Study on the merged flame height and radiative heat flux distribution from square propane fire arrays

Abstract

SummaryThe remote ignition and accelerated flame spread in multiple fires accidents are mainly due to the thermal radiation. The merged flame height and external radiative heat flux distribution of the square fire arrays were investigated numerically. Different burner spacing, total number of burners and heat release rate (HRR) of an individual burner were considered. Results show that the fire plume centerline temperature can be predicted accurately by achieving grid independence on a fine enough grid. A correlation for predicting the merged flame height of the multiple fires is developed involving the number of burners, HRR of each burner and burner spacing. The comparison of calculated and simulated data in this work validated the accuracy of the proposed correlation. The radiative heat flux distributions surrounding the fire array can be divided into two regions, that is, the near‐ and far‐field regions. The total heat release rate of the fire array is shown to be the dominant effect on the radiation distribution throughout the whole region, whilst the burner spacing is shown to only have an effect in the near‐field region. To distinguish the two regions, the critical distance of 0.7 ( is the characteristic fire array length) was obtained.