Hiroki Ishida

SHORT COMMUNICATIOI\J

Abstract Flame spread aspect along the pool surface of gelled (O/W emulsified) II-octane with high internal phase ratio was investigated from the viewpoint of spilled-fuel fire prevention. The temperature field in the vicinity of the spreading flame front was measured by thermocouples (chromel-alurnel, 0.1 mm dia.) and Mach-Zehnder interferometry, and temperature histories on the unburned surface and in the gas phase adjacent to the surface were shown.From the measured results, the mode of heat transfer from the spreading flame to the unburned pool surface was estimated. The dependence of flame spread velocity on the initial temperature of gelled η-octane and on the oil content in gel (internal phase ratio of O/W emulsion) were also investigated.

Ignition Characteristics of Gelled (0/W Emulsified) Hydrocarbon Fuel Pool

Abstract Ignition characteristics of the pool surface of an O/W emulsified gelled hydrocarbon fuel with high internal phase ratio were investigated from the standpoint of spilled-fuel fire prevention. Flash points of miscellaneous gelled fuels with single and multiple components, and of commercial fuels were measured and compared with those of neat hydrocarbon fuels. The Tag Closed-Cup method was used for flash point measurement. A dispersive type infrared gas analyzer (DIR)was used to measure the temperature dependence of the equilibrium vapor concentration of the emulsified fuel. Ignition aspects of an emulsified fuel pool surface were studied and compared with those for neat liquid fuel, here a small hot Nichrome wire adjacent to the pool was used to heat the surface locally. The procedure was also recorded in a 16 mm movie and inter-ferogram form. It was found that whether the neat fuel is a single substance or a multi-component mixture has an effect aside from that of emulsification on the elevation ...

Flame Suppression over Liquid Pool by W/O Emulsification

Abstract The suppression of spread of flame over A-Heavy oil pool by W/O (water-in-oil) type emulsification was studied experimentally in detail. W/O emulsified A-Heavy oil, in which the water content is 2-10 vol %, was prepared by mixing A-Heavy oil with water without surface active agent in the gear pump type emulsification apparatus. The effects of W/O emulsification on the flash point, the velocity of flame spread over the pool and on the development of preceding surface flow ahead of flame leading edge were studied. The results were discussed comparing the W/O type emulsified A-Heavy oil with the original one, The flash point of the W/O emulsion rises 2 ∼ 4°C from that of the original A-Heavy oil with increase in the water content up to 2 vol %. The velocity of flame spread can be suppressed owing to the emulsification to about ½ ~ ⅔of that over the original A-Heavy oil. Preceding surface flow ahead of flame is promoted owing to the emulsification. From these results, the present study concludes that...

Flame Spreading Along the Surface of Gelled (0/W Emulsified) Hydrocarbon Fuel Pool

Abstract Flame spreading along the pool surface of O/W (oil-in-water) emulsion type gelled hydrocarbon fuels with high internal phase ratios have been investigated from the standpoint of spilled-fuel fire prevention. Aspects of flame spreading and temperature field in the vicinity of the spreading flame front were observed and measured by 16 mm movie pictures, interferometry and thermocouples. It was found that a thin liquid layer flow ahead of and below the flame exists if the neat hydrocarbon fuel has a flash point higher than the ambient temperature and or has considerably different flash and fire points. No such liquid layer flow can be observed if the neat fuel has a flash point below the ambient temperature and consists of a single component. Whether such a liquid layer flow exists or not would have a large influence on such aspects of flame spreading as velocity, direction and steadiness. The influences of the initial temperature and the oil content of O/W emulsion on flame spreading velocity were ...