Incomplete ring MRF zones

Attesz · June 2, 2017, 04:14

Dear all,

I have a case with an MRF zone that is diverging but only after 2000 iterations. It is a high pressure regenerative turbine pump. In one section of the pump the MRF zone is discontinued, so the MRF "ring" is not a complete ring but only a 270deg section.

As MRF is just adding a tangential velocity to the flow I assume this should not introduce divergence problems. Am I right? Can the MRF zone be "incomplete ring"?

Thanks

hjasak · June 3, 2017, 05:16

The outside surface of the MRF zone must be a body of rotation - that's all.

If you have cyclics on tour 270 deg segment, all is well.

I run tirbomachinery CFD with FOAM like that all the time. For validation studies look at

www.fsb.hr/cfd

under Dissemination - Master Theses

June 2, 2017, 04:14	Incomplete ring MRF zones	#1
Attesz Senior Member Attesz Join Date: Mar 2009 Location: Munich Posts: 368 Rep Power: 17	Dear all, I have a case with an MRF zone that is diverging but only after 2000 iterations. It is a high pressure regenerative turbine pump. In one section of the pump the MRF zone is discontinued, so the MRF "ring" is not a complete ring but only a 270deg section. As MRF is just adding a tangential velocity to the flow I assume this should not introduce divergence problems. Am I right? Can the MRF zone be "incomplete ring"? Thanks

June 3, 2017, 05:16		#2
hjasak Senior Member Hrvoje Jasak Join Date: Mar 2009 Location: London, England Posts: 1,905 Rep Power: 33	The outside surface of the MRF zone must be a body of rotation - that's all. If you have cyclics on tour 270 deg segment, all is well. I run tirbomachinery CFD with FOAM like that all the time. For validation studies look at www.fsb.hr/cfd under Dissemination - Master Theses __________________ Hrvoje Jasak Providing commercial FOAM/OpenFOAM and CFD Consulting: http://wikki.co.uk

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