Influence of Temperature and Nanoparticle Concentration on the Electrical Conductivity of Water-Based TiO₂ Nanofluids: Experimental Study, Correlation, and Model Assessment

Different volume fractions of TiO 2 /water nanofluids were created using TiO 2 nanoparticles synthesized via the chemical coprecipitation technique. The electrical conductivity (EC) of each nanofluid was then measured at specific temperatures, ranging from 10 to 60 °C. X-ray diffraction (XRD) analysis confirmed the presence of the TiO 2 anatase phase and a minor presence of the rutile phase. Measurements from dynamic light scattering (DLS) and UV-Vis spectroscopy revealed that the nanoparticles exhibit an average diameter close to 26 nm, with an optical band gap estimated to be about 3.8 eV. Experimental findings demonstrated that both temperature and volume fraction play significant roles in enhancing the EC of nanofluids. These findings were evaluated compared to an earlier model for nanofluid conductivity that includes nanoparticle Brownian motion and electrophoretic effects, demonstrating a close alignment between the predicted and observed values. Furthermore, the long-term stability of the nanofluids was validated, and a reliable correlation was established between the nanofluid’s EC, temperature, and volume fraction.