柴油在非饱和带运移分布及模拟研究

Study on the distribution and transport Simulation of diesel in unsaturated zone

以中砂和0号柴油为研究对象,通过室内物理模拟试验以及构建的描述柴油在包气带运移的多相流动力学模型,定性定量研究了柴油泄漏后在非饱和带内的运移分布特征。结合物理模拟试验及数学模拟,描述柴油泄漏进入巾砂介质中的过程,得到毛细带以上的残余油区及毛细带至地下水面的聚集油区的油相在非饱和带的分布特征。结果表明,利用室内二维渗流装置,可较好揭示柴油渗漏后在地下环境中运移过程。

With medium sand and 0 # diesel oil as targets, this paper has qualitatively and quantitatively described the distribution of diesel leakage in unsaturated zone through the indoor physical simulation testing and the muhiphase flow dynamics modeling. The results show that the indoor two-dimensional flow device can better reveal the migration process of diesel in the underground environment after the leak. The numerical simulation shows that the oil front kept vertical movement at the initial stage of diesel leakage due to the gravity as it has not arrived at the edge of the capillary zone. The diesel migration kept the rule of arc movement and the saturation level of the contaminated area decreased gradually from the center towards the outside. The centered oil saturation was nearly 0.6 but the water saturation in capillary zone did not change. The diesel frontal has still maintained the initial distribution. After the oil front reached the capillary zone, the oil flow front broadened as a whole because of the capillary force jacking and the centered saturation was found slightly lower than the center area near the top sources. If the leakage continued, the front would expand horizontally. Combined with the physical simulation and mathematical modeling of diesel leakage migrating through the medium sand, the oil frontal can be divided into residual oil zone above the capillary zone and capillary band as well as aggregated oil zone from the capillary zone to underground water phase. The paper provides a theoretical basis and experimental support for the study on diesel pollution control and pollution prediction.