Numerical Study On Leakage And Diffusion Of Liquefied Petroleum Gas

In recent years,a large number of rural population moved to the city with the rapid urbanization in China.The consumption of gas used in daily life and production also increased rapidly.In addition,in order to alleviate the increasingly serious environmental pollution problems,the state strongly advocated "coal to gas" in the field of life and production in our country.Relatively clean types of gas instead of coal is used,which also increases the use of gas scale.The large-scale utilization of all kinds of gas reduces the use of coal,which alleviates the environmental pollution to a certain extent.This paper is based on mass conservation,momentum conservation,energy conservation and multi component gas transport equation.A mathematical model is established.Numerical simulation of gas leakage and diffusion is carried out by CFD method.The influence of temperature,relative humidity,solar radiation and the upward and leeward obstacle on the leakage source is studied.The distributions of mass fraction,temperature and flow are obtained to reveal the transfer mechanism of gas leakage and diffusion and its evolution law.The area where the explosion may occur in accordance with the explosion limit is found,and then the safety range is determined.The results show that temperature,relative humidity,solar radiation and obstacle have obvious influence on gas leakage and diffusion.The higher the temperature is,the greater the degree of active air molecules is,which increased the dilution rate of heavy gases,shorten the gas into non heavy gas time and increased the explosion area.With the increasing of relative humidity of the air,the effect of heavy gas cloud is increased.It accelerates the speed of spreading to the near ground,slows down the diffusion speed in the downward wind direction and reduces the explosion area.Solar radiation increases the temperature of the ground and the leakage gas.It increases the kinetic energy of the molecules,speeds up the diffusion rate of the leaking gas and increases the explosion area.The obstacle changes the law of the wind field and the diffusion velocity and diffusion law of the leakage gas.The windward obstacle changes the flow law of the fluid.It increases the uneven degree of the air and changes the leakage and diffusion law of the liquefied petroleum gas;The explosion distance in the horizontal direction is increased,but the distance in the vertical direction is reduced.The downwind barrier has a direct blocking effect on the gas diffusion,which greatly slows down the leakage and diffusion velocity and reduces the explosion area.