Theoretical and numerical study on influence of wind on mass loss rates of heptane pool fires at different scales

Abstract

The paper presents an investigation of the influence of wind on the mass loss rate per unit area (MLRPUA) of heptane pool fires at different scales. This work was done by a theoretical analysis and numerical simulations. Correlations are developed to show how results from a small-scale pool fire might be used to estimate MLRPUA for a large-scale pool fire. The calculated results demonstrate that in the presence of wind, the MLRPUA in large-scale pool fires (side length>1 m) does not increase several times as the small-scale tests have revealed, and the 1.5 m heptane square pool fire only varies within a range of −20% and 30% of that in the free burn. Numerous heptane pool fires with different pool scales and wind speeds were simulated using FDS (Fire Dynamics Simulator). Results indicate that within a certain range of Froude number (0–2.5), the overall variation trend of MLRPUA with wind speed varies from increasing significantly to decreasing as the pool scale increases gradually (0.15 m–6 m). For large-scale heptane pool fires, the MLRPUA most likely fluctuates within ±40% for a wide range of Froude number. The outcomes of this study could contribute to improving the understanding of burning characteristics of different scales of pool fires under windy conditions in an open environment.