Researchers from Purdue University (funded by Intel) have developed a new cooling technology called ionic wind engines. This new technique promises to deliver increased heat transfer coefficients of up to 250 percent over current air cooled technologies. The technology aims to reduce the layer of stationary air above chips (no-slip layer – http://en.wikipedia.org/wiki/Boundary_layer) as air is blown over them using fans.
The experimental cooling device, which was fabricated on top of a mock computer chip, works by generating ions – or electrically charged atoms – using electrodes placed near one another. The device contained a positively charged wire, or anode, and negatively charged electrodes, called cathodes. The anode was positioned about 10 millimeters above the cathodes. When voltage was passed through the device, the negatively charged electrodes discharged electrons toward the positively charged anode. Along the way, the electrons collided with air molecules, producing positively charged ions, which were then attracted back toward the negatively charged electrodes, creating an “ionic wind.”
Reseachers have built a test device on top of a mock computer chip at Purdue’s Birck Nanotechnology Center in the university’s Discovery Park that was able to demonstrate a reduction in temperature from 140 degrees F (60 Celsisus) to 95 degrees F (60 Celsisus). This effect is attributed to increasing the airflow very near the surface of the chip:
Conventional cooling technologies are limited by a principle called the “no-slip” effect – as air flows over an object, the air molecules nearest the surface remain stationary. The molecules farther away from the surface move progressively faster. This phenomenon hinders computer cooling because it restricts airflow where it is most needed, directly on the chip’s hot surface… The new approach potentially solves this problem by using the ionic wind effect in combination with a conventional fan to create airflow immediately adjacent to the chip’s surface.