The analysis on calculation model of heat-wave velocity during the process of crude oil storage tank fire
The formation mechanism of boilover fire in crude oil storage tank is very complex and harmful. Heat-wave velocity is an important research topic in the boilover fire. After introducing boilover mechanism, the models of heat transfer and heat-wave velocity was built by heat transfer analysis for oil layer. Comparing the calculation results of model with the experimental data, this heat-wave speed calculation model is reasonable. Through the research, several conclusions were found: the main factors that impact heat-wave rate are the viscosity and component of oil, heat of heat-wave comes mainly from thermal radiation of flame; Emulsified water in the oil will not trigger boilover fire normally. Only the heat-wave encountered bottom water cushion at the bottom of the tank, did boilover fire take place. In practice, the heat-wave moving speed can be valued 1m/h to estimate the occurrence time of boilover. The results of this study are important for control and security of boilover fire accident.
A Study of Boilover in Liquid Pool Fires Supported on Water Part I: Effects of a Water Sublayer on Pool Fires
Abstract Under certain circumstances, the water on which a burning pool of liquid fuel is supported may begin to boil. The water vapor that is released and escapes through the fuel surface tends to atomize the oil, which results in an emulsive-droplet flame above the fuel surface. This phenomenon, called boilover, has been observed for large scale pool fires, but the mechanism causing it to occur has not been fully investigated yet. This paper describes fundamental aspects of the effect of a boiling water sublayer on the behavior of pool fires. A burner system in which the burning surface of the fuel can be fed into the flame so that the fuel/water interface with respect to the edge of the container remains fixed was used. Ten different single-component and six different multicomponent fuels were tested. Conventional flow visualization techniques were applied to study the liquid motion, and results for an ethylbcnzene pool in a 4.8cm diameter pan are presented. Data obtained include temperatures and mass ...
Flame spreading across liquid fuels
The various mechanisms postulated to control the rate of flame propagation across a liquid fuel surface are discussed in detail. Major consideration is given to the surface tension induced flows which control the propagation at liquid temperatures well below the closed cup flash point and the cause of the flame pulsation noted at liquid temperatures just below the flash point. Some new considerations are given to the concepts and methods of experimentally evaluating flash and fire point phenomena. Analytical developments which correctly predict the very high propagation rates across liquids at temperatures well above their flash points are discussed.