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-   -   Simulating rotating machinery in oposite directions (http://www.cfd-online.com/Forums/star-ccm/99390-simulating-rotating-machinery-oposite-directions.html)

 j.abernathie April 2, 2012 11:10

Simulating rotating machinery in oposite directions

I am a student at the University of Houston and am using Star CCM+ on my Sr. Capstone project. I am simulating the circulation of water in a tank with two different paddle wheels, rotating in two different directions.

I have referred to the rotating machinery tutorials and still cannot get the simulation to run properly. I am greatful for any pointers or help i can get...

Thank you,

Jess

 abdul099 April 2, 2012 14:51

What's the issue? There are no visionaries here, so could you please tell us a little about your specific problem? Is it meshing? Physics? Geometry preparation? Postprocessing? Coffee making?

 j.abernathie April 2, 2012 15:24

the issue is that instead of the paddle wheels rotating on the inside of the tank, the entire tank geometry rotates.

questions:

how do i insert the geometry so that the tank and paddle wheel meshing read each other, (Boolean subtract? different regions etc?) but the rotation is only applied to the paddle wheels?

How to i specify two different rotation axis?

 eRzBeNgEl April 2, 2012 16:06

In general for stationary simulations:

-Always divide between rotating and none rotating areas. Your paddle should be in a cylindrical region.

- If you want to rotate a whole region set hte Motion Specificitaion to Rotation of this region. If some walls in this region are not rotating set the Boundary -> Motion specifications to "absolute" for this specified region (i.e.: walls). Check this agains by watching the velocity magnitude after a few iterations. The velocity of none rotating areas should be zero.

- Of course you can specify different directions. Therefore you can find some options in the Rotating Frame under Tools-> Motion you have created before. There must be something like "specify axis".

There are some good tutorials how to set up a "rotating frame". Just search for keywords in the star-ccm+ help file

 j.abernathie April 2, 2012 17:28

I was able to figure out how to achieve the rotation for each of the paddle wheels... thank you so much for your help.

However, now Im having issues getting the mesh of the paddle region and the fluid region to interact with eachother. In other words im not seeing any fluid flow.

I have tried inserting the parts as a boolean subtract and as different regions, but neither way is working. Im sure its something small that im doing wrong.

Any pointers?

 abdul099 April 28, 2012 08:24

Did you create interfaces between your rotating and stationary region?

 saleh alsubari August 12, 2012 22:42

Dear friends

i'm having problem regarding reference frame set up...my project is to simulate a turbine blades and find out its RPM ...given data is mass flow rate ,and out put should be rpm ...is there one can help ..
thanx

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