Thermal diffusivity measurement of silver nanofluid by thermal lens technique

The thermal lens technique was utilized in silver nanofluid containing silver nanoparticles in polyvinylpyrrolidone solution to study the effect of nanoparticle size on thermal diffusivity. The different sizes of silver nanoparticles were prepared by irradiating the solution of silver nitrate in polyvinylpyrrolidone with respective dose of γ-radiation. The average sizes of particle in the prepared samples were measured using nanophox machine. The thermal lens measurement was carried out by using a diode laser of wavelength 514 nm and a He–Ne laser for the excitation source and the probe beam, respectively. The obtained result showed a decrease in the thermal diffusivity of nanofluid with the decrease in particle size.