Abstract: To obtain the dynamic process and characteristic parameters' law of fire whirls formation, and do a comparative analysis with ordinary fire's risk, a new experiment platform was designed, using wind tunnel to generate environment wind,and the square oil pool length was 6 m and width is 6 m, using hot wire anemometers, DV and heat release rate instrument to collect data. Experiment results verified that the fire whirls formation process includes four stages as ordinary oil fire, intermittent fire whirls, steady fire whirls and boilover. At stable stage,the fire whirls' maximum quality loss rate is 2.44 times that of ordinary fire, the average flame height is 1.49 times; The average radiation in vertical direction is 1.89 times, and the flame temperature will increase with the space rate occupied by fire whirls.

Key words: entertainment wind, middle scale oil fire, fire whirls, mass loss rate, flame height, fire plume temperature