Ignition behavior and critical distance of flammable liquids by radiant heat flux from adjacent pool fire

Abstract

The experimental investigations are designed to study ignition behaviors of ethanol and heptane pool by adjacent fires. Four quartz glass pools with diameters of 74, 114, 150 and 200 mm are used. The multiple of pool diameter is selected as a criterion to characterize critical ignition distance with different pool diameters. The influences of pool diameter and interval distance on critical ignition time and ignition distance are explored. Results show that the critical ignition time depends slightly on pool diameter, but significantly on interval distance. The critical ignition distance falls into the range of 0.20 D - 0.47 D for ethanol, while it is 0.95 D - 1.40 D for heptane. Based on cylindrical model, an integration method is proposed to calculate the flame radiation imposed to adjacent pool. The calculated radiant heat flux is basically consistent with measurement for heptane, but it deviates for ethanol. The cylinder model is not suitable for predicting radiant heat flux near the fire contour. The average radiant heat flux received by neighbouring pool is obtained by the method of doubly integrating configuration factor. Then, the equivalent radiation distance and equivalent radiation area are calculated under various pool diameters and non-dimensional interval distances.