Effect of Green Processing on Enhancement of Thermal Conductivity of Nanofluid for Thermal Applications

Thermal tuning properties of nanofluid from lower to higher value is a challenging issue in the field of thermal industries and microelectronic industries as well as in medical sciences. Nanofluids of aluminum oxide has been prepared with different volume fraction varies from 0.01– 0.05 vol%. The crystal structure and surface shape of the synthesized aluminum oxide nano powder has been studied using X-ray diffraction technique (XRD), scanning-electron-microscopy (SEM) and electron transmission microscopy (TEM). The nanofluids are characterized by experimental technique such as FTIR, UV-visible, photoluminescence and particle distribution with particle size analyzer. Thermal conductivity of the alumina nano fluid was found to vary from 0.5378–0.7299 W/mK for volume percentage 0.01–0.05 respectively with enhancement from 1.8 % to 21.44% which is better than other works in the literature. With increase of sonication time, thermal conductivity varies appreciably from 0.531–0.736 W/mK with volume fraction of nanofluid. This significant increase in thermal conductivity of alumina nanofluid in different operating condition may be attributed to extraction and oxidation of alumina nitrate assisted with leaf extracted surfactants.