Effect of discrete flow distribution on heat transfer at a vertical surface in natural convection

1965 ◽  
Vol 8 (2) ◽  
pp. 183-185 ◽  
Author(s):  
P. M. Brdlik ◽  
I. A. Turchin
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Flow Distribution ◽  
Vertical Surface ◽  
Discrete Flow

Natural convection flow of a non-Newtonian power-law fluid from a slotted vertical surface with uniform surface heat flux

2008 ◽  
Vol 223 (3) ◽  
pp. 637-642 ◽  
Author(s):  
R S R Gorla ◽  
M A Hossain
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Power Law ◽  
Vertical Surface ◽  
Surface Heat ◽  
Convection Flow ◽  
Natural Convection Flow ◽  
Boundary Layer Equations ◽  
Power Law Index ◽  
Type Power

In the present paper, the natural convection flow of an Ostwalde—de Waele type power-law non-Newtonian fluid past a uniformly heated vertical slotted surface has been investigated numerically. The equations governing the flow and heat transfer are reduced to local non-similarity form. The transformed boundary-layer equations are solved numerically using implicit finite-difference method for values of ξ in the interval [0, ∞]. Solutions for heat transfer rate obtained for the rigid surface compared well with those documented in the published literature. From the present analysis, it is observed that an increase in ξ leads to increasing the skin-friction as well as reduction in heat transfer at the surface. As the power-law index n increases, the friction factor as well as the surface heat transfer increases.

Laminar Natural Convection From Isothermal Vertical Cylinders: Revisting a Classical Subject

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Jerod C. Day ◽  
Matthew K. Zemler ◽  
Matthew J. Traum ◽  
Sandra K. S. Boetcher
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Convection Heat Transfer ◽  
Vertical Cylinder ◽  
Vertical Surface ◽  
Nusselt Numbers ◽  
Recent Interest ◽  
Laminar Natural Convection ◽  
Vertical Cylinders ◽  
Classical Subject

Although an extensively studied classical subject, laminar natural convection heat transfer from the vertical surface of a cylinder has generated some recent interest in the literature. In this investigation, numerical experiments are performed to determine average Nusselt numbers for isothermal vertical cylinders (102<RaL<109,0.1<L/D<10, and Pr = 0.7) situated on an adiabatic surface in a quiescent ambient environment. Average Nusselt numbers for various cases will be presented and compared with commonly used correlations. Using Nusselt numbers for isothermal tops to approximate Nusselt numbers for heated tops will also be examined. Furthermore, the limit for which the heat transfer results for a vertical flat plate may be used as an approximation for the heat transfer from a vertical cylinder will be investigated.

Maximum Density Effects on Natural Convection over an Isothermal Vertical Plate Embedded in an Anisotropic Porous Medium

2019 ◽  
Vol 393 ◽  
pp. 1-15
Author(s):  
Gérard Degan ◽  
Franck M. Egboho ◽  
Djidjoho Christian Akowanou
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Porous Medium ◽  
Natural Convection ◽  
Transfer Rate ◽  
Vertical Plate ◽  
Vertical Surface ◽  
Convective Transfer ◽  
Industrial Sectors ◽  
Anisotropic Porous Medium

Keywords: Natural convection, anisotropic porous medium, inversion of density.Abstract. The natural convection in the porous medium has attracted considerable attention with its applications in various industrial sectors, such as the agro-alimentary, the pharmaceutical and oil processing industries. The present work is about the study of the phenomenon of natural convection at 4°C on the vertical plate lining in an anisotropic porous medium in permeability. The wall of the vertical surface is subjected to a constant temperature with defined hydrodynamic conditions and thermal limits. Generalized Darcy’s law was used to establish the governing equations of the system. The control parameters governing the system are respectively the permeability ratio K*, the angle ϴ of the major axis and the inversion parameter R. The general basic equations were solved numerically using Runge-Kutta and shooting method. There was validated against previous work. The effect of these parameters on the heat transfer was highlighted. From the analysis result, it comes out the following conclusions: The convective flow is significantly affected by the anisotropic parameter; heat transfer along the vertical surface is maximum (minimum) when the main shaft having the high permeability is oriented parallel (perpendicular) to the gravitational field; the rate of heat transfer is depending on the inversion parameter R. The convective transfer rate illustrated by the local Nusselt number is symmetric with respect to R=0.45, where it reaches its smallest value. It is inversely proportional to the distribution of the thickness of boundary layer. A high convective transfer rate corresponds to a low boundary layer thickness and this inversely.

Laminar Natural Convection From Isothermal Vertical Cylinders: A Revisit to a Classical Subject

2011 ◽  
Author(s):  
Jerod C. Day ◽  
Matthew J. Traum ◽  
Sandra K. S. Boetcher
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Convection Heat Transfer ◽  
Vertical Cylinder ◽  
Vertical Surface ◽  
Nusselt Numbers ◽  
Laminar Natural Convection ◽  
Nusselt Number Correlation ◽  
Vertical Cylinders ◽  
Classical Subject

Laminar natural convection heat transfer from the vertical surface of a cylinder is a classical subject, which has been studied extensively. Furthermore, this subject has generated some recent interest in the literature. In the present investigation, numerical experiments were performed to determine average Nusselt numbers for isothermal vertical cylinders (103 < RaL < 109, 0.5 < L/D <10, and Pr = 0.7) situated on an adiabatic surface in a quiescent ambient environment which will allow for plume growth. Results will be compared with commonly used correlations and a new average Nusselt number correlation will be presented. Furthermore, the limit for which the heat transfer results for a vertical flat plate may be used as an approximation for the heat transfer from a vertical cylinder will be investigated.

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