Key words: Nanofluid, Natural convection, Partially active walls, Inclination angle.

Abstract: Effects of inclination angle on natural convection heat transfer and fluid flow in an enclosure with partially heated side walls filled with cu-water nanofluid has been analyzed numerically. A two heat sources maintained at a constant heat flux q’’ are embedded in the right and the left wall. The enclosure was cooled from the top and bottom walls. The remaining boundary parts are kept insulated. The angle of inclination is used as a control parameter for improve flow and heat transfer enhancement depicted in our recently work. Using a home developed code a parametric study is conducted and a set of graphical results is presented and discussed to illustrate the effects of inclination angle on the flow and heat transfer characteristics. The inclination angle was varied from 0 to 90° and two mainly case are considered, namely Middle-Middle (MM) and Down-Top (DT) depending of the two vertical sources location along the two side walls. It is found that optimal heat transfer enhancement can be improved. A percentage of heat transfer enhancement using 10% of Cu- nanoparticles is obtained for an inclination angle of 15° at higher Rayleigh number (Ra=105).