NUMERICAL INVESTIGATION OF NATURAL CONVECTION HEAT TRANSFERFROM SQUARE CYLINDER IN AN ENCLOSED ENCLOSURE FILLED WITH NANOFLUIDS (original) (raw)

The enhancement of natural convection heat transfer using nanofluids from horizontal square cylinder placed in a square enclosure is investigated numerically. Water-based Cu is used as the working nanofluid. The investigation covered a range of Rayleigh numbers of 104 - 106 , nanoparticles volume fraction of (0<ϕ≤0.2), enclosure width to cylinder height ratio, W/H of 2.5. The investigation includes the solution of the governing equations in the Vorticity-Stream function space with the aid of a body fitted coordinate system. Algebraic grid generation is used in the initial transformations, followed by an elliptic transformation to complete the grid generation to computational domain. The resulting discretized system of equations is solved using an ADI method. The built code is validated and the results showed an increase in average Nusselt number with increasing the volume fraction of the nanoparticles for the whole range of Rayleigh number. The isotherms are nearly similar when the volume fraction of nanoparticles is increased from 0 to 0.2 for each Rayleigh number but a change in the streamlines is observed.