Computational analysis of natural convection with water based nanofluid in a square cavity with partially active side walls: Applications to thermal storage

Heat transport induced by buoyancy caused natural convection inside a segmented or selectively heated enclosure has grown in importance over the decades due to its significance in many fields in industrial imple-mentations such as heat source cooling, food sterilizers, crystal growth, geothermal power systems, solar thermal collectors, melting and recrystallization procedures, microelectronic and nuclear industries, biomedical, and so forth. The novelty of current modern analysis is to scrutinize the natural convection of Titanium Oxide-water nanofluid in the cavity with partially active walls simulated by the finite element (FEM) method. The fluid flow and the thermal transportation within the enclosure are scrutinized. Two cases are carried out in this novel study, heat sink with constant temperature Tc consists in case 1 from the left and right partially active cavity walls and isothermal heat source having temperature Th correspondingly, where(Th > Tc). While upper and lower walls with inactive portions of the left and right walls are kept insulated. In case 2 the left and right walls of the cavity are heated while a partially active bottom wall is cold with other inactive parts insulated by the cavity walls. The finite element method is applied to tackle the governing equations. The Significance of Rayleigh number (100 <= Re <= 1e6) and volume fractions of nanopowders (0.01 <=phi <= 0.06) against fluid flow and heat transfer is demonstrated through streamlines and isotherms. From the results it is concluded that velocity amount is increased with escalating the values of Rayleigh number. The thermal results are enhanced with Rayleigh number. Furthermore the heat transfer is rised with volume fraction of nanoparticles. Additionally, from the analysis reveals that local Nusselt number is enhanced with Rayleigh number and nanoparticle volume fraction.