Category: Transient Plane Source
Author(s): Carine Tchamakam Wamkam, Haiping Hong, Michael Kwabena Opoku, Pauline Smith
Keywords: Heat Transfer, IEP, isoelectric point, isoelectric point (IEP), Nanofluids, Nanoparticles, particle size, pH, precipitate, repulsive forces, rheology, Thermal Conductivity, Thermal properties testing, TiO2, titanium dioxide, Titanium dioxide (TiO2), TPS, Transient Plane Source, Transient plane source (TPS) method, viscosity, Zeta Potential, zirconium dioxide, zirconium dioxide (ZrO2), ZrO2
Abstract: This study looks at the effects of pH on heat transfer, among other things, of nanofluids. Over 20% enhancement of thermal conductivity was noted with nanofluids containing 3wt% zirconium dioxide and titanium dioxide. Also noted, was the influence of pH on the stability of the nanofluids. The Derjaguin-Landau-Verwey-Overbeek theory states that nanoparticles become unstable, form clusters and precipitate, when their pH is near the isoelectric point. This leads to large clusters of nanoparticles within the fluid that trap water, which increases the volume fraction and leads to irregular shaped nanoparticles. These new structures form pathways and enhance the thermal transport between nanoparticles, leading to the overall enhancement of thermal conductivity of these nanofluids.
Reference: Journal of Applied Physics 109, (2011)