Natural convection from a vertical permeable cone in a nanofluid saturated porous media for uniform heat and nanoparticles volume fraction fluxes

Author(s):  
A.J. Chamkha ◽  
A.M. Rashad
Author(s):  
A Chamkha ◽  
S Abbasbandy ◽  
A.M. Rashad

Purpose – The purpose of this paper is to investigate the effect of uniform lateral mass flux on non-Darcy natural convection of non-Newtonian fluid along a vertical cone embedded in a porous medium filled with a nanofluid. Design/methodology/approach – The resulting governing equations are non-dimensionalized and transformed into a non-similar form and then solved numerically by Keller box finite-difference method. Findings – A comparison with previously published works is performed and excellent agreement is obtained. Research limitations/implications – The model used for the nanofluid incorporates the effects of Brownian motion and thermophoresis. It is assumed that the cone surface is preamble for possible nanofluid wall suction/injection, under the condition of uniform heat and nanoparticles volume fraction fluxes. Originality/value – The effects of nanofluid parameters, Ergun number, surface mass flux and viscosity index are investigated on the velocity, temperature, and volume fraction profiles as well as the local Nusselt and Sherwood numbers.


2019 ◽  
Vol 392 ◽  
pp. 123-137 ◽  
Author(s):  
Mohamed A. Medebber ◽  
Abderrahmane Aissa ◽  
Mohamed El Amine Slimani ◽  
Noureddine Retiel

The two dimensional study of natural convection in vertical cylindrical annular enclosure filled with Cu-water nanofluid under magnetic fields is numerically analyzed. The vertical walls are maintained at different uniform hot and cold temperatures, THand TC, respectively. The top and bottom walls of the enclosure are thermally insulated. The governing equations are solved numerically by using a finite volume method. The coupling between the continuity and momentum equations is effected using the SIMPLER algorithm. Numerical analysis has been carried out for a wide range of Rayleigh number (103≤Ra≤106), Hartmann number (1 ≤Ha≤100) and nanoparticles volume fraction (0 ≤φ≤0.08). The influence of theses physical parameters on the streamlines, isotherms and average Nusselt has been numerically investigated.


2019 ◽  
Vol 9 (13) ◽  
pp. 2673 ◽  
Author(s):  
Raizah

In the current work, the natural convection of dusty hybrid nanofluids in an enclosure including two inclined heated fins has been studied via mathematical simulation. The inclined heated fins are arranged near to the enclosure center with variations on their orientations and lengths. The present simulation is represented by two systems of equations for the hybrid nanofluids that are dusty. The pressure distributions for the dusty phase and hybrid nanofluids phase are evaluated using a SIMPLE algorithm based on the finite volume method. The numerical results are examined using contours of the streamlines, isotherms for the hybrid nanofluids and velocity components for the dusty phase. In addition, the graphical illustrations for profiles of the local and average Nusselt numbers are presented. The main results reveal that an increase in the mixture densities ratio and dusty parameter reduces the rate of the heat transfer. Both the local and average Nusselt numbers are supported as the fins lengths increase regardless of the fins’ rotation. In addition, the nanoparticles volume fraction enhances the thermal boundary layer near the top wall.


Author(s):  
Abdelraheem Mahmoud Aly ◽  
Ehab Mahmoud

The numerical simulations of the uniform circular rotation of paddles on circular cylinder results natural convection flow of Al2O3-water in a cross-shaped porous cavity were performed by incompressible representation of smoothed particle hydrodynamics entitled ISPH method. The two vertical area of a cross-shaped cavity is saturated with homogeneous porous media and the whole horizontal area of a cross-shaped cavity is saturated with heterogeneous porous media. The inner paddles on the circular cylinder are rotating around their center by a uniform circular velocity. The whole embedded body of paddles on a circular cylinder has temperature Th. The wall-sides of a cross-shaped cavity are positioned at a temperature Tc. The current geometry can be applied in analysis and understanding the thermophysical behaviors of the electronic motors. The angular velocity is taken as ! = 7:15 and consequently the natural convection case is only considered due to the low speed of inner rotating shape. The performed simulations are represented in the graphical for the temperature distributions, velocity fields and tabular forms for average Nusselt number. The results revealed that an augmentation on paddle length rises the heat transfer and speed of fluid flow inside a cross shaped cavity. Also, an incrementation on Rayleigh number augments the heat transfer and speed of the fluid flow inside a cross-shaped cavity. The fluid flow is circulated only around the rotating inner shape when Darcy parameter decreases to Da = 105. Average Nusselt number Nu enhances by an increment on the paddle lengths and nanoparticles volume fraction


Sign in / Sign up

Export Citation Format

Share Document