" However, when I calculate the heat transfer rates (which should be equal), I get weird results."
could you be more specific?
what do you mean by calculate the heat transfer rates
and what are the weird results?
you can post a pack and go of your model at the top right using the "advanced editor"
i'm also trying to follow your setup
you applied a heat input on the bottom of your model and convection on your model as well. but no where else? IE its ok to assume everything else is insulated?
When I look at the plot of the AL 300 and the Cu, I see they are both 1.249e2 at the center. I'm not sure how you could get better agreement than that. The only way the min of one would correspond to the max of the other is of you are plotting through the thickness. At any rate, the AL 300 is isothermal in x and z, the difference between the max and min of it is pure noise.
With respect to the heat flux, I'm going to take a stab and say you did a bulk temp of 40 C. In that case, you have:
29426 (W/m2K)*.0001 m2*(124.9-40)K = 250 W
If you have some other bulk temp, then there is some more work to do.
Thanks for the help/concern.
The problem was that i was getting a heat flow rate on the copper of 250w (sounds good so far).
I was getting a heat transfer rate of around 4000w, or something outrageous like that on the ceramic. (not good).
Yes Mike the bulk temp was 40 C.
For some reason I couldn't post replies here from my other computer, but I got your questions in my e-mail.
I am back on the same computer I posted from, and now I can reply. (?)
After complaining to SWX, I finally broke out my dusty slide ruler and calculated that the delta T thru the ceramic should be roughly .01 C. Simulation said it was more like .4 C.
SWX was messing up, so I spent some time figuring out how to make the chart more precise. Then (since the ceramic is only 100 nm thick, which is the the thinnest SWX will do, I wanted 10-25 nm) I spent another day and a half getting the mesh as fine as I could along the 100 nm wall without crashing. Oh, and you can't do a 100nm mesh in SWX by the way.
Finally, I got a heat transfer rate thru the copper of 249.89C and a heat transfer rate thru the ceramic of .019C.
I called it done, and then hand calculated the derived results that I was investigating which was for a 10nm thick coating and a 25nm coating.
Anyways, with enough perseverance SWX simulation works OK within its limits.
I just have to learn to be more patient and spend more time understanding what is going on in the simulations.
so the answer was that the mesh was too coarse?
The answer is:
A: The default units on the chart were too course, (my fault, but in training we never changed them).
B: The ideal mesh for a 100nm surface would be a 50nm mesh. Unable to do that in SWX.
C: The results still were not consistent with mathematical equations.
But in simplicity, yes Jared, the answer is the mesh. However it took me four days to get a mesh that would not crash the solver, but would come close to a real answer. Then I had to estimate and derive the answer I wanted. I needed a 25nm max. coating.
SWX Simulation has once again not been able to do what we (my company) thought it would do.
Don't get me wrong, It great in certain applications.