基于正交试验的埋地输油管泄漏污染物扩散规律数值模拟

Numerical Simulation of Diffusion Mechanism of Leakage Pollutants from Buried Oil Pipeline Based on Orthogonal Test

针对埋地输油管道泄漏后油品污染物在土壤内的扩散迁移行为,利用计算流体动力学CFD中的多孔介质流动数值模拟方法,分别研究了土壤孔隙率、土壤含水量、油品密度、油品黏度四个因素与泄漏油品纵向扩散深度的关系,结果表明纵向扩散深度与土壤孔隙率、油品密度、油品黏度呈正相关,与土壤含水量呈负相关。针对泄漏油品纵向扩散深度受多种因素耦合影响的情况,设计正交试验,通过对正交试验中数量较少的数值模拟,得到了影响泄漏油品显著性由强到弱的四种因素排序为土壤含水率、土壤孔隙率、油品密度、油品黏度。土壤孔隙率越大,土壤内部的毛细作用力与表面张力相对越小,油品在泄漏过程中所受到的阻力越小,黏度越大的流体在多孔介质中的渗流率越大。模拟结果可为输油管道的设计、泄漏事故的应急处置与土壤环境修复提供技术依据。

In view of the diffusion behavior of oil pollutants in soil after buried pipeline leakage,numerical simulation method for flow in porous media among CFD(computational fluid dynamics)is applied to the re-search of relationship between four factors of soil porosity,soil moisture content,oil density and oil viscosity and longitudinal diffusion depth of leaked oil.The results show that the longitudinal diffusion depth has positive correlation with the soil porosity,oil density and oil viscosity,and has negative correlation with the soil moisture content.In view of the situation that the longitudinal diffusion depth of the leaked oil is affected by a variety of factors,an orthogonal test was designed.Through few numerical simulations in the orthogonal tests,the four factors that affect the significance of the leaked oil from strong to weak were obtained,which were the soil moisture content,soil porosity,oil density and oil viscosity.The larger the soil porosity,the smaller the capillary force and surface tension inside the soil,the smaller the oil leakage resistance,and the higher the flow efficiency of the fluid with greater viscosity in the porous media.The simulation results can pro-vide a technical basis for the design of oil pipeline,emergency treatment of leakage accident and soil environmental remediation.