This subject is part of a long-standing collaboration (over 15 years) between Siemens Energy in Berlin and the AEEPT team from LAPLACE laboratory. With the experience gained 1-5 in the field of high voltage circuit breakers and the technological advances brought about by previous studies, Siemens Energy and the LAPLACE laboratory now wish to make progress in the field of vacuum arc circuit breakers. Siemens Energy is a key player in the field of electrical switchgear. In particular, the company develops medium and high voltage circuit breakers in SF6, a greenhouse gas whose use will be limited and banned in the coming years. One of the alternatives envisaged is to use vacuum arc interrupters. This type of device exists in the medium-voltage range 1 - 52kV but must be adapted to allow cutting at higher voltages The Plasma and Energy Conversion Laboratory (LAPLACE), headed by Oliver Eichwald, is a joint research unit of the Centre National de la Recherche Scientifique (CNRS), the Institut National Polytechnique de Toulouse (INPT) and the Université Toulouse 3-Paul Sabatier (UPS). Located on the campus of the Paul Sabatier University, LAPLACE hosts the highest concentration of research in Electrical Engineering and Plasma in France and covers the "plasma/materials/systems" continuum in an integrated manner. In particular, the Electric Arcs and Thermal Plasma Processes team at Laplace is specialised in the development of CFD models to describe the behaviour of electric arcs and thermal plasmas. This thesis is part of a long-term collaboration between industrial and academic partners with two members of the LAPLACE AEPPT team who will supervise the thesis with the intention of producing excellent scientific results.
The main objective of the thesis will be to set up a three-dimensional numerical model describing the plasma medium as a two-temperature fluid. A first model has already been developed within the team from User Defined Funcions of the Ansys Fluent software (developed in C language) and the PhD student will be able to use this base and improve it from a focused bibliography on the subject. Although this cutting technology has exists for many years, few works are present in the literature. However, the candidate will be able to benefit from the expertise of the team and of the industrial partner 1-5. Conduct of the thesis The thesis will be located at LAPLACE in Toulouse. The PhD student will be in close contact with his supervisors and the industrial partner. In particular, he/she will be responsible for presenting the progress of his/her work at meetings with the industrial partners, which will take place at least every six months. The thesis will start with a bibliographical review of the subject and the use of the CFD model already developed by the AEPPT team. From a physical point of view, depending on the level of intensity in the cell (and therefore of the current density) two regimes exist: one subsonic (current density greater than 3000 kA/m2), the other supersonic. Today, the existing model only describes the subsonic regime. The student will be responsible for improving the existing model in order that it describes both regimes and the transition between them. Other improvements resulting from the literature review may be considered. In this phase, the model will be applied to a simplified geometry in order to test its capacity to correctly transcribe the physical phenomena (temperature of electrons, ions, speed, pressure). A study of the influence of the parameters (intensity, dimensions of the electrodes, value of the magnetic field, etc.) will be carried out. In a second phase, once the model has been developed and validated with the experimental results available from the industrial partner and the literature, a real (more complex) geometry will be considered. Different shapes of electrodes will be studied as well as the movements of the electrodes in terms of spacing and rotation. 1F. Reichert, J.J. Gonzalez and P. Freton, “Modelling and simulation of radiative energy transfer in high voltage circuit breaker”, J. Phys. D: Appl. Phys. 45 (2012) 375201 (11pp) 2 J.J. Gonzalez, P. Freton, F. Reichert, D. Randrianarivao, “Turbulence and magnetic field calculations in high voltage circuit breakers, IEEE Transactions on Plasma Science, ID TPS5280.R1 (2012) 3 J.J. Gonzalez, P. Freton, P. Reichert, A. Pechanka, “PTFE vapor contribution to pressure changes in high voltage circuit breakers” IEEE Transactions on Plasma Science, vol. 43, Issue: 8, (2015). 4 A. Petchanka, F. Reichert, J.J. Gonzalez and P. Freton, “Modelling of deformation of PTFE nozzles in high voltage circuit breaker due to multiple interruptions”, J. Phys. D: Appl. Phys. 49 (2016) 135201 5 F. Reichert, A. Petchanka, P. Freton and J.J. Gonzalez, “Studies on the Thermal Re-ignition in SF6 High-Voltage Circuit-Breakers by means of Coupled Simulation” Plasma Physics and Technology journal, vol 2, ISSN: 2336-2626 (2015) 6 E. Schade and D. L. Shmelev, Numerical Simulation of High-Current Vacuum Arcs With an External Axial Magnetic Field, IEEE Trans. Plasma Sci. 31, 890 2003Web site for additional job details
https: // emploi.cnrs.fr/Offres/Doctorant/UMR5213-STETRI-020/Default.aspxRequired Research Experiences
Engineering: Master Degree or equivalent
Chemistry: Master Degree or equivalent
Physics: Master Degree or equivalent
FRENCH: BasicContact Information