Une méthode expérimentale d'évaluation globale du pompage d'un agitateur - application au mélangeur Maxblendtm en milieux newtonien et non-newtonien

Une méthode expérimentale permettant l'évaluation du pompage global d'un agitateur et basée sur la technique de décoloration a été développée dans cette étude. Actuellement, les méthodes expérimentales les plus utilisées pour déterminer localement le pompage d'un agitateur sont la vélocimétrie par image de particules (PIV) et la vélocimétrie laser (LDV), méthodes coûteuses et complexes. Cette nouvelle méthode proposée ici est simple d'utilisation, peu coûteuse et peut être utilisée afin de rapidement combler les manques dans la littérature relatifs aux effets de la géométrie de l'agitateur ou de la rhéologie du fluide sur le pompage généré par un système de mélange. Cette méthode a tout d'abord été validée en évaluant le pompage généré par des agitateurs bien documentés dans la littérature. Ces agitateurs sont une turbine Rushton à six pales (RT), une turbine à pales inclinées (PBT) et un hydrofoil à trois pales (HP). Ces agitateurs ont été testés en milieu newtonien. La capacité de pompage du Maxblend™ a par la suite été évaluée en milieu newtonien et non-newtonien, en régime transitoire et turbulent, puis comparée aux précédents agitateurs. Ainsi, si l'on considère la capacité de pompage normalisée par la puissance consommée, l'hydrofoil est l'agitateur le plus performant en turbulence complète (Nq*g = 2,8) grâce à sa faible consommation de puissance, suivit par la turbine à pales inclinées (Nq*g = 0,94), le Maxblend™ (Nq*g = 0,77) et finalement la turbine Rushton (Nq*g = 0,4). Cependant, le mélangeur Maxblend™ génère les meilleurs résultats en termes de temps de mélange sur la gamme complète de nombre de Reynolds testée. Finalement, la rhéologie du fluide ne semble que peu affecter les performances du mélangeur Maxblend™ en termes de temps de mélange et de capacité de pompage en régime transitoire et turbulent. En revanche, pour des nombres de Reynolds inférieur à 10, le Maxblend™ a généré des situations de mélange pathologiques avec le fluide non newtonien. Mots clefs: méthode expérimentale, capacité de pompage global, mélangeur Maxblend™, fluides newtoniens et non-newtoniens. ---------- This investigation introduces an experimental method to determine the macro pumping capacity of an impeller in a transparent vessel using a decolorization method, contrary to commonly used experimental methods such as Particle Image Velocimetry (PIV) and Laser Doppler Velocimetry (LDV). This new inexpensive and easy-to-use method can be employed to quickly fill the lack of data available in the literature about geometrical effects on the global pumping efficiency of an impeller. This method was first applied to three well-known mixing systems and a Newtonian fluid to assess its reliability and accuracy: a six blades Rushton turbine (RT), a pitched blade turbine (PBT) with four 45° blades, and a three-blade hydrofoil propeller (HP). The global pumping capacity of the Maxblend™ impeller is then evaluated for both Newtonian and non-Newtonian fluids and compared to the other impellers in the transient to the turbulent regime. As results, considering the global pumping number normalized by the power consumption (Nq*g), the hydrofoil appears to be the most efficient (Nq*g = 2.8) in the fully turbulent regime. However, in terms of mixing time, the Maxblend™ impeller shows the best results over the entire range of Reynolds numbers. Finally, the shear-thinning behavior of the non-Newtonian fluid used does not affect the Maxblend™ impeller pumping and mixing capacity for Reynolds numbers below 80. Keywords: experimental method, global pumping capacity, Maxblend™ impeller, Newtonian, non-Newtonian

Nuclear decommissioning: project management and leadership

Management and leadership for safety relate to managerial competencies necessary to develop, promote and sustain a safety culture and to set goals, lead others and manage knowledge and projects to enhance safety performance. The development of these competencies is needed to enrich and complement the predominant technical background and skills of engineers and/or managers involved in the nuclear sector and particularly in decommissioning and dismantling (D&D) projects. The recent recognition of the importance of managing for safety led the International Atomic Energy Agency (IAEA) to develop formal safety requirements that are now implemented by its member states. This includes the need to develop training and education for beginning- and mid-career managers with nuclear safety responsibilities and, considering the time frame of D&D projects, for future generations of managers. Training and education challenges are acute in all Instrument for Nuclear Safety Cooperation (INSC) and European countries, where managers need to develop knowledge and comprehensive safety-related competencies to run the D&D projects of nuclear facilities in a context where the generational change of managers in the nuclear field is happening fast. In 2016/2017 the IAEA and the European Commission (EC) developed a cooperative framework to jointly address a similar challenge related to operation and regulatory oversight of nuclear installations. The development of these projects was possible by funding from the European Union (EU) through its INSC instrument. The first project, led by the IAEA in 2017, was the development of a pilot school for safety leadership at the University Côte d\u27Azur (UCA), France. Encouraged by this success, the agency has since then developed the syllabus into a 2-week programme, still based on experiential learning, which is offered to IAEA member states who wish to organise sessions for their managers (regulatory bodies or industry). The second project, named ELSE, was operated by UCA and aimed to develop training to help managers acquire leadership for safety capabilities, which are key professional requirements in complex, high-risk and highly regulated sectors such as the nuclear sector. The originality of the ELSE project stemmed from its science-based approach, integrating the most recent findings of management and other social sciences. The dedicated ELSE training programme is composed of a massive online open course (MOOC), a 10 d of face-to-face training and an individually tutored project. Based on the success of these experiences, the EU decided to prolong these actions in the field of nuclear D&D, leading to the start-up, in 2023, of the Decommissioning Management and Leadership for Safety Education (DMaLSE) project. This project has also been entrusted to UCA, in partnership with SKEMA Business School, the Karlsruhe Institute of Technology (KIT) and Jacques Repussard Conseil. DMaLSE has two main objectives, namely to develop a science-based training programme for future D&D project managers and to extend the impact of the project through bachelor-degree-level on-site training for operators involved in D&D projects

Ethical Risk Management Education in Engineering: A Systematic Review

International audienc

Empowering Engineering Students in Ethical Risk Management: An Experimental Study

International audienc