Post-doc on 2D numerical simulation of perovskites/silicon heterojunction tandem solar cells
CEA-INES is looking for a post-doc to work on 2D simulation of perovskites/silicon heterojunction tandem solar cells. The candidate will have the responsibility to develop a model of the PK/SHJ tandem cell on the TCAD simulation package Silvaco. A realistic description of the materials will be implemented, based on in-house characterization of actual layers used (potentially performed during the post-doc), or based on literature. Then the focus will be set on the adjustment of the interface between the two sub-cells (so-called recombination junction, or tunnel junction). This model will afterwards be used to improve our understanding of the tandem cell working principle. In particular, inhomogeneity in layer properties, defects and there influence on cell efficiency will be investigated and brought face to face with experimental results. Finally, strategies to mitigate the influence of these defects will be defined to help the development teams to increase the device efficiency on large areas. For this post-doc position, the candidate needs solid background in semi-conductor physics, as well as previous record in working with simulation tools. He/She will need strong organization skills, and be willing to conduct theoretical work. The results will be published in peer-reviewed journals, as well as in conferences.
simulation of bi-metallic componants by 3D printing
This position will take place in the frame of MADE 3D European project. The objective of this is to build and run numerical simulations of bi-material L-PBF process taking account both thermal and mechanical behaviors. ANSYS© software will be used for this work. Numerical results will be compared to experimental results from Dedicated samples wich will be designed and manufactured by the post-doctoral student.
ACCELERATING a DSN SWEEP KERNEL ALGORITHM FOR NEUTRONICS BY PORTING ON GPU.
In the framework of the Programmes Transversaux de Compétences (PTC or literally Cross-XXX Programme), the DES/ISAS/DM2S/SERMA/LLPR and the CEA-DIF are both working on the porting of deterministic neutron transport codes on GPU.
The DM2S within the Energies Direction (DES) is responsible for research and development activities on the numerical methods and codes for reactor physics, amongst which the APOLLO3® code. The neutronics laboratory of CEA-DIF is responsible for developing tools for deterministic methods in neutronics for the Simulation programme.
These two laboratories are actively preparing for the advent of new generation of supercomputers where GPU (Graphical Processing Units) will be predominant. Indeed, the underlying numerical problems to be solved along with the working methodology as well as the conclusions and experience which will be obtained from such studies may be rationalised between both laboratories. Thus, this work has given rise to this postdoctoral position which will be common to both teams. The postdoctoral researcher will be formally based at SERMA at CEA Saclay, with nevertheless regular meetings with the CEA-DIF scientists.
The postdoctoral research work is to study the acceleration of a toy model of a 3D discrete ordinates diamond-differencing sweep kernel (DSN) by porting the code on GPU. This work hinges on porting experiments which have previously been carried by both teams following two different approaches: a ‘’high-level’’ one based on the Kokkos framework for DES and a ‘’low-level’’ approach based on Cuda for CEA-DIF.
Cascade of circulicity in compressible turbulence
In this post-doctorate, we propose to study the properties of the small scales of forced compressible homogeneous turbulence. More precisely, exact statistical relations similar to the Monin-Yaglom relation will be investigated. The idea, detailed in reference , is to understand how the transfer of circulicity is organized in the inertial range. Circulicity is a quantity associated with angular momentum and, by extension, with vortex motions. The analysis of its inertial properties allows to complete the description of the energy cascade already highlighted in previous works [2,3].
The objective of the post-doctorate is to carry out and exploit direct simulations of compressible homogeneous turbulence with forcing, in order to highlight the inertial properties of circulicity .
To this end, the post-doctoral student will be given access to the very large computing center (TGCC) as well as a code, Triclade, solving the compressible Navier-Stokes equations . This code does not have a forcing mechanism and the first task will therefore be to add this functionality. Once this task has been accomplished, simulations will be carried out by varying the nature of the forcing and in particular the ratio between its solenoidal and dilatational components. These simulations will then be exploited by analyzing the transfer terms of circulicity.
 Soulard and Briard. Submitted to Phys. Rev. Fluids. Preprint at arXviv:2207.03761v1
 Aluie. Phys. Rev. Lett. 106(17):174502, 2011.
 Eyink and Drivas.Phys. Rev. X 8(1):011022, 2018.
 Thornber et al. Phys. Fluids 29:105107, 2017.
HPC simulations for PEM fuel cells
The goal is to improve TRUST-FC software -a joint development between LITEN and DES institutes at CEA- for detailed full 3D simulation of hydrogene PEM fuel cells and to run simulations on whole real bipolar plate geometries. Funded by AIDAS virtual lab (CEA/Forshungs Zentrum Juelich), a fully coupled electro-chemical, fluidic and thermal model has been built, based on CEA software TRUST. The model has been benchmarked against its FZJ counterpart (Open fuelcell, based on OpenFoam). The candidate will adapt the software and toolchain to larger and larger meshes up to billion cells meshes required to model a full bipolar plate. Besides, he will introduce two phase flow models in order to address the current technological challenges (local flooding or dryout). This ambitious project is actively supported by close collaboration with CEA/DES and FZJ.