A study of flame spread over alcohols using holographic interferometry

This study was undertaken as an effort to improve our understanding of the flame spread mechanism over subflash-point liquids. Studies of flame spread over liquids are of interest due to our fundamental curiosity about its mechanism and practical concern about accidental occurrence of fires on liquid fuels. A holographic interferometry technique was applied to obtain detailed temperature profiles in the liquid phase for pulsating and uniform spread over liquids with subflash point. Subsurface liquid convection motion, which is composed of two different circulation zones, was found in the liquid phase for both pulsating and uniform spread regions. In the uniform region, energy balance calculations are made for the liquid phase from the obtained interferograms. The calculation confirms that the flame spread is governed by the convective heat carried by subsurface liquid convection. In addition, the flame spread behavior was recorded by a video camera. The spread rate and pulsation frequency were then deduced.