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-   -   thin less boundary (http://www.cfd-online.com/Forums/openfoam/109938-thin-less-boundary.html)

 ling40 November 30, 2012 11:47

thin less boundary

Ok I am modelling a positive displacement pump as seen in the picture below. I am running openFoam 2.1.1 and used the MixerVesselAMI2D tutorial which uses the pimpleDyMFoam solver. The gear is able to rotate which would cause flow to move upward or downward but I am having a difficult time determining how to block flow on the right side of the gear.

Generally this kind of pump has two gears that are able to mesh together in the center. The right wall is a symmetryplane and the left wall is the housing of the pump so it is type wall. I was hoping get by using one gear and setting some kind of boundary on the right side of the gear forcing flow to move along the gear as it rotates.

Problems I have run into would be the gear is a cellzone so any boundarys I've placed within its block will rotate along with the gear.

http://i1357.photobucket.com/albums/...t1987/Mesh.png

eventually I want to have a high pressure at top with low at the bottom and have the gear rotate clockwise. This should display an example of back-flow within a pump.

Any help would be great.

 Maged_CFD December 3, 2012 15:11

I don't think you can simulate an external gear pump by considering only one of the two gears and a symmetry boundary condition. Even though the geometry is symmetric around the mid-plane, but the fact that you ignore the inter-meshing teeth of the two gears and the deforming mesh in this region will lead to unrealistic simulation results. Here is an example of how this type of pump is simulated using the full geometry: http://www.simerics.com/gallery_gear_pump

 wyldckat December 3, 2012 17:39

Greetings to all!