On Laminar Magnetoconvection Flow in a Vertical Channel in the Presence of Heat Generation and Heat Absorption

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
J. C. Umavathi ◽  
B. Patil Mallikarjun ◽  
S. Narasimha Murthy
Keyword(s):  
Electrical Conductivity ◽  
Boundary Conditions ◽  
Heat Generation ◽  
Vertical Channel ◽  
Perturbation Parameter ◽  
Perturbation Series ◽  
Convection Flow ◽  
Thermal Boundary Conditions ◽  
Laminar Mixed Convection ◽  
Reversal Flow

The problem of hydromagnetic fully developed laminar mixed convection flow in a vertical channel and asymmetric wall heating conditions in the presence of electrical conductivity effect is considered through proper choice of dimensionless variables. The governing with symmetric equations are developed and three types of thermal boundary conditions are presented. These boundary conditions are isothermal–isothermal, isoflux–isothermal, and isothermal–isoflux for the left–right walls of the channel respectively. The velocity field and the temperature field are obtained by perturbation series method which employs a perturbation parameter proportional to the Brinkman number. In addition, closed form expressions for reversal flow conditions at both the left–right channel walls are derived. Selected set of graphical results illustrating the effects of the various parameters involved in the problem including magnetic dissipation, heat generation or absorption, and the electrical conductivity on the velocity and temperature profiles as well as flow reversal situation are presented. The solutions obtained are also compared with that of results obtained by finite difference method.

Analysis of Combined Forced and Free Flow in a Vertical Channel With Viscous Dissipation and Isothermal-Isoflux Boundary Conditions

1999 ◽  
Vol 121 (2) ◽  
pp. 349-356 ◽  
Author(s):  
A. Barletta
Keyword(s):  
Boundary Conditions ◽  
Parallel Plate ◽  
Vertical Channel ◽  
Uniform Heat Flux ◽  
Viscous Heating ◽  
Perturbation Expansions ◽  
Nusselt Numbers ◽  
Buoyancy Parameter ◽  
Laminar Mixed Convection ◽  
Friction Factors

Fully developed and laminar mixed convection in a parallel-plate vertical channel is investigated in the case of non-negligible viscous heating. The channel walls are subjected to asymmetric boundary conditions: One wall experiences a constant and uniform heat flux, while the other is kept at a uniform and constant temperature. The velocity field and the temperature field are evaluated analytically by means of perturbation expansions with respect to a buoyancy parameter, i.e., the ratio between the Grashof number and the Reynolds number. The Nusselt numbers and the friction factors are obtained as functions of the buoyancy parameter.

Natural convection flow in a vertical micro-annulus with time-periodic thermal boundary conditions

2018 ◽  
Vol 14 (5) ◽  
pp. 1064-1081
Author(s):  
Basant Kumar Jha ◽  
Michael O. Oni
Keyword(s):  
Nusselt Number ◽  
Natural Convection ◽  
Boundary Conditions ◽  
Skin Friction ◽  
Convection Flow ◽  
Natural Convection Flow ◽  
Content Type ◽  
Thermal Boundary Conditions ◽  
The Impact ◽  
Time Periodic

PurposeThe purpose of this paper is to investigate the impact of time-periodic thermal boundary conditions on natural convection flow in a vertical micro-annulus.Design/methodology/approachAnalytical solution in terms of Bessel’s function and modified Bessel’s function of order 0 and 1 is obtained for velocity, temperature, Nusselt number, skin friction and mass flow rate.FindingsIt is established that the role of Knudsen number and fluid–wall interaction parameter is to decrease fluid temperature, velocity, Nusselt number and skin friction.Research limitations/implicationsNo laboratory practical or experiment was conducted.Practical implicationsCooling device in electronic panels, card and micro-chips is frequently cooled by natural convection.Originality/valueIn view of the amount of works done on natural convection in microchannel, it becomes interesting to investigate the effect that time-periodic heating has on natural convection flow in a vertical micro-annulus. The purpose of this paper is to examine the impact of time-periodic thermal boundary conditions on natural convection flow in a vertical micro-annulus.

Effects of Thermal Boundary Conditions on Entropy Generation During Natural Convection in a Differentially Heated Square Cavity

2010 ◽  
Author(s):  
Ram Satish Kaluri ◽  
Tanmay Basak ◽  
A. R. Balakrishnan
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Boundary Conditions ◽  
Entropy Generation ◽  
Bottom Wall ◽  
Convection Flow ◽  
Uniform Heating ◽  
Square Cavity ◽  
Fluid Friction ◽  
Thermal Boundary Conditions

Natural convection is a widely occurring phenomena which has important applications in material processing, energy storage devices, electronic cooling, building ventilation etc. The concept of ‘entropy generation minimization’, which is a thermodynamic approach for optimization, may be very useful in designing efficient thermal systems. In the current study, entropy generation in steady laminar natural convection flow in a square cavity is studied with following isothermal boundary conditions: (1) Bottom wall is uniformly heated (2) Bottom wall is sinusoidally heated. The side walls are maintained cold and the top wall is maintained adiabatic. The thermal boundary condition in non-uniform heating case (case 2) is such that the dimensionless average temperature of the bottom wall is equal to that of uniform heating case (case 1). The prime objective of this work is to investigate the influence of uniform and non-uniform heating on entropy generation. The governing mass, momentum and energy equations are solved using Galerkin finite element method. Streamlines, isotherms, contour maps of entropy generation due to heat transfer and fluid friction are studied for Pr = 0.01 (molten metals) and 7 (water) in range of Ra = 103–105. Detailed analysis on the effect of uniform and non-uniform thermal boundary conditions on entropy generation due to heat transfer and fluid friction has been presented. Also, the average Bejan’s number which indicates the relative dominance of entropy generation due to heat transfer or fluid friction and the total entropy generation are studied for each case.

scholarly journals Hydromagnetic Natural Convection Heat Transfer of Copper-Water Nanofluid within a Right-Angled Triangular Cavity

2020 ◽  
Vol 7 (3) ◽  
Author(s):  
I. Tarikul ◽  
P. Nazma ◽  
F.A.A. Md
Keyword(s):  
Rayleigh Number ◽  
Boundary Conditions ◽  
Volume Fraction ◽  
Convection Heat Transfer ◽  
Convection Flow ◽  
Average Temperature ◽  
Linear Partial Differential Equations ◽  
Thermal Boundary Conditions ◽  
Nanoparticles Volume Fraction ◽  
Horizontal Side

This investigation on free convection flow and temperature transfer within a right-angled triangular cavity loaded uniformly by Cu-H2O nanofluid including heated boundary conditions at horizontal side is performed numerically. The standing side is cooled at low heat while the hypotenuse of the triangular is insulated. The governing non-dimensional highly non-linear partial differential equations are performed by employing Galerkin weighted residual finite element method. The simulated numerical findings are exhibited using streamline contours, isotherm contours and average Nusselt number for the sampling parameters named nanoparticles volume fraction, Rayleigh number, and Hartmann number. The outcome demonstrates temperature transfer value reduces for the enhancement of Hartman number whereas improve significantly for the increase of buoyancy driven parameter Rayleigh number. Also, an excellent average temperature transfer is observed for uniform heated boundary condition (case I) compared to non-uniform thermal boundary conditions (case II & case III).

Sign in / Sign up

Export Citation Format

Share Document