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apc3161 August 23, 2009 17:46

novice star ccm+ questions
 
2 Attachment(s)
Hello,

I'm new to this program and CFD in general. I was wondering if anyone can help me with a few questions I have. See the attached photos for references to my questions.

I have turbomachinery blading that I want to study. See "cascade". I was wondering if there was any way I could set it so that the conditions at one boundary would repeat at a different boundary, see "example".

In the figure "example", I would want boundary walls A & B to be linked, as well as boundary walls C & D. If there was a way to do this, this would seem easier than having to CAD up a linear cascade with enough blades to represent infinity (say 20+ blades) and running simulations on that. Does anyone know of a way to achieve this?

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My second question is this. Is there a way to directly import say a CAD file of a blade, and then create inlets, outlets, and boundary walls within CCM+? Right now, I have to go into CAD, and sort of make a "negative" image of my blade. That is, a thin plate with the blade cut out of it. I then use the flat blade-cut plate to represent the "fluid region".

Is there an easier way? One where I could just use my CAD files as is? I discovered something called "boolean subtraction" which seems promising, but was unable of finding a way to create an artificial box within CCM+ from which to subtract the blade profile from.

Thanks for reading, and all responses are greatly welcomed.

SKK August 25, 2009 08:17

With regards to your first question, if you set A+B, and C+D as periodic boudary condition, it will do what you want, as in it will simulate periodicity of flow as if there were infinite number of blades.

With second question, import your CAD using File>Import Surface Mesh. Then create a box so that when you operate relevant boolean operation you get the geometry in your second figure. To create the box, right click on the surface representation you are working on, and right click the mouse and select create surface>create block surface. So, Representation>Import>(righ click)create surface>create blcok surface.

Once you have the block use the appropriate boolean operation to get the geometry you want.

I suggest you try some of the tutorials which will help a lot with geomtry preparation.

apc3161 August 25, 2009 10:15

Quote:

Originally Posted by SKK (Post 227427)
With regards to your first question, if you set A+B, and C+D as periodic boudary condition, it will do what you want, as in it will simulate periodicity of flow as if there were infinite number of blades.

With second question, import your CAD using File>Import Surface Mesh. Then create a box so that when you operate relevant boolean operation you get the geometry in your second figure. To create the box, right click on the surface representation you are working on, and right click the mouse and select create surface>create block surface. So, Representation>Import>(righ click)create surface>create blcok surface.

Once you have the block use the appropriate boolean operation to get the geometry you want.

I suggest you try some of the tutorials which will help a lot with geomtry preparation.

Thanks SKK, I'll look into all of this.


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