Flame Characteristics of Group Fires

Abstract

In this paper, simulating a group fire in a densely inhabited area with weak small wooden buildings, we performed reduced scale model experiments to investigate flame merging. To study this phenomenon, a lot of experiments were performed using crib and liquid fuel. In this work, however two or more square propane porous burners are used, and the flame height, heat flux, and temperature distribution on the center axis of fires are measured. Consequently, the influence of the heat release rate, the number of fire sources and the distance between fire sources upon flame merging has been investigated.It is found that each of those parameters affected flame merging, although the number of fire sources seemed to be the most important parameter.

A Study of the Flow Field Surrounding Interacting Line Fires

“…In general, flame length was not significantly affected by interaction ( Figure 15). This differs from the results obtained by other researchers using gas burners, who observed increases in flame length as fires converged [12,54]. However, in their studies, the burning rate was kept constant.…”

Experimental study on flame merging behaviors from two pool fires along the longitudinal centerline of model tunnel with natural ventilation

“…However, most of them [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] were conducted in open space to investigate the effects of fuel type, fire shape, size, number, spacing and array pattern on the mass loss rate (MLR), flame height, flame merging, heat feedback, fire whirl, etc.. For example, Weng et al [2] , Kamikawa et al [3] and Fukuda et al [4] studied the effects of fire spacing and heat release rate (HRR) http …”

“…Once the fires are located sufficiently close to each other, the air entrainment around the flames could be restricted and the resulting pressure drop between fires might lead to flame merging which will cause the increase of flame height compared to a single fire [2,3] . The flame merging will make the fire more destructive, leading to difficulties in firefighting and may even lead to fire whirls [2][3][4][5] . Therefore, it is worthwhile to study the interacting fires.…”

A Correlation for the Flame Height in "Group" Fires

“…A recent paper by Fukuda et al [1] reports on the flame heights in group fires having a square source consisting of N x N (N=2 to 5) square (D = 15cm) porous burners of size D=15cm burning propane with their top on the floor so that air entrainment to the fire was possible from the edge of the group fire assembly. Variables were the heat release rate of each burner and the separation distance, S, between the sides of the burners .…”

“…This papers presents and examines first a correlation of merging flame heights for some recent experiments performed in Japan [1]. A discussion of the conditions for merging of these flames is then discussed followed by comparison with some previous correlations.…”