FREE CONVECTION HEAT TRANSFER OF Al₂O₃-Cu/WATER HYBRID NANOFLUID IN A RECTOTRAPEZOIDAL ENCLOSURE HEATED UNIFORMLY FROM THE BOTTOM WALL

We investigated, numerically, the heat transfer characteristics of Al₂O₃-Cu/water hybrid fluid inside a rectotrapezoidal enclosure whose bottom wall is uniformly heated, the upper horizontal wall is insulated, and the remaining walls are cold. The simulated results with the proposed thermal conductivity correlation for the hybrid fluid echoed with the experimental results when the dispersed particles volume fraction is less than 2%. The results show that when the dispersed particles loading is less than one percent, the thermal efficiency index of Al₂O₃:Cu = 50:50 mixture in water is the highest. Besides, when these particles loading exceeds one percent, the dispersion of pure Cu nanoparticles in water gives the highest thermal efficiency index in the rectotrapezoidal cavity.