Fan Turbo Volume for CFD

[bimbo666]

Hi all,<?:namespace prefix = o ns = "urn:schemas-microsoft-comfficeffice" />

I posted it here, instead of Analysis forum, cause is a modeling issue.

Here is my problem explanation

I need to do the turbo volume that is the air volume surrounding the fan blades, since the hub surface to the casing surface (-virtual surface that will enclosed the air in the barrel), cause a fan behaves in a cyclic way, I only need to do one turbo volume instead of all, to define my pressure and suction surfaces and then perform my CFD, but I

 

[Bob_W]

I am not sure exactly what you need but I thought this link may provide info that could be useful to you:


http://e-cognition.net/pages/Surf-Model-1.html

 

[jsantangelo]

Put the fan in an assembly then create a volume (box?) that represents the "air". Subtract the fan from the "air" via Edit-->Component Operations --> Cut Out. Then you can do a mass/volume analysis of the "air". Will that work?


Edited by: jsantangelo

 

[bimbo666]

James,


If you look at the picture in detail, it's what I did, but I need the real "Pressure and Suction" surfaces enclosing by the air, so I can setup a good CFD, the procedure you're talking about, is what I alreday done, but is not a robust model to CFD


Regards


Pablo

 

[bimbo666]

Hi guys,

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Take a look at this picture, maybe I did a mistake cause I assumed that everybody have a CFD turbo-machinery experience (Computational Fluid Dynamics). So please see the picture above and noted the propeller centermost picture, look at the blades and the spacing between them, that spacing is that I

 

[design-engine]

you guys need Fan Engienering Howden Buffalo, Inc and Fan Handbook Frank P. Bleier

 

[bimbo666]

I met one of the engineering guys you're talking about in the Mexico city facility, and used the book you're referencing a couple of years ago when was working on a low noise-highspeed fan nothing fancy..., I prefer this, has a lot of fan - compressor - turbine and applies the dynamics also thru the design stage.





Pablo

 

[jimshaw]

Pablo - It looks like you're trying to get the bounds of your analysis space to be the surfaces of the adjacent blades, and not the simple pie piece. You've got a good start with your 1/4 model from your original post, but you'll need to enlarge that fluid volume so it encompasses the adjacent blades. Then remove material to obtain the proper symmetry, and get your inelt/outlet perpendicular to the flow.


The easiest way may be to create boundary blends at your inlet/oulet/walls, then use them to trim an oversized pie piece.


Does this make sense?

 

[bimbo666]

Jim,


You're right that's what I'm looking for, still trying

 

[jimshaw]

Did you try what I have written in my previous post? Do you understand what I wrote or do you need more detail?

 

[bimbo666]

Jim,


What do you think about this?








Thanks Jim

 

[jimshaw]

Fantastic, great job! What are the inputs/outputs of your analysis if you don't mind me asking?


I'm used to system level CFD where I represent fans with a cylindrical volumeof certain axial and rotational flow, never this detail around the blades... Are you trying to predict cavitation?

 

[bimbo666]

Jim,


Remember that cavitationis the formation of vapour bubbles of a flowing liquid in a region where the pressure of the liquid falls below its vapor pressure.


So cavitation occurs in in pumps, propellers, impellers, and turbines.


Regards


PAblo

 

[jimshaw]

oh yes, you did mention that it was air already, didn't you...