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I need some advice with my boundary conditions (picture attached) |
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January 18, 2018, 04:56 |
I need some advice with my boundary conditions (picture attached)
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#1 |
Senior Member
Mr CFD
Join Date: Jun 2012
Location: Britain
Posts: 361
Rep Power: 14 |
I have a system with three inlets and one outlet.
I am usually a CFX user. In CFX I would model inlet 1, 2 and 3 as an opening boundary condition:
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January 18, 2018, 13:38 |
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#2 |
Senior Member
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,677
Rep Power: 66 |
You need to supply the inlet pressures of the 3 inlets. Otherwise the problem has many solutions.
For the filter. Do you mean that you know the loss curve? For a given filter (i.e. a given loss curve), if you know the pressure drop then that implies you already know the flowrate across the filter. You shouldn't need to use the porous media as a cell zone model. Several BC's and interface options are available, i.e the porous interface, or even the fan BC allows you to input a loss coefficient or pressure jump. Or you could just give inlet 2 a lower inlet pressure. |
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January 19, 2018, 05:03 |
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#3 | ||
Senior Member
Mr CFD
Join Date: Jun 2012
Location: Britain
Posts: 361
Rep Power: 14 |
Thanks for your response LuckyTran.
Just to be clear - there is a suction pump at outlet 1 sucking at 10 L/min. Air is drawn through the inlets from atmosphere. Quote:
Since the operating pressure is atmospheric, I set the inlet pressure to 0 Pa. Quote:
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January 23, 2018, 09:04 |
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#4 |
Senior Member
Mr CFD
Join Date: Jun 2012
Location: Britain
Posts: 361
Rep Power: 14 |
Hi, could anyone offer any further thoughts on this?
Thanks |
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January 26, 2018, 16:24 |
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#5 |
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Daniel Edebro
Join Date: Feb 2016
Location: Gothenburg
Posts: 41
Rep Power: 10 |
One thought (except use total pressure inlet) is that you model a part of the space outside the inlet of the pipes in order to get correct contraction of the flow.
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January 29, 2018, 05:15 |
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#6 |
Senior Member
Mr CFD
Join Date: Jun 2012
Location: Britain
Posts: 361
Rep Power: 14 |
Thanks DEd. I'll try that and see if I get better results.
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