter of pipeline on run-up distances.- 5.11 Effect of additives on pre-detonation distances.- 5.12 Effects of surface roughness and obstacles on the acceleration of confined flames.- 5.13 Pressure piling (cascading).- 5.14 Concluding remarks.- 6 Interaction of a detonation with confinement.- 6.1 Introductory remarks.- 6.2 Diffraction at an isolated wall, ?w < 0°.- 6.3 Diffraction at an isolated wall, 0° < ?w < ?crit.- 6.4 Diffraction at an isolated wall, ?crit < ?w < 90°; standard two- and three-shock theory for non-reactive media and the effects of reaction.- 6.5 Normal reflection of a detonation wave.- 6.6 Transmission of a planar detonation wave through an abrupt expansion in area.- 6.7 Propagation of detonations through bends and junctions.- 6.8 Interaction of a detonation with an inert surrounding gas.- 6.9 Refraction of detonations in mixtures of different composition.- 6.10 Concluding remarks.- 7 Damage caused by detonations.- 7.1 Introduction.- 7.2 Early experiments on effective pressures generated by detonations.- 7.3 Damage produced by detonations in chemical plant.- 7.4 Experimental studies of failure resulting from detonations.- 7.5 Concluding remarks.- 8 Prevention and mitigation of detonations.- 8.1 Introductory remarks.- 8.2 Inhibition of flames of normal burning velocity.- 8.3 Venting in the early stages of an explosion.- 8.4 Quenching of flame-shock complexes.- 8.5 Suppression of detonations.- 8.6 Mitigating the effects of detonations.- 8.7 Concluding remarks.- 9 Concluding recommendations.- 9.1 Introductory remarks.- 9.2 Stress waves in confining walls.- 9.3 Planned deformations as safety measures.- 9.4 Designing to minimize the effects of local peaks in pressure.- 9.5 Suggestions for further studies of detonations.- References.- Author index.