Researchers at Rochester Institute of Technology have taken another step toward meeting the demanding cooling needs for the complex internal components found in today’s microelectronic devices and systems.
Energy to power electronic devices generates heat, and effectively managing and removing that heat is the subject of work being done by Satish Kandlikar, professor of mechanical engineering in RIT’s Kate Gleason College of Engineering. He introduced micro-structured enhanced boiling surface technology, an enhanced surface technology that consists of advanced high heat flux removal applications using evaporation momentum force.
This technology increases the heat transfer coefficient—the rate at which heat is conducted through materials—in boiling systems. This breakthrough can be advantageous in high heat flux removal applications in industries such as nuclear energy, microprocessors, data centers, refrigeration and military or biomedical applications, he says.
The new surface technology concept was presented at the American Society of Mechanical Engineers’ recent International Conference on Nanochannels, Microchannels and Minichannels, July 8–12, where Kandlikar was one of the plenary speakers.
“Even though we are making the chips smaller, the heat generated remains the same,” Kandlikar says. “By coming up with new techniques, we are able to remove heat efficiently.”
As one of the foremost experts in the field of heat transfer and boiling utilizing nano- and micro-technologies, he and his research team have advanced the high heat flux removal process. The developments took place based on better management of vapor removal and liquid influx to the heated surface. This force, called evaporation momentum force, was presented as one of the main features of the boiling phenomena.
“A new non-dimensional number incorporating the evaporation momentum force was introduced,” Kandlikar says. “This led to a new record in terms of heat transfer coefficient—a heat flux of over 300 watts per square centimeter—while maintaining the wall superheat below 5 degrees Celsius.”
A record heat transfer coefficient of 629,000 watts-per-meter squared per degree Celsius was achieved, while the previous record, set by Kandlikar’s group last year, was 280,000.
This concept is comparable to the heat generated by an electric iron being dissipated over an area the size of a human thumbnail, while keeping the temperature below 80 degrees. By better understanding boiling phenomena, and this new pathway, it will make headway into every application where boiling is used, Kandlikar explains.
This new process will lead to power savings because heat can be dissipated with very small temperature differences. The new information extends the boundaries in the field to provide both simultaneous increase in heat flux and reduction in surface temperature, key areas in the field. A patent on this technology is pending.
“We are making boiling a very efficient heat transfer mechanism, again, at micro-scale,” Kandlikar says. “At the microscale, boiling is not living up to the promise. We really need to go to macro-scale to understand what is going on. That is going to change the way boiling surfaces are designed.”