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April 5, 2006, 19:04 |
Mass flow rate
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#1 |
Guest
Posts: n/a
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Hello All,
I have a mass flow rate (0.0468 kg/s) outlet result for a 2D model and need to apply this to a 3D model for inlet mass flow rate boundary. What does this mass flow rate means in term of 3D? How can I use this result and apply to the 3D model? Thank you |
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April 6, 2006, 01:36 |
Re: Mass flow rate
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#2 |
Guest
Posts: n/a
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Was your 2D model axisymmetric? If yes then the mass flow rate is real. Apply directly to the 3D model.
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October 14, 2010, 00:45 |
contrast case
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#3 |
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Dokeun, Hwang
Join Date: Apr 2010
Location: Korea, Republic of
Posts: 98
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hello~ everyone
I have a another question about this post What if I have mass flow rate for 3d and i want to apply that flow rate to 2d axisymmetric casek for reducing computational cost? |
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October 14, 2010, 02:33 |
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#4 |
Super Moderator
Maxime Perelli
Join Date: Mar 2009
Location: Switzerland
Posts: 3,297
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Same date for axisymmetric and 3d.
But you can also use velocity inlet, and check the massflow rate (report/)
__________________
In memory of my friend Hervé: CFD engineer & freerider |
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October 17, 2010, 06:54 |
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#5 |
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Marta Lazzarin
Join Date: Jun 2009
Location: Italy
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Dear All, I have simulated a combustion flow in CFX some time ago. It was possible to define a surface which was a wall, but from which some reacting species were inserted into the domain.
This boundary was a wall+source, so that I was able to specify both mass fractions of the various species and the mass flow rate coming in; it was also possible to have a certain heat flux at that boundary. It was one of the parameters calculated during the simulation. Is there a similar condition in Fluent? 'cause i saw just traditional walls and mass flow inlet boundaries. If not, is there any other way to make Fluent do what i need? (which is basically introducing a certain amount of mass from the boundary, with specified mass fractions and calculating the heat flux without imposing it at the beginning). Thanks a lot Marta |
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July 30, 2013, 15:42 |
Negative mass flow rate in everywhere except inlet
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#6 |
Senior Member
Tanjina Afrin
Join Date: May 2013
Location: South Carolina
Posts: 169
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Hi all,
In my 2D model, I found negative mass flow rate in everywhere except in the inlet. What does it mean? Please enlighten me . Thanks in advance. |
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July 30, 2013, 17:03 |
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#7 |
Super Moderator
Alex
Join Date: Jun 2012
Location: Germany
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It means that the flow exits the computational domain.
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July 30, 2013, 17:52 |
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#8 |
Senior Member
Tanjina Afrin
Join Date: May 2013
Location: South Carolina
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July 30, 2013, 18:27 |
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#9 |
Super Moderator
Alex
Join Date: Jun 2012
Location: Germany
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Boundary faces like an inlet have an orientation, indicated by the normal vector of the face.
For example the normal vector of the inlet face points towards the computational domain. If the flux vector is pointing in the same direction, the mass flow rate is positive (the flow enters the computational domain). For faces where the normal vector and the flux vector are pointing in opposite directions, the mass flow rate is negative. For an outlet this indicates that the flow is leaving the domain. |
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July 30, 2013, 18:50 |
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#10 | |
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Tanjina Afrin
Join Date: May 2013
Location: South Carolina
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Quote:
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July 28, 2014, 23:39 |
negative mass flow rate at outlet
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#11 |
New Member
Join Date: Dec 2012
Posts: 24
Rep Power: 14 |
I am facing the same problem of negative mass flow rate & I don't quite understand what's meant by the fluid's leaving the domain.
Isn't the direction of my flow supposed to be the same at all positions? and that's what I'm getting when I display the velocity vectors, then how come my mass flow rate is negative? Please help me understand this. |
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July 29, 2014, 05:17 |
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#12 | ||
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Quote:
Quote:
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August 12, 2014, 10:15 |
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#13 |
New Member
Join Date: Dec 2012
Posts: 24
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Thanks a lot Pakk, that was really helpful
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July 19, 2017, 08:01 |
Flow rate
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#14 |
New Member
saeed
Join Date: Dec 2009
Posts: 12
Rep Power: 17 |
Hi all
I want to measure Flow rate in a Manifold with one inlet and two outlet in Fluent. my question is that, how can I measure the flow rate at the beginning of every path? In Report.....could be just measure the flow rate in Inlet and Outlet. I used the Iso Surface to define a surface but because entrances of both of the paths are in a same surface, I need a way to define a surface for every path separately!! Thanks alot (I attached my model's pic) |
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July 19, 2017, 10:04 |
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#15 |
Member
Join Date: Mar 2014
Posts: 56
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So you want to check the mass flow in the two outlet channels? The reports for both of the outlets would suffice surely, but if you would like to check how the flow field develops in the y direction, you could just creat a surface (y=0 m or something like that which would intersect both of the channels) and then iso-clip them into submission. Now you have two separate surfaces for your monitoring pleasures!
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July 19, 2017, 10:31 |
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#16 |
New Member
saeed
Join Date: Dec 2009
Posts: 12
Rep Power: 17 |
Thanks a milllllllion divergence my problem was solved
by your guidance, Thanks alot |
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