Natural convection heat transfer using water-based nanofluid in a shell and helical coil heat exchanger

Abstract

Industry is looking for more efficient ways to use nanomaterials to decrease water consumption. The addition of greater thermal conductivity nanoparticles to the water enhances the fluid's thermal conductivity and, thus, increases the coefficient of heat transfer. In this work, water-based nanofluids were used to perform heat transfer enhancement studies in a shell and helical coil heat exchanger. Natural convection heat transfer using three water-based nanofluids (Al2O3, CuO and TiO2/water) was investigated in shell and helical coil heat exchanger. Experiments were performed at different hot water flow rates through coil (Dean number) and hot water feed temperatures (40, 50 and 60 °C). The use of water-based nanofluid led in a greater coefficient of shell-side heat transfer compared to the use of pure water on the shell side. The Nusselt number improved due to an increase in nanoparticle concentration. It was observed that with a rise in nanofluid concentration, Dean number and greater coil-side fluid feed temperature, the Rayleigh number increased.