Natural Convection Heat Transfer of Copper-Water Nanofluid in an Inclined Square Cavity with Time-Periodic Boundary Conditions

Abstract

Abstract-The paper presents a numerical study of natural convective heat transfer of copper-water in an inclined square cavity where the temperature of one sidewall sinusoidal oscillates, the opposite sidewall is cooled at a relatively low temperature and the other walls keep adiabatic. The transport equations are solved numerically with the finite volume approach using SIMPLEC algorithm. The influence of pertinent parameters such as the inclined angle (-75°～ 75°), the solid volume fraction of copper nanoparticles (0～0.2) and the Rayleigh number (104～106) on the convective heat transfer characters are studies. The results show that the heat transfer rate increases with the increase of the solid volume fraction and the Rayleigh number. And the percentage increase in the time-averaged Nusselt number is 37.61%, when the solid volume fraction is increased from ϕ =0 to ϕ =0.2 at Ra=106. The positive inclined angle is more conducive to heat transfer enhancement than the negative inclined angle, especially for the higher Ra number. And there is the best inclined angle for a given Ra number, and this angle is 15°at the Ra=106.