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December 2, 2011, 07:50 |
transient BC profil at INLET
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#1 |
Senior Member
Join Date: May 2011
Location: Germany
Posts: 130
Rep Power: 14 |
Hey guys,
I do a transient calculation of a ribbed cooling channel and therefore I need a velocity profil at the Inlet. Problem is, that my massflow is a function of time and the tempertaure at the inlet is a function of time. So how can I implement a fully developed inlet profil for velocity? Thanks in advance! |
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December 2, 2011, 10:08 |
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#2 |
Senior Member
Lance
Join Date: Mar 2009
Posts: 669
Rep Power: 22 |
This must be one of the most asked questions on the forum.
Use a 1D interpolation function. (http://www.cfd-online.com/Forums/cfx...condition.html) Have look in the tutorials on how to get a fully developed profile. |
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December 2, 2011, 11:30 |
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#3 |
Senior Member
omid
Join Date: Apr 2011
Posts: 105
Rep Power: 15 |
You can do it with very simple Expression. Do you have any relation or function for variation of mass flow and temperature with time?
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December 2, 2011, 12:01 |
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#4 | |
Senior Member
Join Date: May 2011
Location: Germany
Posts: 130
Rep Power: 14 |
Quote:
I already read the tutorial but I don't know the profil for every single timestep. And I don't want to calculate it for every step. |
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December 3, 2011, 02:47 |
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#5 |
Senior Member
omid
Join Date: Apr 2011
Posts: 105
Rep Power: 15 |
could you explain more?
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December 3, 2011, 06:46 |
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#6 |
Senior Member
Join Date: May 2011
Location: Germany
Posts: 130
Rep Power: 14 |
Alright, me geometry is a ribbed internal cooling channel for a gas trubine blade.
I am calculating a conjugated simulation (fluid + solid). My outlet condition is 1 atm static pressure (constant with time). I have to validate the experimental data, so I've got mass flow rate and temerature from the experiment (both are different form time to time). t=0 mass flow rate is about 0.04 kg/s and temperature is 22.1°C after t=10s I've got a mass flow rate of 0.0365 kg/s and a temperature of 200°C. Between 0s and 10s mass flow rate and temperature are changing. And in the experiment there is a "reassurance channel" before "my" cooling channel. But I only know the temperature at the beginning of my channel. So we said that at the beginning we have a fully developed velocity- and temperature-profil. It's very important for us to have the same mass flow rate and temperature to compare the experiment with CFD. Thanks |
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December 4, 2011, 04:42 |
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#7 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,703
Rep Power: 143 |
If the inlet flow profile is not simple then the best thing to do is to model upstream a little to where the profile is simpler, or at least until where the flow has time to settle out before it gets to the section of importance.
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