Numerical Study of the Mixed Convection and the Entropy Generation in a Rhombic Enclosure Filled with the Cu-Water Nanofluid with the Heat Absorption/ Generation

The mixed convection heat transfer,the entropy generation in a rhombic enclosure filled with the Cu-water nanofluid in presenceof heat absorption or generation is investigated. The bottom wall is hot, the top wall is cold,the skewed walls are insulated. Thetop wall is moving from left to right at constant speed of U0. The computational grid is generated with the mapping of the geometryinto a square domain. The governing equations are formulated in terms of the dimensionless stream function, the vorticity,theenergy,have been numerically solved using the finite difference scheme. The rhombic angle, the Richardson number, the volumefraction nanoparticles,the heat generation or absorption coefficients effects on the heat transfer,fluid flow characteristics areexaminated. The results show that the increase of the nanoparticles volume fraction leads to the increase of the average nusseltnumber, the total entropy,Bejan number. When the Richardson number is 0.1,for all the nanoparticles volume fraction, theNusselt number has maximum,minimum values at the angles of 120°,30°, respectively. In addition, for all the volumefractions of nanoparticles,skew angles except the angle of 60 degree, the Nusselt number, the total entropy,Bejan numberincrease with the decreasing of the Richardson number. When Ri,0.01, Nusselt number is increased,decreased by the heatabsorption,generation, respectively.