分析城市加气站液化石油气(Liquefied Petroleum Gas,LPG)埋地储罐泄漏后LPG在砂土介质中渗流扩散的物理过程及特点,确定埋地储罐不同位置泄漏出现的物质流动状态,分析LPG在砂中传输过程中与砂、空气、水之间的传热、传质方式.采用LPG渗流扩散传热、传质多相混合数值模型,对某城市加气站LPG埋地储罐气相区发生泄漏事故在含水量不同的罐池中渗流扩散过程进行模拟,得到LPG饱和度、危险浓度、压力、流速等空间分布规律以及流动趋势、出口浓度变化,并对影响LPG流动的主要因素进行分析.模拟结果表明罐池出口位置对气体渗流扩散方向的影响大于储罐壁面形状和重力的影响；泄漏口和出口附近区域压力随距离下降梯度较大,中间压力下降较缓；储存压力是影响LPG在砂土介质渗流过程中压力的关键因素；在同一位置气体在非饱和砂中渗流的压力高于气体在干砂中的压力；存在砂土中的水有阻碍气体扩散的作用.%The physical process and characters of LPG ( Liquefied Petroleum Gas) infiltration dispersion in tank pond for the leak accident of underground storage tank in urban gas station were analyzed. The LPG flow states and the flow transition were studied when leak hole was at different positions of LPG underground storage tank. The ways of heat transfer and mass transfer among LPG, sand, air and water were analyzed. The migration processes of LPG in tank pond filled with different moisture contents for underground storage tank leak in some urban gas station were simulated by the three-dimensional multiphase mixture flow model. The velocity, saturation, hazardous concentration and pressure fields were visualized. The flow development, LPG concentration change process on outlet and the influence condition of various factors on infiltration flow were obtained. The simulation results show that the effect of the outlet position on the direction of LPG vapor flow is more obvious than tank wall shape and gravity; a-round the leak hole and outlet zone, the pressure gradient with distance declines faster than other zones; the storage pressure is a key factor for LPG infiltration dispersion; at the same position of tank pond, the pressure in unsaturat-ed sand is higher than in dry sand; water in sand slows down LPG infiltration velocity.
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