The burning characteristics and flame evolution of hydrocarbon and hydrogen flash fires

A flash fire is a sudden, intense fire caused by ignition of a mixture of air and a dispersed flammable substance such as a solid (including dust), flammable or combustible liquid (such as an aerosol or fine mist), or a flammable gas. The present study aims to gain insight about the combustion processes and flame structure and dynamics associated with flash fires through computational fluid dynamics (CFD) based numerical studies using FireFOAM, the large eddy simulation based fire solver with the frame of open source CFD code OpenFOAM. It will focus on the initial transient development to gain insight about flash fire growth and the underlying combustion process. The scope of the study is, however, limited to flash fires formed following rapid release of relatively large quantities of flammable gas. The predicted flash fire diameter and the lifting height were found to be in reasonably good agreement with published experimental data. To gain further insight of the flash fire transient behaviour, the flame structures, temperature profiles and pressure fields have also been analysed. The predicted incident radiation at different locations is discussed in relation to the resulting thermal radiation hazards