CFD Online Logo CFD Online URL
Home > Forums > General Forums > Main CFD Forum

flow/heat transfer through heat sink (with fins)?

Register Blogs Members List Search Today's Posts Mark Forums Read

LinkBack Thread Tools Search this Thread Display Modes
Old   January 25, 2008, 13:59
Default flow/heat transfer through heat sink (with fins)?
Pei-Ying Hsieh
Posts: n/a
Dear CFD experts:

I am working on a conjugate heat transfer case:

Flow through a heat sink with several vertical fins. Heat source is attached to the bottom of the heat sink. Cool air flows through the fins to take heat away. Flow speed is pretty constant at around 1 m/s. The minimum cell size is about 0.03 meter. Hence, I will assume that the delta t should be around 0.03 seconds, correct? Unfortunately, I need to run a 2 hour simulation to see if the heat sink (fin) design is good. This means, long calculation time.

Now, since the flow itself is pretty steady, can I run a steady state cold flow case first, then, use it as the starting flow for the conjugate heat transfer case? But, in this case, does CFL criteria still applies? Am I still limited to 0.01 seconds delta t? Is there any way to speed up the transient calculation?

  Reply With Quote

Old   January 26, 2008, 06:33
Default Re: flow/heat transfer through heat sink (with fin
TITAN Algorithms
Posts: n/a
Thought I would chime in since no one responded...

Yes I agree. The time step for the complete P,u,v,w (K,E) would be small, perhaps proceeding at about CFL ~ 0.5 to 1.0. This is generally due to the pressure coupling which by nature is elliptic, but is advanced, by varying solution methods, as a parabolized transport equation.

After solution of the velocity state, preserve your velocity field solution S = [u,v,w], then begin your energy equation solution (assuming non-bouyancy effects). Depending on the discretization methods, e.g. implicit advection, you should be able to advance this solution at a much higher CFL number, perhaps 5 to 10.

  Reply With Quote


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

Similar Threads
Thread Thread Starter Forum Replies Last Post
Water subcooled boiling Attesz CFX 7 January 5, 2013 03:32
Simulate heat transfer of heat sink in a box... chien87 CFX 8 February 8, 2011 03:50
Convective / Conductive Heat Transfer in Hypersonic flows enigma Main CFD Forum 2 November 1, 2009 22:53
How can I increase Heat Transfer at Domain Interf? B.Simon CFX 3 October 28, 2008 18:53
Convective Heat Transfer - Heat Exchanger Mark CFX 6 November 15, 2004 15:55

All times are GMT -4. The time now is 05:49.