Pool boiling heat transfer characteristics of vertical cylinder quenched by SiO_2 - water nanofluids

摘要

This study includes an experimental investigation of the pool boiling heat transfer characteristics of a vertical cylinder quenched by SiO_2-water nanofluids. The experiments are performed through a cylindrical rod, at saturated temperature and atmospheric pressure. As the coolant, pure water and SiO_2-water nanofluid suspensions at four different concentrations (0.001, 0.01, 0.05 and 0.1 vol.%) are selected. The test specimen heated at high temperatures is plunged into cooling fluids at saturated conditions in a pool. The cooling curves are obtained via taking the temperature-time data of the specimen into account. The experimental results indicate that the pool film boiling heat transfer in nanofluids is identical to that in pure water. However, during the repetition tests in nanofluids with high concentrations, the film boiling region disappears, and the critical heat flux increases. In addition, the nucleate pool boiling heat transfer coefficient decreases compared with that of pure water, but a considerable decrease in nucleate pool boiling heat transfer is not observed with the repetition tests. A change in surface characteristics due to the deposition of nanoparticles on the surface has a major effect on the quenching process.