Fire whirls occur in urban and wildland fires, intensifying the local burning rate and generating long-distance firebrands. A striking feature of fire whirls is their increased flame heights, and this article provides a review of previous efforts to understand how the height of a fire whirl is determined. This paper mainly discusses four factors that influence fire-whirl height: burning rate, strong vorticity, turbulence reduction, and vortex breakdown. It is shown that each influence can be understood based on a simple constant-density mixture-fraction model. In the constant-density approximation, the flame shape can be analyzed in a prescribed flow field. This paper considers a one-celled Burgers vortex, a two-celled Sullivan vortex, and a strong-vorticity flow in which the axial velocity near the axis of rotation is faster than that in the peripheral region.
!!!All Science Journal Classification (ASJC) codes
- 化学 (全般)