Empirical equation for the prediction of viscosity for some common nanofluids

A new model is proposed for calculating the relative viscosity of some common nanofluids. Based both on the available literature data and some theoretical considerations it was proposed that the relative viscosity can be calculated using only the values of densities of the particles and of the base fluid. The comparison of our results with existing empirical models using various concentrations and temperatures demonstrated that the proposed equation predicts satisfactory the experiments with an average error of about 4%. The model confirms the already published dependence of the relative viscosity on the variation of volume concentration, temperature and of the particle characteristics reported in some experimental studies. One can use the proposed model to predict the behavior of the system in the case of missing of contradicting experimental data and to develop innovative nanofluids.