EXTERNALLY TRIGGERED STEAM EXPLOSION EXPERIMENTS - AMPLIFICATION OR PROPAGATION

A vapor explosion is the rapid exchange of energy between a hot and co ld liquid caused by, and resulting in, the propagation of shock waves through the liquid-vapor mixture. Many vapor explosion experiments hav e been performed using an external trigger to initiate the event. In g eneral, the assessment of the explosive behavior has been to report th e pressure history resulting from the 'explosive interaction'. However , with the mutual dispersion of high temperature liquid within the col der temperature host liquid, the pre-mixed configuration represents su bstantial stored energy. With the imposition of an external trigger to fragment and rapidly mix the debris, some of this stored energy could be released without causing propagation of the event. This paper disc usses the difference between amplification of a trigger pulse due to t he release of stored energy and propagation of the explosion within th e pre-mixed zone. Also, a criterion for deciding if propagation has oc curred is provided. It is recommended that if the experiments do not s atisfy this criterion, propagation of the event should not be conclude d and the results should not be considered as a large-scale explosion. Rather such data should be considered as a characterization of what c ould occur within an explosion if an explosion (shock wave) could be i nitiated.