Investigation on Thermophysical and Optical Properties of Nanofluids

Abstract

This current project is dedicated to an easy, fast and one step method for the synthesis of metallic nanofluids. The gold (Au), silver (Ag) and copper (Cu) nanoparticles have been synthesized by ―laser ablation synthesis in liquid‖ (LASiL) method in de-ionized water. The purpose was to explore the dependence of various properties of metallic nanoparticles and nanofluids on the nature of laser (CW or pulsed). In order to prepare nanofluids, a low power continuous wave (CW) diode laser and a high power pulsed Nd:YAG laser have been utilized. The thermophysical and optical properties of the prepared nanofluids have been investigated to optimize the better laser for synthesis of metallic nanoparticles and nanofluids with desired properties. The morphological and structural properties of the nanoparticles have been analyzed by atomic force microscopy (AFM) and X-ray diffraction (XRD), respectively. Thermal and optical properties of the nanofluids are investigated by thermal conductivity of liquids and gases unit (TCLGU) and UV-Visible spectroscopy, respectively. The diagnostics revel that the synthesized nanoparticles are spherical in shape and have well defined sizes in the range of 1- 49 nm having crystalline structure. The resulting nanofluids exhibited the appreciable enhancement in thermal conductivities as compared to base liquid (de-ionized water). The optical band gap energies are found to be dependent on size of the nanoparticles. It is further inferred that size of nanoparticles can be tuned by the nature of laser.