Experimental investigation for developing a new model for the thermal conductivity of Silica/Water-Ethylene glycol (40%-60%) nanofluid at different temperatures and solid volume fractions

In this study, thermal conductivity of Silica and Water-Ethylene glycol as the base nanofluid, was measured within the temperature range of 25-50 °C for samples with volume fractions of 0.1, 0.5, 1, 1.5, 2, 3, and 5%. According to our measurements, thermal conductivity increased with increasing temperature and volume fraction. In comparison, volume fraction showed a greater incremental effect on thermal conductivity. Measurements showed that the highest thermal conductivity (45.5%) occurred in the volume fraction of 5% at 50 °C. Due to the lack of a precise and appropriate equation for the prediction of thermal conductivity of Silica/Water-Ethylene glycol nanofluid, an equation was provided based on the measurement results, which was a function of volume fraction and temperature. Investigations showed that maximum value for the margin of deviation for the proposed equation was equal to 2.2%, which is acceptable for an experimental equation.