A new apparatus has been designed, built, and extensively tested for making short-duration autoignition temperature measurements of hydrocarbon fuels under conditions where the fuel/air stoichiometry, the nature of the hot metal surface, and the contact time are well controlled. This approach provides a much more reliable database to establish the importance of fuel structure effects than the current ASTM E659 procedure. Over 1100 individual autoignition temperature determinations have been made for the ignition of 15 hydrocarbon fuels on heated nickel, stainless steel, and titanium surfaces for three different fuel/air mixtures (stoichiometry theta = 0.7, l.0, and l.3). Excellent reproducibility has been achieved with the new apparatus. The measured autoignition temperatures generally decrease for the larger hydrocarbons and for richer mixtures, with the C2 hydrocarbons (ethane, ethylene, and acetylene) having particularly low values. The highest autoignition temperatures are observed for nickel surfaces and the lowest for stainless steel, with titanium being an intermediate case. A review of the autoignition literature suggests that the branched alkanes should be more resistant to autoignition than the linear isomers, and thus present a reduced hazard. Limited data obtained in this study are consistent with this prediction. Promising directions for substantiating these observations and additional areas for future research are outlined.

This study develops an experimental method for the reliable determination of autoignition temperatures under a variety of conditions which involve short duration exposures of controlled fuel/air mixtures on three metal surfaces. Over 1100 autoignition temperature determinations have been made for the ignition of 15 hydrocarbons on heated nickel, stainless steel, and titanium surfaces for three different fuel/air mixtures. The measured autoignition temperatures generally decrease for the larger hydrocarbons and for richer mixtures, with the C[2 hydrocarbons having particularly low values. The highest autoignition temperatures are observed for nickel surfaces and the lowest for the stainless steel, with titanium being an intermediate case.

Combustion has played a central role in the development of our civilization which it maintains today as its predominant source of energy. The aim of this book is to provide an understanding of both fundamental and applied aspects of low-temperature combustion chemistry and autoignition. The topic is rooted in classical observational science and has grown, through an increasing understanding of the linkage of the phenomenology to coupled chemical reactions, to quite profound advances in the chemical kinetics of both complex and elementary reactions. The driving force has been both the intrinsic interest of an old and intriguing phenomenon and the centrality of its applications to our economic prosperity. The volume provides a coherent view of the subject while, at the same time, each chapter is self-contained.