Evaluation of temperature distribution and heat transfer in fixed-beds through particle-resolved and effective homogeneous CFD approaches

• Heat transfer analysis in fixed-bed reactors through CFD simulation. • Using experiments to derive thermal conductivity of particle and particle packing. • Temperature distributions from PRCFD models and experiments show good agreement. • Modified homogeneous CFD model aligns well with PRCFD for heat transfer analysis. Thermal management in fixed-beds reactors is crucial for many industrial applications, including Power-to-Gas (PtG) technology. Computational Fluid Dynamics (CFD) is a key tool for tackling this issue. This study employs Particle-Resolved CFD (PRCFD) and effective homogeneous CFD models to evaluate the temperature distribution within packed particles in fixed-beds of varying diameters, thereby assessing their respective capabilities in predicting heat transfer performance inside the beds. A nitrogen cooling is selected for experimental validation, and the experimental data are also used to derive the thermal conductivity of the unknown particle, which serves as a key parameter for defining the simulation boundary conditions. Results show that PRCFD aligns well with experimental temperature profiles, also indicating that an increased ratio of bed-to-particle diameter reduces the heat transfer capacity of particle stacking. Compared to the effective homogeneous CFD model with a fixed porosity, the effective homogeneous CFD model modified with porosity distribution calculated in Blender, provides results close to PRCFD, within acceptable deviation for temperature distribution at reactor scale. This highlights that the effective homogeneous CFD model considering porosity distribution serves as a compromise for heat transfer analysis between the accuracy of gas–solid conjugate heat transfer captured by PRCFD and the computational efficiency of a fully homogeneous model.