The investigation of buoyancy-driven heat transfer in a square cavity with multiple mounted variable length heaters under magnetic field

Weight loss, dimensions, and energy consumption are important issues in the aerospace industry (spacecraft and space station), which requires a high capacity cooling system and smaller dimensions. Nanofluids can play an important role in cooling systems. In this paper, natural convection of water-alumina nanofluid in a square cavity with a thin partition mounted at the middle of the cavity is studied. The cavity has different orientation angles with respect to the horizon. For the horizontal cavity, the top and bottom walls are adiabatic and the left and the right walls are considered to be hot and cold, respectively. At the center of cavity, a vertical baffle with negligible thickness is mounted. The nanofluid inside the cavity is under a magnetic field. Governing equations were discretized through control volume approach and were solved simultaneously applying SIMPLER algorithm. Based on obtained results from numerical method, the influence of pertinent parameters such as the orientation angle of the cavity, Rayleigh number, the volume fraction of nanoparticles and Hartman number on the flow field and heat transfer are investigated. The results show that maximum heat transfer occurs when the angle of hot wall with respect to the horizon is 45. Also, the existence of the baffle and increase of Hartman number reduce the heat transfer while the increase of Rayleigh number enhances the transfer of heat. Depending on Rayleigh number, the increase of nanoparticle volume fraction may increase or decrease the thermal performance.