RBF simulation of natural convection in a nanofluid-filled cavity

In this study, natural convection in a cavity filled with a nanofluid is solved numerically utilizing a radial basis function pseudo spectral (RBF-PS) approach in the space domain and a differential quadrature method (DQM) in the time domain. The governing dimensionless equations are solved in terms of stream function, temperature and vorticity. In the cavity, thermally insulated top and bottom walls are maintained while the left and right walls are at constant temperatures.Numerical solutions present the average Nusselt number variation as well as streamlines, isotherms and vorticity contours. The non-dimensional problem parameters, Rayleigh number $Ra$, solid volume fraction $\chi$ and aspect ratio $AR$ are varied as $10^3\leq Ra \leq 10^6,\, 0 \leq \chi \leq 0.2$ and $AR=0.25,\, 0.5,\,1,\, 2,\, 4$, respectively.It is found that the fluid velocity and the heat transfer are enhanced in presence of nanoparticles, and the convective heat transfer is reduced in a rectangular cavity

Entropy Generation Due to Magneto-Convection of a Hybrid Nanofluid in the Presence of a Wavy Conducting Wall

The two-dimensional, time-independent conjugate natural convection flow and entropy generation are numerically investigated in three different cases of a wavy conducting solid block attached to the left wall of a square cavity. A hybrid nanofluid with titania (TiO2) and copper (Cu) nanoparticles and base fluid water in the fluid part is considered in the presence of a uniform inclined magnetic field. The leftmost wall of the cavity is the hot one and the rightmost one is the cold one. Radial-basis-function-based finite difference (RBF-FD) is performed on an appropriate designed grid distribution. Numerical results in view of streamlines and isotherms, as well as average Nusselt number in an interface and total entropy generation are presented. The related parameters such as Hartmann number, Rayleigh number, conductivity ratio, amplitude in wavy wall, number of waviness, and inclination angle of magnetic field are observed. Convective heat transfer in the fluid part is an increasing function of kr,Ra,γ, while it deflates with the rise in Ha in each case. Total entropy generation increases with the increase in Ra and kr but it decreases with Ha values. Average Bejan number ascends with the rise in Ha and descends with the rise in Ra

Entropy Generation Due to Magneto-Convection of a Hybrid Nanofluid in the Presence of a Wavy Conducting Wall

The two-dimensional, time-independent conjugate natural convection flow and entropy generation are numerically investigated in three different cases of a wavy conducting solid block attached to the left wall of a square cavity. A hybrid nanofluid with titania (TiO2) and copper (Cu) nanoparticles and base fluid water in the fluid part is considered in the presence of a uniform inclined magnetic field. The leftmost wall of the cavity is the hot one and the rightmost one is the cold one. Radial-basis-function-based finite difference (RBF-FD) is performed on an appropriate designed grid distribution. Numerical results in view of streamlines and isotherms, as well as average Nusselt number in an interface and total entropy generation are presented. The related parameters such as Hartmann number, Rayleigh number, conductivity ratio, amplitude in wavy wall, number of waviness, and inclination angle of magnetic field are observed. Convective heat transfer in the fluid part is an increasing function of kr,Ra,γ, while it deflates with the rise in Ha in each case. Total entropy generation increases with the increase in Ra and kr but it decreases with Ha values. Average Bejan number ascends with the rise in Ha and descends with the rise in Ra