MIXED CONVECTION IN AN INCLINED AND LID-DRIVEN RECTANGULAR ENCLOSURE HEATED AND COOLED ON ADJACENT WALLS

2008 ◽  
Vol 32 (2) ◽  
pp. 213-226 ◽  
Author(s):  
Elif Büyük Öğüt
Keyword(s):  
Mixed Convection ◽  
Differential Quadrature Method ◽  
Side Wall ◽  
Temperature Fields ◽  
Convection Flow ◽  
Rectangular Enclosure ◽  
Aspect Ratios ◽  
Laminar Mixed Convection ◽  
Inclination Angles ◽  
Steady Laminar

Steady, laminar, mixed convection flow was considered in an inclined lid-driven rectangular enclosure heated from one side moving with a constant speed and cooled from the stationary adjacent side while the other sides are kept stationary and adiabatic. The governing equations were solved numerically for the stream function, vorticity, and temperature ratio using the differential quadrature method for various Reynolds, Grashof, and Richardson numbers as well as different aspect ratios and inclination angles for the enclosure. The results show that the motion of the side wall, the aspect ratio, and the inclination angle of the enclosure had significant effects on the flow and temperature fields.

The effect of an external magnetic field on natural convection in an inclined rectangular enclosure

2007 ◽  
Vol 221 (12) ◽  
pp. 1609-1622 ◽  
Author(s):  
M C Ece ◽  
E Büyük
Keyword(s):  
Magnetic Field ◽  
Natural Convection ◽  
Differential Quadrature Method ◽  
Convection Flow ◽  
Rectangular Enclosure ◽  
Aspect Ratios ◽  
Inclination Angles ◽  
Side Walls ◽  
Vertical Walls ◽  
The Magnetic Field

Steady, laminar, natural-convection flow in the presence of a magnetic field of an arbitrary direction in an inclined rectangular enclosure with isothermal vertical walls and adiabatic horizontal walls was considered. The governing equations were solved numerically for the stream function, vorticity, and temperature ratio using the differential quadrature method for various Grashof and Hartman numbers and three different magnetic field directions, aspect ratios, and inclination angles. Counter-clockwise inclination of the enclosure enhances the convection whereas the clockwise inclination retards it. The magnetic field applied normal to the side walls are more effective for square and tall enclosures whereas the magnetic field applied parallel to the side walls is more effective for shallow enclosures.

Combined Mixed Convection and Radiation Heat Transfer in an Obstacle Wall Mounted Lid-driven Cavity

2016 ◽  
Vol 17 (6) ◽  
pp. 277-289 ◽  
Author(s):  
M. Moein Addini ◽  
S. A. Gandjalikhan Nassab
Keyword(s):  
Heat Transfer ◽  
Mixed Convection ◽  
Gas Flow ◽  
Radiation Heat Transfer ◽  
Simple Algorithm ◽  
Bottom Wall ◽  
Temperature Fields ◽  
Convection Flow ◽  
Driven Cavity ◽  
Laminar Mixed Convection

AbstractThis paper presents a numerical investigation for laminar mixed convection flow of a radiating gas in a lid-driven cavity with a rectangular-shaped obstacle attached on the bottom wall. The vertical walls of the square cavity are assumed to be adiabatic, while other walls of cavity and obstacle are kept at constant temperature. The fluid is treated as a gray, absorbing, emitting and scattering medium. The governing differential equations consisting the continuity, momentum and energy are solved numerically by the computational fluid dynamics techniques to obtain the velocity and temperature fields. Discretized forms of these equations are obtained by the finite volume method and solved using the SIMPLE algorithm. Since the gas is considered as a radiating medium, besides convection and conduction, radiative heat transfer also takes place in the gas flow. For computation of the radiative term in the gas energy equation, the radiative transfer equation is solved numerically by the discrete ordinate method. The streamline and isotherm plots and the distributions of convective, radiative and total Nusselt numbers along the bottom wall of cavity are presented. The effects of Richardson number, obstacle location, radiation–conduction parameter, optical thickness and albedo coefficient on the flow and temperature distributions are carried out. Comparison between the present numerical results with those obtained by other investigators in the cases of conduction–radiation and pure convection systems shows good consistencies.

Magnetohydrodynamics Mixed Convection Flow of a Nanofluid in an Isothermal Vertical Cone

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
Palani Sudhagar ◽  
Peri K. Kameswaran ◽  
B. Rushi Kumar
Keyword(s):  
Brownian Motion ◽  
Mixed Convection ◽  
Cone Angle ◽  
Convection Flow ◽  
Physical Parameters ◽  
Mixed Convection Flow ◽  
Vertical Cone ◽  
Laminar Mixed Convection ◽  
Layer Analysis ◽  
Steady Laminar

A boundary layer analysis is laid out for the steady, laminar, mixed convection flow past an isothermal vertical cone embedded in a porous medium filled with a nanofluid. The model used for the nanofluid is one which includes the effects of Brownian motion and thermophoresis. A parametric study is performed for different physical parameters, such as magnetic (M), cone angle (m), mixed convection (χ), Brownian motion (Nt), and thermophoresis (Nb), on the velocity, temperature, and nanoparticle concentration profiles. The local Nusselt, Sherwood, and nanoparticle Sherwood number have been laid out in a graphical way. The dependency of the rate of heat and mass transfer on the governing parameters has been discussed.

scholarly journals Laminar Mixed Convection Flow from a Vertical Surface with Induced Magnetic Field and Convective Boundary

2018 ◽  
Vol 23 (2) ◽  
pp. 307-326 ◽  
Author(s):  
K. Chaudhary ◽  
A. Sharma ◽  
A.K. Jha
Keyword(s):  
Magnetic Field ◽  
Mixed Convection ◽  
Vertical Surface ◽  
Temperature Fields ◽  
Radiation Absorption ◽  
Convection Flow ◽  
Mixed Convection Flow ◽  
Induced Magnetic Field ◽  
Convective Boundary ◽  
Laminar Mixed Convection

AbstractThe objective of this investigation is to study the influence of thermal radiation and radiation absorption parameter on a mixed convection flow over a continuously moving porous vertical plate under the action of transverse applied magnetic field taking into account the induced magnetic field with convective boundary. Under certain assumptions, the solutions for the velocity field, temperature distribution and induced magnetic field are obtained. The influences of various parameters on the velocity, temperature fields and on induced magnetic fields are studied graphically. It is also found that the dimensionless Prandtl number, Grashof number, Schmidt number and magnetic parameter have an appreciable influence on the independent variables.

Coupled Thermal Radiation and Mixed Convection Step Flow of Nongray Gas

2016 ◽  
Vol 138 (7) ◽  
Author(s):  
M. Atashafrooz ◽  
S. A. Gandjalikhan Nassab ◽  
K. Lari
Keyword(s):  
Mixed Convection ◽  
Radiative Transfer Equation ◽  
Convection Flow ◽  
Mixed Convection Flow ◽  
Discrete Ordinate ◽  
Full Spectrum ◽  
Step Flow ◽  
Laminar Mixed Convection ◽  
Gray Medium ◽  
Hydrodynamic Behaviors

The main goal of this paper is to analyze the thermal and hydrodynamic behaviors of laminar mixed convection flow of a nongray radiating gas over an inclined step in an inclined duct. The fluid is considered an air mixture with 10% CO2 and 20% H2O mole fractions, which is treated as homogeneous, absorbing, emitting, and nonscattering medium. The full-spectrum k-distribution (FSK) method is used to handle the nongray part of the problem, while the radiative transfer equation (RTE) is solved using the discrete ordinate method (DOM). In addition, the results are obtained for different medium assumptions such as pure mixed convection and gray medium to compare with the nongray calculations as a real case. The results show that in many cases, neglecting the radiation part in computations and also use of gray simulations are not acceptable and lead to considerable errors, especially at high values of the Grashof number in mixed convection flow.

Visualization and Prediction of Natural Convection of Water Near Its Density Maximum in a Tall Rectangular Enclosure at High Rayleigh Numbers

2000 ◽  
Vol 123 (1) ◽  
pp. 84-95 ◽  
Author(s):  
C. J. Ho ◽  
F. J. Tu
Keyword(s):  
Natural Convection ◽  
Vertical Wall ◽  
Three Dimensional ◽  
Temperature Fields ◽  
Convection Flow ◽  
Oscillatory Convection ◽  
Uniform Temperature ◽  
Density Maximum ◽  
Rectangular Enclosure ◽  
Rayleigh Numbers

An experimental and numerical investigation is presented concerning the natural convection of water near its maximum-density in a differentially heated rectangular enclosure at high Rayleigh numbers, in which an oscillatory convection regime may arise. The water in a tall enclosure of Ay=8 is initially at rest and at a uniform temperature below 4°C and then the temperature of the hot vertical wall is suddenly raised and kept at a uniform temperature above 4°C. The cold vertical wall is maintained at a constant uniform temperature equal to that of the initial temperature of the water. The top and bottom walls are insulated. Using thermally sensitive liquid crystal particles as tracers, flow and temperature fields of a temporally oscillatory convection was documented experimentally for RaW=3.454×105 with the density inversion parameter θm=0.5. The oscillatory convection features a cyclic sequence of onset at the lower quarter-height region, growth, and decay of the upward-drifting secondary vortices within counter-rotating bicellular flows in the enclosure. Two and three-dimensional numerical simulations corresponding to the visualization experiments are undertaken. Comparison of experimental with numerical results reveals that two-dimensional numerical simulation captures the main features of the observed convection flow.

scholarly journals Mixed convection of functionalized DWCNT-water nanofluid in baffled lid-driven cavities

2018 ◽  
Vol 22 (6 Part A) ◽  
pp. 2503-2514 ◽  
Author(s):  
Esfe Hemmat ◽  
Arani Abbasian ◽  
Wei-Mon Yan ◽  
Alireza Aghaie ◽  
Masoud Afrand ◽  
...  
Keyword(s):  
Nusselt Number ◽  
Mixed Convection ◽  
Richardson Number ◽  
Average Nusselt Number ◽  
Volume Fraction ◽  
Minimum Length ◽  
Convection Flow ◽  
Flow And Heat Transfer ◽  
Inclination Angles ◽  
Nanoparticles Volume Fraction

The present study aims to evaluate the mixed convection flow and heat transfer of functionalized DWCNT/water nanofluids with variable properties in a cavity having hot baffles. The investigation is performed at different nanoparticles volume fraction including 0, 0.0002, 0.001, 0.002, and 0.004, Richardson numbers ranging from 0.01 to 100, inclination angles ranging from 0 to 60? and at constant Grashof number of 104. The results presented as streamlines and isotherms plot and Nusselt number diagrams. According to the finding with increasing nanoparticles volume fraction and distance between the left hot baffles of nanoparticles average Nusselt number enhances for all considered Richardson numbers and cavity inclination angles. Also with increasing Richardson number, the rate of changes of average Nusselt number increase with increasing distance between the left hot baffles. For example, at Richardson number of 0.01, by increasing L1 from 0.4 to 0.6, the average Nusselt number increases 7%; while for similar situation at Richardson number of 0.1, 1.0, and 10, the average Nusselt number increases, respectively, 17%, 24%, and 26%. At all Richardson numbers, the maximum value of average Nusselt number is achieved for a minimum length of left baffles. <br><br><font color="red"><b> This article has been corrected. Link to the correction <u><a href="http://dx.doi.org/10.2298/TSCI190203032E">10.2298/TSCI190203032E</a><u></b></font>

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