Film Free Convection in Helium II

1966 ◽  
Vol 88 (4) ◽  
pp. 343-349 ◽  
Author(s):  
W. J. Rivers ◽  
P. W. McFadden
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Liquid Helium ◽  
Convection Heat Transfer ◽  
Temperature Profiles ◽  
Fourth Degree ◽  
Helium Ii ◽  
Boundary Layer Equations ◽  
Integral Forms ◽  
Free Convection Heat

Free-convection heat transfer from a solid surface to liquid Helium II in the presence of a film of either liquid Helium I or helium gas is analyzed mathematically. The analysis includes two heater shapes, a vertical flat plate and a horizontal circular cylinder, each with an isothermal surface. The integral forms of the boundary-layer equations are used to describe the heat transfer and fluid flow processes that occur within the film. The velocity and temperature profiles within the film are approximated by fourth degree polynomials whose coefficients were evaluated by applying a system of boundary conditions which were derived in the usual fashion but are based on assumed discontinuities in both the velocity and temperature profiles at the film-Helium II interface. Calculated results, which include the film thickness, the heat transfer coefficient, and the mass flow in the film, are presented and discussed.

Exploratory Studies of Free-Convection Heat Transfer Through an Enclosed Vertical Liquid Layer With a Vertical Baffle

1969 ◽  
Vol 91 (1) ◽  
pp. 163-165 ◽  
Author(s):  
A. F. Emery
Keyword(s):  
Heat Transfer ◽  
Free Convection ◽  
Nuclear Reactors ◽  
Convection Heat Transfer ◽  
Temperature Profiles ◽  
Two Dimensional ◽  
Convection Heat ◽  
Free Convection Heat ◽  
Vertical Baffle ◽  
Appreciable Reduction

Overall heat transfer measurements and temperature profiles were obtained for free convection in a narrow, vertical, two-dimensional layer with a vertical baffle. This configuration was chosen to model commonly used coolant channels in nuclear reactors. The results show that there is no appreciable reduction of the overall free-convection heat transfer, although fairly significant changes do occur in the local temperature profiles.

scholarly journals Free Convection Heat Transfer from Horizontal Cylinders

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 559
Author(s):  
Janusz T. Cieśliński ◽  
Slawomir Smolen ◽  
Dorota Sawicka
Keyword(s):  
Heat Transfer ◽  
Rayleigh Number ◽  
Free Convection ◽  
Convection Heat Transfer ◽  
Horizontal Tube ◽  
Correlation Equations ◽  
Convection Heat ◽  
Number Range ◽  
Heated Cylinder ◽  
Free Convection Heat

The results of experimental investigation of free convection heat transfer in a rectangular container are presented. The ability of the commonly accepted correlation equations to reproduce present experimental data was tested as well. It was assumed that the examined geometry fulfils the requirement of no-interaction between heated cylinder and bounded surfaces. In order to check this assumption recently published correlation equations that jointly describe the dependence of the average Nusselt number on Rayleigh number and confinement ratios were examined. As a heat source served electrically heated horizontal tube immersed in an ambient fluid. Experiments were performed with pure ethylene glycol (EG), distilled water (W), and a mixture of EG and water at 50%/50% by volume. A set of empirical correlation equations for the prediction of Nu numbers for Rayleigh number range 3.6 × 104 < Ra < 9.2 × 105 or 3.6 × 105 < Raq < 14.8 × 106 and Pr number range 4.5 ≤ Pr ≤ 160 has been developed. The proposed correlation equations are based on two characteristic lengths, i.e., cylinder diameter and boundary layer length.

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