1. General Model Information

Name: Multiphase Flow and Transport of Multicomponent Organic Liquids

Acronym: MOFAT22

Contact:

Author(s):

Abstract:

MOFAT is a two-dimensional finite element model developed for the EPA for coupled multiphase flow and multicomponent transport in 2-D planar or radially symmetric vertical sections. Flow and transport of three fluid phases - water, nonaqueous phase liquid (NAPL) and gas - is simulated by the program. MOFAT also handles cases in which gas and/or NAPL phases are absent in part or all of the domain at any given time. Transport of up to five partitionable species through saturated and unsaturated zones in Cartesian or radial coordinates can be investigated.

MOFAT achieves a high degree of computational efficiency by solving flow equations at each node (on the finite element mesh) only for phases that are undergoing changes in pressures and saturations above specified tolerances using a new "adaptive solution domain" method. Therefore, if NAPL is absent or exists at a residual saturation, MOFAT will locally eliminate those flow equations. MOFAT analyzes convective-dispersive transport in water, NAPL, and gas phases by assuming local equilibrium or nonequilibrium partitioning among the fluid phases and with the solid phase. The model considers interphase mass transfer and compositional dependence of phase densities. A concise but accurate description of soil capillary pressure relations is used which assures natural continuity between single-phase, two-phase and three-phase conditions. The user can estimate soil properties using DAEM's SOILPARA.

Model with MOFAT:

• Simulate multiphase transport of up to five noninert chemical species
• Model flow of light or dense organic liquids in three fluid phase systems
• Solve flow equations for phases exhibiting transient behavior using ASD method
• Simulate dynamic gas as a full three-phase flow problem
• Use a three-phase van Genuchten model for saturation-pressure-permeability relations
• Handle flux-type, specified head, specified concentration or mixed type (type 3) boundary conditions
• Consider hysteresis in oil permeability due to fluid entrapment
• Model water flow only, oil flow with steady-state water or coupled oil-water flow

• True WindowsTM pre- and post-processor
• Finite element mesh generator
• Editors for defining heterogeneity and anisotropy in the domain
• Full graphing built in
• Simple contouring with export capabilities to Surfer for WindowsTM and to Environmental WorkBenchTM for runtime animation of model results

Further information: MOFAT 2.2

II. Technical Information

II.1 Executables:

• 486 processor or higher
• Math coprocessor
• At least 4MB of RAM
• 2.5MB of hard disk space

II.2 Source-code:

II.3 Manuals:

II.4 Data:

III. Mathematical Information

III.1 Mathematics

III.2 Quantities

III.2.1 Input

III.2.2 Output

IV. References

Parker, J.C., Lenhard, R.J. and Kuppusamy, T., 1987.A parametre model for constitutive properties governing multiphase flow in porous media. Water Resour. Res. 23:618-624.

Parker, J.C., 1989.Multiphase flow and transport in porous media. Reviews of Geophysics. 27:311-328.

Sleep, B.E. and Sykes, J.F., 1989.Modeling the transport of volatile organics in varibly saturated media.Water Resours. Res. 25:81-92.

V. Further information in the World-Wide-Web

VI. Additional remarks

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