Optimal Design of Hybrid Solar Heat and Power Systems for Industrial Processes
Industrial processes use heat in the 50-1500°C temperature range, and heat accounts for around 70% of industrial energy consumption. Heat consumption in industry is generally classified into three temperature ranges: low (400°C), which can be addressed by different solar collector technologies. Concentrating solar technologies are needed to produce solar heat at T>150°C. The central issue of integrating solar heat into industrial processes is addressed in the SHIP4D project (PEPR SPLEEN programme). As part of this postdoc, the work will focus on the optimal design of hybrid solar systems for industrial processes. To this end, the PERSEE internal code will be developed to address the problems of optimally integrating solar thermal and photovoltaic technologies for the production of heat and electricity on industrial sites or parks.. The work will also serve as a basis for the European INDHEAP project (Optimal Solar Systems for Industrial Heat and Power), coordinated by the CEA, and started in January 2024.
Exploring microfluidic solutions for manufacturing targets for fusion power generation
As part of a call for projects on "innovative nuclear reactors", the TARANIS project involves studying the possibility of energy production by a power laser-initiated inertial confinement fusion power plant. The current context, which encourages the development of low-carbon energies, and the fusion experiments carried out by the NIF's American teams, make it very attractive to conduct high-level research aimed at eventually producing an economically attractive energy source based on inertial fusion.
Among the many technical hurdles to be overcome, the production of fusion targets with a suitable reaction scheme compatible with energy production is a major challenge. The CEA has the know-how to produce batches of capsules containing the fusible elements of the reaction. However, the current process is not suitable for mass production of hundreds of thousands of capsules per day at an acceptable cost.
One high-potential avenue lies in the use of microfluidic devices, for which the Microfluidic Systems and Bioengineering Laboratory (LSMB) of the Health Technologies and Innovation Department (DTIS) of CEA's DRT has recognized expertise.
Study of the seismic behavior of piping systems using mechanical models of different degrees of fidelity
Piping systems are part of the equipment to which particular attention is paid as part of the safety review or design of nuclear installations. They are designed in accordance with codes, standards and regulations to withstand loads that occur or may occur over the life of a facility. These systems must therefore be designed to withstand accidental loads such as earthquakes. Feedback shows that piping systems generally behave well in the event of an earthquake. When failures are observed, they are more likely to be due to significant anchor movement, brittle materials, unwelded joints, corrosion, piping support failures, or seismic interactions. In practice, to be able to estimate the beyond design seismic behavior and the associated failure risks, the engineer can implement numerical models involving varying degrees of refinement depending on needs. This study consists of taking stock of the numerical modeling capabilities of piping systems under earthquake. For reasons of computational burden, global modeling based on beam elements is often favored, considering simplified material laws such as bilinear material laws with kinematic hardening. We know the “theoretical” limits of these models but it is difficult to have clear ideas about their real limits of applicability depending on the level of loading and the damage targeted. To make this assessment, we propose to interpret, using different numerical models involving different degrees of fidelity, the results of the experimental campaign carried out by the BARC and which was used for the MECOS benchmark (METallic COmponent margins under high Seismic loads).
Development of piezoelectric resonators for power conversion
CEA-Leti has been working to improve energy conversion technologies for over 10 years. Our research focuses on designing more efficient and compact converters by leveraging GaN-based transistors, thereby setting new standards in terms of ultra-fast switching and energy loss reduction.
In the pursuit of continuous innovation, we are exploring innovative paths, including the integration of piezoelectric mechanical resonators. These emerging devices, capable of storing energy in the form of mechanical deformations, offer a promising perspective for increased energy density, particularly at high frequencies (>1 MHz). However, the presence of parasitic resonance modes impacts the overall efficiency of the system. Therefore, we are in need of an individual with skills in mechanics, especially in vibrational mechanics, to enhance these cleanroom-manufactured micromechanical resonators.
You will be welcomed in Grenoble within a team of engineers, researchers and doctoral students, dedicated to innovation for energy, which combines the skills of microelectronics and power systems from two CEA institutes, LETI and LITEN, close to the needs of the industry (http://www.leti-cea.fr/cea-tech/leti/Pages/recherche-appliquee/plateformes/electronique-puissance.aspx).
If you are a scientifically inclined mind, eager to tackle complex challenges, passionate about seeking innovative solutions, and ready to contribute at the forefront of technology, this position/project represents a unique opportunity. Join our team to help us push the boundaries of energy conversion.
References : http://scholar.google.fr/citations?hl=fr&user=s3xrrcgAAAAJ&view_op=list_works&sortby=pubdate
Seismic behavior of an overhead crane
Overhead cranes are part of the equipment in industrial installations to which special attention must be paid. They are generally located in the upper part of buildings and are potentially subject to significant levels of acceleration in the event of an earthquake, due to the amplification induced by the supporting structure. Consequently, they are potentially subjected to significant forces and can be the source of significant forces on the supporting structure. This study is a continuation of two previous test campaigns carried out on the Azalée shaking table of the EMSI laboratory, on a mock-up of an overhead crane. It aims to provide validated numerical models of this kind of equipment. Two lines of research are considered. The first axis aims to complement the “historical” test campaigns with static tests to justify the adjustment of the numerical models. The second axis consists of exploiting, by comparison tests/calculations, all of the tests that were carried out as part of a previous test campaign for statistical analysis purposes.
Earthquake effect on underground facilities
The Industrial Centre for Geological Disposal (Cigeo) is a project for a deep geological disposal facility for radioactive waste to be built in France. These wastes will be put in sealed packages in tunnels designed at 500 meters depth. The seals are made of a bentonite/sand mixture which has a high swelling capacity and a low water permeability. As a part of the long-term safety demonstration of the repository, it must be demonstrated that the sealing structures can fulfill their functions under seismic loads over their entire lifetime. In order to guarantee this future nuclear waste repository, CEA and Andra are collaborating to work on the potential scientific and engineering challenges involved.
The responses of underground repository to earthquake events are complex due to the spatially and temporally evolving hydro-mechanical properties of the surrounding media and the structure itself. Accurate modeling of the behavior, therefore, requires a coupled multiphysics numerical code to efficiently model the seismic responses for these underground repositories within their estimated lifespan of 100 thousand years.
The research will therefore, propose a performance assessment for sequential and parallel finite element numerical modeling for earthquake analysis of deep underground facilities. Then perform a synthetic data sampling to account for material uncertainties and based on the obtained results in the previous assessment, run a sensitivity analysis using a FEM or a metamodeling process. Finally, the results and knowledge gained within the span of this project will be processed and interpreted to provide responses for industrial needs.
Multiphysics modeling of an experimental sintering furnace
In the scope of the development and improvement of the performance of low-carbon energy sources, the CEA has a software platform for modeling the behavior of nuclear fuel from its manufacture to its use in the reactor. Sintering, a key step in fuel fabrication is the heat treatment process used to consolidate and densify nuclear fuel to form the solid solution U1_yPuyO2-x. The sintering cycle generally comprises a rise in temperature with a linear ramp, a constant temperature plateau and a controlled cooling, with possibly a continuous adaptation of the oxygen potential through the oxidation-reduction buffer imposed by the H2 over H2O ratio of the carrier gas to reach the target oxygen-metal ratio. A first modeling of an industrial sintering furnace was carried out using the OpenFOAM software suite and the C++ finite elements library DIFFPACK. A second step aims to validate the models used in the simulation of this industrial furnace based on a separate effects approach and the modeling of a laboratory sintering furnace. This post-doctorate will be carried out at CEA Cadarache within the multiscale modeling laboratory (LM2Cà of the fuel studies department. This work will be carried out in close collaboration with the teams of experimenters from the Solid Chemistry and Actinide Materials Development Laboratory (LSEM) of CEA Marcoule who are developing and operating the experimental furnace. The collaboration will focus on the modeling input data (furnace geometry, temperature and atmospheric conditions) and the measurements to be compared with the simulation data. The post-doctoral student will evolve in a stimulating environment, within a dynamic laboratory where about fifteen doctoral and post-doctoral students are already working, in contact with experts in fuel physics modeling and in collaboration with experimenters. The work can be enhanced by presentations at conferences and the writing of articles.
Experimentation and numerical simulation of lithium battery thermal runaway
In the current Energy transition context, the lithium battery is an essential technology to address the strong challenge of the electrical energy storage. However, Li battery severe solicitations/loadings can lead to a thermal runaway phenomenon, which can cause an outbreak of fire, even an explosive combustion of the cell or of the whole battery pack. If this phenomenon is well known, the research and development dedicated to the battery safety is emerging and must be consolidated. The post-doctorate global objective is to develop a numerical modelling and simulation strategy for thermal runaway occurring when a Li battery is subjected to mechanical/thermal/electrical abuse, in order to gain an understanding of the phenomenon, estimate the thermal spreading risk as a result of gas combustion, or study the runaway mechanical consequences (fluid structure interaction). This strategy relies on physical testing campaigns carried out as part of the post-doctorate, and on numerical tools developed by CEA (EUROPLEXUS, Cast3M). The work will be organised into three main content areas: Understanding and modelling of the phenomena on the basis of experimental tests (shock tube, abusive tests), Development of a numerical model representative of identified phenomena, Modelling including fluid-structure interaction (case deformation due to pressure increase).
Wood modifications by supercritical CO2
In order to replace current high environmental impact construction materials, CEA leads research work on chemical functionalization of wood (from French local forests) to improve its properties and make them a viable substitute of these construction materials or imported construction wood.
In this frame, chemistry under supercritical CO2 appears to be an efficient way to carry innovative chemistries while liùmiting the environmental impact & VOCs emissions of such processes.
Thus, you will be in charge of the development of new processes of chemical modification of local wood species under supercritical CO2. You will lead the research project by perfroming the state of the art, making technical propositions (around the adapted functionalization chemistries), carrying out the eperiments & the characterizations and will be in charge of respecting the deadlines & redacting the associated deliverables.