Fire Whirl Experimental Facility with No Enclosure of Solid Walls: Design and Validation

In this work, a fire whirl facility with no enclosure of solid walls was designed, for experimental simulation of fire whirls in open field. Air curtains were used to produce the generating eddy of fire whirl. Tests were conducted to evaluate the capability of the new facility. It was found that there was an optimal tilt angle for the air curtains to produce stable fire whirls. Experiments of fire whirls under different pool diameters showed that the mass loss rate \( \dot{m} \) depended on the circulation \( \varGamma \) by \( \dot{m}\sim \varGamma^{1.18} \) and the dimensionless flame height satisfied \( H^{*} \sim \varGamma^{*0.71} \) (where the asterisks denote dimensionless variables). It was also found that the ratio of the continuous flame height to the whole flame height for different pool diameters was 0.67. The centerline temperatures varied with the normalized height \( Z \) by \( Z^{0.08} \), \( Z^{ - 1.30} \) and \( Z^{ - 2.18} \), respectively in the regions of the continuous flame, intermittent flame and plume. The radiative fraction was calculated to be close to 44%. All these results fit well with literature data, thereby the capability of the new facility for producing stable fire whirls was fully validated. Some potential applications of the new facility were discussed in detail. Especially, instruments such as infrared camera can be used to investigate the flame radiation of fire whirls by the new facility.