[alan81]

Dear all,

I am going to do my master thesis on (estimate erosion in oil and gas pipeline due to sand presence).

I have two options two do that either using ANSYS/CFX or using STAR-CCM+, I would like to get some information how could be difficult to model that in ANSYS, and how long does it take to finish for me as a beginner of ANSYS.

I am looking forward to hearing from you

kind regards,
Alan

[ghorrocks]

CFX can certainly do this sort of model. I am sure Star can to be I have never used it and have no idea what is the better tool for this.

I strongly recommend you get both software and firstly check they have the physical models you need (I suspect you have specific erosion models you are looking for). If they both have the physical models you need then run an example simulation on both and choose the one which looks best, maybe fastest solve time, easiest to use, prettiest pictures, most accurate - what ever is important for you.

[pros]

Hi Alan,
Did you manage to get answer to this question? I am doing a similar project and wondered if I can get a better software to use.
Regards,
Pros

[ghorrocks]

Yes, he got an answer to his question - did you see my post?

[ken]

hi all,

currently i am doing cfd simulation on sand erosion in pipe. Read the post and know that u guys r doing that as well. Hows progress? Can I have your email address so that we can have some discussion on it?

thank you

Regards,
ken

[tarang]

hi..
can anyone please tell me that how i can import finne or tabakoff model (pre-defined in ansys 12) .

Mesh was generated in turbogrid and boundry conditions in CFX-pre

[Far]

http://www.cfd.com.au/cfd_conf06/PDFs/073Bro.pdf

http://www.edr.no/blogg/ansys_blogge...d_ansys_fluent

http://www.google.com.pk/url?sa=t&rc...jRCw3snV8zuaKw

https://www.sharcnet.ca/Software/Flu...th/node266.htm

[tarang]

thanks far ..
those tuts solved my problem

although my simulation is running well but i am facing errors at various steps due to high aspect problem during meshing. I have tried to relocate the control points and selecting diff geom but high aspect ratio is not getting less. Moreover i receive this error after meshing in turbogrid
maximum element volume ratio value: 29.2864 %bad: 30.25
Maximum edge length ratio value: 670.775 %bad: 13.4096

I have to mesh in turbogrid and solve in CFX only.
please see my case at the link below. please correct the errors and mail me
at tarang.agarwal1@gmail.com
thanks in advance

http://www.mediafire.com/?k7kpe1cq34owle1

[Far]

Aspect ratio up to 1000 is not a problem in boundary layer. Edge length is equivalent to aspect ratio. Check this mesh in CFX,error you get there are more important than the turbogrid warnings.

[Far]

Although I did not find any specific problem in the turbo-grid file. I have made few improvement to original mesh by changing the no of nodes in span wise direction, o-grid, y+ and ATM optimized topology. Hope it helps you.

Do you have boundary conditions for this geometry or just trying the ANSYS bladegen and Turbogrid for learning?

http://www.4shared.com/rar/cr0n3ZVS/...correct_2.html

[tarang]

thanks for the help

i have boundary conditions for geom..i m trying to study the effect of different erosion theories on different material of impellers in centrifugal pumps.

[Far]

Good work. If you need further help then I am here.

Glenn's comments are always correct and very useful.

[ghorrocks]

No, I am not always correct. I have made a few mistakes - I challenge you to find them . But I am happy when people correct me because then we all learn something. That is a key reason why I post stuff on the forum.

[Far]

very true Well I am more inclined in finding the qualities than mistakes (except myself), that's the positive way of learning.

[juliom]

Hi dear colleague,
You can use ANSYS CFX for this problem, you can use the euler - lagrange approach (discrete model).
Thre you´ll find a an aplication to model the erosion due to particles at walls.
I hope this help you, my master thesys is in multiphase fluid flow, and I am using the same model!!! with oil and gas separators.
Regards Julio M

[tarang]

can anyone mesh this impeller ..?
i have meshed this but there were still many errors including Min and max face angles due to which when i am defining a rough wall it is giving error in CFX solution

http://www.mediafire.com/?452ay22kvz4s26y

(i have to mesh this in turbogrid only)


thanks
tarang

[Parisa]

Hi guys,

I followed your discussion on the erosion subject. It was quite helpful to me. I read the suggested article "USE OF CFD TO PREDICT AND REDUCE EROSION IN AN INDUSTRIAL SLURRY PIPING SYSTEM". There the stokes number is less than 2.
I am currently simulating a case with quite large particle diameter, 5mm, which gives a stokes number around 12. But the particle mass loading is quite low, 0.009.
I wonder if the assumption of one way flow coupling is still valid?
I tried simulating this case in CFX and one way flow coupling and Finnie model, and I got quite low erosion rates.
Does that mean that I am neglecting some important effect in the system and get unrealistic results or is this method of calculating the erosion rate still valid for my case?
I'm really struggling if I can trust the results...

I really appreciate your help on this.

Regards

[ghorrocks]

One way coupling is likely to be OK for low particle loadings (have a think about it, it makes sense).

Are you sure the Finnie model is appropriate for your particle?

[Parisa]

Thanks for the reply.
Well, the particles are Quartz and the piping is Steel. I used Finnie cause the model constants are quite well established for this material combination. I also tested it with Tabakoff and then it was a bit higher erosion rates.
But really no, I am not sure if Finnie or Tabakoff are the best models for this. I haven't found any articles that recommend when to use Finnie or other erosion models. If you know of any recommendations how to choose an erosion model I would really appreciate it if you share them.

About my former question, I also thought about it more and it makes sense to use the Euler-Lagrange because of the low particle loading. But I am still unsure if Euler-Lagrange is applicable for such large particles. I have read somewhere before, that for using Euler-Lagrange the particles should be much smaller than the computational cells. Which in my case they are actually bigger than the cell size, cause it is not a very large domain. I actually don't have a good understanding of what happens if paticles are larger than the cells. I would appreciate your comments on this.

Regards

[ghorrocks]

Lagrangian models are OK if the particle is larger than the mesh size providing you do not care about the detailed flow around a particle. The effects of the particle on the flow is modelled to just occur at a point (which is modelled as a single control volume) and so as long as this is close enough you are OK.