Published in Military & Aerospace Electronics
Written by John Keller
Here’s the good news: electronic and electro-optic subsystems for aerospace and defense applications progressively are becoming higher performance, smaller sized, and lighter weight. Now here’s the bad news: all those benefits have a major system tradeoff: a growing amount of waste heat.
It’s a fact of life that aerospace and defense systems designers can’t escape: the higher the performance and the smaller the size, the greater the amount of heat that designers must confront. It’s not as though electronic components can be designed economically that can tolerate huge amounts of heat. Instead, designers have to find ways to cool these ever-hotter electronic components, and they must do it affordably, and in small, lightweight packages.
Conduction Cooling
Perhaps the most widespread and best-known thermal management approach for rugged aerospace and defense applications is conduction cooling. These systems typically are sealed against airborne contaminants like dust and salt spray, and conduct heat outward from hot components inside the chassis to cold walls or ambient outside air. It’s relatively simple, reliable, and affordable, and has been a thermal management go-to for decades.
Conduction cooling often calls for wedge-lock devices along the edges of circuit cards to help transfer heat from the card, along rails, through the chassis, and eventually to the outside of the chassis where it is dissipated.
“Conduction cooling is by far the biggest cooling approach in terms of COTS hardware out there,” says Ivan Straznicky, chief technology officer of advanced packaging at the Curtiss-Wright Corp. Defense Solutions segment in Ashburn, Va. “Still, as power goes up, it becomes more difficult for conduction-cooled modules to handle cooling.”