CPS Based Liquid Metal Divertor Target for EU-DEMO

Abstract Power exhaust is a key mission in the roadmap to the realization of a future fusion reactor. Among the different solutions, the use of liquid metals as plasma facing materials are of interest due to their potential increased lifetime. Several liquid metal limiters have been successfully tested in the Frascati Tokamak Upgrade over the last 10 years. Liquid materials such as lithium and tin have been investigated using capillary porous systems (CPSs), and their impact on plasma performance has been explored. From such experience, a liquid metal divertor (LMD) concept design, CPS-based, is here proposed. Tin has been preferred as plasma facing material. The proposed LMD would operate, in low evaporative regime, with matching heat exhausting capabilities to those of the baseline ITER-like divertor. Continuous refilling of the CPS is guaranteed with a reservoir at the back of the unit, where the metal is kept liquid through a gas heating circuit. The study has been carried out using ANSYS and the thermal results will be shown. All the design choices are compatible with the current materials and the constraints adopted for the DEMO W divertor. Using such configuration, thermal loads up to 20 MW/m2 are exhausted while keeping the surface temperature below 1250 °C. The design foresees values of pressure, temperature and flow rate of the water coolant in the same range expected for the W DEMO divertor, thus facilitating the integration of such solution in the current cassette design. Technological and practical aspects are addressed, i.e. tin corrosion and CPS wettability. Possible solutions to prevent tin corrosion, and its compatibility with structural materials, will be outlined.

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Effects of slowly varying meniscus curvature on internal flows in the Cassie state

Journal of Fluid Mechanics ◽

10.1017/jfm.2019.366 ◽

2019 ◽

Vol 872 ◽

pp. 272-307 ◽

Cited By ~ 3

Author(s):

Simon E. Game ◽

Marc Hodes ◽

Demetrios T. Papageorgiou

Keyword(s):

Liquid Metal ◽

Small Parameter ◽

Cross Section ◽

Flow Rate ◽

Pressure Difference ◽

Liquid Metals ◽

Three Dimensional ◽

Reynolds Numbers ◽

Local Conditions ◽

Cassie State

The flow rate of a pressure-driven liquid through a microchannel may be enhanced by texturing its no-slip boundaries with grooves aligned with the flow. In such cases, the grooves may contain vapour and/or an inert gas and the liquid is trapped in the Cassie state, resulting in (apparent) slip. The flow-rate enhancement is of benefit to different applications including the increase of throughput of a liquid in a lab-on-a-chip, and the reduction of thermal resistance associated with liquid metal cooling of microelectronics. At any given cross-section, the meniscus takes the approximate shape of a circular arc whose curvature is determined by the pressure difference across it. Hence, it typically protrudes into the grooves near the inlet of a microchannel and is gradually drawn into the microchannel as it is traversed and the liquid pressure decreases. For sufficiently large Reynolds numbers, the variation of the meniscus shape and hence the flow geometry necessitates the inclusion of inertial (non-parallel) flow effects. We capture them for a slender microchannel, where our small parameter is the ratio of ridge pitch-to-microchannel height, and order-one Reynolds numbers. This is done by using a hybrid analytical–numerical method to resolve the nonlinear three-dimensional (3-D) problem as a sequence of two-dimensional (2-D) linear ones in the microchannel cross-section, allied with non-local conditions that determine the slowly varying pressure distribution at leading and first orders. When the pressure difference across the microchannel is constrained by the advancing contact angle of the liquid on the ridges and its surface tension (which is high for liquid metals), inertial effects can significantly reduce the flow rate for realistic parameter values. For example, when the solid fraction of the ridges is 0.1, the microchannel height-to-(half) ridge pitch ratio is 6, the Reynolds number of the flow is 1 and the small parameter is 0.1, they reduce the flow rate of a liquid metal (Galinstan) by approximately 50 %. Conversely, for sufficiently large microchannel heights, they enhance it. Physical explanations of both of these phenomena are given.

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Liquid metal-based nanocomposite materials: Fabrication technology and applications

Nanoscale ◽

10.1039/d0nr07479a ◽

2021 ◽

Author(s):

Hiroki Ota ◽

Nyamjargal Ochirkhuyag ◽

Ryosuke Matsuda ◽

Zihao Song ◽

Fumika Nakamura ◽

...

Keyword(s):

Liquid Metal ◽

Flexible Electronics ◽

Liquid Metals ◽

Nanocomposite Materials ◽

Fabrication Technology

Research on liquid metals has been steadily garnering more interest in recent times because the properties of these metals are conducive to flexible electronics applications; further, these metals are in...

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Liquid Metals: Liquid Metal Marbles (Adv. Funct. Mater. 2/2013)

Advanced Functional Materials ◽

10.1002/adfm.201370007 ◽

2013 ◽

Vol 23 (2) ◽

pp. 137-137 ◽

Cited By ~ 4

Author(s):

Vijay Sivan ◽

Shi-Yang Tang ◽

Anthony P. O'Mullane ◽

Phred Petersen ◽

Nicky Eshtiaghi ◽

...

Keyword(s):

Liquid Metal ◽

Liquid Metals

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Special Features of First-Wall Heat Transfer in Liquid-Metal Fusion Reactor Blankets

Fusion Technology ◽

10.13182/fst87-a25054 ◽

1987 ◽

Vol 12 (1) ◽

pp. 104-113 ◽

Cited By ~ 4

Author(s):

K. Taghavi ◽

M. S. Tillack ◽

H. Madarame

Keyword(s):

Heat Transfer ◽

Liquid Metal ◽

Fusion Reactor ◽

Wall Heat Transfer ◽

First Wall

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Laminar Natural Convection About Downward Facing Heated Blunt Bodies to Liquid Metals

Journal of Heat Transfer ◽

10.1115/1.3450520 ◽

1976 ◽

Vol 98 (2) ◽

pp. 208-212 ◽

Cited By ~ 2

Author(s):

G. M. Harpole ◽

I. Catton

Keyword(s):

Heat Flux ◽

Surface Temperature ◽

Series Expansion ◽

Surface Heat Flux ◽

Liquid Metals ◽

Surface Heat ◽

Surface Shape ◽

Boundary Layer Equations ◽

Stagnation Points ◽

Shape Dependence

The laminar boundary layer equations for free convection over bodies of arbitrary shape (i.e., a three-term series expansion) and with arbitrary surface heat flux or surface temperature are solved in local Cartesian coordinates. Both two-dimensional bodies (e.g., horizontal cylinders) and axisymmetric bodies (e.g., spheres) with finite radii of curvature at their stagnation points are considered. A Blasius series expansion is applied to convert from partial to ordinary differential equations. An additional transformation removes the surface shape dependence and the surface heat flux or surface temperature dependence of the equations. A second-order-correct, finite-difference method is used to solve the resulting equations. Tables of results for low Prandtl numbers are presented, from which local Nusselt numbers can be computed.

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Flow rate measurements in turbulent liquid metal channel flow using Time-of-Flight Lorentz force velocimetry

PAMM ◽

10.1002/pamm.201210277 ◽

2012 ◽

Vol 12 (1) ◽

pp. 577-578

Author(s):

Dandan Jian ◽

Christian Karcher

Keyword(s):

Liquid Metal ◽

Lorentz Force ◽

Channel Flow ◽

Flow Rate ◽

Time Of Flight ◽

Lorentz Force Velocimetry

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Unusual Wetting Behavior of Liquid Metals on Porous Layer Formed at Surface of Iron Substrate Prepared by Oxidation-Reduction Process

Materials Science Forum ◽

10.4028/www.scientific.net/msf.561-565.1699 ◽

2007 ◽

Vol 561-565 ◽

pp. 1699-1701

Author(s):

Nobuyuki Takahira ◽

Takeshi Yoshikawa ◽

Toshihiro Tanaka

Keyword(s):

Liquid Metal ◽

Porous Layer ◽

Liquid Metals ◽

Reduction Process ◽

Surface Oxidation ◽

Porous Iron ◽

Normal Contact ◽

Wetting Behavior ◽

Oxidation Reduction ◽

Oxidized Iron

Unusual wetting behavior of liquid Cu was found on a surface-oxidized iron substrate in reducing atmosphere. Liquid Cu wetted and spread very widely on the iron substrate when a droplet was attached with the substrate in Ar-10%H2 after the surface oxidation of the substrate. The oxidationreduction process fabricates a porous layer at the surface of the iron substrate. The pores in the porous iron layer are 3-dimensionally interconnected. Thus, liquid metals, which are contacted with the reduced iron samples, penetrate into these pores by capillary force to cause the unusual wetting behavior. It has been already confirmed that liquid Ag, Sn, In and Bi show this phenomenon onto surface-porous iron samples as well as liquid Cu. This unusual wetting behavior of a liquid metal has been correlated to the normal contact angle of the liquid metal on a flat iron substrate.

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Suitability of Eutectic Field’s Metal for Use in an Electromagnetohydrodynamically-Enhanced Experimental Two-Phase Flow Loop

Volume 5: Fusion Engineering; Student Paper Competition; Design Basis and Beyond Design Basis Events; Simple and Combined Cycles ◽

10.1115/icone20-power2012-54103 ◽

2012 ◽

Cited By ~ 1

Author(s):

A. Lipchitz ◽

Lilian Laurent ◽

G. D. Harvel

Keyword(s):

Liquid Metal ◽

Two Phase Flow ◽

Nuclear Reactors ◽

Liquid Metals ◽

Metal Flow ◽

Phase Flow ◽

Laboratory Setting ◽

Flow Loop ◽

Fast Reactors ◽

Two Phase

Several Generation IV nuclear reactors, such as sodium fast reactors and lead-bismuth fast reactors, use liquid metal as a coolant. In order to better understand and improve the thermal hydraulics of liquid metal cooled GEN IV nuclear reactors liquid metal flow needs to be studied in experimental circulation loops. Experimental circulation loops are often located in a laboratory setting. However, studying liquid metal two phase flow in laboratory settings can be difficult due to the high temperatures and safety hazards involved with traditional liquid metals such as sodium and lead-bismuth. One solution is to use a low melt metal alloy that is as benign as reasonably achievable. Field’s metal is a eutectic alloy of 51% Indium, 32.5% Bismuth and 16.5% Tin by weight and has a melting point of 335K making it ideal for use in a laboratory setting. A study is undertaken to determine its suitability to use in a two-phase experimental flow loop enhanced by magnetohydrodynamic forces. The study investigated its reactivity with air and water, its ability to be influenced by magnetic fields, its ability to flow, and its ease of manufacture. The experiments melted reference samples of Field’s metal and observed its behaviour in a glass beaker, submerged in water and an inclined stainless steel pipe. Then Field’s metal was manufactured in the laboratory and compared to the sample using the same set of experiments and standards. To determine Field’s metal degree of magnetism permanent neodymium magnets were used. Their strength was determined using a Gaussmeter. All experiments were recorded using a COHU digital camera. Image analysis was then performed on the video to determine any movements initiated by the magnetic field forces. In conclusion, Field’s metal is more than suitable for use in experimental settings as it is non-reactive, non-toxic, simple to manufacture, easy to use, and responds to a magnetic force.

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Convective Cooling of Compact Electronic Devices via Liquid Metals with Low Melting Points

Journal of Heat Transfer ◽

10.1115/1.4050404 ◽

2021 ◽

Author(s):

Guilin Liu ◽

Jing Liu

Keyword(s):

Heat Transfer ◽

Melting Point ◽

Liquid Metal ◽

High Performance ◽

Flow Resistance ◽

Heat Dissipation ◽

Liquid Metals ◽

Electronic Devices ◽

Convective Cooling ◽

Heat Exchanger Design

Abstract The increasingly high power density of today's electronic devices requires the cooling techniques to produce highly effective heat dissipation performance with as little sacrifice as possible to the system compactness. Among the currently available thermal management schemes, the convective liquid metal cooling provides considerably high performance due to their unique thermal properties. This paper firstly reviews the studies on convective cooling using low-melting-point metals published in the past few decades. A group of equations for the thermophysical properties of In-Ga-Sn eutectic alloy is then documented by rigorous literature examination, following by a section of correlations for the heat transfer and flow resistance calculation to partially facilitate the designing work at the current stage. The urgent need to investigate the heat transfer and flow resistance of forced convection of low-melting-point metals in small/mini-channels, typical in compact electronic devices, is carefully argued. Some special aspects pertaining to the practical application of this cooling technique, including the entrance effect, mixed convection, and compact liquid metal heat exchanger design, are also discussed. Finally, future challenges and prospects are outlined.

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