Magnetohydrodynamic Natural Convection of Liquid Metal Between Coaxial Isothermal Cylinders Due to Internal Heating

2013 ◽  
Vol 65 (5) ◽  
pp. 401-418 ◽  
Author(s):  
S. C. Kakarantzas ◽  
I. E. Sarris ◽  
N. S. Vlachos
Keyword(s):  
Natural Convection ◽  
Liquid Metal ◽  
Internal Heating ◽  
Isothermal Cylinders

Oscillatory Natural Convection of a Liquid Metal in Circular Cylinders

1994 ◽  
Vol 116 (3) ◽  
pp. 627-632 ◽  
Author(s):  
Y. Kamotani ◽  
F.-B. Weng ◽  
S. Ostrach ◽  
J. Platt
Keyword(s):  
Experimental Study ◽  
Natural Convection ◽  
Liquid Metal ◽  
Oscillatory Flow ◽  
Circular Cylinders ◽  
Flow Structures ◽  
Supercritical Flow ◽  
Aspect Ratios ◽  
Oscillation Frequencies ◽  
Rayleigh Numbers

An experimental study is made of natural convection oscillations in gallium melts enclosed by right circular cylinders with differentially heated end walls. Cases heated from below are examined for angles of inclination (φ) ranging from 0 deg (vertical) to 75 deg with aspect ratios Ar (height/diameter) of 2, 3, and 4. Temperature measurements are made along the circumference of the cylinder to detect the oscillations, from which the oscillatory flow structures are inferred. The critical Rayleigh numbers and oscillation frequencies are determined. For Ar=3 and φ = 0 deg, 30 deg the supercritical flow structures are discussed in detail.

scholarly journals Natural Convection From Isothermal Horizontal Cylinders

2009 ◽  
Author(s):  
Ian M. O. Gorman ◽  
Darina B. Murray ◽  
Gerard Byrne ◽  
Tim Persoons
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Local Heat Transfer ◽  
Local Heat ◽  
Separation Distance ◽  
Thermal Plume ◽  
Number Range ◽  
Vertically Aligned ◽  
Isothermal Cylinders ◽  
Horizontal Cylinders

The research described here is concerned with natural convection from isothermal cylinders, with a particular focus on the interaction between a pair of vertically aligned cylinders. Prime attention was focused on how the local heat transfer characteristics of the upper cylinder are affected due to buoyancy induced fluid flow from the lower cylinder. Tests were performed using internally heated copper cylinders with an outside diameter 30mm and a vertical separation distance between the cylinders ranging from two to three cylinder diameters. Plume interaction between the heated cylinders was investigated within a Rayleigh number range of 2×106 to 6×106. Spectral analysis of the associated heat transfer interaction is presented showing that interaction between the cylinders causes oscillation of the thermal plume. The effect of this oscillation is considered as a possible enhancement mechanism of the heat transfer performance of the upper cylinder.

Natural Convection Heat Transfer in a Rectangular Liquid Metal Pool With Bottom Heating and Top Cooling

2006 ◽  
Author(s):  
Il S. Lee ◽  
Yong H. Yu ◽  
Hyoung M. Son ◽  
Jin S. Hwang ◽  
Kune Y. Suh
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Liquid Metal ◽  
Convection Heat Transfer ◽  
Bottom Surface ◽  
Natural Convection Heat Transfer ◽  
Metal Pool ◽  
Convection Heat ◽  
Integral System ◽  
Bottom Heating

An experimental study is performed to investigate the natural convection heat transfer characteristics with subcooled coolant to create engineering database for basic applications in a lead alloy cooled reactor. Tests are performed in the ALTOS (Applied Liquid-metal Thermal Operation Study) apparatus as part of MITHOS (Metal Integrated Thermo Hydrodynamic Operation System). A relationship is determined between the Nusselt number Nu and the Rayleigh number Ra in the liquid metal rectangular pool. Results are compared with correlations and experimental data in the literature. Given the similar Ra condition, the present test results for Nu of the liquid metal pool with top subcooling are found to be similar to those predicted by the existing correlations or experiments. The current test results are utilized to develop natural convection heat transfer correlations applicable to low Prandtl number Pr fluids that are heated from below and cooled by the external coolant above. Results from this study are slated to be used in designing BORIS (Battery Optimized Reactor Integral System), a small lead cooled modular fast reactor for deployment at remote sites cycled with MOBIS (Modular Optimized Brayton Integral System) for electricity generation, tied with NAVIS (Naval Application Vessel Integral System) for ship propulsion, joined with THAIS (Thermochemical Hydrogen Acquisition Integral System) for hydrogen production, and coupled with DORIS (Desalination Optimized Reactor Integral System) for seawater desalination. Tests are performed with Wood’s metal (Pb-Bi-Sn-Cd) filling a rectangular pool whose lower surface is heated and upper surface cooled by forced convection of water. The test section is 20 cm long, 11.3 cm high and 15 cm wide. The simulant has a melting temperature of 78°C. The constant temperature and heat flux condition was realized for the bottom heating once the steady state had been met. The test parameters include the heated bottom surface temperature of the liquid metal pool, the input power to the bottom surface of the section, and the coolant temperature.

Unsteady natural convection in a cavity with internal heating and cooling

1984 ◽  
Vol 140 ◽  
pp. 135-151 ◽  
Author(s):  
John C. Patterson
Keyword(s):  
Steady State ◽  
Natural Convection ◽  
Numerical Solutions ◽  
Transient Flow ◽  
Scaling Analysis ◽  
Steady State Flow ◽  
Internal Heating ◽  
Sources And Sinks ◽  
Heating And Cooling ◽  
Unsteady Natural Convection

The problem of transient natural convection in a cavity of aspect ratio A < 1 driven by internal buoyancy sources and sinks distributed linearly in the horizontal and uniformly in the vertical is considered. Scaling analysis is used to show that a number of possible transient flow regions are possible, collapsing ultimately onto one of conductive, transitional, or convective steady-state flow regimes. A number of numerical solutions are obtained, and their relationships to the scaling analysis are discussed.

Natural Convection Heat Transfer of Cold Water Within an Eccentric Horizontal Cylindrical Annulus

1988 ◽  
Vol 110 (4a) ◽  
pp. 894-900 ◽  
Author(s):  
C. J. Ho ◽  
Y. H. Lin
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Cold Water ◽  
Convection Heat Transfer ◽  
Orientation Angle ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Density Inversion ◽  
Cylindrical Annulus ◽  
Isothermal Cylinders

Natural convection heat transfer of cold water, encompassing a density inversion, within an eccentric horizontal annulus made of two isothermal cylinders, is numerically studied via a finite difference method. Numerical results have been obtained for an annular radius ratio 2.6 with Rayleigh number ranging from 103 to 106, the inversion parameter being 0.0 to 1.0, the eccentricity varying from 0 to 0.8, and the orientation angle of the inner cylinder between 0 and π. Results indicate that the flow patterns and heat transfer characteristics are strongly influenced by the combined effect induced by the density inversion of water and the position of the inner cylinder of the annulus. For the cases considered in the present study, a minimum in heat transfer arises with the inversion parameter between 0.4 and 0.5 depending primarily on the position of the inner cylinder.

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