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Active Member
alestk
Posts: 6
Registered: ‎04-19-2013
Accepted Solution

Internal Recirculating Flow

389 Views, 11 Replies
04-19-2013 10:40 AM

 

I was wondering if anyone had any tips or best-practices for simulating internal recirculating flow with the CFD package. I'm optimizing a simple exchanger + peltier block for my heat transfer class, but no matter how I assign boundrary conditions I can't seem to get my fluid volume to flow. 

 

So far i've tried the following approaches:

 

Let inventor export directly to CFD. CFD correctly detects and creates the internal surface.

 

Let inventor export to Fusion, cap all ports, assign mass flow BCs to each capped port with corresponding zero-pressure BCs on the outlet. Although this internal surface is segemented into many pieces instead of just one continous piece like the direct-export approach does.

 

Both approaches yield the same result wether transient or steady-state so i'm really scratching my head at how to proceed. I've checked the wiki but it doesn't seem to have much reference on how to best set BCs between parts. 

 

I've attached an image of my current mass-flow BCs and the full assembly. This is using the second approach.

 

Either way, when evaluating the model CFD detects "0 inlets, 0 outlets, 0 unknown" 

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*Expert Elite*
OmkarJ
Posts: 440
Registered: ‎10-02-2012

Re: Internal Recirculating Flow

04-19-2013 07:31 PM in reply to: alestk

Can you attach cfz? 

 

OJ

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Product Support
Royce_adsk
Posts: 645
Registered: ‎08-24-2011

Re: Internal Recirculating Flow

04-20-2013 06:08 AM in reply to: alestk
My guess without looking at the model is that you didn't put the boundary conditions on the external surface, but they are in the middle of the flow.

If you share you support share (.cfz) file the community can review your model.

-Royce


Royce Abel
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Active Member
alestk
Posts: 6
Registered: ‎04-19-2013

Re: Internal Recirculating Flow

04-21-2013 10:22 AM in reply to: Royce_adsk

Sorry for taking so long to get back to both of you, I've attached the .cfz below. 

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Product Support
Royce_adsk
Posts: 645
Registered: ‎08-24-2011

Re: Internal Recirculating Flow

04-21-2013 02:39 PM in reply to: alestk
Your intention seems to be a closed loop system. I would suggest you explore using an internal fan/pump.

The basic reason why your model doesn't work is because you have a mass flow rate assigned to a solid wall. If you suppress the mesh for the Nylon parts then you would have seen at least some sort of result.

Having variable material properties for your water is probably not necessary either.

Good luck!


Royce Abel
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Active Member
alestk
Posts: 6
Registered: ‎04-19-2013

Re: Internal Recirculating Flow

04-21-2013 03:12 PM in reply to: Royce_adsk

Ah, thank you for the advice, and yes I am trying to emulate a closed system. I've read up on the documentation for the fan, and it looks like I would just designate one of my barbs as the fan/pump during the materials assignement phase? 

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Product Support
Royce_adsk
Posts: 645
Registered: ‎08-24-2011

Re: Internal Recirculating Flow

04-22-2013 05:52 AM in reply to: alestk
I would probably look at adding an extra part in the flow path that would be the shape of a hockey puck. That is the typical shape you will see this material used as.


Royce Abel
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Active Member
alestk
Posts: 6
Registered: ‎04-19-2013

Re: Internal Recirculating Flow

04-22-2013 05:56 AM in reply to: Royce_adsk

Thanks again for the help. I'll try that and let you know how it goes.

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Active Member
alestk
Posts: 6
Registered: ‎04-19-2013

Re: Internal Recirculating Flow

04-22-2013 11:06 AM in reply to: alestk

Using the internal fan has fixed the problem. Just wanted to post this for anyone else who might have a similar problem to mine.

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Product Support
Royce_adsk
Posts: 645
Registered: ‎08-24-2011

Re: Internal Recirculating Flow

04-22-2013 01:21 PM in reply to: alestk
Excellent! Thanks for the feedback.


Royce Abel
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