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在混合模型理论基础上,建立LPG(liquefied petroleum gas)在非饱和砂土中渗流扩散的传热、传质模型,研究LPG埋地储罐在砂土介质中发生泄漏时LPG渗流扩散的物理过程。该模型综合考虑了LPG泄漏相态、重力、黏滞力、毛细压力、扩散、非达西效应、气液相之间相互作用等影响因素的作用;在Forchheimer方程基础上,推导出多相混合流的非达西流动方程,并根据LPG实际渗流过程中流动状态的变化,将多相流非达西系数根据Reynolds数变化进行相应的改变,实现对多相流体从非达西流动向达西流动的转变现象的描述,能够模拟多种流动状态变化,扩展了模型的适用范围;根据LPG不溶于水的特性,简化了组分方程,推导出LPG体积浓度计算式。该模型能描述LPG埋地储罐泄漏后在砂土中流动趋势和对周围造成的影响,为埋地储罐场地选取、周边区域规划和事故预防、预测、应急提供依据。
Based on the mixed model theory, the heat and mass transfer model of seepage diffusion of liquefied petroleum gas (LPG) in unsaturated sand is established, and the physical process of LPG seepage diffusion when the LPG buried tank leaks in sand media is studied . The model takes into account the influence of LPG leakage phase, gravity, viscous force, capillary pressure, diffusion, non-Darcy effect, interaction between gas and liquid and other influencing factors. On the basis of Forchheimer equation, According to the variation of flow conditions during the actual seepage process of LPG, the non-Darcy coefficient of multiphase flow is changed correspondingly according to the Reynolds number change, so that the flow of multiphase fluid from non-Darcy flow to Darcy According to the properties of LPG insoluble in water, the component equation is simplified, and the formula for calculating the volume concentration of LPG is derived. The model can describe the flow tendency of the LPG buried storage tank in the sand and its impact on the surrounding area after the leakage of the LPG storage tank, and provide the basis for the selection of the site of the buried storage tank, the planning and accident prevention, prediction and emergency of the surrounding area.