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March 30, 2017, 10:58 |
Pressure Driven Flow - Boundary Condition
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#1 |
New Member
Fabrizio
Join Date: Feb 2014
Posts: 10
Rep Power: 12 |
Hi all, I really need a super urgent help because i am going crazy and I hope someone could help me.
I need to solve the system in the attached picture. Attachment 55031 We have 3 inlet side and 1 outlet in the upper side. (they are 3 heating exchanger assembled like in the picture, and a suction fan in the top, but I dont need to solve it, I only need to simulate the flow in the box). I want to understand if the 3 inlets have the same flows or not (i suppose the inlet2 is favorite). So I want to implement a pressure driven flow, imposing the same pressure (for example 150Pa) in the inlets and 0 to the outlet. I tried it, but obiouvsly I have no convergence, bcs I used zeroGradient on all sides for velocity. Can you please let me know how to set in detail boundary for pressure and velocity and maybe also for k and epsilon for this case? Do you have some links for a pressure driven INCOMPRESSIBLE guide? I didnt find anything useful. Thanks Best Regards Fabrizio |
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March 30, 2017, 16:01 |
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#2 |
Senior Member
Uwe Pilz
Join Date: Feb 2017
Location: Leipzig, Germany
Posts: 744
Rep Power: 15 |
Pressure only b.c. are sometimes hard to manage. I recommend to set the pressure gradient to zero at the outlet. You may look in the solution files where it falls and may correct your inlet values if necessary.
__________________
Uwe Pilz -- Die der Hauptbewegung überlagerte Schwankungsbewegung ist in ihren Einzelheiten so hoffnungslos kompliziert, daß ihre theoretische Berechnung aussichtslos erscheint. (Hermann Schlichting, 1950) |
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March 30, 2017, 16:08 |
pressure driven
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#3 |
New Member
Fabrizio
Join Date: Feb 2014
Posts: 10
Rep Power: 12 |
Hi, thanks for your reply. I really tried all possible configuration for boundary. But please, be more clear : if i use zerogradient for pressure at outlet I should set the velocity at outlet and the pressure at inlet, correct?
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March 30, 2017, 23:55 |
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#4 |
Senior Member
Arjun
Join Date: Mar 2009
Location: Nurenberg, Germany
Posts: 1,286
Rep Power: 34 |
The whole top is outlet or the outlet is at the center?
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March 31, 2017, 01:31 |
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#5 |
Senior Member
Uwe Pilz
Join Date: Feb 2017
Location: Leipzig, Germany
Posts: 744
Rep Power: 15 |
> if i use zerogradient for pressure at outlet I should set the velocity at outlet and the pressure at inlet, correct?
Yes, that should fit your problem. You'll see how the flow divides between the three inlets.
__________________
Uwe Pilz -- Die der Hauptbewegung überlagerte Schwankungsbewegung ist in ihren Einzelheiten so hoffnungslos kompliziert, daß ihre theoretische Berechnung aussichtslos erscheint. (Hermann Schlichting, 1950) |
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March 31, 2017, 09:02 |
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#6 |
New Member
Fabrizio
Join Date: Feb 2014
Posts: 10
Rep Power: 12 |
Hi,
the whole top is the outlet. There is a sucting fan in the top (but I didnt make the mesh on it), so I want impose the static pressure at inlet to simulate the fan. thanks |
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