Experimental study on the diffusion and burning characteristics of continuous liquid fuel spillage on sloped ground in open space

When liquid fuel spills on a sloping ground and an ignition source is nearby, it could lead to a continuous spill fire. To investigate the diffusion and burning characteristics of continuous liquid fuel spillage on sloped ground, a series of experiments were conducted, considering different discharge rates (60∼140 ml/min) and ground slopes (2o, 4o, 6o, 8o). Characteristic parameters were measured, including fuel diffusion rate, diffusion shape, flame temperature, and burning rate. A new theoretical model for the diffusion velocity was established and the diffusion shape characteristics of the liquid fuel were revealed for the first time. Results indicate that under non-ignited conditions, the diffusion velocity of the liquid fuel gradually decreases, eventually converging toward an asymptotic velocity. Under ignited conditions, the burning process of the spill fire could be categorized into three distinct stages. Moreover, the mass burning rate per unit area of spill fires is obviously lower than that of pool fires. This is because the fuel thickness in spill fires is so thin that the radiant heat flux emitted by the flame to the fuel cannot be fully absorbed by the fuel. This work could provide a critical reference for predicting the diffusion process of a spill fire.