AnsweredAssumed Answered

Flow simulation to improve heat sink design - Problem! No temperature gradient across fins!

Question asked by Jamshid Sadeghi on Nov 26, 2013
Latest reply on Dec 11, 2013 by Kyu-Hyung Kim

Hello all,


I am trying to do a study into LED heat sink design and performance in Solidworks with the Flow Simulation, but I am getting results which I think are wrong (although this is most likely to do with how I set up the study).


Until now I had been using an external study, selecting Conduction in solids and Gravity from the wizard menus.


I applied a volume heat source to the part that is the LED COB in the assembly.


I then made a thermal joint between the bottom of the LED COB part and the surface of the heat sink which it is sitting on.


Finally I selected all the exposed faces of the heat sink and set a contact resistance of ground aluminium and air.


When I run the study and check the results the temperature throughout the whole heat sink is constant, i.e. it is, say, 100 degree C in ever part so there is no temperature gradient across any of the fins or in the sink.


Of course this cannot be but I do not see where I have made my mistake. I have seen mention of a 2-Resistor component on some other disucssion but am not sure how to apply this.


I am running the study using an assembly of parts, one of which is the heat sink and another one of which is the LED COB package. I have modelled this as a single part made of silicon, i.e. the entire package, not just the chip. Perhaps this is wrong?


Really stuck here so any help would be really appreciated!


Thanks in advance!