NATURAL CONVECTION IN A HORIZONTAL ANNULUS WITH A DIFFERENT NUMBER AND ARRANGEMENTS OF DISCRETE HEAT SOURCE-SINK PAIRS

2016 ◽  
Vol 47 (4) ◽  
pp. 403-421
Author(s):  
M. Mastiani ◽  
H. Mirzaei ◽  
S. S. Sebti ◽  
Abdolrahman Dadvand ◽  
Sina Kashani
Keyword(s):  
Natural Convection ◽  
Heat Source ◽  
Discrete Heat Source ◽  
Source Sink

scholarly journals Computational analysis of viscous dissipation and joule-heating effects on non-Darcy MHD natural convection flow from a horizontal cylinder in porous media with internal heat generation

2014 ◽  
Vol 41 (1) ◽  
pp. 37-70 ◽  
Author(s):  
Ramachandra Prasad ◽  
Subba Rao ◽  
Anwar Bég
Keyword(s):  
Natural Convection ◽  
Heat Source ◽  
Skin Friction ◽  
Viscous Dissipation ◽  
Joule Heating ◽  
Local Skin ◽  
Grashof Number ◽  
Dissipation Parameter ◽  
Local Skin Friction ◽  
Source Sink

In the present paper we examine the effects of viscous dissipation, Joule heating and heat source/sink on non-Darcy MHD natural convection heat transfer flow over permeable horizontal circular cylinder in a porous medium. The boundary layer equations, which are parabolic in nature, are normalized into non-similar form and then solved numerically with the well-tested, efficient, implicit, stable Keller-box finite difference scheme. A parametric study illustrating the influence of Darcy parameter (Da), Forchheimer parameter (?), Grashof number(Gr), heat source/sink parameter (?) and viscous dissipation parameter (Ec) on the fluid velocity, temperature as well as local skin-friction and Nusselt numbers is conducted Increasing Forchheimer inertial drag parameter (?) retards the flow considerably but enhances temperatures. Increasing viscous dissipation parameter(Ec) is found to elevate velocities i.e. accelerate the flow and increase temperatures. Increasing heat source/sink parameter (?) is found to elevate velocities and increase temperatures. Increasing the Grashof number (Gr) is found to elevate the velocity and decrease the temperatures. Local skin friction number is found to be increases with increasing heat source/sink parameter (?) where as Local Nusselt number is found to decrease with increasing heat source/sink parameter (?).

NATURAL CONVECTION HEAT TRANSFER FROM A DISCRETE HEAT SOURCE COUPLED WITH CONDUCTION DOMINATED PHASE CHANGE

1998 ◽  
Vol 22 (3) ◽  
pp. 269-289
Author(s):  
M. Lacroix
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Steady State ◽  
Natural Convection ◽  
Thermal Diffusivity ◽  
Heat Source ◽  
Phase Change ◽  
Numerical Study ◽  
Thermal Conductivity Ratio ◽  
Discrete Heat Source

A numerical study has been conducted for the heat transfer from a discrete heat source by natural convection in air above coupled with conduction dominated melting of a phase change material (PCM) below via a wall of finite thermal diffusivity. Results indicate that the presence of a PCM layer underneath the wall significantly delays the temperature rise of the heat source. The time delay increases as the thermal diffusivity of the wail material decreases and as the thickness of the PCM layer increases. For high thermal conductivity wall materials [Formula: see text] the steady state heat source temperatures are similar and independent of the PCM layer. On the other hand, for [Formula: see text], the steady state temperatures are higher and dependent on the thickness of the PCM layer. A correlation is proposed in terms of the thickness of the PCM layer and the thermal conductivity ratio of the wall.

Combined Natural Convection–Conduction and Radiation Heat Transfer in a Discretely Heated Open Cavity

1996 ◽  
Vol 118 (1) ◽  
pp. 56-64 ◽  
Author(s):  
A. A. Dehghan ◽  
M. Behnia
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Source ◽  
Radiation Heat Transfer ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Radiation Heat ◽  
Transfer Coefficients ◽  
Thermal Fields ◽  
Discrete Heat Source

Combined natural convection, conduction, and radiation heat transfer in an open-top upright cavity containing a discrete heat source has been modeled numerically. The surface emissivity has been varied and its effects on the flow and thermal fields have been determined for different values of Rayleigh number. The complex interaction of the three modes of heat transfer mechanisms is explored by solving the coupled convection, conduction, and radiation equations. It is noted that the inclusion of radiation has a significant effect on the flow, resulting in the formation of a recirculation zone within the cavity. Comparison of the local heat transfer coefficients for the conjugate analysis and no radiation case reveals that the inclusion of radiation has a negligible effect on the heat transfer performance of the heat source. However, comparison of the numerical results with experimental observations shows that accurate prediction of the flow and thermal fields is strongly dependent on the consideration of radiation heat transfer in the numerical case.

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