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What is km and epsilonm in MultiphaseEulerFoam?

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Old   February 27, 2022, 00:42
Default What is km and epsilonm in MultiphaseEulerFoam?
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I am trying to validate MultiphaseEulerFoam (twoPhaseEulerFoam) for a 2 phase (water and air) flow through a horizontal pipe.

I am using Open Foam version 8 and I am using the below-mentioned research paper for validation.

Ekambara, K.; Sanders, R. S.; Nandakumar, K.; Masliyah, J. H. (2008): CFD simulation of bubbly two-phase flow in horizontal pipes. In Chemical Engineering Journal 144 (2), pp.*277288. DOI: 10.1016/j.cej.2008.06.008.

As per the reacheacr work I have considered 50.4mm dia pipe with 9m length,
superficial gas velocity of 0.42 m/s and superficial liquid velocity is 4.67 m/s and average gas volume fraction is 0.085.

I am using the bubble column tutorial case as a reference.

Regarding the mesh quality, I have no issues since I have very good values of nonorthogonality and skewness.

In 0 folder there is a separate km and epsilonm. Could someone please explain what are these?

The simulation crashes since my case is developing large amounts of bounding km and bounding epsilonm. Also, the epsilon does not converge.

I have attached all the details regarding the case file.
Your help is reallz appreciated.

Thank you.

HTML Code:
    Mesh stats
    points:           314154
    internal points:  273132
    faces:            898010
    internal faces:   856990
    cells:            292500
    faces per cell:   6
    boundary patches: 3
    point zones:      0
    face zones:       1
    cell zones:       1

Overall number of cells of each type:
    hexahedra:     292500
    prisms:        0
    wedges:        0
    pyramids:      0
    tet wedges:    0
    tetrahedra:    0
    polyhedra:     0

Checking topology...
    Boundary definition OK.
    Cell to face addressing OK.
    Point usage OK.
    Upper triangular ordering OK.
    Face vertices OK.
    Number of regions: 1 (OK).

Checking patch topology for multiply connected surfaces...
    Patch               Faces    Points   Surface topology
    inlet               260      279      ok (non-closed singly connected)
    walls               40500    40536    ok (non-closed singly connected)
    outlet              260      279      ok (non-closed singly connected)

Checking geometry...
    Overall domain bounding box (0 -0.0252 -0.0252) (9 0.0252 0.0252)
    Mesh has 3 geometric (non-empty/wedge) directions (1 1 1)
    Mesh has 3 solution (non-empty) directions (1 1 1)
    Boundary openness (-2.3893e-17 -5.72203e-15 1.9e-15) OK.
    Max cell openness = 3.03186e-16 OK.
    Max aspect ratio = 8 OK.
    Minimum face area = 1.25e-06. Maximum face area = 3.95216e-05.  Face area magnitudes OK.
    Min volume = 1e-08. Max volume = 1.46563e-07.  Total volume = 0.0178609.  Cell volumes OK.
    Mesh non-orthogonality Max: 30.8909 average: 6.3203
    Non-orthogonality check OK.
    Face pyramids OK.
    Max skewness = 0.729903 OK.
    Coupled point location match (average 0) OK.

Mesh OK.

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solver convergence, turbulencemodels, twophaseeulerfoam

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