Distributed and shared memory implementation of the multiscale two-phase flow model for analyzing water transport in fuel cells on HPC architectures: 15/03/2021 – 15/09/2021 (Prace project, Marenostrum (Barcelona Supercomputer)).

This project aims at the parallelization and testing of the numerical solver developed for modeling multi-phase flows inside different components of Polymer Electrolyte Membrane fuel cells (PEMFC). This solver constitutes a new module merged to KRATOS Multiphysics open-source code, the core of which is optimized for high performance computations with OpenMP/MPI architectures. The development of the new computational module is done as a part of the AMADEUS project (“Advanced Multi-scAle moDEling of coupled mass transport for improving water management in fUel cellS”) funded by the Spanish Ministry of Science, Innovation, and Universities granted within the framework of the competitive call for “research excellence”(reference PGC2018-101655-B-I00, website: https://www.cimne.com/webcimne/sigpro/Ficha.aspx?id=847). The project will be carried out by the AMADEUS research team composed by researchers of the Polytechnic University of Catalunya (UPC) and the UPC-based research centre CIMNE. The newly developed solver to be tested and optimized on an HPC architecture utilizes the enriched finite element method to solve the conservation equations governing the multi-phase flow along with the level-set method to capture the evolution of the interface between phases. It is also complemented with the model for capturing liquid spreading on solid substrates which combines hydrodynamics (HD) and molecular kinetic theory (MKT) approaches for describing the contact line physics. So far, this solver has been applied to several benchmarks for surface tension dominated two-phase flows and the results were successfully compared with reference solutions and presented in a scientific journal paper [Hashemi et al., Comp. Met. App. Mech. Eng. 370 (2020): 113277] and presented in World Congress on Computational Mechanics (WCCM-ECCOMAS 2020, Paris) and Advanced Problems in Mechanics conference (APM-2020, Saint-Petersburg). The aim of the present project (Type B PRACE) is to perform further tests and optimizations in order to prepare the developed solver for executing the ultimate application cases on supercomputing facilities utilizing the distributed memory architecture. We strive to address the performance bottlenecks associated with the unevenly distributed computational load in the domain, which is arised from the numerical implementation of the physical conditions at the liquid-gas interface and liquid-gas-solid contact line. The simulation cases to be executed within the present project will involve the analysis of the dynamics of sessile micro-droplets on solid substrates. The ultimate case to be solved using the optimized solver is the liquid water/air transport phenomena in a real diffusion layer of a PEMFC.