Experimental Study On Fire Risk Of Automotive Non-power Oils Under External Radiation

Automobile as a means of transportation has entered into our daily life,while providing convenience it also brought a series of security risks.During the running process there are a lot heat accumulated which can be the radiation to the oils.Fires caused by bumps or oil spill are numerous.Automobile oil is a kind of fuel with high calorific value and high risks thus it is a major hazard to automobile fire.Therefore,it is of great significance to study the combustion characteristics and fire risk of automobile oil under the external radiation condition in order to prevent and control the spread of oil pool fire and to reduce the degree of fire hazard.Currently there are few researches about automobile oils under radiant heat flux both here and abroad.This paper summarized two main reason of oil burning based on current automobile oil fire investigation:one is ignite by external fire,namely oil encountered electric spark or other fire;the other is spontaneous combustion due to a series of physical chemistry reaction under radiant heat flux.In this paper,two kind of situations are studied on cone calorimeter.The selected oil samples are commonly used in the market which are supplied by Anhui Jianghuai Automobile Co.,Ltd.In order to get the fire performance of typical flammable transmission oils(ATF and CVTF),automotive antifreeze(JHOA)and lubricant oil(PAG),so bench scale fire performances based on the cone calorimeter and the standard oxygen consumption method were conducted at different levels of heating radiation.Specific parameters,for example ignition time?heat release rate and total heat release have been studied to demonstrate a comprehensive fire hazard assessment of the fluids.ATF and CVTF-EXI tend to cause a fire of long duration while JHOA and PAG trend to cause a quick growing fire.This paper discuss the fire hazard of this typical oils through the fire grow index,fire performance index and other fire evaluation criterion based on the experiment data.Taking all this factors into consideration,it can be remarkably concluded that ATF has a higher fire hazard than CVTF while JHOA has the lowest fire hazard.Spontaneous combustion experiment of transmission oil ATF and CVTF was studied under external radiant heat flux.By linear fitting of transformed ignition time and the radiant heat flux can get the critical spontaneous radiant heat flux of ATF and CVTF.Compare the result with the electric spark test we can find that the critical radiant heat flux of spontaneous combustion is larger than electric spark.It is mainly because the autoignition process is not only pyrolysis-dependent but also reaction-dependent while pilot ignition is pyrolysis-controlled.Petrella's evaluation system was also adopted to define the fire risk of oils spontaneous and pilot combustion.By comparing with the spontaneous combustion,pilot ignition is more dangerous under some radiation.This article also studied the combustion rate and flame height of automobile oil under different external heat flux on a self-made experimental platform.Through the theoretical analysis,the 2/3 exponential relationship between the radiant heat flux and flame height is obtained.Based on the experiment data,the flame height change with the external heat flux and a model for prediction of the flame height under different radiant heat flux is proposed.The data obtained from the experiment in this paper laid a solid foundation for the establish of the database of combustion character of the oils,which can help to conduct the numerical simulation of the vehicle fire in the future.