Convection Coefficient

[frankjconway]

Our company just got CosmosWorks Advanced Professional with Geostar and I have very little FEA experience. I am attending a training course next week on this, so I have been playing around with it a bit. And have a question.

I am looking at designing an extruded vertical-finned heat sink to replace our legacy horizontal-finned heat sink on our cryocooler. I needed to compare the performance of the two in order to justify the redesign effort. In doing so, the software asked me for the convection coefficient, h. Now back in my college days, I remember most of the work involved in a similar problem revolved around finding h (using a bunch of charts, dimensionless numbers, etc). Seems to me that the software would have the available data needed to find this (geometry, boundary conditions). Is there a way to find this without going through all the hand calculations and let the software do the work for me? If not, it seems this would negate some of the worth of this module. Has anyone had similar experiences?

Thanks,

Frank

 

[corus]

No software will calculate the boundary conditions for you. The value of h will depend on a number of factors such as the surface orientation, the fluid velocity/temperature etc. Best to dig out your college notes and work it out.

corus

 

[frankjconway]

Thanks Corus. I had thought that was the case but just wanted to make sure. The upshot of this is that I really enjoyed my heat transfer classes in college but haven't used it since. I'll get cracking on it.

 

[jte]

I dabbled in computational fluid dynamics years ago but can't claim any real competence in the field. I think that the approach of getting some hand calc'ed convection coefficients makes sense - that's the approach I would normally take since that's what is available to me.

On the other hand, there definitely are CFD programs out there which will determine the convection for you. Not cheap, but available. For example:

http://www.solidworks.com/pages/products/cosmos/cosmosfloworks/cfwfeatures.html?pid=45

If developing products which are hugely dependent on convection for their functionality it may be a worthwhile investment to get a CFD package.

jt