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August 14, 2003, 11:12 |
boundary conditions
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#1 |
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Is it possible to use this set of boundary conditions in Fluent for 2D pipe flow:
Pressure inlet and constant mass flow rate? |
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August 14, 2003, 12:41 |
Re: boundary conditions
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#2 |
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For compressible flow: Total Pressure inlet & Static Pressure outlet
or Mass Flow Inlet & Static Pressure Outlet For incompressible flow: Velocity inlet & outlet condition |
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August 15, 2003, 01:19 |
Re: boundary conditions
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#3 |
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Hi!
I'm not shure what you want. Maybe you have the same problem as me...I have a known upstream pressure and velocity, but in Fluent you can't define both parameters on inlet bc. What I do is I define velocity inlet and pressure outlet (upstream pressure - pressure losses in pipe), and after simulation converges check if the pressure on inlet agrees with experimental one. It's a bit awkward solution but I think most of the people with this problem solve it this way... regards MATEUS |
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August 15, 2003, 10:38 |
Re: boundary conditions
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#4 |
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Thanks all. I am suprised that Fluent doesn't have a constant mass flowrate outlet boundary condition.
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August 17, 2003, 04:58 |
Re: boundary conditions
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#5 |
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I think the outlet boundary condition 'outflow' may help you for your problem and get constant mass flow rate. thomas
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August 17, 2003, 20:54 |
Re: boundary conditions
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#6 |
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constant mass flow rate is controled by approciate pressure. this may be the reason for no boundary conditions of constant mass flow rate in fluent software.
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August 20, 2003, 05:23 |
Re: boundary conditions
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#7 |
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Note that outflow boundaries cannot be used in the following cases:
if a problem includes pressure inlet boundaries; use pressure outlet boundary conditions (see Section 6.8) instead |
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August 21, 2003, 13:31 |
Re: boundary conditions
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#8 |
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For non critical flow, the mass flow rate is governed by both inlet and outlet pressures. To obtain a constant mass, it seems that I should use constant pressure inlet and try-and-error outlet pressure. Is this a correct way?
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August 21, 2003, 20:24 |
Re: boundary conditions
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#9 |
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for the compressible flow,you can use these boundary condition:"Mass Flow Inlet & Static Pressure Outlet " then you have made the mass flow as a constant when you define the "Mass Flow Inlet".
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August 24, 2003, 23:37 |
Re: boundary conditions
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#10 |
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To be clear, the conditions I have are: constant mass flow rate and constant inlet pressure. But I don't know the downstream pressure. The question was: How to set the boundary conditions?
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