Mathematical modelling of alternating electromagnetic and hydrodynamic fields, induced by bar type conductors in a cylinder

The heating of buildings by ecologically clean and compact local devices is an interesting and actual problem. One of the modern areas of applications developed during last ten years is an effective usage of electrical energy by alternating current to produce heat energy. This work presents the mathematical model of one of such devices. It is a finite cylinder with viscous incompressible liquid and with metal electrodes of the form of bars placed parallel to the cylinder axis in the liquid. These conductors are connected to the alternating current. First published online: 14 Oct 201

Hydrodynamics and electrical insulation of PbLi flow with SiC flow channel inserts in a strong magnetic field

Experimental and numerical research in a strong magnetic field is described in this article testing silicon carbide (SiC) flow channel inserts (FCI) in lead-lithium (PbLi) liquid metal flow. The study aims to further develop the High-Temperature Dual-Coolant Lead-Lithium nuclear fusion blanket concept by testing new variations of SiC inserts operating in the relevant electromagnetic conditions. These inserts act as electrical insulators in magnetohydrodynamic lead-lithium flow and can also play the role of the thermal insulator in the potentially real fusion environment. The liquid metal pressure and integral flowrate measurements were performed on up to 5T DC magnetic field created by a superconducting magnet at high temperatures up to 700 °C, which is close to the real fusion environment. Comparisons of several cases with and without inserts are provided, demonstrating their impact on hydraulic resistance. Additionally, electrical potential distribution is recorded on the lead-lithium channel walls, which can be used to evaluate the character of liquid metal velocity distribution in the lead-lithium channel

Challenges of Target and Irradiation Diagnostics of the IFMIF-DONES Facility

IFMIF-DONES will be a first-class scientific infrastructure consisting of an accelerator-driven neutron source delivering 1e17 n/s with a broad peak at 14 MeV. Such neutron flux will be created by impinging a continuous wave 125 mA, 40 MeV, 5 MW deuteron beam onto a liquid Li jet target, circulating at 15 m/s. Material specimens subjected to neutron irradiation will be placed a few millimeters downstream. Some of the most challenging technological aspects of the facility are the Diagnostics to monitor the Li jet, beam parameters on target, and characterization of the neutron irradiation field, with transversal implications in the scientific exploitation, machine protection and safety. Multiple solutions are foreseen, considering among others, Li jet thickness measurement methods based on optical metrology and millimeter-wave radar techniques, Li electromagnetic flowmeters, beam footprint measurements based on residual gas excitation, online neutron detectors such as SPNDs and micro-fission chambers, as well as offline neutron fluence measurements by activation foils or spheres. This contribution provides an overview of these aspects and the associated R activities

In-situ and real-time analysis of TEM forces induced by a permanent magnetic field during solidification of Al-4wr%Cu

International audienc

In Situ and Real-Time Analysis of TEM Forces Induced by a Permanent Magnetic Field during Solidification of Al-4wt%Cu

International audienceIt is well known that the application of a magnetic field during the growth process can have pronounced effects on cast material structures and their properties, so that magnetic fields have been widely applied since the 1950’s. In the case of a permanent magnetic field, some recent results revealed a dual effect on the liquid metal flow. 1: the magnetic field has a selective damping action on the flow at the scale of the crucible, due to the Lorentz force; 2: the interaction of thermoelectro-magnetic (TEM) currents in the close vicinity of the solid-liquid interface with the applied magnetic field leads to the generation of electromagnetic forces, which act both on the liquid and on the solid at the scale of the microstructure. We present an experimental investigation of the TEM forces induced by a permanent magnetic field during columnar and equiaxed solidification of Al-4wt%Cu. In situ visualization was carried out by means of synchrotron X-ray radiography, which is a method of choice for studying dynamic phenomena. It was shown that the TEM forces were at the origin of a motion of dendritic particles, perpendicular to the direction of gravity. A heuristic analysis allowed us to estimate the fluid velocities and the velocities of the solid particles, and a good agreement was achieved with the experimental data. Similar observations were also made during equiaxed growth in a temperature gradient. The in situ observation of the grain trajectories for various values of the temperature gradient demonstrated that gravity and TEM forces were the driving forces which controlled the grain motion

Magnetic Fields, Convection and Solidification

International audienceIn solidification processes the fluid flow occurs almost at every scale from the bulk, near the interfaces and deeply in the mushy zone. Numerical modeling is a valuable tool for understanding and master the solidification processes, however, macro-scale models are not always able to predict in detail the random behavior of the solidification process whereas models for micro scales are not capable to take into account a complex structure of flows which enter into the mushy zone. In the present paper the variety of the flows and imprints they left on solidification structure are discussed and illustrated with experimental data which naturally comprise every flow occurring in the process

PROCEDES, ENERGETIQUE

codirigée par « Leonids / BULIGINS

Challenges of Target and Irradiation Diagnostics of the IFMIF-DONES Facility

International audienceIFMIF-DONES will be a first-class scientific infrastructure consisting of an accelerator-driven neutron source delivering 1e17 n/s with a broad peak at 14 MeV. Such neutron flux will be created by impinging a continuous wave 125 mA, 40 MeV, 5 MW deuteron beam onto a liquid Li jet target, circulating at 15 m/s. Material specimens subjected to neutron irradiation will be placed a few millimeters downstream. Some of the most challenging technological aspects of the facility are the Diagnostics to monitor the Li jet, beam parameters on target, and characterization of the neutron irradiation field, with transversal implications in the scientific exploitation, machine protection and safety. Multiple solutions are foreseen, considering among others, Li jet thickness measurement methods based on optical metrology and millimeter-wave radar techniques, Li electromagnetic flowmeters, beam footprint measurements based on residual gas excitation, online neutron detectors such as SPNDs and micro-fission chambers, as well as offline neutron fluence measurements by activation foils or spheres. This contribution provides an overview of these aspects and the associated R&D activities