Vapor Cloud Explosions

Abstract

A vapor cloud explosion (VCE) results from rapid flame propagation through a large outdoor, unconfined, flammable vapor, or gas cloud. This chapter discusses the shape of the overpressure curves and then discusses modeling approaches for predicting overpressure as a function of distance for VCEs. It covers models used to scale explosion pressure as a function of distance: the classical model, trinitrotoluene (TNT) equivalent model, the TNO model, the Baker–Strehlow–Tang model, and the Williams model, along with examples. Most VCEs usually involve flammable hydrocarbon vapors. An equivalent TNT model estimates blast damage parameters using pressure vs. time curves developed for TNT explosions. The disadvantages of the TNT equivalent model led to the formulation of a more accurate VCE model based on the concept of multienergy. Computational fluid dynamics methods available for performing VCE modeling include commercial codes like ANSYS FLUENT and FLACS.