Please, please don’t use pre-heated air in your thermal designs and PLEASE simulate the design using CFD or at least have a nice, calm chat with your mechanical/thermal team prior to design freeze on your electrical layout.  Once a design gets locked down the thermal design options start to get limited or expensive or ugly. Or all three!
Here’s what we’d like our readers to do instead:
- Do have a nice chat with the EE and ME team together. Maybe bring some bagels and make it peaceful.
- Do some quick look over of any designs for obvious issues, like, walls of memory in front of hot cpus.  Yes, as ME’s and Thermal Engineers we understand that there are ever sticter rules in layout and routing of high speed memory buses. BUT, let’s compromise together so we can keep them happy and cool 🙂
- Do some first order modeling, on paper or a spreadsheet. How do things look relative to your thermal budget? (please click to our nice white paper on how to do first order thermal modeling if you need a reminder)
- Then, as the EE design gets placed out, maybe do some CFD to see how everything looks thermally.
While this seems like it’ll add a week to your design, it won’t. Maybe two or three days and the end result is a less expensive design that is:
- More reliable with higher MTBF
- Operates at the maximum frequencies
- Is safer
Robin Bornoff, a Product Manager at Flomerics UK (now Mentor Graphics), has some great thoughts on this topic. We’d recommend having a read of her article, “Get On Board: Solving Thermal Problems at Board Level“.