Measurements of Fire Whirls From a Single Flame in a Vertical Square Channel With Symmetrical Corner Gaps

One of the most destructive forces in large urban fires is the occurrence of fire whirls. Despite the relatively recent experimental and numerical simulation studies on the global behaviors of small-scale whirling fires, much of the whirling fire phenomena still remain unknown. The purpose of this experimental study is to examine closely the detailed structures of the velocity and temperature fields in a stable whirling flame generated in a vertical square channel with symmetrical corner gaps by both physical measurements using conventional means and by quantitative observations using both a high-speed motion camera and a thermographic infrared camera. The results showed a rather complex non-uniform velocity and temperature field in the lower half of the whirling flame and could provide an important basis to validate the fire field models for the study of real large-scale fire whirls.