An investigation on effects of blade angle and magnetic field on flow and heat transfer of non-Newtonian nanofluids: A numerical simulation

摘要

Effects of blade angle on thermal-hydraulic efficiency of two-phase non-Newtonian nanofluid flow in the presence of a magnetic field in a helical channel were studied numerically. The numerical 3D governing system of equations was resolved using the SIMPLEC technique-based control volume method to achieve the highest possible economic efficiency. The governing equations were also solved based on the Eulerian-Eulerian Two-Phase Model (TPM). The optimization was conducted to accomplish the most beneficial geometry in order to view the maximum Hydro-Thermal-Performance (HTP). The results showed that higher Reynolds numbers lead to an increase in velocities causing more heat transfer and higher Nusselt numbers. Moreover, velocities increase results in further formation of vortex and pressure drop. Besides, the higher magnetic field power, the higher heat transfer, pressure drop, friction factor and HTP index are expected. Based on the acquired results, the variation trend of Nu/Nu_0 is similar for all studied corrugation angles and its ratio always reduces by increasing Reynolds number. For a configuration with α = 60°, the maximum values of Nu/Nu_0 ratio are achieved regardless of the amount of all studied Reynolds numbers which is followed by configurations with α = 45° and α = 30°, respectively. The maximum values of the HTP index are achieved for all studied Reynolds numbers for the configuration with α = 60° which are followed by configurations with α = 30° and α = 45°.