Thermal convection of liquid metal in a long inclined cylinder

2017 ◽  
Vol 2 (11) ◽  
Author(s):  
Andrei Teimurazov ◽  
Peter Frick
Keyword(s):  
Liquid Metal ◽  
Thermal Convection

Thermoelectric magnetohydrodynamics

1979 ◽  
Vol 91 (2) ◽  
pp. 231-251 ◽  
Author(s):  
J. A. Shercliff
Keyword(s):  
Magnetic Fields ◽  
Liquid Metal ◽  
Ab Initio ◽  
Thermoelectric Power ◽  
Thermal Convection ◽  
Thermal Field ◽  
Fusion Reactor ◽  
Nuclear Reactors ◽  
Fusion Reactor Blanket ◽  
Discontinuous Variation

Thermoelectric currents in the presence of magnetic fields can cause pumping or stirring of liquid-metal coolants in nuclear reactors or stirring of molten metal in industrial metallurgy. The interaction between the thermal and magnetohydrodynamic fields is a mutual one owing to alterations in the thermal convection and to the Peltier and Thomson effects (although these are usually small). This paper sets up the equations of magnetohydrodynamics and thermal convection when coupled by thermoelectricity and solves some illustrative problems in which the thermal field is known ab initio. Examples where the effects are due to either continuous or discontinuous variation of material composition are included. Practical magnitudes are discussed for the case of a fusion-reactor blanket, where the effects are potentially important owing to the unusual thermoelectric power of lithium.

Thermal convection studies in liquid metal flow inside a horizontal duct under the influence of transverse magnetic field

2020 ◽  
Vol 32 (6) ◽  
pp. 067107 ◽  
Author(s):  
S. Sahu ◽  
C. Courtessole ◽  
A. Ranjan ◽  
R. Bhattacharyay ◽  
T. Sketchley ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Liquid Metal ◽  
Transverse Magnetic Field ◽  
Thermal Convection ◽  
Metal Flow ◽  
Transverse Magnetic ◽  
Liquid Metal Flow

Rotating thermal convection in liquid gallium: multi-modal flow, absent steady columns

2018 ◽  
Vol 846 ◽  
pp. 846-876 ◽  
Author(s):  
Jonathan M. Aurnou ◽  
Vincent Bertin ◽  
Alexander M. Grannan ◽  
Susanne Horn ◽  
Tobias Vogt
Keyword(s):  
Liquid Metal ◽  
Thermal Convection ◽  
Convective Flow ◽  
Laboratory Experiments ◽  
Liquid Metals ◽  
Low Frequency ◽  
Working Fluid ◽  
Liquid Gallium ◽  
Thermally Driven ◽  
Convective Motions

Earth’s magnetic field is generated by convective motions in its liquid metal core. In this fluid, the heat diffuses significantly more than momentum, and thus the Prandtl number$Pr$is well below unity. The thermally driven convective flow dynamics of liquid metals are very different from moderate-$Pr$fluids, such as water and those used in current dynamo simulations. In order to characterise rapidly rotating thermal convection in low-$Pr$number fluids, we have performed laboratory experiments in a cylinder of aspect ratio$\unicode[STIX]{x1D6E4}=1.94$using liquid gallium ($Pr\simeq 0.025$) as the working fluid. The Ekman number varies from$E\simeq 5\times 10^{-6}$to$5\times 10^{-5}$and the Rayleigh number varies from$Ra\simeq 2\times 10^{5}$to$1.5\times 10^{7}$. Using spectral analysis stemming from point-wise temperature measurements within the fluid and measurements of the Nusselt number$Nu$, we characterise the different styles of low-$Pr$rotating convective flow. The convection threshold is first overcome in the form of container-scale inertial oscillatory modes. At stronger forcing, sidewall-attached modes are identified for the first time in liquid metal laboratory experiments. These wall modes coexist with the bulk oscillatory modes. At$Ra$well below the values where steady rotating columnar convection occurs, the bulk flow becomes turbulent. Our results imply that rotating convective flows in liquid metals do not develop in the form of quasisteady columns, as in moderate-$Pr$fluids, but in the form of oscillatory convective motions. Thus, thermally driven flows in low-$Pr$geophysical and astrophysical fluids can differ substantively from those occurring in$Pr\simeq 1$models. Furthermore, our experimental results show that relatively low-frequency wall modes are an essential dynamical component of rapidly rotating convection in liquid metals.

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