| dc.description.abstract | Buried pipelines are one of the major transportation methods for natural gas and other light hydrocarbons around the world. With that comes the risk of pipeline failure and the release of the flammable materials, which have caused many incidents in the past including significant human and economic losses. Thus, understanding the behavior of underground gas flow and the way it escapes to the atmosphere is necessary for consequence modeling, in order to have the best possible prevention and mitigation barriers.
Depending on the conditions, the gas flow regime can be divided into three categories: diffusion, fluidization, and crater formation. The main objective of this project is to develop a CFD model that is able to simulate all underground gas flow regimes. The model was developed using the ANSYS Workbench Software. The dimensions of the simulated systems were based on the information given by industries in Qatar. The adopted approach included the Eulerian-Eulerian multicomponent model, the standard k-€ turbulence model, and the Gidaspow drag model. The model was configured and refined by testing the effect of various parameters such as the type of boundary conditions used, and the effect observed by changing some of the input data.
The configured model was validated against experimental data, with emphasis on testing its ability to predict the underground gas flow regime, and local methane concentrations. The model was then used to simulate various scenarios with differing the gas inlet velocity and soil density values. The results for each simulation were recorded with the gas underground gas flow regime identified, and then plotted using dimensionless numbers such as the Reynolds’ and Archimedes’ numbers. The obtained graph helps identifying the boundaries between each flow regime. The results of one of the simulations were used as an input for a consequence modeling software, and the threat zone based on the inputted data was reported. | en |
