Numerical study of entropy generation in the convection heat transfer of nanofluid inside a tilted closed compartment with five constant-temperature heat sources in the presence of a magnetic field

Due to the significance of irreversibility, the entropy production of the natural and forced convection heat transfer of a nanofluid in a two-dimensional closed compartment is examined in the present paper. The side walls of the enclosed compartment are insulated, while the top and bottom walls of the compartment are cold and hot, respectively. The moving top wall causes forced convection in the closed compartment. Five rectangular heat sources are placed in the middle of the closed compartment to create free convection in the closed compartment. A horizontal magnetic field is applied to the closed compartment. The Bejan number (Be), the tilt angle of the closed compartment, the entropy generation, and the Richardson number (Ri) are all assessed as a function of the magnetic field's intensity. The Lattice Boltzmann method (LBM) is used for the numerical simulations. The re-sults reveal that the entropy production is reduced with the closed compartment tilt angle up to 60 degrees. Larger angles lead to an increment in entropy production. Angles of 0 degrees and 60 degrees are connected to the maximum and lowest amounts of entropy production, respectively. The Hartmann number (Ha) enhancement for strong forced convection (Ri = 0.1 and 1) intensifies entropy production. For weak forced convection (Ri = 10 and 100), an increment in the Ha reduces the amount of entropy production. Ri increase decreases the amount of entropy production.

Automated summary

This paper examines the irreversibility of natural and forced convection heat transfer of a nanofluid in a two-dimensional closed compartment, focusing on the significance of entropy production. The study considers insulation of the side walls, with the top and bottom walls being cold and hot respectively. The effects of the tilt angle of the closed compartment, the magnetic field's intensity, the Bejan number, and the Richardson number on entropy generation are analyzed using numerical simulations. The results indicate that entropy production decreases with increasing tilt angle up to 60 degrees, but further increase in angle leads to an increment in entropy production. The Hartmann number enhancement intensifies entropy production for strong forced convection, while it reduces entropy production for weak forced convection. An increase in Richardson number decreases entropy production.