CFD Online Logo CFD Online URL
www.cfd-online.com
[Sponsors]
Home > Forums > OpenFOAM Pre-Processing

Boundary condition analysis for turbomachinery

Register Blogs Members List Search Today's Posts Mark Forums Read

Reply
 
LinkBack Thread Tools Display Modes
Old   November 1, 2013, 06:15
Default Boundary condition analysis for turbomachinery
  #1
Senior Member
 
sivakumar selvaraju
Join Date: Mar 2009
Location: Cape Town - South Africa
Posts: 186
Rep Power: 8
sivakumar is on a distinguished road
Send a message via Skype™ to sivakumar
Hi there,
I am working on axial flow fan, its an annular case.
I am using OpenFOAM for my simulation.
I have give the BC, as discribed in the user manual
inlet - massflow or velocity (fixed value)
outlet - fixedValue (0), I know its not wrong, however we are forcing the pressure to zero at outlet face, so I want to say its not an appropriate one.

Then, I have given a try to fixedMeanValue (0) at outlet for pressure, it seems the result which I obtained from this BC is reasonably fine. however I want to check the deviation from the radial equilibrium solution. I am bit confused here to get the analytical solution for radial equilibrium condition. dp/dr = rho *v^2/r
v --> swirl velocity
r --> radius


my question is:

how can I get the swirl velocity?

can you people give a hit to solve the problem?

Thanks,
Sivakumar
sivakumar is offline   Reply With Quote

Old   November 4, 2013, 04:46
Default
  #2
New Member
 
Antonio
Join Date: Jan 2013
Posts: 9
Rep Power: 4
avigrod is on a distinguished road
Quote:
Originally Posted by sivakumar View Post
Hi there,
I am working on axial flow fan, its an annular case.
I am using OpenFOAM for my simulation.
I have give the BC, as discribed in the user manual
inlet - massflow or velocity (fixed value)
outlet - fixedValue (0), I know its not wrong, however we are forcing the pressure to zero at outlet face, so I want to say its not an appropriate one.

Then, I have given a try to fixedMeanValue (0) at outlet for pressure, it seems the result which I obtained from this BC is reasonably fine. however I want to check the deviation from the radial equilibrium solution. I am bit confused here to get the analytical solution for radial equilibrium condition. dp/dr = rho *v^2/r
v --> swirl velocity
r --> radius


my question is:

how can I get the swirl velocity?

can you people give a hit to solve the problem?

Thanks,
Sivakumar
I guess there are better and easier options in paraFoam for getting Vu, but I would try in this two ways:
1) Getting Vx, Vy and Vz in the disk rotor by using a sampleDict* (and also angular position/velocity of the rotor if not steady), and calculating Vr, Vu and Vx by hand in Octave/Matlab/Python whatever...
2) Writing a function Object for defining a coordinate transform tensor which moves Cartesian coordinates to cylindrical within the rotor disk.
avigrod is offline   Reply With Quote

Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Wind turbine simulation Saturn CFX 34 October 16, 2014 05:27
Radiation interface hinca CFX 15 January 26, 2014 18:11
An error has occurred in cfx5solve: volo87 CFX 5 June 14, 2013 17:44
External Radiation Boundary Condition (Two sided wall), Grid Interface CFD XUE FLUENT 0 July 8, 2010 06:49
RPM in Wind Turbine Pankaj CFX 9 November 23, 2009 05:05


All times are GMT -4. The time now is 23:22.