NSF-SGER: Exploring New‑Hybrid Polymer-Nanofluids
with Enhanced Flow and Heat Transfer Characteristics  

M. Kostic, Department of Mechanical Engineering, Northern Illinois University, July 2007.
More at: www.kostic.niu.edu/DRnanofluids

Summary: An exploratory work on untested and novel idea to combine drag-reducing, polymer additives with nanoparticles, and thus develop new-hybrid, drag-reducing heat-transfer nanofluids, namely, stable suspensions of metal and metal-oxide nano-scale particles in common base fluids, is proposed. The goal will be to produce, for the first time, hybrid nanofluids that not only have the observed heat transfer enhancement of existing nanofluids, but equally importantly, have improved suspension stability and reduced flow friction. Complexities in fluid structure introduced by macromolecular polymer additives and unpredicted interactions with nanoparticles in different base fluids, should open up a lot of challenges to be explored and possibly unforeseen opportunities for tailoring new hybrid fluids with desired and enhanced characteristics. Initial studies using different nanoparticles in base fluids have demonstrated much higher thermal conductivity than in the base fluids or with comparable volume fractions of the same type but larger size particles. Furthermore, the increase was much higher with very-small metal nanoparticles using the so called one-step, direct vapor-deposition method, than with larger metal-oxide nanoparticles using the two-step mixing method. However, the existing one-step method developed in Argonne National Laboratory (ANL), although an excellent concept, has critical shortcomings, and is virtually stalling further development since only very limited quantities of enhanced nanofluids have been produced so far. The first objective will be to develop drag-reducing heat-transfer nanofluids by combining drag-reducing, polymer additives with nanoparticles. Subsequently, thermo-mechanical, macroscopic flow and heat transfer properties of these new polymer-nanofluids will be undertaken.

Intellectual Merit: The core of this proposal is the novel idea of combining drag-reducing polymers with high thermal conductivity nanofluids.  The development of reduced flow friction and high thermal conductivity fluids may revolutionize the field of heat transfer. The results of such studies could be used to optimize fluid properties and their use for existing critical applications as well as emerging and novel applications.

Broader Impact: This exploratory research may open the road for development of diverse, complex nanofluids with polymer additives (including biological nanofluids), dubbed POLY-nanofluids, with unprecedented application potential. Nature is full of nanofluids, like blood, a complex biological nanofluid where different nanoparticles (at molecular level) accomplish different functions. By studying (and understanding) nanofluids in the lab and nature, using new and available experimental techniques, and by developing computer based models of these fluids and related phenomena, new methods and tools for custom-design of nanofluids with enhanced properties may be developed. This exploratory research should also lead to future projects where macro-scale measurements will be combined with nano-scale measurements of structure and dynamics using laser light and small angle x-ray and neutron scattering techniques. Possible applications include more efficient cooling and heating in new and critical applications, environmental control and cleanup, bio-medical applications, and directed self-assembly of nanostructures.