In the present work, natural convection heat transfer of Cu-water nanofluid inside a wavy wall enclosure is investigated numerically by using the finite volume discretization method. The study examines the effect of the nanoparticle volume fraction, the Rayleigh number, the wave amplitude, and the undulations number on the heat transfer rate. The results show that the heat transfer rate inside the wavy enclosure enhances by decreasing the wavy surface amplitude and increasing undulations number. It is also found that by increasing the volume fraction of nanoparticles and Rayleigh number, the heat transfer rate increases.Keywords: Wavy Enclosure, Natural Convection, Nanofluid, Undulation, amplitude, circular Cylinder
INTRODUCTIONNatural convection fluid flow and heat transfer inside a wavy enclosure is found in many engineering applications, such as industrial heat radiators, heat exchanger design, cooling of micro-electronic devices, solar collector, and double-wall thermal insulation. The heat transfer inside a wavy enclosure has not been investigated widely due to the complexity of the geometry. Natural convection in a wavy enclosures show enhanced heat transfer when compared to the corresponding enclosure with flat walls (Abu-Nada and Oztop, (2011)). Thus, the study of fluid flow and heat transfer within wavy-walled enclosures is useful for many engineering problems related to geometrical design requirements. One of the first works on the numerical simulation of natural convection inside cavities is the pioneering work of De Vahl Davis, (1983). He performed a numerical simulation on a square cavity with two vertical isothermal walls, one cold and one hot, and two horizontal adiabatic walls. This cavity with those boundary conditions is known as differentially heated cavity (DHC). Boulahia et al., (2016) analyzed the natural convection in a wavy bottom walled shallow enclosure without internal heat generation. They found that the heat transfer was increased with decreasing values of the non-dimensional wave length whereas it increased with increasing values of the aspect ratio and the Rayleigh number. Other examples can be found in reference Das and Mahmud, (2003). The aim of this study is to explore the heat transfer rate of natural convection heat transfer of nanofluid (Cu-water) in a wavy-wall enclosure. The first case under investigation is characterized the numerical models used in our study. The computational procedure elaborated in this study is validated against the numerical results of other investigations. We studied the effects wave amplitude a (from 0.05 to 0.2) and undulations number (from 1 to 3) on the heat transfer rate. Wide range of parameters such as Rayleigh number 10 10 , and volume fraction of nanoparticles 0 0.05 have been used. The new models of the thermal conductivity and effective viscosity investigated by Corcione, (2011) are used to estimate themophysical proprieties of the nanofluid. Our numerical results are presented in the form of plots of isotherms, streamlines and ave...