A CFD S S T k − ω − k θ − ε θ four parameter heat transfer turbulence model for the 19-pin fuel assembly in LBE cooled reactors

Key findings from this study

• The study found that constant turbulent Prandtl number assumptions fail to capture the nonlinear local turbulent Prandtl number behavior in liquid lead-bismuth eutectic alloys.
• The researchers demonstrate that a four-parameter turbulence heat transfer model significantly improves prediction accuracy for heat and mass transfer in LBE compared to conventional approaches.
• The authors report that LBEHMTFoam, implemented as an OpenFOAM solver, successfully predicts thermo-hydraulic behavior in 19-pin fuel assemblies cooled by LBE.

Overview

This study develops a four-parameter turbulence heat transfer model specifically designed for liquid lead-bismuth eutectic (LBE) cooled fast reactors. Conventional turbulent Prandtl number assumptions fail for LBE because its local turbulent Prandtl number exhibits nonlinear behavior. The researchers systematized derivation of the four-parameter model and implemented it as a computational fluid dynamics solver called LBEHMTFoam based on OpenFOAM.

Methods and approach

The authors derived the four-parameter turbulence heat transfer model under constant heat flux boundary conditions. They developed LBEHMTFoam, a custom solver within OpenFOAM, to implement the model. Validation employed direct numerical simulation data from planar flow heat transfer cases. The model was then applied to 19-pin fuel assembly configurations in LBE and compared against established empirical correlations.

Results

Validation against DNS data for planar flow demonstrated improved prediction accuracy compared to conventional constant turbulent Prandtl number approaches. Heat and mass transfer simulations for the 19-pin fuel assembly showed favorable agreement with empirical correlations. The nonlinear turbulent Prandtl number behavior in LBE was successfully captured through the four-parameter formulation.

Implications

The LBEHMTFoam solver provides a computational tool capable of accurately predicting thermo-hydraulic coupled phenomena in LBE systems. This capability extends beyond heat transfer prediction to include coupled corrosion behavior assessment, which is critical for LBE reactor material compatibility. The model addresses a significant gap in existing tools, as constant turbulent Prandtl number assumptions systematically underestimate local heat transfer in LBE fluids.

The four-parameter approach represents a methodological advance in turbulent heat transfer modeling for liquid metal coolants with low Prandtl numbers. Accurate prediction of thermo-hydraulic coupled corrosion behavior is essential for advancing liquid metal cooled fast reactor design and material selection. The open-source implementation within OpenFOAM facilitates adoption by the broader fast reactor research community.

Scope and limitations

This summary is based on the study abstract and available metadata. It does not include a full analysis of the complete paper, supplementary materials, or underlying datasets unless explicitly stated. Findings should be interpreted in the context of the original publication.