Researchers are working on tech so machines can thermally 'breathe'


Date:
October 13, 2020
Source:
University of Central Florida
Summary:
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 superhot. To counter this, researchers
are developing a way for large machines to 'breathe' in and out
cooling blasts of water to keep their systems from overheating. The
findings are detailed in a recent study in the journal Physical
Review Fluids.



FULL STORY ==========================================================================
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 superhot.


==========================================================================
To counter this, University of Central Florida researchers are developing
a way for large machines to "breathe" in and out cooling blasts of water
to keep their systems from overheating.

The findings are detailed in a recent study in the journal Physical
Review Fluids.

The process is much like how humans and some animals breath in air to cool their bodies down, except in this case, the machines would be breathing
in cool blasts of water, says Khan Rabbi, a doctoral candidate in UCF's Department of Mechanical and Aerospace Engineering and lead author of
the study.

"Our technique used a pulsed water-jet to cool a hot titanium surface,"
Rabbi says. "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." "It is essentially like exhaling the heat
from the surface," he says.



==========================================================================
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 and 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 their study held about 10 ounces of water.

Using high-speed, infrared thermal imaging, the researchers were able
to find the optimum amount of water for maximum cooling performance.

Rabbi says everyday applications for the system could include cooling
large electronics, space vehicles, batteries in electric vehicles and
gas turbines.

Shawn Putnam, an associate professor in UCF's Department of Mechanical
and Aerospace Engineering and study co-author, says that this 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," Putnam says.

The researcher says 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.

However, it has its drawbacks, namely either over or underwatering that
results in floods or dry hotspots. The UCF method overcomes this problem
by offering a system that is tunable to hardware needs so that the only
water applied is the amount needed and in the right spot.

The technology is needed since once device temperatures surpass a
threshold value, for example, 194 degrees Fahrenheit, the device's
performance decreases, Rabbi says.

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

========================================================================== Story Source: Materials provided by
University_of_Central_Florida. Original written by Robert H Wells. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Khan Md. Rabbi, Jake Carter, Shawn A. Putnam. Understanding
pulsed jet
impingement cooling by instantaneous heat flux matching at
solid-liquid interfaces. Physical Review Fluids, 2020; 5 (9) DOI:
10.1103/ PhysRevFluids.5.094003 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/10/201013124205.htm

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