scholarly journals Mhd Mixed Convection in Copper-Water Nanofluid Filled Lid-Driven Square Cavity Containing Multiple Adiabatic Obstacles with Discrete Heating

2020 ◽  
Vol 25 (2) ◽  
pp. 57-74
Author(s):  
R.S.R. Gorla ◽  
S. Siddiqa ◽  
A.A. Hasan ◽  
T. Salah ◽  
A.M. Rashad
Keyword(s):  
Heat Source ◽  
Mixed Convection ◽  
Convection Flow ◽  
Square Cavity ◽  
Left Wall ◽  
Simpler Algorithm ◽  
Position Parameter ◽  
The Right ◽  
Volume Method ◽  
Good Agreement

AbstractThe objective of the present work is to investigate the influence of nanoparticles of copper within the base fluid (water) on magneto-hydrodynamic mixed-convection flow in a square cavity with internal generation. A control finite volume method and SIMPLER algorithm are used in the numerical calculations. The geometry is a lid-driven square cavity with four interior square adiabatic obstacles. A uniform heat source is located in a part of the left wall and a part of the right wall of the enclosure is maintained at cooler temperature while the remaining parts of the two walls are thermally insulated. Both the upper and bottom walls of the cavity are considered to be adiabatic. A comparison with previously published works shows a very good agreement. It is observed that the Richardson number, Ri, significantly alters the behavior of streamlines when increased from 0.1 to 100.0. Also, the heat source position parameter, D, significantly changes the pattern of isotherms and its strength shifted when D moves from 0.3 to 0.7.

Ventilation of Square Cavity Containing a Heat Source

2021 ◽  
Vol 406 ◽  
pp. 149-163
Author(s):  
Djelloul Chati ◽  
Said Bouabdallah ◽  
Badia Ghernaout
Keyword(s):  
Heat Source ◽  
Mixed Convection ◽  
Governing Equations ◽  
Square Cavity ◽  
Numerical Resolution ◽  
Ventilated Cavity ◽  
Lower Left Corner ◽  
Left Corner ◽  
Volume Method ◽  
Cavity Effect

A numerical simulation of turbulent mixed convection of a ventilated cavity containing a heat source placed of the center has been carried out. This cavity is outfitted along couple holes: one placed within the lower left corner and the other in the top right corner. The width of the hole "H" represents is 1/5 of the length of the cavity side. The diameter regarding the round heat source "D" is equal in accordance with the breadth of the inlet gap’s H (D = H). The walls of the cavity considered are maintained adiabatic, while the temperature of the heat source T is higher than the ambient temperature. The turbulence model k-ε was used for governing equations of turbulent mixed convection inside the cavity. The finite volume method was used for numerical resolution. The parameters of flow are: the Grashof number is set to Gr = 109 and the Reynolds number (Re) varies so that the number of Richardson (Ri) takes the values Ri = 0.01, 0.05, 0.1, 1, 2, 5, 10, 20 and 30 (Ri = Gr/ Re2). The effect of thermo-dynamic parameters and the shape geometric cavity effect are investigated.

Impact of Partial Slip and Heat Source on MHD Mixed Convection Flow of Nanofluid in a Double Lid-Driven Cavity Containing Insulated Obstacle

2020 ◽  
Vol 9 (3) ◽  
pp. 230-241
Author(s):  
M. A. Mansour ◽  
S. Sivasankaran ◽  
A. M. Rashad ◽  
T. Salah ◽  
Hossam A. Nabwey
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Source ◽  
Mixed Convection ◽  
Vertical Wall ◽  
Partial Slip ◽  
Convection Flow ◽  
Uniform Heat Flux ◽  
Mixed Convection Flow ◽  
Left Wall

The current investigation analyzes the effects of partial slip and heat generation on the mixed convection flow with heat transfer in an inclined double lid-driven square cavity containing centered square adiabatic obstacle in the presence of magnetic field. The used cavity is subjected to constant heat flux and filled with Cu-water nanofluid. The top and bottom horizontal walls are thermally insulated and move with uniform velocity while the right vertical wall is maintained at a constant low temperature. A uniform heat flux is located in a part of th left wall of the cavity while the remaining part of this wall is thermally insulated. Finite volume technique is utilized to solve dimensionless governing equations of the problem. The proposed method is validated with the previous published numerical studies which distinctly offer a good agreement. The obtained results show that changing in the heat source length affects much the flow and thermal fields than the position of heat source. The averag Nusselt number decreases when the aspect ratio of the obstacle and heat source length increases. The heat transfer rate behaves nonlinearly with inclination of the cavity.

scholarly journals Numerical investigation of natural convection heat transfer in a symmetrically cooled square cavity with a thin fin on its bottom wall

2014 ◽  
Vol 18 (4) ◽  
pp. 1119-1132 ◽  
Author(s):  
Saeid Jani ◽  
Mostafa Mahmoodi ◽  
Meysam Amini ◽  
Jafar Jam
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Constant Temperature ◽  
Convection Heat Transfer ◽  
Bottom Wall ◽  
Square Cavity ◽  
Remarkable Effect ◽  
Simpler Algorithm ◽  
The Right ◽  
Volume Method

In the present paper, natural convection fluid flow and heat transfer in a square cavity heated from below and cooled from sides and the ceiling with a thin fin attached to its hot bottom wall is investigated numerically. The right and the left walls of the cavity, as well as its horizontal top wall are maintained at a constant temperature Tc, while the bottom wall is kept at a constant temperature Th ,with Th > Tc. The governing equations are solved numerically using the finite volume method and the couple between the velocity and pressure fields is done using the SIMPLER algorithm. A parametric study is performed and the effects of the Rayleigh number and the length of the fin on the flow pattern and heat transfer inside the cavity are investigated. Two competing mechanisms that are responsible for the flow and thermal modifications are observed. One is the resistance effect of the fin due to the friction losses which directly depends on the length of the fin, whereas the other is due to the extra heating of the fluid that is offered by the fin. It is shown that for high Rayleigh numbers, placing a hot fin at the middle of the bottom wall has more remarkable effect on the flow field and heat transfer inside the cavity.

Heat Transfer Enhancement Using Cu-Water Nanofluid in an Enclosure with Moving Cold Sidewalls

2012 ◽  
Vol 326-328 ◽  
pp. 440-445
Author(s):  
Ghanbar Ali Sheikhzadeh ◽  
M. Tavakoli ◽  
H. Alizadeh
Keyword(s):  
Heat Source ◽  
Richardson Number ◽  
Volume Fraction ◽  
Maximum Temperature ◽  
Source Surface ◽  
Governing Equations ◽  
Transfer Enhancement ◽  
Square Cavity ◽  
Simpler Algorithm ◽  
Volume Method

Mixed convection of Cu-water nanofluid in a lid-driven square cavity with a heat source embedded in the bottom wall is studied numerically. The governing equations together with the respective boundary conditions are solved numerically using the finite volume method and the SIMPLER algorithm. The computations are performed for various Richardson numbers (), heat source length () and volume fraction of the nanoparticles (). It is observed from the results that the average Nusselt number is increased by increasing the Richardson number and the volume fraction of the nanoparticles. Moreover, the maximum temperature at the heat source surface decreases by increasing the Richardson number and the volume fraction of the nanoparticles.

scholarly journals Hydrodynamic Mixed Convection in a Lid- Driven Porous Square Cavity with Internal Heat Generating Elliptic Block

2018 ◽  
Vol 37 ◽  
pp. 175-183 ◽  
Author(s):  
Abdul Halim Bhuiyan ◽  
M Jahirul Haque Munshi
Keyword(s):  
Mixed Convection ◽  
Internal Heat ◽  
Darcy Number ◽  
Constant Speed ◽  
Working Fluid ◽  
Square Cavity ◽  
Left Wall ◽  
Thermal Fields ◽  
Nusselt Numbers ◽  
The Right

Hydrodynamic mixed convection in a lid-driven porous square cavity with internal heat generating elliptic block is numerically simulated in this paper by employing finite element method. The working fluid is assigned as air with a Prandtl number of 0.71 throughout the simulation. The top lid moves left to right at a constant speed (U0)with cold temperature and while the bottom lid moves right to left at a constant speed (−U0) with hot temperature. The left wall is heated while the right wall is linearly heated and heat generating elliptic block is placed at the center of square cavity. The effects of governing parameters in the present study are namely, Rayleigh number Ra, Darcy number Da, Grash of number Gr. The effects of heat generation and the porosity of the medium on the streamlines, isotherms, temperature profiles, velocity field and average Nusselt numbers are presented in graphical and tabular forms and discussed. An optimum combination of the governing parameters would result in higher heat transfer. Moreover, it is observed that both the Darcy number and moving lid ordination have significant effects on the flow and thermal fields in the enclosure.GANIT J. Bangladesh Math. Soc.Vol. 37 (2017) 175-183

scholarly journals Entropy Generation and Mixed Convection Flow Inside a Wavy-Walled Enclosure Containing a Rotating Solid Cylinder and a Heat Source

Entropy ◽  
2020 ◽  
Vol 22 (6) ◽  
pp. 606 ◽  
Author(s):  
Ammar I. Alsabery ◽  
Tahar Tayebi ◽  
Rozaini Roslan ◽  
Ali J. Chamkha ◽  
Ishak Hashim
Keyword(s):  
Heat Source ◽  
Mixed Convection ◽  
Rotational Velocity ◽  
Vertical Surface ◽  
Convection Flow ◽  
Bejan Number ◽  
Complex Boundary ◽  
Lower Temperature ◽  
The Galerkin Method ◽  
The Right

The current study investigates the 2D entropy production and the mixed convection inside a wavy-walled chamber containing a rotating cylinder and a heat source. The heat source of finite-length h is placed in the middle of the left vertical surface in which its temperature is fixed at T h . The temperature of the right vertical surface, however, is maintained at lower temperature T c . The remaining parts of the left surface and the wavy horizontal surfaces are perfectly insulated. The governing equations and the complex boundary conditions are non-dimensionalized and solved using the weighted residual finite element method, in particular, the Galerkin method. Various active parameters are considered, i.e., Rayleigh number R a = 10 3 and 10 5 , number of oscillations: 1 ≤ N ≤ 4 , angular rotational velocity: − 1000 ≤ Ω ≤ 1000 , and heat source length: 0 . 2 ≤ H ≤ 0 . 8 . A mesh independence test is carried out and the result is validated against the benchmark solution. Results such as stream function, isotherms and entropy lines are plotted and we found that fluid flow can be controlled by manipulating the rotating velocity of the circular cylinder. For all the considered oscillation numbers, the Bejan number is the highest for the case involving a nearly stationary inner cylinder.

Effects of Important Parameters on the Transition from Forced to Mixed Convection Flow in a Square Cavity

2021 ◽  
Vol 406 ◽  
pp. 36-52
Author(s):  
Sofiane Boulkroune ◽  
Omar Kholai ◽  
Brahim Mahfoud
Keyword(s):  
Reynolds Number ◽  
Prandtl Number ◽  
Mixed Convection ◽  
Forced Convection ◽  
Temperature Fields ◽  
Navier Stokes ◽  
Convection Flow ◽  
Square Cavity ◽  
Left Wall ◽  
Energy Equations

Combined free and forced convection in a square cavity filled with a viscous fluid characterized by a small Prandtl number is studied numerically. The left wall is moving with a constant velocity v and is maintained at a local cold temperature Tc, while the right wall is fixed and maintained at a local hot temperature Th (Tc <Th). The top and bottom walls of the cavity is assumed to be adiabatic. The governing Navier-Stokes, and energy equations along with appropriate boundary conditions are solved using the finite-volume method. The flow and temperature fields are presented by stream function and isotherms, respectively. The effects of important parameters such as Reynolds number, Prandtl number, and Grashof number on the transition from forced convection to mixed convection are investigated. Results indicate that increasing Reynolds number results to fluid acceleration and, thus, to flow transition. Results also show that Grashof and Prandtl's numbers influenced the conditions for the transition to the mixed convection regime.

Conjugate Mixed Convection in a Differentially Heated Lid-Driven Square Cavity With Rotating Cylinders

2020 ◽  
Author(s):  
Durjoy Kumar Paul ◽  
Abdullah Al Mehedi ◽  
Emdadul Haque Chowdhury ◽  
Sumon Saha ◽  
Mohammad Ali ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Mixed Convection ◽  
Rotational Speed ◽  
Heated Wall ◽  
Element Formulation ◽  
Rotating Cylinders ◽  
Square Cavity ◽  
Left Wall ◽  
Peripheral Velocity ◽  
The Right

Abstract Conjugate mixed convection in a lid-driven differentially heated square cavity with two heat-conducting rotating cylinders is numerically investigated. The right and the left walls of the enclosure, respectively, are maintained at a constant higher temperature (Th) and lower temperature (Tc), keeping the horizontal walls adiabatic. Both the cylinders are rotating in the counterclockwise direction. Only the left wall is moving downwards with a constant velocity. The governing nondimensional partial differential equations are resolved by means of Galerkin weighted residual finite element formulation. The average Nusselt number (Nu) is calculated along the right vertical heated wall. Flow and thermal fields are presented via streamlines and isotherms. Parametric simulations are performed for various pertinent parameters which are Grashof number (Gr), Reynolds number based on lid velocity (Re), Reynolds number based on cylinders’ peripheral velocity (Rec), and Richardson number (Ri). At first, the effects of variation of cylinders’ diameter are observed by considering six different cases for a particular peripheral velocity. It is found that the maximum Nu is obtained when the diameters of both cylinders are 0.1L. Further simulation is done for varying the Rec in the range of 5 to 50, to observe the effect of cylinders’ rotational speed. It has been found that for a particular Re, Nu increases with increasing rotational speed, but the effect is more pronounced at low Re. Finally, the combined effects of both Re and Gr on Nu have been investigated, keeping the Ri in the laminar mixed convection region. It has been demonstrated that when the Ri is increased from 0.1 to 10, the Nu enhances about 395.7%.

Impact of Partial Slip on Magneto-Ferrofluids Mixed Convection Flow in Enclosure

2020 ◽  
Vol 12 (5) ◽  
Author(s):  
Ali J. Chamkha ◽  
A. M. Rashad ◽  
A. I. Alsabery ◽  
Z. M. A. Abdelrahman ◽  
Hossam A. Nabwey
Keyword(s):  
Heat Source ◽  
Mixed Convection ◽  
Volume Fraction ◽  
Partial Slip ◽  
Convection Flow ◽  
Mixed Convection Flow ◽  
Square Enclosure ◽  
Vertical Walls ◽  
Volume Method ◽  
Ferromagnetic Particles

Abstract Magneto-ferrofluid mixed convection flow inside a lid-driven square cavity with partial slip is investigated numerically using the finite volume method. The vertical walls of the enclosure are heated partially by a constant temperature, while the horizontal moving walls are kept adiabatic. The square enclosure is filled with a mixture of kerosene–cobalt ferrofluids. The numerical computations are obtained for various parameters of the heat source length, position of the heat source, Hartmann number, Richardson number, fraction ferromagnetic particles, and constant movement parameter. It is shown that the transfer rate is clearly affected by the augmentation of the ferromagnetic particles volume fraction under the influence of a relative magnetic field and by the opposite-direction horizontal walls movement.

Unsteady MHD natural convection flow of a nanofluid inside an inclined square cavity containing a heated circular obstacle

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
M. A. Mansour ◽  
Rama Subba Reddy Gorla ◽  
Sadia Siddiqa ◽  
A. M. Rashad ◽  
T. Salah
Keyword(s):  
Nusselt Number ◽  
Natural Convection ◽  
Average Nusselt Number ◽  
Convection Flow ◽  
Square Cavity ◽  
Natural Convection Flow ◽  
Symmetric Pattern ◽  
Inclined Cavity ◽  
The Right ◽  
Good Agreement

Abstract The phenomena of unsteady magnetohydrodynamics (MHD) natural convection flow in an inclined square cavity filled with nanofluid and containing a heated circular obstacle at its center with heat generation/absorption impact are examined numerically. The cavity’s right and left walls are maintained at low temperatures, while the remaining walls are adiabatic. The volumetric external force, MHD, is applied across the inclined cavity. A penalty formulation-based finite element method is used to solve the nonlinear set of governing equations iteratively. The numerical scheme and results are validated through a comparison with the benchmark results, and it shows that our solutions are in good agreement with them. The results are shown in terms of contours of streamlines, isotherms, and average Nusselt number. It is observed that MHD alters the streamlines, isotherms, and average Nusselt number and dominates the flow as compared to any other physical parameter. The average Nusselt number is found sensitive to the central obstacle’s size, and it reduces sufficiently when the radius of the inner cylinder increases. For all the parameters, the streamlines’ symmetric pattern holds, such that the anti-clockwise cells on the left side of the cavity have their symmetric clockwise cells on the right side.

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