Modular CFD Solver for Hydrogen Sulfide and Oxygen Transport: Implementation in OpenFOAM 11

Numerical modeling environments are subject to continuous evolution, leading to frequent software updates that often render custom solver modifications obsolete. This work presents the solver massTransferVoF, which is fully compatible with OpenFOAM 11. The solver describes mass transfer processes of hydrogen sulfide and oxygen across the water surface in two-phase flow simulations using a volume of fluid approach. The implementation process, challenges in maintaining backward compatibility, and the advantages of modular solvers over legacy structures are discussed. Validation results of three different test cases indicate that the new solver maintains consistency with previous implementations while offering access to new functionalities, improved maintainability and future- proofing for upcoming OpenFOAM versions.