Test Case 09 2D Channel multiphase transport - GeoChemFoam/GeoChemFoam GitHub Wiki

This test case is an example of how to compute an interface transfer coefficient at phase equilibrium. For this, we consider a 2D microchannel of size 800x100 microns with thin film deposition. The fluids considered here are air (density = 1 kg/m^3,  viscosity = 18 microPa.s) and ethanol (density = 789 kg/m3, viscosity = 1.2 mPa.s), and the interfacial tension is equal to 20 mN/m. The top and bottom boundaries are wall conditions with a fixed contact angle of 20 degrees. The domain is initially filled with ethanol and we inject air from the left boundary with a constant velocity U = 0:4 m/s while fixing the pressure on the right boundary. These flow parameters correspond to a capillary number of 2.4x10^-2. In addition to this, the gas phase carries a species T with a concentration C = 1 kg/m^3. The diffusivity of T in the gas and liquid phases is Dg = Dl = 2x10-7 m^2/s, which corresponds to Pe = 100, and the Henry coefficient H is assumed to be equal to 0.1. The initial concentration of contaminant in the liquid phase is set to zero. The thickness h of the deposited film on the walls is given by the semi-empirical Taylor's law proposed h/R = (1.34Ca^(2/3))/(1+3.35Ca^2/3), where R is the radius of the microchannel. This corresponds to h = 4.5 micron. To capture accurately the thin film, we use a grid with constant size  x = 4 micron in the x-direction and local refinement in the y-direction near the wall with  ymin = 0.6 micron on the wall and  ymax = 4 micron at the center of the channel. The full grid includes 200x40 cells.

  1. Navigate to the correct tutorial: cd $GCFOAM_TUTORIALS/multiphaseTransport/interTransportFoam/channelMultiphaseTransport/. If you are using Docker copy the tutorial into the runs directory cp -r $GCFOAM_TUTORIALS/multiphaseTransport/interTransportFoam/channelMultiphaseTransport/ $GCFOAM_RUNS/..

  2. Create the mesh using the ./createMesh.sh script. If you are using Docker, you need to copy the results in the runs folder to visualise them. cp -r ../channelMultiphaseTransport/* $GCFOAM_RUNS/channelMultiphaseTransport/.

channelMesh Fig 1. Mesh for channel multiphase transport. The paraview filter 'Reflect' was used to represent the symmetrical boundary condition at the top.

  1. Initialise the simulation by running the ./initCase.sh script. This script defines the fluid and flow properties, and initialise the phase volume fraction. If you are using Docker, you need to copy the results in the runs folder to visualise them. cp -r ../channelMultiphaseTransport/* $GCFOAM_RUNS/channelMultiphaseTransport/.

channel0 Fig 2. Initial phase saturation for channel multiphase transport. The paraview filter 'Reflect' was used to represent the symmetrical boundary condition at the top.

  1. Run the case with ./runCase.sh. If you are using Docker, you need to copy the results in the runs folder to visualise them. cp -r ../channelMultiphaseTransport/* $GCFOAM_RUNS/channelMultiphaseTransport/.

channel0 Fig 3. Species concentration at t=0.0025 s for channel multiphase transport. The paraview filter 'Reflect' was used to represent the symmetrical boundary condition at the top.

  1. Run the ./processCase.sh script. This script calculates the concentration of species (kmol/m3) in each phase and the interface flux (kmol/m2/s).
cat Species_phaseConc.csv
time T1 T2
0 0 0
0.0001 6.68363e-122 9.02861e-37
0.0002 3.66599e-53 2.58171e-14
0.0003 0.157118 0.000115028
0.0004 0.942265 0.00197184
0.0005 0.972365 0.00349565
0.0006 0.977944 0.0054085
0.0007 0.97981 0.00790595
0.0008 0.980918 0.0112916
0.0009 0.981752 0.0161315
0.001 0.982429 0.0232629
0.0011 0.982998 0.03375
0.0012 0.983485 0.0552302
0.0013 0.987006 0.089411
0.0014 0.988933 0.0964043
0.0015 0.989688 0.0971281
0.0016 0.990764 0.097483
0.0017 0.991851 0.0977675
0.0018 0.992852 0.0980189
0.0019 0.993752 0.0982461
0.002 0.994554 0.0984516
0.0021 0.995266 0.098637
0.0022 0.995897 0.098804
0.0023 0.996453 0.0989541
0.0024 0.996942 0.0990883
0.0025 0.997371 0.0992079

cat interfaceFlux.csv
 time phi
0 0
0.0001 4.53418e-113
0.0002 8.8322e-45
0.0003 0.000675816
0.0004 0.00407466
0.0005 0.00360816
0.0006 0.00258322
0.0007 0.00197358
0.0008 0.00159595
0.0009 0.00134128
0.001 0.0011578
0.0011 0.00101892
0.0012 0.000909811
0.0013 0.000491994
0.0014 0.000100534
0.0015 3.68964e-05
0.0016 2.71787e-05
0.0017 2.34941e-05
0.0018 2.11309e-05
0.0019 1.91345e-05
0.002 1.72976e-05
0.0021 1.55933e-05
0.0022 1.40083e-05
0.0023 1.25377e-05
0.0024 1.11793e-05
0.0025 9.93112e-06