Control of hybrid nanofluid natural convection with entropy generation: A LBM analysis based on the irreversibility of thermodynamic laws

This article analyzes the irreversibility of the natural convection of water/copper nanofluids in a square enclosure. Thermal entropy generation, frictional entropy generation, and total entropy generation are examined by changing the Hartmann number, thickness and length of baffles, and magnetic field with inclinations angle. Three baffles are mounted on the hot wall of the enclosure. The wall in front of the hot wall is cold and the other walls are insulated. The numerical method is employed for this analysis using the Lattice Boltzmann method. The results of this study demonstrate that an increment in the Ha reduces the horizontal and vertical velocity components of the water/copper nanofluids in the enclosure and reduces the temperature gradient. Also, an enhancement in the Ha reduces all types of ETG. An increment in the angle of the magnetic field enhances thermal entropy generation, frictional entropy generation, and total entropy generation. Enhancing the magnetic field, first decreases and then increases the Bejan number.

Automated summary

This article examines the irreversibility of natural convection in water/copper nanofluids within a square enclosure. The study analyzes thermal entropy generation, frictional entropy generation, and total entropy generation by varying the Hartmann number, baffle thickness and length, and magnetic field angle. The numerical analysis is conducted using the Lattice Boltzmann method. Results show that increasing the Hartmann number reduces the velocity components and temperature gradient in the enclosure and decreases all types of entropy generation. Increasing the magnetic field angle enhances thermal and frictional entropy generation as well as total entropy generation, with the Bejan number initially decreasing and then increasing.