Numerical Simulation Of LPG Tank Subjected To Fire Environment

For liquid gas tank,fire explosion is an accident which happens frequently during the production,storage,and handling of liquid gas.When the tank is subjected to fire,internal pressure will increase,at the meanwhile wall strength decrease,ultimately it can lead to crack on the tank which can easily cause explosion or poisoning accident.Researching for thermal response behavior of liquid petroleum gas(LPG for short) tank in fire can provide theoretical basis for predicting,preventing and controlling accident.In this article,the physical and numerical models for LPG storage tank in fire are set up. RNG k-εmodel and VOF model are used to describe turbulent flow and two-phase flow respectively.Quality and energy change in gas and liquid phase are handled by adding source terms to mass and energy equations.Changes of wall temperature,loading temperature and internal pressure while the LPG tank is subjected to two different types of fires(pool fire and jet fire) are simulated respectively.The CFD software FLUENT is used and the simulation are carried out in three-dimension space.It shows that the simulation results consistent well with the experimental data.The model could simulate LPG tank when subjected to jet fire or pool fire thermal response process by changing boundary and initial conditions to apply to some cases like this:different size,liquid fill level,fire temperature,wall thickness and engulfing fire area.Main factors that affect the thermal response process of LPG tank are considered. Compare different factors which are fill level,fire temperature,wall thickness and engulfing fire percent influence on wall temperature,loading temperature and pressure with LPG tank subjected to jet and pool fire.The higher fill level is,the faster pressure and loading temperature increase,the less tank fail time.Tank which is 85%fill level pressure response is almost twice 20%fill level tank. The higher external flame temperature is,the faster wall temperature,loading temperature and pressure increase.It is remarkable that fire temperature is influence on wall temperature, when fire temperature changing 100K,and then wall temperature change about 100K.Wall thickness has a significant impact on tank pressure,wall temperature and loading temperature, the three parameters all decrease.The higher the engulfing fire degree is,the faster pressure and loading temperature increase,but wall temperature have nothing to do with it.Tank thermal response subjected to jet fire is faster than to pool fire,and need less time to reach the same pressure and temperature;however,when tank pressure and wall temperature are the same,liquid loading temperature is higher when tank subjected to pool fire,this means higher superheat degree.If tank ruptures at the time,BLEVE is more possible, or even if both tank happen BLEVE,higher superheat degree of the tank resulting from the explosion is more powerful...