| Abstract: | A control volume, finite element method is used to discretize the three phase, three component equations for simulation of gas venting. The discrete equations are solved using full Newton iteration. Any combinations of phases can exist, and variable substitution is used to take into account phase appearance and disappearance. Some example computations are presented for two dimensional axisymmetric geometry. Several different scenarios for gas venting are examined. High rate air injection can be effective at removing NAPL both in the unsaturated and saturated zones. The numerical techniques can handle problems having node pore volume gas throughputs (in a timestep) of the order of 106, which greatly exceeds the maximum stable explicit timestep size. |
