Super-hot machines could stay cool by ‘breathing’

In the era of electric cars, machine learning and ultra-efficient vehicles for space travel, computers and hardware are operating faster and more efficiently. But this increase in power comes with a trade-off – they get super-hot.

To counter this, University of Central Florida (UCF) researchers are developing a way for large machines to “breathe” cooling blasts of water to keep their systems from overheating.

The process is much like how humans breathe in air, which cools the body, said lead author Khan Rabbi.

“Our technique used a pulsed water-jet to cool a hot titanium surface,” said Rabbi. “The more water we pumped out of the spray jet nozzles, the greater the amount of heat that transferred between the solid titanium surface and the water droplets, thus cooling the titanium. Fundamentally, an idea of optimum jet-pulsation needs to be generated to ensure maximum heat transfer performance.”

He added: “It is essentially like exhaling the heat from the surface.”

The water is emitted from small water-jet nozzles, about 10-times the thickness of a human hair, that douse a hot surface of a large electronic system. The water is collected in a storage chamber, where it can be pumped out and circulated again to repeat the cooling process. The storage chamber in the study held less than 300ml of water.

Using high-speed, infrared thermal imaging, the researchers found the optimum amount of water for maximum cooling performance.

Applications for the system could include cooling large electronics, space vehicles, batteries in electric vehicles and gas turbines, said Rabbi.

Study co-author Shawn Putnam said the research is part of an effort to explore different techniques to efficiently cool hot devices and surfaces.

“Most likely, the most versatile and efficient cooling technology will take advantage of several different cooling mechanisms, where pulsed jet cooling is expected to be one of these key contributors,” he said.

The researcher said there are multiple ways to cool hot hardware, but water-jet cooling is a preferred method because it can be adjusted to different directions, has good heat-transfer ability and uses minimum amounts of water or liquid coolant.

It has drawbacks however, specifically either over- or underwatering, which results in floods or dry hotspots. The UCF method overcomes this problem by offering a system that is tuneable to hardware needs, so the correct amount of water is applied where it is needed.

Cooling technology is needed because device performance decreases over threshold temperatures.

“For this reason, we need better cooling technologies in place to keep the device temperature well within the maximum temperature for optimum operation,” said Rabbi. “We believe this study will provide engineers, scientists and researchers a unique understanding to develop future generation liquid cooling systems.”

The research was published in Physical Review Fluids.

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