Synthesis and characterization of silver/water nanofluids

Nanofluid is a new class of fluid that has been reported to exhibit higher thermal conductivity and viscosity compared to the base fluid. This work is concerned about the synthesis and characterization of low concentrations aqueous silver nanofluids (i.e., silver nanoparticles dispersed in distilled water), as well as the effect of concentration and particle size on the effective properties. The synthesis of nanofluids was performed by a new method called high-pressure homogenization in the range of volume fraction 0.1–0.3%. The characterization of thermal conductivity and viscosity was performed by the transient hot wire method and a cone plate viscometer, respectively. The highest increase in the thermal conductivity was found to be 18% at the concentration of 0.3%, with little increase in the effective viscosity. The developed correlations for the effective thermal conductivity of nanofluids under-predicted the experimental results obtained in the present investigation.