Liquid Metal Flow Studied by Positron Emission Tracking

Abstract To improve the properties of castings, a new technique to observe the fluid flow and study the motion of oxygen-bearing inclusions has been developed. This new technique, Positron Emission Particle Tracking (PEPT), enabled a single radioactive tracer particle, moving inside a liquid metal casting, to be tracked with an accuracy of some millimeters, depending on the properties of the liquid metal and the mold. These novel experiments give promising results to observe the liquid metal flow and locate the tracked particle in a casting. Experiments have shown that various particle sizes (200 to 600 μm presented here) can be used to observe the liquid metal flow, if the particle has sufficiently initial radioactivity. Different sizes of particles are considered and their radioactivity compared in terms of their usefulness for tracking in flowing liquid aluminum according to the specific surface area.

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Experimental study on liquid metal free surface flow under magnetic and electric field for nuclear fusion

Nuclear Fusion ◽

10.1088/1741-4326/ac4b9c ◽

2022 ◽

Author(s):

Xu Meng ◽

Z H Wang ◽

Dengke Zhang

Keyword(s):

Magnetic Field ◽

Free Surface ◽

Liquid Metal ◽

Electric Field ◽

Liquid Film ◽

Metal Flow ◽

First Wall ◽

Flowing Liquid ◽

Liquid Metal Flow ◽

The Magnetic Field

Abstract In the future application of nuclear fusion, the liquid metal flows are considered to be an attractive option of the first wall of the Tokamak which can effectively remove impurities and improve the confinement of plasma. Moreover, the flowing liquid metal can solve the problem of the corrosion of the solid first wall due to high thermal load and particle discharge. In the magnetic confinement fusion reactor, the liquid metal flow experiences strong magnetic and electric, fields from plasma. In the present paper, an experiment has been conducted to explore the influence of electric and magnetic fields on liquid metal flow. The direction of electric current is perpendicular to that of the magnetic field direction, and thus the Lorentz force is upward or downward. A laser profilometer (LP) based on the laser triangulation technique is used to measure the thickness of the liquid film of Galinstan. The phenomenon of the liquid column from the free surface is observed by the high-speed camera under various flow rates, intensities of magnetic field and electric field. Under a constant external magnetic field, the liquid column appears at the position of the incident current once the external current exceeds a critical value, which is inversely proportional to the magnetic field. The thickness of the flowing liquid film increases with the intensities of magnetic field, electric field, and Reynolds number. The thickness of the liquid film at the incident current position reaches a maximum value when the force is upward. The distribution of liquid metal in the channel presents a parabolic shape with high central and low marginal. Additionally, the splashing, i.e., the detachment of liquid metal is not observed in the present experiment, which suggests a higher critical current for splashing to occur.

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A Positron Emission Particle Tracking (PEPT) Study of Inclusions in Liquid Aluminium Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.922.43 ◽

2014 ◽

Vol 922 ◽

pp. 43-48

Author(s):

D.J. Burnard ◽

A.J. Caden ◽

J. Gargiuli ◽

T. Leadbeater ◽

D.J. Parker ◽

...

Keyword(s):

Particle Tracking ◽

Imaging System ◽

Metal Flow ◽

Al Alloy ◽

Liquid Aluminium ◽

Cross Sectional ◽

Flowing Liquid ◽

Positron Emission ◽

Liquid Metal Flow ◽

Alumina Particles

Inclusions have a detrimental effect upon casting properties but it is known empirically that a slow liquid metal flow has a beneficial effect by reducing the number of inclusions entering the casting. Positron Emission Particle Tracking (PEPT) is a method that can be used to track the path taken by radioactive particles, and can be used to follow the behaviour of inclusions as they make their way from a furnace, along the launder and into the casting. A new PEPT camera geometry was developed and used to track radioactively labelled γ-alumina particles, in the region of 600 μm size. The camera detectors were arranged radially around a launder, into which was poured 150 kg of liquid Al alloy, the radioactive particles being released at intervals during the pour. The positron camera was 0.7 m in length and 0.1 m2 in cross-sectional area, and this matched the dimensions of an industrial launder. A model of inclusion behaviour in a flowing liquid Al alloy was also developed, and the Positron Imaging system described was used to validate this model.

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