Exergy efficiency of a novel heat exchanger under MHD effects filled with water-based Cu-SiO.sub.2-MWCNT ternary hybrid nanofluid based on empirical data

The need to improve the heat transfer rate in various industries due to its increasing growth, the need to use new turbulators, and the simultaneous use of hybrid nanofluids with them as new methods are inevitable. In this paper, studies are done to analyze the exergy efficiency of ternary hybrid nanofluid flow in a heat exchanger with novel compound twisted turbulator and helical blades. System is under magnetic field from top to bottom in four different values which are related with four different Hartmann numbers (Ha = 50, 100, 200 and 400). The optimization is carried out due to fulfilling the highest exergy efficiency value. According to numerical results, in all the studied Reynolds numbers, the exergy efficiency values of systems with turbulator are more than the basic system. The combined system has well increased the exergy efficiency in the whole range of studied Reynolds numbers and can be introduced as the optimal geometry in the present work. The combination with counterclockwise direction of blades and clockwise direction of twisted tape is more efficient than the system with clockwise blades and twisted tape. Adding helical blades and increasing their number leads to increased exergy efficiency. The highest exergy efficiency according to the PEC index is related to the twisted rotating bar with hemispherical surface barriers, which increases by 7% in Re = 12,000.