Computer Chips Cooled With NANOFLUIDS

According to the Physorg the next generation of cooling devices could be cooled with Nano fluids. Dr.Hongbin MA with the group of students at the University of Missouri-Columbia and colleagues at Argonne National Laboratory and Intel Corporation presents the findings of a unique cooling device that makes use of an Oscillating Heat Pipe and Nano fluids.

Dr. Hongbin said that the next generation of computer chips will produce localized heat flux over 10MW/m^2, with the total power exceeding 300W. No existing low-cost cooling device can effectively manage the heat produced at this level. This study will accelerate the development of the next generation of cooling devices that incorporate Nano fluids for ultrahigh heat-flux electronic system.

The results of the experiment show that when an oscillating heat pipe (OHP) is charged with a Nano fluid, the ability of the OHP to transport heat increases. As this experiment illustrates, finding more efficient cooling for the next generation of computer chips, microchips, and electronic devices is under way. As society desires its gadgets to shrink ever smaller resulting in high power density, teams that work to develop the technology will find themselves in high demand. “There are lots of applications that come from this experiment,” says Ma. “We really need to develop this further.” While neither the study of Nano fluids nor the study of OHPs is anything new, combining the unique features of each is an innovative approach. “Here we use a Nano fluid and an oscillating motion. The oscillating motions make the nanoparticles suspend in the base liquid. This is unique.” says Ma. “No cooling device has been made using a Nano fluid-charged OHP, but the development of such a device is now a few steps closer, and with it the enabling ability to take our technology even farther than it has already gone.” The unique characteristics of both Nano fluids and OHPs contribute to the fitness of such devices for cooling functions. Traditional liquids have much lower thermal conductivities than Nano fluids. Additionally, Nano fluids have strong temperature-dependent thermal conductivity, as well as showing a non-linear relationship between thermal conductivity and concentration. These particular features, which belong to fluids that exist on the Nano scale, make them high performance conductors with an increase in critical heat flux. Oscillating heat pipes have their own set of unique features. First of all, an OHP is known as an “active” cooling device. It takes intense heat from a high-power device and turns it into kinetic energy of fluids. Additionally, with an OHP, liquid flow and vapor flow move in the same direction, so neither phase interferes with the other. Because the flow in an OHP is one that oscillates from a thermally driven flow, there are some blank surfaces that appear along the pipe. This allows for enhanced evaporating and condensing heat transfer.

So, while the OHP already has good heat transporting ability, the addition of a Nano fluid can enhance the ability of the OHP significantly. In this particular experiment, the Nano fluids used contained diamond nanoparticles. The diamond particles were introduced into high performance liquid chromatography (HPLC) water. HPLC water is water that is specially purified and that has low organic carbon content. Even though diamond particles might settle in liquid without motion, the movement of an OHP keeps those particles from settling, allowing them to remain suspended. While the experiment shows that the Nano fluid-charged OHP has increased efficiency, the ‘why’ behind the fact has yet to be discovered? “We know some of the reasons,” explains Ma, “but not all. We are trying to find the reason for the higher