Nanoliquid thermal convection in I-shaped multiple-pipe heat exchanger under magnetic field influence

Abstract

The present work is investigated the heat management of thermogravitational convection inside a shell and tube heat exchanger filled with Fe3O4/water nanoliquid by lattice Boltzmann method (LBM). The seven internal pipes with hot or cold temperature insert in the I-shaped heat exchanger. The impacts of Rayleigh number (104-106), nanoparticles concentration (0–0.06), Hartmann number (0–60), magnetic field inclination angle (0-π/2) and the thermal arrangement of active pipes (Case 1–4) on the flow structure and energy transport characteristics are examined. The computational data are shown by streamlines, isothermal lines and the variations of the mean Nusselt number. It has been ascertained that the thermal arrangement of active pipes affects the velocity patterns and thermal transmission performance significantly. However, an increasing in the volume fraction of nano-size particles and Rayleigh number, the average Nusselt number raises regardless of the thermal arrangement. The rate of energy transport showed an opposite dependence with Hartmann number, but a direct relationship with the magnetic field inclination angle. The most suitable thermal arrangements for heat transfer rate of heated and cooled pipes are same at low magnitudes of the Rayleigh number, but different at high Rayleigh number.