Experimental study of some characteristics of nonstationary wall-free fire whirls

This paper is aimed to demonstrate an opportunity of the generation of nonstationary wall-free fire whirls under laboratory conditions without using mechanical swirling devices and to estimate their integral parameters. A simple experimental facility, making possible the generation of concentrated fire vortex structures by means of combustion of solid fuel (urotropine) arranged symmetrically on a metallic underlying surface, is described. With the use of photography, some novel data on the probability of generation of fire whirls depending on the experimental mode have been obtained.