Experimental set-up to measure the maximum mass burning rate of storage tank fires

Abstract

The correct measurement of the maximum mass burning rate of flammable liquids in real sized storage tanks in industrial facilities is necessary to develop appropriate safety measures. Burning a fixed quantity of fuel in small diameter pans may not reflect the actual burning behaviour of different flammable liquids stored in large tanks. To overcome this, an experimental set-up by imposing realistic boundary conditions replicating tank fires and burning duration is demonstrated in this work. Fully developed steady burning conditions in model storage tanks of diameters d=0.05m and 0.10m, with 0.10m constant fuel filling height, are established to report the maximum mass burning rate. Flammable liquids used for the present study are diesel, gasoline, ethanol and biodiesel. The mass burning rates are measured by using two methods being the conventional method of using a fixed amount of fuel and hence decreasing fuel height and the present method in which the model tanks are continuously fed with fuel so that a steady state is achieved in terms of fuel height and burning rate. The measured higher flame lengths and higher temperatures in the liquid phase indicated that higher heat flux was transferred from the fire to the liquid surface in the present set-up compared to earlier method which resulted in higher maximum mass burning rates. Furthermore, to achieve wind boundary conditions in present model tanks, swivel fan at 0.5m distance from the fire was placed. With such an equivalent air entrainment and using proper scaling techniques, it is possible to measure the maximum burning rates of flammable liquids in real-sized storage tanks in the present set-up itself. These maximum mass burning rates can further be used to establish proper safety measures such as plant layout and storage group determinations for different flammable liquids.