Heat transfer performance of submerged impinging jet using silver nanofluids

Silver-water nanofluids used in this paper, has been prepared by a one step method adopting an ultrasound-assisted membrane reaction. Experimental investigations on heat transfer of submerged jet in plate and pin-fin heat sinks were carried out with different concentrations of silver nanofluids. The results indicate that the silver nanoparticles can be uniformly distributed in the base fluid with an average grain size of 4.8 nm. The used surfactant had a great influence on the viscosity of the nanofluids. Compared with the base fluid (water and surfactant), the heat transfer coefficient of the nanofluids, for the same jet velocity, increases in average by 6.23, 9.24 and 17.53 % for the silver nanoparticles weight fractions of 0.02, 0.08 and 0.12 %, respectively. Compared with water, the heat transfer coefficient is enhanced by 6.61 % with a silver nanoparticles weight fraction of 0.12 %. The Nu of pin fin heat sink are obviously higher than that of plate one, at corresponding Re. The exit of nanoparticles can intense internal energy transmission of fluids, and then enhance the heat transfer, while the Re is small.