Parameters of natural convection simulation

Hi there!
Just watched Simscale video: How to Simulate Natural Convection for a Heat Sink - YouTube
But many of simulation settings were not explained and some of the settings were wrong for my opinion.
Let’s dive into details:

  1. Why you choose epoxy as a heatsink and LED?
  2. What is “seed face” and why did you choose exactly the side of the heatsink?
  3. Why you have choosen “k-omega SST” as turbulance model?
  4. Why you have choosen 1 m/s as a Y-direction velocity?
  5. Why you haven’t choose a top face as a natural convection face?
  6. Why did you leave “Amount of substance” (at 4:30) as 1 mol of air? At your settings you have 0.4992 cubic meters of air, which in turn equal to about 22.3 mols of air. This leads to your air will be much thinner - 34 mm of mercury only!!!

I tried my own simulation ( and have some weird results:

  1. Why I’m having a cold spot at the edge of the radiator? My amient temperatude was set to 19.85C.
  2. The hottest temperature is 21.31 C only, while the radiator has 3x30 W of power sources (90 W total). I’d estimated that the overheat would be at least 15-20 degrees.

What is wrong with my simulation?

Hi there, thanks for using the forum!

And more thanks for pointing this out. I will reach out internally to the author of the video so he is aware of your comments and questions, then we can discuss them all.

I will get back soon!