Nanofluids: Advance Heat Transfer Fluids

Nanofluids are stable dispersions of ultrafine or nanoscale metallic, metal
oxide, ceramic particles in a given base fluid. Nanofluids are known to
exhibit an extraordinarily high level of thermal conductivity, and thus
possess immense potential in the improvement of heat transfer and energy
efficiency of several industrial applications such as cooling of IC engines,
nuclear reactors, microelectronics, medical devices and defense equipments.
The key issues with nanofluids however, are: (i) a robust, cost-effective and
scalable method for large scale production of nanofluids has not yet been
developed, (ii) stability in industrial applications is not yet established,
and (iii) meaningful data in flow based heat transfer process do not exist.
Our research attempts to address all these issues. We have developed an
in-situ process for the preparation of stable nanofluids by wet-milling of the
colloidal powders in the base fluid along with a dispersant. We have applied a
novel molecular modeling based approach for the selection of an appropriate
dispersant for the given base fluid and nanoparticles system. The nanofluids
are tested for heat transfer efficiency under flow conditions in double pipe
heat exchangers. Our nanofluids have been found to show enhancements of around
10–60% for various base fluids flown under different flow conditions. Thermal
enhancements have been found to depend on the flow-rate, particle
concentration, type of base fluid, and material of the thermal contact surface
of the heat exchanger. Our nanofluids exhibit sustained stability for very
long time (>36 months) and their stability remains unaltered for several
heating-cooling cycles. We are currently working on the commercialization of
these nanofluids in vehicle cooling and metal quenching applications.

About the Speaker:
Dr. Beena Rai, a Ph. D from National Chemical Laboratory, Pune, is recipient
of prestigious Chevening Scholarship at Said Business School, University of
Oxford, UK and visiting scientist at LEM, INPL-CNRS, Nancy, France. She
authored 80 publications, 23 patents and 1 edited book. She is a winner of
“Maha- Intrapreneur 2013 Award” instituted by Praj Industries and Symbiosis
International Institute of Business and Best WILL Mentee Award 2012 given by
WILL-Women in Leadership Forum, India.