Circular rotation of different structures on natural convection of nanofluid-mobilized circular cylinder cavity saturated with a heterogeneous porous medium.

The incompressible smoothed particle hydrodynamics (ISPH) method is utilized for studying the circular rotations of three different structures, circular cylinder, rectangle and triangle centered in a circular cylinder cavity occupied by Al2O3 nanofluid. The novelty of this work is appearing in simulating the circular rotations of different solid structures on natural convection of a nanofluid-occupied a circular cylinder. The circular cylinder cavity is suspended by heterogeneous/homogeneous porous media. The embedded structures are taken as a circular cylinder, rectangle and triangle with equal areas. The first thermal condition considers the whole structure is heated, the second thermal condition considers the half of the structure is heated and the other is cooled and the third thermal condition considers the quarter of the structure is heated and the others are cooled. The outer boundary of cylinder cavity is cooled. Due to the small angular velocity ω=3.15 (low rotational speeds), then the natural convection case will be considered only. The results are representing the temperature, velocity fields. The simulations revealed that the presence of the inner hot/cold structures affects on the velocity distributions and temperature field inside a circular cylinder cavity. The triangle shape has introduced the highest temperature distributions and maximum values of the velocity fields compare to other shapes inside a circular cylinder cavity. The homogeneous porous level reduces the maximum values of velocity field by 25% compared to the heterogeneous porous level.

Effect of dual-rotation on MHD natural convection of NEPCM in a hexagonal-shaped cavity based on time-fractional ISPH method.

The time-fractional derivative based on the Grunwald-Letnikove derivative of the 2D-ISPH method is applying to emulate the dual rotation on MHD natural convection in a hexagonal-shaped cavity suspended by nano-encapsulated phase change material (NEPCM). The dual rotation is performed between the inner fin and outer hexagonal-shaped cavity. The impacts of a fractional time derivative [Formula: see text] [Formula: see text], Hartmann number Ha [Formula: see text], fin length [Formula: see text], Darcy parameter Da [Formula: see text], Rayleigh number Ra [Formula: see text], fusion temperature [Formula: see text] [Formula: see text], and solid volume fraction [Formula: see text] [Formula: see text] on the velocity field, isotherms, and mean Nusselt number [Formula: see text] are discussed. The outcomes signaled that a dual rotation of the inner fin and outer domain is affected by a time-fractional derivative. The inserted cool fin is functioning efficiently in the cooling process and adjusting the phase change zone within a hexagonal-shaped cavity. An increment in fin length augments the cooling process and changes the location of a phase change zone. A fusion temperature [Formula: see text] adjusts the strength and position of a phase change zone. The highest values of [Formula: see text] are obtained when [Formula: see text]. An expansion in Hartmann number [Formula: see text] reduces the values of [Formula: see text]. Adding more concentration of nanoparticles is improving the values of [Formula: see text].

Energy and Entropy Production of Nanofluid within an Annulus Partly Saturated by a Porous Region.

The flow and heat transfer fields from a nanofluid within a horizontal annulus partly saturated with a porous region are examined by the Galerkin weighted residual finite element technique scheme. The inner and the outer circular boundaries have hot and cold temperatures, respectively. Impacts of the wide ranges of the Darcy number, porosity, dimensionless length of the porous layer, and nanoparticle volume fractions on the streamlines, isotherms, and isentropic distributions are investigated. The primary outcomes revealed that the stream function value is powered by increasing the Darcy parameter and porosity and reduced by growing the porous region's area. The Bejan number and the average temperature are reduced by the increase in Da, porosity ε, and nanoparticles volume fractions ϕ. The heat transfer through the nanofluid-porous layer was determined to be the best toward high rates of Darcy number, porosity, and volume fraction of nanofluid. Further, the local velocity and local temperature in the interface surface between nanofluid-porous layers obtain high values at the smallest area from the porous region (D=0.4), and in contrast, the local heat transfer takes the lower value.

MHD mixed convection of hybrid nanofluid in a wavy porous cavity employing local thermal non-equilibrium condition.

The current study treats the magnetic field impacts on the mixed convection flow within an undulating cavity filled by hybrid nanofluids and porous media. The local thermal non-equilibrium condition below the implications of heat generation and thermal radiation is conducted. The corrugated vertical walls of an involved cavity have [Formula: see text] and the plane walls are adiabatic. The heated part is put in the bottom wall and the left-top walls have lid velocities. The controlling dimensionless equations are numerically solved by the finite volume method through the SIMPLE technique. The varied parameters are scaled as a partial heat length (B: 0.2 to 0.8), heat generation/absorption coefficient (Q: - 2 to 2), thermal radiation parameter (Rd: 0-5), Hartmann number (Ha: 0-50), the porosity parameter (ε: 0.4-0.9), inter-phase heat transfer coefficient (H*: 0-5000), the volume fraction of a hybrid nanofluid (ϕ: 0-0.1), modified conductivity ratio (kr: 0.01-100), Darcy parameter [Formula: see text], and the position of a heat source (D: 0.3-0.7). The major findings reveal that the length and position of the heater are effective in improving the nanofluid movements and heat transfer within a wavy cavity. The isotherms of a solid part are significantly altered by the variations on [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text]. Increasing the heat generation/absorption coefficient and thermal radiation parameter is improving the isotherms of a solid phase. Expanding in the porous parameter [Formula: see text] enhances the heat transfer of the fluid/solid phases.