COMBUSTION research, which may be said to have begun with Sir Humphrey Davy's experiments nearly 150 years ago, has grown enormously in recent times and now covers a very wide field. Davy was particularly concerned with flame as the combustion of an explosive mixture of an inflammable gas and air and few people even today regard it simply as a phenomenon which may accompany any vigorous chemical reaction in the gas phase. In the last decade, however, a number of studies have been reported on flames which might be termed unusual because they do not depend on air or oxygen. The reasons for these studies lie partly in pure scientific interest and partly in the need for a better knowledge of many reactions which occur in the combustion of propellants and explosives, or which constitute chemical processes or hazards in industry.
SELF-DECOMPOSITION FLAMES
To underline the fact that air is not essential for the production of a flame let us consider first a few simple compounds which in the gaseous state can decompose in a self-propagating reaction. Although it has long been known that acetylene could provide a self-decomposition flame, one of the first stationary self-decomposition flames to be studied in detail is that of hydrazine.