Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Tiny bubbles are key to liquid-cooled system for future computers

14.04.2003


Issam Mudawar, a professor of mechanical engineering at Purdue University, demonstrates the liquid-cooling system he has developed for future computers. Within about three years, microprocessor chips are expected to generate four times the amount of heat as current chips, requiring innovative cooling systems to keep the chips from being damaged by heat. (Purdue News Service Photo/David Umberger)


Purdue University researchers have made a discovery that may lead to the development of an innovative liquid-cooling system for future computer chips, which are expected to generate four times more heat than today’s chips.

Researchers had thought that bubbles might block the circulation of liquid forced to flow through "microchannels" only three times the width of a human hair. Engineers also thought that small electric pumps might be needed to push liquid through the narrow channels, increasing the cost and complexity while decreasing the reliability of new cooling systems for computers.

Purdue researchers, however, have solved both of these potential engineering hurdles, developing a "pumpless" liquid-cooling system that removes nearly six times more heat than existing miniature pumpless liquid-cooling systems, said Issam Mudawar, a professor of mechanical engineering.



Liquid forced through microchannels forms smaller bubbles than expected, Mudawar said he was surprised to learn. Moreover, decreasing the diameter of the microchannels increased the cooling efficiency of the system by causing the liquid to form even smaller bubbles, which is contrary to the expected result.

Because the bubbles are much smaller than the diameter of the microchannels, they flow easily through the channels. The Purdue-developed system does not require a pump because the liquid circulates in a self-sustaining flow in a closed loop that carries heat away from a computer chip.

Findings about the new cooling system are detailed in a research paper appearing in the March issue of IEEE Transactions on Components and Packaging Technologies, published by the Institute of Electrical and Electronics Engineers. The paper was written by Mudawar and graduate student Swaraj Mukherjee.

Innovative cooling systems will be needed in about three years for personal computers expected to contain microprocessor chips that will generate four times more heat than chips in current computers. Whereas current high-performance chips generate about 75 watts per square centimeter, chips in the near future will generate more than 300 watts per square centimeter, Mudawar said.

"Any time you squeeze more circuitry into the same space, you are producing more heat per unit area and per unit volume," he said.

Today’s computers use fans and heat sinks containing fins to help cool circuitry. But this technology will not be efficient enough to remove the increasing heat generated by future chips, Mudawar said.

His research team created a liquid-cooling system that uses a closed loop of two vertical, parallel tubes containing a dielectric liquid – or a liquid that does not conduct electricity. The liquid flows through microchannels in a metal plate that is touching the chip. As liquid flows through the channels, it is heated by the chip and begins to boil, producing bubbles of vapor. Because the buoyant vapor bubbles are lighter than the liquid, they rise to the top of the tube, where they are cooled by a fan and condensed back into a liquid. The cool liquid then flows into the parallel tube and descends, creating a self-sustaining flow that eventually re-enters the microchannel plate and starts all over again.

"We were surprised to see that the dielectric liquid forms really miniature bubbles, so they slip through really fast," Mudawar said. "The bubbles don’t block the flow, as you would expect."

The researchers found that the system was 5.7 times better at removing heat than existing miniature pumpless liquid-cooling systems.

"This is only a starting point, and much better performance might be possible," Mudawar said.

Future research will focus on testing various designs to see which configurations work best.

"Now that we have a system that we know will work, we are going to test different geometries that will be beneficial to industry," said Mudawar, director of the Purdue University International Electronic Cooling Alliance. The alliance brings together researchers from industry, government agencies and Purdue to design cooling systems for applications ranging from personal computers to spacecraft.

The research was funded by the U.S. Department of Energy’s Office of Science.

Writer: Emil Venere, (765) 494-4709, venere@purdue.edu

Source: Issam Mudawar, (765) 494-5705, mudawar@ecn.purdue.edu

Purdue News Service: (765) 494-2096; purduenews@purdue.edu

Emil Venere | Purdue News
Further information:
http://news.uns.purdue.edu/html4ever/030411.Mudawar.cooling.html
http://me.www.ecn.purdue.edu/ME/Fac_Staff/mudawar.whtml
http://www.ecn.purdue.edu/PUIECA/main.html

More articles from Process Engineering:

nachricht Diamond watch components
18.06.2018 | Schweizerischer Nationalfonds SNF

nachricht Quick and safe laser joining of steel-aluminum mixed connections
05.06.2018 | Laser Zentrum Hannover e.V.

All articles from Process Engineering >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Creating a new composite fuel for new-generation fast reactors

20.06.2018 | Materials Sciences

Game-changing finding pushes 3D-printing to the molecular limit

20.06.2018 | Materials Sciences

Could this material enable autonomous vehicles to come to market sooner?

20.06.2018 | Materials Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>