Simple flame height correlation for buoyancy-controlled diffusion plumes generated by rectangular sources fire with different aspect ratios

Abstract Flame heights of buoyancy-controlled diffusion plumes generated by a rectangular source fire were investigated. Different fire burners having the same surface area but different aspect ratios were used for the fire experiments. A modified expression in terms of the heat release rate was established for estimating the flame height of buoyancy-controlled diffusion plumes generated by the rectangular fire. This expression was developed by modifying the Heskestad relation with a new definition of equivalent diameter for an axis-symmetric fire. Comparing the experimental results and data available in the literature, the modified expression yields reasonably accurate prediction. The standard error of prediction by the modified expression was approximately 9.1%, which is significantly smaller than those of other models in the literature. In addition, the expression proposed takes a much simpler mathematical form.