Experimental investigation of turbulent flow convection heat transfer of MgO/water nanofluid at low concentrations - Prediction of aggregation effect of nanoparticles

The extent of increase in the convection heat transfer of MgO/water nanofluid was investigated at low concentrations within the range of 0.02 to 0.12 % vol, under turbulent flow and within the Reynolds number range of 11,000 to 49,000. It was found that at about 12 %, the heat transfer coefficient was increased compared with the base fluid, where on average, around 6 % increase was observed within the entire concentration range and the investigated Reynolds number. The aggregate effect of particles was examined in predicting the models for the determination of the physical properties of thermal conductivity and viscosity. It was observed that fractal models enjoy a greater accuracy when compared with other models. In addition, a model was proposed to predict the local heat transfer coefficient, in which the aggregate effect of nanoparticles was also investigated. It was observed that the relative average deviation of the proposed model is around 2.5 %, when compared with experimental values.