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[ICEM] Quarter O-grid topology for propeller blade

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Old   August 27, 2012, 09:55
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Sijal Ahmed Memon (turboenginner@gmail.com)
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Quote:
Originally Posted by venkat_aero2007 View Post
Far you are too quick

I seen your reply after posting my last message. so do you mean that I have to keep same shroud height for both the rotors.

yes...................
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Old   August 27, 2012, 10:12
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Quote:
yes I am giving both rotors motion with +ve and -ve rpms. It is not possible to give the one rotor rpm1+rpm2 and other one as stationary because in contra rotaing rotor, the front rotor rotates in clockwise and rear in anti clockwise direction. I am sure it is not because of meshing problem because I ran a simulation with unstructured mesh which worked perfectly fine.
Analogy: Aircraft moving with Mach 0.8 in free-stream and while solving in CFD we give air the velocity of Mach 0.8. Because it is relative to each other and we get the same effect.

Why I am saying this is because once I tried to solve the high pressure and low pressure turbine coupled with S-type diffuser with increasing radius. It was single stage high pressure turbine and two stage low pressure turbine and rotating in opposite direction. But i was not able to do this. What I concluded is that the mixing plane model availabe in commercial codes is only valid for rotor stator system with rotation in -ve or +ve direction and you can have more than 15 stages (or even more) but rotating in same direction.

So either you should modify the implementation of mixing plane model as did by following references or ask Fluent support if they have ever solved the contra rotating rotors (one in +ve and second in -ve direction) with available mixing plane model. For record this mixing plane model implemented in Fluent or CFX was originally developed by Denton and Dawes at Whittle Lab, Cambridge university.

Ref1 : https://stacks.stanford.edu/file/dru...-augmented.pdf

Ref2 : http://adl.stanford.edu/papers/AIAA-2007-1117-275.pdf

Ref3: http://adl.stanford.edu/papers/AIAA-3893-286.pdf

Ref4: http://adl.stanford.edu/papers/AIAA-2007-519-239.pdf


Quote:
"why are you merging meshes in ICEM?"Actually the front rotor consist of 11 bades with peridic angle 32.72727 and the rear rotor with 9 blades (peridic angle 40). So meshes them seperately and merged it.
This should be done in Fluent. Output both meshes separately and glue them in Fluent with Append command. This is standard practice for mixing plane. Merging meshes in ICEM is done for other reasons.




Quote:
Could please tell me how to change the domain geomentry shape.
Geometry shape looks fine to me. They only requirement for periodic boundary is that it must have same shape on both sides. For mixing plane I have already disccused in previus posts.
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Old   August 29, 2012, 05:54
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This may be helpful for you.

http://dspace.mit.edu/bitstream/hand...401.pdf?sequ..

I have also started thread on mixing plane model in CFX:

Validaty of mixing plane model for contra rotating rotors
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Old   August 29, 2012, 06:04
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You can model this as unsteady and still use the single rotor from both rotors using the advance models available in CFX or you can switch to NUMECA. ANSYS is updating turbo machinery models in CFX, not in Fluent.

http://www.numeca.com/fileadmin/news..._Corporate.pdf

http://www.numeca.be/index.php?id=41...ash=101540dfc0

http://www.google.com.pk/search?q=un...hrome&ie=UTF-8

http://www.google.com.pk/url?sa=t&rc...p14RIQ3REScuSQ

http://documents.irevues.inist.fr/bi...pdf?sequence=1
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Old   August 29, 2012, 06:07
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Hi far, thanks a lot for your information. I have discussed with my professor about the mixing plane model available in fluent. He said that the contra rotating simulation can be done just by giving one in +ve rotation and other in -ve rotation. I am going to start my simulation today. I will update the result soon
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Old   February 17, 2013, 02:49
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Quote:
Originally Posted by venkat_aero2007 View Post
I created quater O-grid and tried to adapt block as suggested in post 4. but could not get a fine mesh. I don't know where I am going wrong.

Firstly I made a horizontal and vertical split (Figure1) and then to create quarter O-grid, I selected 4 faces as shown in figure2. I thought of associating the edges parallel to the two curves (figure3). I made horizontal split at each section of the blade. then associated edges to curves. I tried to make a O-grid but ICEM should me an error message saying that O-grid not successful.

The mesh around the pressure side of the blade flows the profile of the blade (figure 4) but where as near the suction side, mesh does not follows the blade's profile (figure5). mesh near the trailing edge are clustered. The quality at the tip of the blade is also bad. should we want to do a special treatment
near the tip region.

Here are the files
https://www.dropbox.com/s/k28abvd4b3...quater%20O.prj
https://www.dropbox.com/s/indjfxjj4b...quater%20O.blk
https://www.dropbox.com/s/8vcbc6uod3...quater%20O.tin


waiting for your suggestions.
hi . thanks for your gird . but unfortunantely your is link for download doesn't exist.
pleaze send me file (motaffef@gmail.com) or Correct this link , thanks alot
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Old   February 13, 2014, 01:38
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SIR i m new to icem i want to rotate propeller in for cfd analysis plz guide me . looking forward
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Old   March 12, 2014, 03:56
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Originally Posted by M MOHSIN View Post
SIR i m new to icem i want to rotate propeller in for cfd analysis plz guide me . looking forward
hi


you first told what is your question?
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Old   March 14, 2014, 00:49
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Sir my question is how can i rotate the propeller using UDF or any other method i.e to give rotation to it. looking forward . thanks
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Old   March 14, 2014, 15:52
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Quote:
Originally Posted by M MOHSIN View Post
Sir my question is how can i rotate the propeller using UDF or any other method i.e to give rotation to it. looking forward . thanks



is your boundary condition periodic or not ???


if is not you can rotate your mesh in fluent with 1-rotation 2-append case
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Old   March 16, 2014, 23:29
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sir it is not periodic i have to carry out at cruising speed so can u elaborate kindly how can i do it plz . . . . .
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Old   January 31, 2015, 07:27
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Quote:
Originally Posted by venkat_aero2007 View Post
I created quater O-grid and tried to adapt block as suggested in post 4. but could not get a fine mesh. I don't know where I am going wrong.

Firstly I made a horizontal and vertical split (Figure1) and then to create quarter O-grid, I selected 4 faces as shown in figure2. I thought of associating the edges parallel to the two curves (figure3). I made horizontal split at each section of the blade. then associated edges to curves. I tried to make a O-grid but ICEM should me an error message saying that O-grid not successful.

The mesh around the pressure side of the blade flows the profile of the blade (figure 4) but where as near the suction side, mesh does not follows the blade's profile (figure5). mesh near the trailing edge are clustered. The quality at the tip of the blade is also bad. should we want to do a special treatment
near the tip region.

Here are the files
https://www.dropbox.com/s/k28abvd4b3...quater%20O.prj
https://www.dropbox.com/s/indjfxjj4b...quater%20O.blk
https://www.dropbox.com/s/8vcbc6uod3...quater%20O.tin


waiting for your suggestions.
hello
thanks for your work its very good but
unfortunantely your is link for download doesn't exist.
please send me files to (hdrsattar@yahoo.com) or Correct this link
thanks alot
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