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November 23, 2017, 05:22 |
Issues with pressure drops and values
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#1 |
New Member
Mike
Join Date: Nov 2017
Posts: 4
Rep Power: 9 |
Hi all,
Using ANSYS CFX. Need to fine pressure drops across the system (see the attachment). The fluid is air, ref. pressure for the domain 1 atm., no heat transfer involved, k-e model used, convergence is OK (RMS 1e-5 reached, imbalances are OK, the monitored values were stable on the Solver graphs). Issues: - Why max pressure at the outlet is smaller than the area averaged at the outlet? Is something wrong with my formula, then? - Why are all the pressure values negative? I could understand in case of two values substracted (delta) but not for the actual values. - I would normally expect pressure 0 Pa at all inlets (relative pressure is set to 0 Pa after all) but this is not the case. - The combination of Total Pressure at the inlet and Normal Speed at the outlet is claimed as robust in the ANSYS guidelines but the outcome is strange (see above). Some time ago, I did a CFD on a similar situation and assigned Static Pressure = 0 Pa to the inlets and the same normal speed of 6,8 m/s to the outlet. Came to much more predictable results than this “stable” combination. What am I missing? |
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November 24, 2017, 06:18 |
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#2 | ||||
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,864
Rep Power: 144 |
Quote:
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November 24, 2017, 06:34 |
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#3 |
New Member
Mike
Join Date: Nov 2017
Posts: 4
Rep Power: 9 |
Thanks ghorrocks. I think I am onto it.
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