Postdoc M/F : High-Performance Computing for multi-physics simulations of solar receivers with fluidized beds

CNRS; France; On-site; EUR 36,000 - 48,000; Full time

Job summary

The PROMES-CNRS Laboratory invites applications for a postdoctoral researcher focused on high-fidelity modeling of wall-to-bed heat transfers in high-temperature solar receivers. The project aims to develop advanced simulations bridging experiments and simulations using the LBM-based waLBerla framework with DEM for particles and CFD for gas.

You will model radiative heat transfer between particles and walls, account for complex particle shapes, and enable large-scale simulations on CPU clusters

Qualifications

• PhD in Fluid Mechanics, Computational Engineering, Thermal Sciences, or related field.
• Strong background in numerical methods, multiphase flow, and heat transfer.

Responsibilities

• High-Fidelity Simulations of Solar Receivers: Develop fully resolved simulations with waLBerla (DEM for particles + LBM for fluid).
• Multi-Physics Coupling: Investigate couplings between temperature, velocity, and two-phase flow in asymmetrically heated receivers.
• Scalability and Performance Optimization: Perform large-scale simulations (>10^6 particles) and optimize for exascale computing; collaborate with European partners.

Skills

Numerical methods (DEM, LBM, CFD)

Multiphase flow modeling

Heat transfer (conduction, convection,

High-performance computing (HPC)

Scientific programming (C++, Python, F

waLBerla / CFD tools

Particle-resolved simulations

Education

PhD in Fluid Mechanics, Computational Engineering, Thermal Sciences, or related field

Tools

waLBerla

OpenFOAM

Neptune_CFD

TrioCFD

Job description

Organisation/Company CNRS Department Laboratoire Procédés, Matériaux et Energie Solaire Research Field Mathematics History » History of science Researcher Profile First Stage Researcher (R1) Application Deadline 28 Oct 2026 - 23:59 (UTC) Country France Type of Contract Temporary Job Status Full-time Hours Per Week 35 Offer Starting Date 4 Jan 2027 Is the job funded through the EU Research Framework Programme? Horizon Europe Is the Job related to staff position within a Research Infrastructure? No

Offer Description

In solar receivers, solar radiation is concentrated on vertical tubes containing a gas-particle mixture, with the goal of heating particles to ~1000°C. However, current Euler-Euler (Two-Fluid Model, TFM) simulations fail to accurately predict wall-to-bed heat transfer coefficients, with discrepancies of up to a factor of 2 compared to experiments (e.g., 1200 W/(m²·K) vs. 600 W/(m²·K)). The complex physics involves:

• Multi-scale couplings (micrometric particles vs. meter-scale receivers).
• Radiative heat transfer between particles and walls.
• Collective particle phenomena (e.g., "packets" of particles).
• Complex particle shapes (flattened, sharp-edged) affecting hydrodynamics and heat transfer.

This postdoc will address these challenges by developing advanced simulations to bridge the gap between experiments and simulations. The multi-physics waLBerla framework is already capable of simulating particulate flows on large CPU clusters. In the project the challenge will be to extend and adapt the DEM simulation and the fluid coupling to particles of complex shape and taking into account of radiative heat transfers.

The postdoctoral researcher will contribute to the following key tasks:

1. High-Fidelity Simulations of Solar Receivers

• Develop fully resolved simulations using the waLBerla framework (DEM for particles + LBM for fluid).
• Model radiative heat transfer between particles and walls, as well as particle-particle radiation.
• Account for complex particle shapes (non-spherical geometries) and their impact on near-wall concentration and heat transfer.

2. Multi-Physics Coupling

• Investigate couplings between temperature, velocity, and two-phase flow in asymmetrically heated receivers.
• Study local phenomena (e.g., individual particle heating, gas property variations) and their impact on global receiver performance.
• Validate simulations against experimental data.

3. Scalability and Performance Optimization

• Perform large-scale simulations (>10⁶ particles) to capture collective phenomena (e.g., coordinated particle motion near walls).
• Optimize computational performance for exascale computing (CPU/GPU acceleration).
• Collaborate with FAU (Friedrich-Alexander-Universität Erlangen-Nürnberg) and other European partners.

The PROMES-CNRS Laboratory (Processes, Materials, and Solar Energy) invites applications for a postdoctoral position focused on high-fidelity modeling of wall-to-bed heat transfers in high-temperature solar receivers. This research is part of projects which aim to develop innovative concentrated solar power (CSP) technologies using gas-solid circulating dense fluidized beds as an alternative to traditional heat transfer fluids. The proposed work is part of the European project LBM4HPC: Lattice Boltzmann for Exascale. The project introduces a unifying abstraction layer specifically designed for the algorithmic structure and performance requirements of LBM-based solvers that decouples problem formulation from solver implementation and hardware-specific optimization.

PhD in Fluid Mechanics, Computational Engineering, Thermal Sciences, or a related field.

Strong background in:

• Numerical methods (DEM, LBM, CFD).
• Multiphase flow modeling (gas-solid flows, fluidized beds).
• Heat transfer (conduction, convection, radiation).

Experience in:

• High-performance computing (HPC) (MPI, OpenMP, GPU acceleration).
• Scientific programming (C++, Python, Fortran).
• Open-source or commercial CFD codes (waLBerla, OpenFOAM, Neptune_CFD, TrioCFD…).
• Particle-resolved simulations.