# Centrifugal fan impeller CFD simulation in OpenFoam

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 November 26, 2014, 05:53 Centrifugal fan impeller CFD simulation in OpenFoam #1 New Member   Zach Join Date: Nov 2014 Posts: 6 Rep Power: 11 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 DavidWa likes this.

 November 29, 2014, 04:22 #2 Member     Christian Join Date: Apr 2014 Posts: 74 Rep Power: 12 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! DavidWa likes this.

 December 3, 2014, 09:08 #3 New Member   Zach Join Date: Nov 2014 Posts: 6 Rep Power: 11 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?

 December 3, 2014, 10:00 #4 Member     Christian Join Date: Apr 2014 Posts: 74 Rep Power: 12 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!

May 16, 2024, 05:30
#5
New Member

David Walden
Join Date: May 2024
Location: Seminole, Texas USA
Posts: 6
Rep Power: 2
Quote:
 Originally Posted by 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!
@crixman

Apologies to Zach for hijacking his thread.

Hello, I write to ask for help installing Salome Meca on my Windows 10 Pro 64 bit machine so as to use it with OpenFOAM on wsl to investigate my centrifugal fan design having an aggressive inlet blade angle. I'm worried about an excessive angle of attack causing blade stall before spending \$1.1K minimum on Carbon Fiber sheet for the rims and shrouds including the cost of having it cut on a water jet. I am unable to join/view the Salome Forum to ask for help due to detection by Malwarebytes Browser Guard of possible risks. I prefer not to risk it by adding exclusions or disabling Malwarebytes.

I am unable to install Salome Meca using Windows Power Shell as administrator and wsl. I have been duplicating the steps faithfully, as far as I know, from the YouTube video titled: "Installing official Salome Meca on Windows 10/11 using WSL2" on Hassan Berro's channel.

All the preliminary steps are accomplished successfully with the exception that I'm attempting to install on currently updated Windows 10 Pro 64 bit instead of Windows 11.

The difficulty arises at the point of attempting to import smeca_2022_wsl2_ubuntu_22.04.tar from drive D: into a folder on C:\ named SalomeMeca. The offending line is:

wsl --import smeca C:\SalomeMeca .\D:\SALOME\smeca_2022_wsl2_ubuntu_22.04.tar

The result is:
"The system cannot find the path specified."

I've tried everything I can think of, including placing the tar file on Desktop, as was done in the video, installing Microsoft Visual C++ 2017 Redistributable (x64) - 14, as was suggested for a similar post having the same Error message, to no avail. I moved the tar to drive D: to free up space on C: to have 10.5 GB free.

I have searched Microsoft.com and GitHub for help and found posts pertaining to the above error but none relative to Salome Meca.

Can you help?

Kind Regards,

David Walden, self-taught Python and Rhino 3D CAD enthusiast, retired pro pilot ATP ASMEL, CFII ASMEL (expired), Ground Instructor Advanced Instrument, IT nerd, classroom software instructor.

 May 16, 2024, 11:20 #6 New Member   David Walden Join Date: May 2024 Location: Seminole, Texas USA Posts: 6 Rep Power: 2 Please disregard my previous post. I've corrected the path and was able to get the import going. Now having issues with subsequent steps.

 May 21, 2024, 10:05 Selecting Faces in Salome #7 New Member   David Walden Join Date: May 2024 Location: Seminole, Texas USA Posts: 6 Rep Power: 2 I have installed Salome and imported my fan into the geometry module. From a YouTube video tutorial, the presenter explodes a globe (spelling?) valve in order to select faces. I have exploded my fan into 976 faces. How does one select the wetted faces, i.e. the inside surfaces of the fan rim, the fan shroud, forward-facing and backward-facing blade surfaces? Must they all be manually selected using the mouse? My fan has 21 blades. Last edited by DavidWa; May 21, 2024 at 10:22. Reason: context, readibiliy

May 21, 2024, 10:46
#8
Member

Pedro Gouveia
Join Date: Oct 2022
Location: Portugal
Posts: 63
Rep Power: 3
Quote:
 Originally Posted by DavidWa I have installed Salome and imported my fan into the geometry module. From a YouTube video tutorial, the presenter explodes a globe (spelling?) valve in order to select faces. I have exploded my fan into 976 faces. How does one select the wetted faces, i.e. the inside surfaces of the fan rim, the fan shroud, forward-facing and backward-facing blade surfaces? Must they all be manually selected using the mouse? My fan has 21 blades.

Yes, all should be selected manually using the mouse.

June 15, 2024, 11:03
#10
New Member

David Walden
Join Date: May 2024
Location: Seminole, Texas USA
Posts: 6
Rep Power: 2
Quote:
 Originally Posted by ZachJa 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?

Hello Zach,

Did you get a mesh computed successfully? I got some help with this issue from the Salome forum:
https://discourse.salome-platform.or...-9-12-0/1307/2

 Tags centrifugal fan, cfd, impeller simulation, openfoam

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