Lattice Boltzmann-based numerical analysis of nanofluid natural convection in an inclined cavity subject to multiphysics fields

This research conducts a study of natural convection heat transfer (NCHT) in a nanofluid under a magnetic field (MF). The nanofluid is in a cavity inclined at an angle of 45 degrees. The MF can take different angles between 0 degrees and 90 degrees. Radiative heat transfer is present in the cavity in volumetric form. There are two hot semicircles, similar to two half-pipes, on the bottom wall. The top wall is kept cold. The side walls and parts of the bottom wall, except the pipes, have been insulated. The lattice Boltzmann method has been used for the simulation. The studied parameters are the Rayleigh number (in the range 10(3)-10(6)), magnetic field angle, radiation parameter (in the range 0-2), and nanoparticle volume fraction (in the range 0-5%). The generated entropy has been studied as the NCHT. The results indicate that adding nanoparticles improves heat transfer rate (HTR). Moreover, the addition of volumetric radiation to the cavity enhances the Nusselt number by 54% and the generated entropy by 12.5%. With an augmentation in the MF angle from 0 degrees to 90 degrees, HTR decreases and this decrease is observed mostly at higher Rayleigh numbers. An augmentation in the Ra increases NCHT and entropy generation. Indeed, a rise in the Ra from 10(3) to 10(6) increases HTR by almost sixfold.

Automated summary

This research investigates natural convection heat transfer in a nanofluid under a magnetic field. The addition of nanoparticles improves the heat transfer rate, while volumetric radiation increases the Nusselt number and the generated entropy. Furthermore, as the magnetic field angle increases, the heat transfer rate decreases, but the Rayleigh number enhances natural convection heat transfer and entropy generation.