The simulation of monolithic microreactors poses unique challenges, which are typically addressed by the use of specialised codes and solvers that are tightly coupled with one another. Various numerical methods and discretisation schemes may be employed in resolving the involved physics. This demands a flexible and high-performance coupling framework that can integrate diverse solvers. Here, we employ the preCICE library for external coupling, verifying our implementation for microreactor analysis involving diffusion neutronics and heat conduction in both steady-state and transient conditions. We study the accuracy and performance of the library; first in an idealised finite-volume to finite-volume coupling, and then in a hybrid finite-element to finite-volume application. In the former, we obtain near-exact agreement between the preCICE -coupled approach and an internally-coupled multiphysics solver. Meanwhile, the basic performance overhead from using preCICE is found negligible. We also test available high-order mesh mapping and acceleration algorithms, which are found to yield significant improvements in accuracy and computation speed. For the hybrid coupling, we obtain good agreement with a reference solution, and show that the third-order discretisation enabled by FEM neutronics yields a substantial performance gain over the second-order FVM-based reference solver—justifying the code-agnostic approach. • Novel application of preCICE to high-resolution volume-coupled reactor analysis. • Benchmark of preCICE -based external coupling vs. internal coupling in OpenFOAM. • Evaluation of high-order mesh mapping and acceleration algorithms offered by preCICE . • Hybrid FEM–FVM coupling and measurement of speed-up relative to purely FVM analysis.
Tovar et al. (Thu,) studied this question.