| Nowadays,the social and economic development is inseparable from the use of fossil fuels.But over-reliance on fossil fuels has bringing some problems.In China,the terrain is complex and changeable and the elevation drop from west to east is large.Due to the uneven distribution of flammable liquid fuels,the amounts of refined oil transportation pipelines is increasing.In order to satisfy the demand for oil in high altitude areas,some oil transport pipelines need to pass through these areas.Meanwhile,plenty of oil has been stored and consumed in high altitude areas.In addition to civil and commercial use,a special scenario using oil is worth noting,that is the plateau airport.The low pressure and low oxygen environment in high altitude areas have an impact on the combustion process of oil,and the fire raised from fuel leakage in high altitude areas also show different characteristics with the plain area.Compared with other types of fire,the characteristics of the fire arise from oil leakage may lead to a serious damage with a special burning phenomenon-the thin layer of boiling phenomenon.The leakage from oil tanker will formed an oil pool in some range which could cause environmental problem,and direct burning is one of the commonly used method to deal with this problem.In this situation,the thin layer of boiling phenomenon will happen.Besides,when fuel leakage fire occurs,the leakage of thin oil layer will burn over the thin water layer in some conditions,such as the rainy condition.The thin layer boiling phenomenon may occur in these conditions.Therefore,it is necessary to carry out further study on the phenomenon of thin layer boiling and explore the development of this phenomenon.The author hope that this research could be helpful to the extinguishment and rescue of oil leakage fire in the plains and high altitude areas,preventing the damage to rescue team and facilities.The phenomenon of thin layer boiling involves many basic physical and chemical processes.Until now,the mechanism of this phenomenon is still in the exploration stage.This study established a small scale experimental platform to analyze the characteristics of oil-boiling fire.In order to investigate the effects of pressure on the boiling of small scale oil basins and the reason of overheated at the oil-water interface.A series of small scale field pool fire with padded water has been carried out at three different pressure points:Hefei(Alt:58m P:101kPa),Lijiang(Alt:2400m P:76Pa)and Lhasa(Alt:3650m P:64Pa).At the same time,considering the combustion control factors four oil basin with diameters of 0.15m,0.18m(convection dominant),0.30m and 0.40m(radiation dominant)were selected.The initial thickness of the oil layer is specified as 0.5cm identically and the thicknesses of water layer are 1cm,1.5cm and 2cm,respectively.Considering the frequently of usage and the safety of the oil in the highland airport mentioned before,the types of experimental oil is determined as the aviation coal kerosene Jet A and 0#diesel.Physical parameters which used to characterize the thin layer of boiling fire are:mass,temperature,radiation and sound intensity.From the perspective of mass variation,this study analyzes how the different variables affect the following indexes:the quality loss rate in the stable stage,the remaining oil thickness after boiling and the boiling intensity.In the term of temperature,the overheating of water layer at the oil-water interface is analyzed emphatically. |
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