Flow in a T-shaped branch pipe with a fan

OpenFOAM 4.x

Case directory

$FOAM_TUTORIALS/incompressible/pimpleFoam/TJunctionFan

Summary

We calculate the flow in a T-shaped branch pipe with a fan at the middle of the path from 0 sec to 1.5 sec.

We apply the total pressure condition to the region "inlet", set to 10 m2/s2 (= (kg/(m-s2))/(kg/m3) = Pa/density) at 0 sec and 40 m2/s2 at 1 sec. We also apply a static pressure of 10 m2/s2 and 0 m2/s2 to the outlet side regions "outlet1" and "outlet2" respectively. The channel wall will be set to the no-slip condition.

Model geometry Model geometry

A fan consists of a frame part (region "baffleFaces") that does not allow flow and vanes part (region "cyclicFaces") that provides a pressure gradient. The characteristics of a fan are specified in file 0/p by using "type fan;" and "patchType cyclic;" as boundary conditions.

The fan shape The fan shape 
    cyclicFaces_master
    {
        type            fan;
        patchType       cyclic;
        jump            uniform 0;
        value           uniform 0;
        jumpTable       polynomial
        1((100 0));
    }
    cyclicFaces_slave
    {
        type            fan;
        patchType       cyclic;
        value           uniform 0;
    }

The meshes are as follows, and the number of mesh is 3875.

Mesh Meshes

To visualize the calculated turbulence energy and turbulence dissipation rate, check "k" and "epsilon" in the "Properties" tab on ParaView.

Check k and epsilon Check "k" and "epsilon"

The calculation result is as follows.

Flow velocity at final time (U) Flow velocity at final time (U)
Pressure at final time (p) Pressure at final time (p)
Turbulence energy at final time (k) Turbulence energy at final time (k)
Turbulence dissipation rate at final time (epsilon) Turbulence dissipation rate at final time (epsilon)

We can see that the flow velocity increases at the fan position.

Commands

cp -r $FOAM_TUTORIALS/incompressible/pimpleFoam/TJunctionFan TJunctionFan
cd TJunctionFan

blockMesh

# Create face zones for baffles and fans.
topoSet

cp -r 0.orig 0

createBaffles -overwrite

pimpleFoam

paraFoam

Calculation time

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

Reference