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CFD simulation of Hydro Kinetic Turbine

12 REPLIES 12
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Message 1 of 13
balajig8
1822 Views, 12 Replies

CFD simulation of Hydro Kinetic Turbine

Hi,

 

I am a student in TU-Munich, we are using student version of Inventor and CFD.

 

I am doing my masters, and currently i am interested in CFD simulation of Hydro kinetic Turbine in Water Channel.

 

Basically i Have a Water turbine which is in a free surface water channel.

 

Is it possible to use Autodesk CFD to perform a external fully submerged anaylsis for the water turbine say the water stream velocity is 1-4m/s, I ve looked in the discussion fourms and so far i have found only Wind turbines.

 

Has anyone done an analysis regarding to water turbine.

 

I have provided a pic for example.

 

http://i.ytimg.com/vi/T_KjHWCo0C8/hqdefault.jpg

 

thanks

Balaji

Shaken not Stirred.
12 REPLIES 12
Message 2 of 13
hs.simanto
in reply to: balajig8

Hi!

Have you read Turbomachinery Best Practices and watched the hangout Study Rotating Machinery in Simulation CFD ? Those are really helpful.

Thank You!

Simanto
Message 3 of 13
Jon.Wilde
in reply to: hs.simanto

I also added a pdf of the presentation I gave in that video to the article here: Simulation CFD Rotating Region Best Pratices.

 

Hope it helps!

Thanks,

Jon

 

Message 4 of 13
balajig8
in reply to: Jon.Wilde

Thank you very much guys.

 

Danke schön.

Mit freundlichen Grüßen 

Balaji S.

Shaken not Stirred.
Message 5 of 13
balajig8
in reply to: balajig8

Hi..thank you for your quick reply again.

 

I tried both 'Local' and 'Cloud' Solve options.

 

Both were great...even the Turbulence models K-Omega SST with ADV5 was what i was looking for to define proper wake regions near the blade region.

 

Currently i am running a small test turbine assembly(not complicated).I just wanna test the results.....and still i did uniform mesh.

 

But my whole assembly has like 9+ Million Elements together.

 

I am running right now in Cloud, waiting for the results.

 

I just have one question.

 

Say my 

 

1. Surface boundary condition is 4m/s of water velocity.

2. Surface outlet boundary is 0 Pa Gauge pressure.

3. I have created the rotating mesh ( quite huge)

4. I have created ramped up rpm for the rotating region.

5. My rpm is 1000, and my timestep is 0.02...number of timesteps 300.

 

 

So my question is ... will the total time is 300x0.02 = 6secs, which means the water would have travelled 6x4 = 24 meters.

 

My whole Upstream and downstream length is less than 1 m.

 

Q:Will the inlet water velocity boundary condition reach the rotation region?

 

I am attaching pics for further info.

 

Cheers.

Shaken not Stirred.
Message 6 of 13
Jon.Wilde
in reply to: balajig8

Could you share some images of the mesh?

 

I would suggest you might like to have a P=0 at the inlet and flow rate at the outlet, the pressure will rise right? This means we don't have a negative pressure by default.

Ramp the RR AND flow rate up over the first 50 iterations

 

Run for 1000's of timesteps 🙂

 

Thanks,

Jon

Message 7 of 13
balajig8
in reply to: Jon.Wilde

Hi....i have attached the mesh view...

 

I have made the rotating region transparent so we can see the blade.

 

I have started a new simulation...considering Pressure at inlet P=0, and flow at outlet.

 

My previous simulation is still running...i will post the report once it is finished..

 

Cheers.

 

Shaken not Stirred.
Message 8 of 13
Jon.Wilde
in reply to: balajig8

Can I ask if it was you who logged a case and is now working with our technical sales team?

 

Do you have a uniform mesh on the inlet and outlet faces of your rotating region here? I cannot tell from this image.

You may also like to consider some refinement to the blade leading and trailling edges.

 

Thanks and keep up the good work!

Jon

Message 9 of 13
balajig8
in reply to: Jon.Wilde

Hi...yes it was me who logged a case and i got contacted by the tech support through phone.

 

But right now i am having a problem with the Data Transfer.

 

The Total size of data collected is 44GB.

 

But i dont have really that much size in my C:\.

 

I want to transfer to another drive which is really free, can i transfer the download to another file location.

 

I went to preferences and changed the location, but still it is downloading to C:\ which is running out of space.

 

Because my transfer rate is 12MB/s.

 

I have attached the progress pic and also the Full Mesh pic.

 

Thanks.

Shaken not Stirred.
Tags (2)
Message 10 of 13
heath.houghton
in reply to: balajig8

Whoa that is a lot of data.  I suspect you are saving out every iteration.  Definitely don't do that.  It is good just to save out the last iteration or every couple of full rotations.  If you need a higher fidelity image of the rotation, then save out a few intervals on the last rotation.

 

Hope that helps.

Heath Houghton
Principal Business Consultant
Message 11 of 13
balajig8
in reply to: heath.houghton

Hi...i am attaching the report and some pics for which i received the simulation result.

 

I am sure the results look quite convincing, i have tied to run on smaller mesh size, but i keep on getting geometric error...probably due to small edge size...i think is there any way to optimize the CAD surfaces?

 

Thanks and cheers for the support team.

 

5.png

 

2.png

 

 

 

1.png

 

3.png

 

 

Shaken not Stirred.
Message 12 of 13
Jon.Wilde
in reply to: balajig8

I would certainly say that your mesh is too coarse. Ideally we need more elements along the leading and trailing edges - maybe even add a surface to these in CAD to help achieve this.

Have you tried using the Surface Refinement toggle in the Meshing window before running?

I would also expect to see more flow along the fluid domain, it looks very centered around the impeller.

Message 13 of 13
balajig8
in reply to: Jon.Wilde

Yes...this was a short test.

 

I will try to do Mesh Enhancement along the surfaces similar to this given example 

 

http://knowledge.autodesk.com/support/simulation-cfd/learn-explore/caas/CloudHelp/cloudhelp/2014/ENU...

 

Also i will increase the Mesh Fineness.

 

Please coud you explain me, you said "maybe even add a surface to these in CAD to help achieve this".

 

I did not understand the above sentance,what does it do?.

 

Thanks once again.

Shaken not Stirred.

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