Volume fraction effects on thermophysical properties of Fe3O4/MWCNT based hybrid nanofluid

Abstract

In this work, Polyalphaolefin oil-based hybrid nanofluid containing Fe3O4/MWCNT nanocomposite has been prepared to consider the impact of volume fraction on thermal conductivity through graphical representation. The heat transfer of the prepared nanofluids is investigated via adjusting the surface morphology, molar ratios and size of the nanocomposite. Phase and composition of the synthesized sample was inspected through XRD and FTIR spectroscopy. The average crystallite size was observed to be 7.74 nm from Debye-Scherrer equation. Thermophysical parameters such as diffusivity, specific heat and thermal conductivity were measured through transient plane source method. The sample showed 2% enhancement in thermal conductivity with addition of nanocomposite as compared to pure polyalphaolefin oil for 0.7 wt.% at 50℃ and this value declined when shifted towards very high temperatures. Similarly, thermal diffusivity and specific heat also showed a linear trend as a function of volume fraction. This shows that the prepared nanofluid contains high stability and thermal conductivity as compared to conventional lubricant (i.e., PAO) and has potential in heat transfer applications as a lubricant and heat transfer fluid.