Modeling of Electrical Conductivity of a Nanofluid Based on Transformer Oil

This study presents a modified model for evaluating the electrical conductivity of nanofluids based on transformer oil, applicable to the lower particle volume fractions. Analysis of experimental and literature data revealed a nonlinear increase in conductivity at higher particle concentrations, suggesting the influence of an additional unaccounted parameter. A hypothesis was proposed that changes in the dielectric permittivity of the liquid, induced by increasing particle concentration, may partially explain this nonlinearity. However, further discrepancies between calculated and experimental results indicate the need to consider additional factors. Two potential parameters were identified for future investigation: the generation of additional charge carriers through ionogenic impurity dissociation and the impact of double electric layer polarization on conductivity. An explanation for the observed discrepancy between the modeling results and experimental measurements of electrical conductivity is also proposed. The primary cause of the discrepancy is hypothesized to be the agglomeration and subsequent sedimentation of particles with adsorbed charges at the bottom of the measurement cell during the experiment. This process leads to a reduction in the mobility of charge carriers in the measurement zone, thereby affecting the results. Further research will focus on these factors to refine the model, enhance nanofluid stability, and improve their performance for broader applications.