Experimental investigation of MHD mixed convection in an inclined elliptic enclosure saturated with Al2O3-water nanofluid

This study experimentally investigated the effects of geometric parameters, inclination, magnetohydrodynamic properties, flow-on-flow behaviour, and axial heat transfer in an oriented elliptic enclosure filled with Al₂O₃ nanofluid. An experimental rig was locally fabricated and set up to examine MHD mixed convection in an inclined elliptic enclosure subjected to continuous heat flux at the center of the test-section of 0.4 m with the aid of a surface heater, and the top air was cooled, while the 0.3 m on either side of the geometry were insulated using fiberglass of 1.5 cm thickness. The effects of nanoparticle volume fractions and inclination angles on the thermal field were examined and discussed under laminar flow conditions. The results showed that the magnetic field effect on nanoparticle volume concentrations deteriorated with fluid flow strength (velocity profiles). At 0inclination angle, 28% heat transfer enhancement was achieved, while 30 inclination showed 24 % augmentation, and 60 inclination angle presented approximately 23% enhancement. Additionally, the rate of heat transfer for φ at 4.5% (0.045) nanoparticle volume fraction was found to be almost 10% higher than that of the base fluid (distilled water), φ at 0%. Close observation revealed that, in all cases, T_wall values were slightly higher than T_fluild and both increased with inclination angle and nanoparticle volume fraction. The percentage difference for Re at 400 mm, 600 mm, and 800 mm values along the axial direction with respect to the rate of heat transfer was not significant for angles of inclinations 0, 30 and 60.