Numerical analysis on liquid seepage - Diffusion coupled with heat in soil of low - Pressure buried pipelines leakage

The incident of buried pipeline leakage has become one of the main concerns since the consequences of social economy and soil environment. The main objective in this study is to develop a numerical model for the low - pressure buried water pipeline leakage by CFD (Computational Fluid Dynamics). In this model, the process inside and outside of the pipeline is connected through the orifice, and the heat transfer is coupled during the leakage water seepage - diffusion in soil. In this way, the degree and diffusion range of buried pipeline leakage by considering soil as porous medium are investigated. Comparison of the numerical and experimental results demonstrated that the model has a higher precision in predicting accident severity and influencing range. Further, the effects of inlet water temperature, pipe pressure, orifice's diameter, orifice's position and soil porosity are systematically researched. Some acquired results are as follows: temperature can promote soil moisture transfer and the two are positively correlated. The degree and diffusion range increase with the increasing pipe pressure, orifice's diameter and soil porosity. Orifice's position only affects diffusion direction, not diffusion range. The conclusions will provide theoretical foundation for soil environment remediation.