A study of wall and corner fire plumes

Measurements are presented of flame heights and mass fluxes of industrial methylated spirits fires burning in different sizes and configurations of rectangular trays in the open (away from walls), close to a wall and in a corner. The measurements confirm previous observations that adjacent walls decrease the mass flux of plumes and increase the mean and peak flame heights. They also show that the dimensionless span of the flame height fluctuations in confined fires is larger than that of free fires, so that the increase of the peak values due to walls is larger than the increase of their mean values. On the basis of the experimental data, an approximate, simple model for describing the effect of walls on the mass flux above the flaming region is offered. It is shown that the model provides a good description of the present measurements, when used with an assumption by Hansell (1993), that the reduction of the air entrainment into the plume is equal to the ratio of the open to the total perimeters of the trays. Two similar, simple models for predicting the effects of walls on the mean flame height are also presented. These models overestimate the measured values of the mean flame height above fuel trays close to a wall and in a corner by approximately 15-30%, respectively. (C) 2000 Elsevier Science Ltd. All rights reserved.