I've sent the model in to tech support but wanted to ask the question here too because it might help someone else. Picture attached.
- Heat sink with total power of about 130 watts applied to a surface.
- Ambient temp about 55C
- No forced flow. Cube shaped air volume with 0 psig on inlet and outlets to allow for buoyancy flow.
- 50C temp applied at bottom of cube.
- Using symmetry (half model)
- The analysis gets very close to converging after 400 iterations but never stops. Temperature deltas are extremely small so I stop analysis.
- The flow vectors are correctly rising from the heat source but only locally near the surface of the heat sink. About 10 to 20 in/sec.
- Elsewhere in the air volume, the vectors are pointing in the opposite direction (towards gravity) and moving fast - 200 in/sec
I can't figure out what is causing the air to flow in the opposite direction. It really is acting as though I have placed a velocity on the top of the volume
but I haven't. Only zero pressure. Has anyone else seen this in their models? If so, how did you resolve it?
Solved! Go to Solution.
Seems I had forgotten to set the air to "Variable" instead of "Fixed" though I swear I made that selection before running the analysis. Running correctly now.