multiRegionFoam -- A Unified Multiphysics Framework for Multi-Region Coupled Continuum-Physical Problems

TL;DR

multiRegionFoam is a flexible, modular framework within OpenFOAM for solving complex multi-region multiphysics problems, supporting various coupling methods and boundary conditions, demonstrated on heat transfer, multiphase flows, and fuel cells.

Contribution

The paper introduces a new, modular multiphysics framework in OpenFOAM that unifies multi-region coupling with flexible boundary condition formulation and coupling strategies.

Findings

Successfully implemented for conjugate heat transfer

Extended to multiphase flows and fuel-cell problems

Supports both monolithic and partitioned coupling methods

Abstract

This paper presents a unified framework, called multiRegionFoam, for solving multiphysics problems of the multi-region coupling type within OpenFOAM (FOAM-extend). It is intended to supersede the existing solver with the same name. The design of the new framework is modular, allowing users to assemble a multiphysics problem region-by-region and coupling conditions interface-by-interface. The present approach allows users to choose between deploying either monolithic or partitioned interface coupling for each individual transport equation. The formulation of boundary conditions is generalised in the sense that their implementation is based on the mathematical jump/transmission conditions in the most general form for tensors of any rank. The present contribution focuses on the underlying mathematical model for these types of multiphysics problems, as well as on the software design and resulting code structure that enable a flexible and modular approach. Finally, deployment for different multi-region coupling cases is demonstrated, including conjugate heat, multiphase flows and fuel-cells.