How Embedded Systems Are Coping with the Heat of Today's Avionics
General Micro Systems (GMS) builds small form factor servers, switches, and routers for military applications; including avionics. Although it also builds fan-cooled avionics systems, the company recently unveiled Titan, which it bills as ‘the industry’s first sealed, fan-less, conduction-cooled rackmount servers with artificial intelligence (AI) and mil-circular (38999) connectors for superior ruggedness in the most demanding defense and aerospace applications.’
Given that the Titan uses up to four of Intel’s latest second generation Scalable Xeon processors in either a 1U or 2U chassis, how does GMS get rid of the heat?
“We use the air frame itself to provide plenum cooling to this server,” replied Chris Ciufo, the company’s chief commercial officer. “Custom internal heat sinks conduct heat to the plenum, and air is either forced through the server or evacuated out the back in a vacuum-like fashion. This allows for a 100% silent server, which makes it ideal for use in operator spaces.”
Blowing air across circuit boards is a time-honored cooling method. The approach embodied by the VITA 48.8 open standard makes air cooling more efficient by spacing the circuit cards within the chassis to allow enhanced air flow. Cool air is bought in from numerous directions at the bottom of the cards, flowing upwards across them all and venting through the top sideways. This eliminates dead spots in the airflow, and harnesses the natural power of convection to move the air through.
“VITA 48.8 allows you to blow air directly through the cards, which creates a much shorter thermal path for removing heat,” said Brian Hoden, principal mechanical engineer at Abaco Systems.
Not only does VITA 48.8 deliver much better cooling than conventional air-based approaches, but it is less complicated than admittedly efficient liquid cooling. “With liquid cooling, you have to incorporate a liquid-to-air heat exchanger than takes up additional space; along with the piping and pumps,” Hoden said. “There is also the risk of leaks when components are switched out, or when a connection fails; which is not something you want to happen in an avionics bay.”
In this Avionics International article, GMS CTO Chris Ciufo explains how cooling is achieved without using fans.