Phase change of water in a vertical 3-way channel (unsteady)

Update: September 29, 2018
OpenFOAM 4.x

Case directory

$FOAM_TUTORIALS/lagrangian/reactingParcelFoam/verticalChannel

Summary

We calculate the flow in a channel that has 3 inlets and a single outlet for 0.5 s. Air flows in at 473 K from 2 side inlets and 573 K from the center inlet. The inflowing air is assumed to contain 1 % water (liquid). The Z-axis direction of the model is assumed to be a symmetrical plane, and the other walls are assumed to be no-slip walls. The negative direction of the Y-axis is assumed to be the gravity direction.

Model geometry (entire) Model geometry (entire)
Model geometry (around inlets) Model geometry (around inlets)

In the file "reactingCloud1Properties" in the directory "constant", We set the "phaseChangeModel liquidEvaporation" so that the water will evaporate.

In the file "controlDict" in the directory "system", the following settings are made to output the weighted average of volume the water and temperature at the region "outlet".

functions
{
    surfaceRegion1
    {
        type            surfaceRegion;
        libs            ("libfieldFunctionObjects.so");
        writeControl    writeTime;
        log             yes;
        writeFields     no;
        regionType      patch;
        name            outlet;
        operation       weightedAverage;
        weightField     phi;
        fields
        (
            H2O
            T
        );
    }
}

The meshes are as follows, and the number of mesh is 93400.

Meshes on the inlet side Meshes on the inlet side
Meshes on the outlet side Meshes on the outlet side

The calculation results are as follows. All the results are at the final time.

We can see that as it flow through the channel, the water in the center channel where the temperature is higher, evaporates and takes away heat, increasing the (volume) ratio.

Temperature on the inlet side (T) Temperature on the inlet side (T)
Temperature at 3-way junction (T) Temperature at 3-way junction (T)
Temperature on the outlet side (T) Temperature on the outlet side (T)
Water on the inlet side (H2O) Water on the inlet side (H2O)
Water at 3-way junction (H2O) Water at 3-way junction (H2O)
Water on the outlet side (H2O) Water on the outlet side (H2O)
Air on the inlet side (air) Air on the inlet side (air)
Air at 3-way junction (air) Air at 3-way junction (air)
Air on the outlet side (air) Air on the outlet side (air)

The weighted average of water volume and temperature in the outlet region is as follows.

Weighted average of water volume at each calculation time (H2O) Weighted average of water volume at each calculation time (H2O)
Weighted average of temperature at each calculation time (T) Weighted average of temperature at each calculation time (T)

Commands

cp -r $FOAM_TUTORIALS/lagrangian/reactingParcelFoam/verticalChannel verticalChannel
cd verticalChannel

blockMesh
cp -r 0.orig 0

# Initialize with potentialFoam result
potentialFoam
rm -f 0/phi

reactingParcelFoam

paraFoam

gnuplot
gnuplot>plot "postProcessing/surfaceRegion1/0/surfaceRegion.dat" using 1:2 lc rgb "black"
gnuplot>plot "postProcessing/surfaceRegion1/0/surfaceRegion.dat" using 1:3 lc rgb "black"

Calculation time

  • potentialFoam: 3.44 seconds
  • reactingParcelFoam: 40 minutes 54.02 seconds

*Single, Inter(R) Core(TM) i7-2600 CPU @ 3.40GHz 3.40GHz