Abstract: In order to design a more reasonable fire whirlwind generator, the formation conditions and related laws of the fire whirlwind are explored based on the method of geometric conductivity, and then the relationship between the height of the fire whirlwind and the gap size, and the burning speed of the oil pan is proposed. The results show that the formation of fire whirlwind requires a certain amount of vortex, generated vortex, fluid sink and friction; The change of gap size will make the mass burning rate of oil pan show a parabola trend. When the bottom edge size of the fire cyclone generator is 400 mm × 400 mm, the oil pan diameter is 150 mm and the gap is 10 mm, the fire whirlwind height is the highest; When a 200 mm oil pan is used, the height of the fire whirlwind is the highest when the gap is controlled at 30 mm, and the fire whirlwind will be affected by both the burning rate and the shear flow field.

Key words: fire whirlwind, generator, gap size, combustion rate, shear flow field