ABSTRACT

The existence of a critical explosive size or characteristic physical dimension for ignition occurs repeatedly in combustion. In thermal ignition problems the chemical kinetics are crucial. The simplest way to think about the spark as an ignition source, however, is as a heat source. Regardless of the size of the containment vessel, there are some explosives that are in metastable equilibrium below a certain temperature, which has been called the ignition temperature. This chapter discusses two methods in some depth, recognizing that there are many other ways of igniting an explosive mixture. The two chosen are thermal ignition and spark ignition. A mixture capable of supporting an explosion or flame can always be ignited by heating it to a high enough temperature. It is only a question of getting the chemical kinetics going fast enough to overwhelm any heat losses.