Flame propagation over a liquid surface


Book Description

Experiments were carried out wit acetone, ethanol, benzene, and toluene. In the first series the temperature of the liquids varied within the limits o ignition, and in the second series it was below the flash point of the liquid. In a general way the mechanism of flame propagation over a liquid can be represented in the following manner: as the closest layer of liquid is heated the surface tension over it increases to the value at which the vapor-air mixture is ignited. This flame in turn heats the next layer of liquid and ignites the combustible mixture over this layer, etc., so that the flame propagation velocity is determined by the burning rate of the liquid layers following each other. The higher the initial temperature of the surface, the smaller the time interval necessary for igniting the liquid and the higher the flame propagation velocity. On reaching the flash point the concentration of vapor over the surface was sufficient for the formation of an igniting mixture and the flame was propagated in the mixture without causing a noticeable heating of the liquid. (Author).




Introduction to Physics and Chemistry of Combustion


Book Description

Most of the material covered in this book deals with the fundamentals of chemistry and physics of key processes and fundamental mechanisms for various combustion and combustion related phenomena in gaseous combustible mixture. It provides the reader with basic knowledge of burning processes and mechanisms of reaction wave propagation. The combustion of a gas mixture (flame, explosion, detonation) is necessarily accompanied by motion of the gas. The process of combustion is therefore not only a chemical phenomenon but also one of gas dynamics. The material selection focuses on the gas phase and with premixed gas combustion. Premixed gas combustion is of practical importance in engines, modern gas turbine and explosions, where the fuel and air are essentially premixed, and combustion occurs by the propagation of a front separating unburned mixture from fully burned mixture. Since premixed combustion is the most fundamental and potential for practical applications, the emphasis in the present work is be placed on regimes of premixed combustion. This text is intended for graduate students of different specialties, including physics, chemistry, mechanical engineering, computer science, mathematics and astrophysics.







Combustion Phenomena


Book Description

Extensively using experimental and numerical illustrations, CombustionPhenomena: Selected Mechanisms of Flame Formation, Propagation, and Extinction provides a comprehensive survey of the fundamental processes of flame formation, propagation, and extinction. Taking you through the stages of combustion, leading experts visually display, mathematically explain, and clearly theorize on important physical topics of combustion. After a historical introduction to the field, they discuss combustion chemistry, flammability limits, and spark ignition. They also study counterflow twin-flame configuration, flame in a vortex core, the propagation characteristics of edge flames, instabilities, and tulip flames. In addition, the book describes flame extinction in narrow channels, global quenching of premixed flames by turbulence, counterflow premixed flame extinction limits, the interaction of flames with fluids in rotating vessels, and turbulent flames. The final chapter explores diffusion flames as well as combustion in spark- and compression-ignition engines. It also examines the transition from deflagration to detonation, along with the detonation wave structure. With downloadable resources of images that beautifully illustrate a range of combustion phenomena, this book facilitates a practical understanding of the processes occurring in the conception, spread, and extinguishment of a flame. It will help you on your way to finding solutions to real issues encountered in transportation, power generation, industrial processes, chemical engineering, and fire and explosion hazards.













Mechanism of Fires


Book Description

This textbook on fire dynamics provides a comprehensive description of fuels involved in fires, definitions related to fire, thermodynamics for fire calculations, basics of transport processes and fundamental aspects of combustion related to fire, physical descriptions of premixed and non-premixed flames, detailed analysis of the characteristics of fires from solid and liquid fuels, including ignition, spread and burning rates and physical aspects of fire plumes, compartment fires and dust fires. The contents also highlight fundamental aspects related to the evaporation of liquid fuels and pyrolysis of solid fuels which are explained with simplified mathematical expressions. The book includes pedagogical features such as worked examples to illustrate mathematical calculations involved in fire analysis and end-of-chapter review questions. This book proves useful for students, researchers and industry professionals alike.