中文摘要：

液化石油气（LPG）是炼油厂在进行原油催化裂解与热裂解时所得到的副产品,由丙烷、丙烯、丁烷和丁烯等易燃易爆气体组成,一旦发生瞬时泄漏,后果十分严重。基于计算流体力学（CFD）理论,采用商业软件Fluent模拟LPG瞬时泄漏扩散,对泄漏产生的两相云团在风场下的扩散及其特性开展研究。模拟计算在欧拉-拉格朗日体系下进行,分别对气液相采用欧拉和拉格朗日法计算,并从宏观云团和微观液滴两个角度分析了风速对云团演化的影响。模拟结果表明,云团先膨胀成球体随后在风力作用下成为沿水平方向拉长的椭球体,云团运动速度随风速增大而加快,而浓度随风速增大而快速减小。云团扩散时最低温度变化先快速减小,在最低值附近保持小段时间,最后逐步恢复到环境温度。过热液滴释放后速度迅速下降,然后随风运动,最终速度与风速一致。液滴在风场下加速蒸发,风速越大,液滴群平均直径下降得也越快。该研究结果可为泄漏事故的后果和风险评估的提供一定的参考。

英文摘要：

Liquefied petroleum gas（LPG） is a byproduct of the refinery industry during the catalytic cracking and pyrolysis of crude oil,consisting of propane,propylene,butane and butene which are flammable and explosive.Once the leakage occurs,it would lead to disastrous consequence.Based on the computational fluid dynamics（CFD）,this paper carried out research on the diffusion and characters of the two-phase cloud from an instantaneous release using commercial software Fluent under different wind field.The Euler-Lagrangian approach was applied to the simulation,where the continuous phase was computed by Euler method and droplets by Lagrangian method respectively,the effect of wind was analyzed from both the macroscopic cloud and microscopic droplet.Results showed that the cloud shape varied from the initial sphere to the ellipsoid along the horizontal direction,and the cloud moved faster at a higher wind speed while the concentration decreased at the same time.The lowest temperature continued to decrease during the dispersion to the bottom and then recover to the environment temperature gradually.The droplet velocity dropped rapidly as soon as entering into the atmosphere and followed the wind finally.It could be seen that wind field helped evaporation because the droplet diameter decreased if the wind velocity rose.The research of this paper can provide guidance for consequence and risk assessment for such accidents.