The aim of this study is to quantitatively grasp the effect of excess fuel gas on the temperature distribution of the fire plume ejected from an opening when the amount of combustible gas generated in the compartment was changed using a large-scale model.
In this study, the experiment device composed of compartment and facade. The compartment size was Width 2 [m] x Depth 2 [m] x Height 2 [m]. The dimensions of the facade were Width 3 [m] and Height 3.5 [m]. The urban gas was used as a fire source, and a gas burner (Width 0.3 [m] x Length 1.8 [m]) was installed in the center of the compartment floor. The measurement items were temperature inside compartment and temperature of the fire plume ejected from an opening, which were measured using a thermocouple. As the experimental conditions, the opening shape and the heat release rate of the fire source were changed. The opening aspect ratio was in the range of 1 to 6, and the opening conditions were 6 conditions and the heat release rate of the fire source was set to 6 conditions.
The following findings were obtained from this study.
(a)The central axis of fire plume ejected from an opening
・The central axis of fire plume ejected from an opening tends to be away from the facade surface under the opening
condition with the opening aspect ratio of 3 or less, and move along the vicinity of the facade surface under the opening condition with the opening aspect ratio of 4 or more.
(b) Relationship between average temperature rise within the compartment and of ejected fire plume at opening
・Under the condition that the heat release rate is set by Qvcrit, the change in the dimensionless temperature within the compartment and above neutral plane of the opening is not remarkable even if AT/AH1/2 increases.
・The non-dimensional temperature ΔTo,p/ΔTf,p obtained by dividing the average temperature rise of ejected fire plume at opening by the average temperature rise within the compartment is about 0.8 to 0.9.
・The non-dimensional temperature ΔTo,p/ΔTf,p exceeds 1 under the condition that the flame is ejected from the opening where value of AT/AH1/2 is small.
(c) Temperature distribution of fire plume ejected from an opening
・By using the non-dimensional value Z*/Q*ef,w2/3 in consideration of excess fuel gas and temperature rise ΔTz, the temperature rise of RegionⅢ could be nearly expressed by Eq.(15) as Z*/Q*ef,w2/3 increases.
