Modelling of a two-dimensional rack storage fire

Abstract

A theoretical model to predict mass flow rate, gas temperature, gas velocity and flame height in a two dimensional rack storage fire has been developed. Experiments have been carried out using inert boxes and a propane diffusion flame on a line burner located at the bottom of the rack. Reasonably good correlation is found between the theoretical model and the experiments. The model calculates the flow within the rack with the aid of the equations of continuity, and conservation of momentum and energy. The model distributes fractions of the total convective heat from the burner along a calculated flame height in accordance with an empirical relationship obtained from measured convective heat. The flame height is calculated by comparing the amount of available air flow and fuel at each height for different heat release rates and widths of regular spaces between noncombustible boxes. The theoretical results were compared to experimental results based on an approximately two dimensional, four box high rack storage with a total height ranging from 1·14 m to 1·34 m and with a 0·59 m long diffusion line burner placed at the bottom of the vertical flue. The size of the rack is about 1/3 that of real rack storage.