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#1 |
New Member
Rameez
Join Date: May 2013
Posts: 19
Rep Power: 13 ![]() |
I had run a simulation of a stator-rotor combination, for which I had chosen the medium as Air Ideal Gas. After the simulations were done, when i generated report, i was surprised to see the considered density to be 2.23 kg/m-3. Shouldn't it have been 1.2256 kg/m-3? Also how do i rectify it to make it as 1.2256 kg/m-3
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#2 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,933
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This looks like an error in your reference pressure. If the reference pressure is 1atm and you have a pressure of 1atm then you have 2atm absolute and densities about 2.2kg/m3.
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#3 |
New Member
Rameez
Join Date: May 2013
Posts: 19
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Thanks a lot for your valuable reply. Could you please respond to the following questions too.
Should i take the reference pressure as 0 atm? So now do i have to re run the simulations? And how do i rectify it? |
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#4 |
Super Moderator
Glenn Horrocks
Join Date: Mar 2009
Location: Sydney, Australia
Posts: 17,933
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You should put the reference pressure as a typical pressure in your domain. The documentation explains this.
And yes, you will have to redo the simulation as your current results are wrong. |
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#5 |
New Member
Rameez
Join Date: May 2013
Posts: 19
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Thanks again. I would like to explain my problem definition-
I had specified the reference pressure as 1 atm Boundary condition: mass flow inlet to static pressure outlet So accordingly i plugged in the values as Inlet: Normal speed as 8.49 m/s Outlet: 1 atm as my turbomachine opens into atmosphere. So to rectify the problem of density, should i change the reference pressure as 0 atm or the outlet pressure as 0 atm or some other changes should be done. |
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#6 |
Senior Member
Erik
Join Date: Feb 2011
Location: Earth (Land portion)
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Outlet pressure should be zero, reference pressure should be 1 atm.
Either will work fine, as long at they add up to 1atm, but this way is better for round off errors and things of that nature. |
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#7 |
New Member
Rameez
Join Date: May 2013
Posts: 19
Rep Power: 13 ![]() |
Thanks for your help.
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