Marangoni-induced thermal convection enhancement within a micropolar nanofluid filled enclosure under inclined magnetic field

Abstract

Marangoni convection is relevant in controlling the heat transfer between surfaces in modern microfluidic and thermal systems. Therefore, this work seeks to elucidate the role of Marangoni-induced convection in the flow and thermal behavior of a micropolar nanofluid within a square enclosure exposed to an oblique static magnetic field. Thermal regulation occurs through partly heated and cooled sections of the vertical walls, whereas the remaining walls are adiabatic. The discretized algebraic equations are obtained through finite-differences and solved iteratively by applying over- and under-relaxation techniques with a tolerance error of 10–7. The influences of pertinent parameters on flow and thermal regulation are computed and analyzed through graphs. The findings demonstrate that Nuav upsurges with a rise in Ra and φ but is suppressed with a rise in Ha. Increasing Cu-nanoparticles concentration up to 4%, the Nuav rises by 11.7037%, 11.8758%, 12.14%, 12.0991%, 12.043%, and 11.9836% for Ma = 0, 200, 400, 600, 800, and 1000, respectively. Also, rising in ‘Ha’ from 0 to 20 reduces Nuav by 18.43% at Ra = 105 but by only 4.46% at Ra = 103, showing that Lorentz forces become more influential under stronger buoyancy. Furthermore, an upsurge in vortex viscosity from 0.5 to 5 leads to a decline in Nuav by 36.67%. These findings indicate that heat transfer can be efficiently controlled with changes in the Marangoni number, nanoparticles concentration, and magnetic field direction.