[en] In order to characterize an inductively coupled plasma torch used in refining of metallurgical silicon, we have developed a spectroscopic method based on absolute emissivity measurements and Abel inversion. This method permitted to measure the concentrations of atomic hydrogen and atomic oxygen, which are among the reactive species involved in the purification process. Assuming LTE, the temperature profiles are deduced from the emissivity of the Argon lines. The concentration of atomic oxygen is deduced from the intensity ratio O/Ar. The hydrogen concentration measurement has to take into account the Stark broadening and the Doppler broadening of the hydrogen lines. The comparison between experimental and simulated line profiles permits to determine this concentration. The method has been tested on 2 kW and 30 kW inductively coupled plasma torches at atmospheric pressure. The results show that the concentrations of atomic oxygen and atomic hydrogen can be measured with an accuracy of 25%. The main disadvantage of this method is that, using emission, it does not permit to measure the concentration in the 'cold' zone of the plasma, i.e. at the edges.

[en] Modelling of inductively coupled plasmas at atmospheric pressure has been developed for years, integrating fluid dynamics, electromagnetism and heat transfer. In this work, special attention has been devoted to radiation transfer. Two radiation models have been implemented: the net emission coefficient and the P1 model. These models have been run with different torch geometries and input powers. The parametric study shows that they are very sensitive to parameters such as the thermal and electrical conductivity of the gas and input power. The temperature distributions have been compared with the measurements available in the literature. The spectral P1 model is more accurate at the expense of the computing time. The radiative heat losses are below 5% in small torches such as those used in spectrochemical analysis, but can exceed 40% in large torches (40 mm diameter or more), becoming the main cooling mechanism

[en] The current study presents a magnetohydrodynamic (MHD) numerical model describing the performance of an annular linear induction electromagnetic pump (ALIP), and its validation using experiments issued in the framework of the ASTRID demonstrator project for Gen IV sodium-cooled fast reactor. Model bases are first presented theoretically in the form of a coupled non-linear MHD system (Navier-Stokes and Maxwell equations). The magnetic field in the pump inductor (without sodium) is derived analytically and used to validate the numerical model. The real pump is modeled numerically using stationary 2D axisymmetric CFD equations strongly coupled with electromagnetism (EM) using a user developed module solving induction equation in A-V formulation. Magnetic field distributions over the length of the channel are calculated and compared with the theoretical solution obtained analytically and with experimental data. The MHD cases were run at imposed flowrate in order to obtain the pressure developed by the pump, and plotted as a P-Q performance curve. These results give insight to MHD phenomena involved for different electric supply parameters (current and frequency). The PEMDYN experiment is presented as a scaled mock-up facility which aim is to validate the pump behavior and study the undesirable instable regimes for ASTRID secondary loop electromagnetic pump. Finally the first experimental points are compared to those obtained in simulations for the same working regime. (author)

[en] Measurement of the thermophysical properties of liquid metals is challenging because of their high chemical activity and high temperatures. The electromagnetic levitation allows one to hold the electrically conductive liquid sample containerless in an inert atmosphere in thermal equilibrium while measurements on the sample can be taken in a non-contact way followed by extraction of some thermophysical properties. Yet, the electromagnetic forces within the skin layer inside the sample cause convective flow of the liquid thus disabling the data extraction. A static magnetic field imposed over a sample is known to damp the convective flow. With these ideas, an experimental set-up with a DC magnetic field directed perpendicular to the gravity vector was constructed and first experiments were performed with liquid Ni and some other materials. In most of the experiments the instability of the levitated sample during a slow variation of the DC magnetic field was observed which is reported in the present article. (paper)