Experimental study on the burning rate of continuously released spill fire on open surface with measurement of burning fuel thickness

Failure of the storage containers often leads to the release of flammable liquid. The fuel may burn while spread, and forms a spill fire. The fuel depth in a spill fire is quite shallow, which makes the burning rate of the spill fire much different with that of the pool fire. In this paper, the n-heptane spill fire was experimentally studied on both flat surface and inclined surface. The burning fuel thickness was measured for the first time. The burning fuel thickness helps establish a theoretical model for the spill fire burning rate, which shows consistent with the experimental data. The result indicates that the spill fire was dominated by the convection, with more than 90% of the total thermal heat feedback, for equivalent diameter ranging from 0.15 m to 0.35 m. It proves that the pool diameter in a spill fire for characterizing the transition from the convective control to the radiative control is larger than that in the pool fire. A comprehensive understanding for the spill fire may be achieved with further studies towards the burning fuel depth, based on the measurement method presented in this work.