An overview on the effect of ultrasonication duration on different properties of nanofluids

Preparation of nanofluid is of prime importance to obtain better thermal and physical properties. Different preparation parameters used in nanofluid preparation sometimes perform contrarily even if prepared with same nanoparticles and base fluid. Stability, thermal conductivity, and viscosity of the nanofluid are significantly affected by the cluster (agglomerate) size of nanoparticles in the base fluid which deteriorate thermal performance. In order to break the agglomerates and improve the dispersion of nanoparticles, ultrasonication is a more prevalent method. Nanofluids react differently for different sonication time and the reaction of the nanofluid with the change in sonication time varies for different nanofluids, which is dependent on various factors. In this regard, research works pertinent to the effect of ultrasonication on different properties of nanofluids are confined. In this paper, review of investigations carried out on experimentally evaluated ultrasonication effects on thermal properties and various physical properties of nanofluid. It is found that with an increased sonication time/energy, reduces the particle size and thus aids in obtaining a better dispersion leading to enhancement of stability, thermal conductivity and reducing viscosity. However, the longer ultrasonication duration was not found to be better in all cases where best performance was obtained for an optimum duration of ultrasonication.