Studying wildland fire spread using stationary fires

Abstract

Experiments were performed using stationary gas burners and liquid fuel-soaked wicks to study fundamental wildland fire behaviour, including unsteady flame heating. These experiments were motivated by observations of instabilities in spreading fire experiments that suggest they play a critical role in fire spread. Stationary fire experiments in forced flow and on inclined surfaces exhibited instabilities similar to those observed in spreading fires but allowed for more detailed analysis of the mechanisms responsible. Large scale inclined experiments were performed using an ethylene gas-fed burner at angles from 10 to 60 degrees. Forced flow experiments were performed on liquid-soaked wicks and small scale gas burners at wind speeds from 0.2 to 3 ms-1. Results presented include observations of the general flame structure, including streamwise streak spacing and flame fluctuation frequencies which relate to instabilities observed in large spreading experiments. A description and correlations of flame geometry, useful for predictions of wildland fire spread are also presented.