Magnetic-induced nanoparticles and rotary tubes for energetic and exergetic performance improvement of compact heat exchangers

In the present study, the effects of rotary tubes and magnetic-induced nanofluid on heat transfer characteristics of a compact heat exchanger are individually investigated. Two-phase Eulerian model is employed to predict the hydrothermal and entropic characteristics of Fe3O4/water ferrofluid in the heat exchanger. Results indicate that utilizing each rotary tubes and magnetic field method can improve the energy and exergy efficiencies of the compact heat exchanger under specific circumstances by forming different types of secondary flow. It is found that employing each method individually can increase the maximum heat transfer rate by more than 60%. In comparison with methods like passive vortex and swirl generators, subtle pressure drop and entropy generation is observed in the new proposed methods since no additional obstacles were employed. Results also reveal that 12.5% of the possible maximum energy can be regenerated along with a 3.5% increase in the exergy efficiency of the heat exchanger at low Reynolds numbers by employing each method. (C) 2020 Elsevier B.V. All rights reserved.