Abstract: The phenomenon of mixed convection heat transfer through Al2O3-water nanofluid inside a horizontal ventilated enclosure is studied numerically. The obtained results demonstrate clearly the positive role of the nanoparticles addition on the improvement of the heat transfer rate and the mean temperature within the cavity. The flow structure and the temperature distribution within the cavity are seen to be very affected by the Reynolds number and the heating type. Also, it is shown that, in general, the decreasing heating mode is more favorable to the heat transfer while the cooling efficiency is found to be more pronounced by applying the increasing heating type.

Key words: Mixed convection, ventilated cavity, injection, nanofluid, varying heating.