Study Of Combustion Characteristics Of Oil Tank Fire Under Multi-factor Conditions

Petroleum and its downstream products have been the major energy suppliers to industrial societies for a long time.And total capacity of storage facilities and their quantities have been increasing with growing petroleum consumption year by year.However,a large amount of flammable and explosive oil in oil tanks has triggered enormous concerns and worries about the safety of the petrochemical industry.Previous studies on oil tank fires mostly focused on pool fires,but because the tank itself has a certain height,its combustion behavior is not exactly the same as the pool fire.Therefore,it is necessary to study the influence of lip height on tank fire.The high thermal radiation in oil combustion can easily cause the adjacent oil tank to ignite or detonate,thus leading to multiple fire source combustion and aggravating the threat to the safety of the tank farm;hence,it is significant to make researches on combustion characteristics of fire of double oil tanks and the influence of their space on the characteristics.In addition,tank fire is also affected by numerous factors like wind speed and roof opening,so the study on the combustion characteristics of tank fire under the coupling of multiple factors can play a certain theoretical guiding role for the actual tank fire.In this study,experiment platforms of single oil tank fire under wind conditions and of double oil tanks fire have been built respectively with diesel as the fuel.The diameter of the tank used in the single oil tanks fire was 30 cm,lip height was 10,15,30 cm,the tank top opening width was 15,18.5,22,26,30 cm,and the wind speed was 0,0.3,0.5,0.8,1.0,1.2,1.5 m/s.The diameter of the tank used in the double oil tanks fire experiment was 30,40,50 cm,the lip height was 2,5,10,15,30 cm,and the tank space was 0.2D,0.4D,0.8D,1.2D,2.0D.A lip height stabilizing device is used during the experiment to make the lip height of the diesel in the tank remain unchanged.The study is on the change law of flame tilt angle,flame height,mass loss rate,temperature and thermal radiation flux of oil tank fire under multiple factors.This experiment study indicates that the flame tilt angle of diesel tank fire quickly increases and then turns flat with the wind speed;it decreases as the speed of fire micro-element at the tank opening accelerates with the increase of lip height;and it decreases as mass loss rate grows with increase of top opening width.The study on double oil tanks fire shows that the mass loss rate,wall temperature and thermal radiation flux first increase and then decrease with the increase of lip height when the flame did not merge.Flame merging can increse the mass loss rate and thermal radiation flux greatly.The study on the internal temperature of the tank finds that the temperature is gradually increasing from the fuel surface to the base of the flame.The mass loss rate,temperature and heat radiation flux increases with the increase of diameter,decreases with the increase of the tank space.The study is also made on the influence of lip height and tank space on radiation view factor,and analyzes thermal feedback mechanisms.It is found that the visible flame height of fire of double oil tanks increases with the increase of the tank diameter,decreases with the increase of the lip height.When the flame not merging,the visible flame height increase with the increase of the tank space.Flame merging can increase the visible flame height sharply.The model of the visible flame height of double tanks is thus studied on this basis,and the characteristic length is selected with consideration of tank diameter,lip height and space.