Paper presented at the 7th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Turkey, 19-21 July, 2010.
Significant controversy over reports of extraordinary heat
transfer in nanofluids has existed. The results of work
performed by our group to help resolve some of these issues
will be discussed. Heat transfer in fluids is complex and
includes phenomena such as conduction (thermal conductivity),
convection (laminar and turbulent), and boiling. The results of
tests performed with custom experimental apparatuses,
including transient hot wire, pool boiling, quench, flow loops,
and high-speed infrared (IR) thermography and digital imaging,
will be discussed. Additionally, single phase pressure drop
measurements for nanofluids will be presented. It will be
shown that the effect of nanofluids on pressure drop and
conductive and convective heat transfer can be explained by
existing theories, if a nanofluid’s thermophysical properties are
used. However, the enhancement of boiling heat transfer,
particularly critical heat flux and quenching, is more
challenging to interpret using existing theory because of surface
effects. Accordingly, the insights gained from measurements
of contact angle, IR imaging, and morphological data will be
presented.
