[ZachJa]

Hello,

I am totally new in OpenFoam at the moment.

Have heart that it is possible to make CFD simulation for rotating mechanisms such as impellers.

My case is shown at picture "1.jpg" - it is an impeller for centrifugal (radial) fan with backwards curved blades (blade is defined by: D1=510 mm, a1=40 deg, D2=1000 mm, a2=40 deg). I need to match the following:
1. Prise (Ptout - Ptin + rPref)
2. W (not really sure now which formula should I use)
3. Efftot (Q*pressure rise/shaft power*100)
4. Effstat (Q*(Paveout - Ptin + rPref)/shaft power*100)
where:
Prise - pressure rise in fan
Ptout - total pressure at outlet
Ptin - total pressure at inlet
Pref - reference pressure (in my case it is 1013.25 hPa)
W - shaft power (kW)
Efftot - total efficiency
Effstat - static efficiency
Q - flow
Paveout - average pressure at outlet

Basic parameters:
Gas density is 1.185 kg/m3 (air)
Temperature: 25 C
Rotation speed: 3000 rpm
Inflow: 1 m3/s

Where should I start from?
Is there kind of tutorial or example in this field?
Or someone maybe did similar simulation?
Do I have to set geometry in OpenFoam from zero or I can transfer existing CAD geometry (iges, step, ...) into OpenFoem directly?

I know that in Ansys simulation is prepared for one blade "2.jpg" and in stetup just amount of blades should be set to get results for entire impeller, is it the same in OpenFoam?
It also could be good to run kind of optimization to find optimal blade geometry.

Thanks in advance!
Attachment 35514

Attachment 35515

[crixman]

Hi Zach,
it is surely possible to simulate impellers in openfoam.
It is not the easiest topic for a beginner, but it can be done.
To import the CAD geometry, I would recommend using Salome as it gives you the opportunity to choose the right patches.
Then you can mesh with Salome itself or with snappyHexMesh or cfMesh.
Have a look here for the workflow:
https://openfoamwiki.net/index.php/S...l_Optimization
For turbomachinery, you should look at AMI or GGI for transient simulations, MRF for static.
check out also the turbomachinery Sig
http://openfoamwiki.net/index.php/Sig_Turbomachinery
If you need more help let me know!

[ZachJa]

Hello Christian,
thank you very much for help.
I started with Salome. Managed to import geometry:
but have problems with mesh:
What am I doing wrong?
Should be impeller geometry simplified somehow from the beginning?
May be instead of solids (front cone, back plate, hub) I should use surfaces?

[crixman]

Hi Zach, can't see the attachments, could you send me a private message with the pics? I'll try to get back to you as soon as I can!