ENHANCED HEAT TRANSFER FROM HOT SURFACE BY NANOFLUID BASED ULTRAFAST COOLING: AN EXPERIMENTAL INVESTIGATION

Nanofluids have promising characteristics of accomplishing high rate of heat removal from hot surfaces. An ultrafast cooling facility was developed at the School of Mechanical Engineering, KIIT University, Bhubaneswar, to investigate the effects of nanofluids impinging onto a heated steel surface of dimension 120 mm × 120 mm and having 4 mm thickness. K-type thermocouples were used for transient temperature measurement. Heat transfer experiments were conducted by using waterbased TiO2 nanofluids with four different particle concentrations (0.01 wt %, 0.03 wt %, 0.05 wt%, and 0.07 wt %) separately and compared with the performance of pure water. The addition of nanosized particles to the base fluid (water) could enhance the cooling process. The influence of nozzle tip to plate distance, mass concentrations, and fluid pressure upon the heat transfer rate was investigated. Detailed heat transfer characteristics in terms of time-dependent temperature distribution and surface cooling rate of the impingement flows with various combinations of mass concentration of nanoparticle were measured using a transient technique. The ultrafast cooling method based on nanofluids spray was found to be an efficient alternative cooling technique over the conventional water impingement cooling to achieve the optimal and high cooling rate. The overall improvement in cooling rate found to be 19.34%, 11.3%, and 7.14% using TiO2, Al2O3, and CuO nanofluids over the conventional liquid (water).