Evaluation of acoustical parameters and thermal conductivity of TiO2-ethylene glycol nanofluid using ultrasonic velocity measurements

Abstract

The nanosized titanium oxide (TiO2) nanoparticles (NPs) were synthesized via sol-gel method. The crystalline nature of the synthesized TiO2 nanoparticles was confirmed by X-ray powder diffractometry method. The surface morphology and particle size of the nanoparticles were analyzed by high-resolution scanning electron microscopic method. UV-visible spectroscopy was employed to determine its band gap energy value. The different concentrations of nanofluid samples of TiO2 NPs dispersed in ethylene glycol were prepared and mixed thoroughly by ultrasonication process. The value of ultrasonic velocity and density were measured for the different concentrations of TiO2 nanofluids. The acoustical parameters such as adiabatic compressibility, intermolecular free length, and acoustic impedance were calculated from the experimental data. It was observed that ultrasonic velocity showed linearity with particle concentration, and the results were discussed. In addition to the TiO2-ethylene glycol (particle-fluid) interaction studies, a new methodology was proposed to find the thermal conductivity of nanofluids using ultrasonic velocity.