Free Convection Through Vertical Plane Layers—Moderate and High Prandtl Number Fluids

1969 ◽  
Vol 91 (3) ◽  
pp. 391-401 ◽  
Author(s):  
R. K. MacGregor ◽  
A. F. Emery
Keyword(s):  
Free Convection ◽  
Vertical Plane ◽  
Constant Heat Flux ◽  
Variable Properties ◽  
Excellent Correlation ◽  
Wall Boundary Conditions ◽  
High Prandtl Number ◽  
Isothermal Wall ◽  
Prandtl Numbers ◽  
Rayleigh Numbers

The results of numerical computations are presented for free convection under isothermal wall and constant-heat-flux wall-boundary conditions. The effects of the Prandtl, Grashof, and Rayleigh numbers, aspect ratio, and variable properties are described. Experimental measurements of net heat transfer through vertical plane layers and of velocity and temperature profiles are given for Prandtl numbers of 1 to 20,000. A comparison of the laminar data with the numerical results shows excellent correlation.

Free Convection Through Vertical Plane Layers of Non-Newtonian Power Law Fluids

1971 ◽  
Vol 93 (2) ◽  
pp. 164-171 ◽  
Author(s):  
A. F. Emery ◽  
H. W. Chi ◽  
J. D. Dale
Keyword(s):  
Free Convection ◽  
Vertical Plane ◽  
Constant Heat Flux ◽  
Experimental Measurements ◽  
Temperature Profiles ◽  
Flat Plates ◽  
Constant Heat ◽  
Layer Height ◽  
Power Law Fluids ◽  
Prandtl Numbers

Experimental measurements of the heat transferred from a constant heat flux hot wall across vertical plane layers of several pseudoplastic non-Newtonian fluids with generalized Prandtl numbers of 10–500 are reported for a range of Grashof moduli and layer height to width ratios. The rheological properties of the fluids are discussed and it is shown that the similarity analysis of free convection for constant-temperature vertical flat plates presented by Acrivos for infinite Prandtl numbers can be used to correlate the data. Several temperature profiles are given and compared to those measured in water.

Laminar and Turbulent Free Convection From Elliptic Cylinders, With a Vertical Plate and Horizontal Circular Cylinder as Special Cases

1976 ◽  
Vol 98 (1) ◽  
pp. 72-80 ◽  
Author(s):  
G. D. Raithby ◽  
K. G. T. Hollands
Keyword(s):  
Heat Transfer ◽  
Circular Cylinder ◽  
Free Convection ◽  
Vertical Plate ◽  
Constant Heat Flux ◽  
Special Cases ◽  
Flux Boundary Conditions ◽  
Large Eccentricity ◽  
Rayleigh Numbers ◽  
Horizontal Circular Cylinder

Heat transfer by free convection from thin elliptic cylinders is predicted, accounting for both the effect of thick boundary layers at low Rayleigh numbers and the influence of turbulence at higher Rayleigh numbers. Isothermal and constant heat flux boundary conditions are treated. The results are compared with experimental data, which are available for the limiting cases of large eccentricity (vertical plate) and small eccentricity (horizontal circular cylinder); the agreement is excellent. Accurate correlation equations, from which the average heat transfer can be calculated, are given.

scholarly journals Transient Numerical Analysis of Free Convection in Cylindrical Enclosure

2020 ◽  
Vol 307 ◽  
pp. 01029
Author(s):  
Mohamed Amine Medebber ◽  
Nourddine Retiel ◽  
belkacem Ould said ◽  
Abderrahmane Aissa ◽  
Mohammed El Ganaoui
Keyword(s):  
Free Convection ◽  
Vertical Wall ◽  
Vertical Cylinder ◽  
Geometrical Parameters ◽  
Uniform Temperature ◽  
Governing Equations ◽  
Simpler Algorithm ◽  
Prandtl Numbers ◽  
Volume Method ◽  
Rayleigh Numbers

A transient two dimensional study of free convection in a vertical cylinder partially annulus is conducted numerically. Uniform temperature is imposed cross a vertical wall, while the top and bottom walls are adiabatic. The governing equations are solved numerically by using a finite volume method. The coupling between the continuity and momentum equations is effected using the SIMPLER algorithm. Solutions have been obtained for Prandtl numbers equal to 7.0, Rayleigh numbers of 103to 106and height ratios 0.5. The influence of physical and geometrical parameters on the isotherms, velocity fields, average Nusselt has been numerically investigated.

Heat Transfer Across Vertical Layers

1965 ◽  
Vol 87 (1) ◽  
pp. 110-114 ◽  
Author(s):  
A. Emery ◽  
N. C. Chu
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Integral Equations ◽  
Temperature Difference ◽  
Vertical Plane ◽  
Measured Data ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Prandtl Numbers

The heat transferred through vertical plane layers by free convection was measured as a function of the temperature difference across the layer, the height of the layer, and its thickness. Heat transfer coefficients are reported for fluids having Prandtl numbers from 3 to 30,000. An analysis of the problem by means of integral equations yielded results which differed by no more than 12 percent from the measured data in the range in which the equations were applicable.

Laminar Free Convection From a Vertical Infinite Plate Subject to Transverse Oscillation

1964 ◽  
Vol 31 (3) ◽  
pp. 383-389 ◽  
Author(s):  
Victor D. Blankenship ◽  
John A. Clark
Keyword(s):  
Shear Stress ◽  
Nusselt Number ◽  
Free Convection ◽  
Perturbation Technique ◽  
Infinite Plate ◽  
Vertical Plane ◽  
Convection Flow ◽  
Convection Boundary Layer ◽  
Flow And Heat Transfer ◽  
Prandtl Numbers

The laminar free-convection boundary layer on a vertical plane wall vibrating transversely at high frequencies is analyzed utilizing a perturbation technique. The zeroth-order solutions are that of the well-known steady free-convection flow. First-order harmonic oscillations in velocity and temperature and a second-order time-independent secondary flow and heat transfer are obtained. Series solution for shear stress and Nusselt number are presented having both time-dependent and time-independent terms. Prandtl numbers of 0.72 and 10 are investigated. The time-independent or steady Nusselt number was found to decrease while the shear stress was found to increase under the influence of oscillations.

The Effects of Property Variations on Natural Convection in a Square Enclosure

1999 ◽  
Vol 121 (1) ◽  
pp. 57-62 ◽  
Author(s):  
A. F. Emery ◽  
J. W. Lee
Keyword(s):  
Natural Convection ◽  
Constant Heat Flux ◽  
Variable Properties ◽  
Temperature Dependent ◽  
Constant Heat ◽  
Square Enclosure ◽  
Average Temperature ◽  
Temperature Dependent Conductivity ◽  
Vertical Walls ◽  
Prandtl Numbers

Natural convection in a square enclosure with heated vertical walls and temperature-dependent conductivity and viscosity was simulated for Prandtl numbers ranging from 0.01 to 1.0 and Ra ≤ 106. Although the variable properties produced observable changes in the the temperatures and velocities, the overall heat transfer, as represented by the Nusselt number, was found to be unaffected and was accurately correlated in terms of the Rayleigh and Prandtl numbers using Nu=0.185Ra00.278Pr00.089 with properties evaluated at the average temperature. This correlation applies to both isothermal and constant heat flux hot walls.

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