Effect of Additional MnFe_2O_4 on a Combination of EG-Water Nanofluid and Volumetric Flowrate Variations towards Heat Transfer in Shell and Tube Heat Exchanger System

摘要

Nanofluid is an efficient fluid when used in heat exchanger system because of its larger thermal conductivity compared to conventional fluids such as water, oil, and ethylene glycol (EG). This research used MnFe_2O_4 nanoparticle due to its higher magnetic sensitivity compared to other ferrite nanoparticles and larger thermal conductivity than TiO_2. This research used the MnFe_2O_4 nanoparticle with a combination of EG-Water base fluids in ratios of 40:60, 60:40, and 80:20. MnFe_2O_4 nanofluid mixed with EG-Water base fluids was made using the two-step method with 0.05% MnFe_2O_4 volume fraction in each base fluid ratio. This research used shell and tube type heat exchanger with heat temperature of 60°C and cold temperature of 26°C that were carried out at volumetric flowrate in each base fluid ratio for 0.22 l/m, 0.44 l/m, and 0.66 l/m. This research aimed to find the best combination ratio of EG-Water in thermophysical (thermal conductivity, specific heat, density, and viscosity) and to find the effect of volumetric flowrate variations on the heat exchange characteristics (the Reynold number, the Nusselt number, AT LMTD, convection coefficient, heat transfer, and overall heat transfer coefficient). The results of this research were that the sample of EG-Water with 40:60 ratio had the best heat transfer characteristics compared to samples with 60:40 and 80:20 ratios. Meanwhile, for the volumetric flow rate, a higher volumetric flow rate resulted in a larger result.