Comprehensive 3D Multiphysics Model on Electrochemical Recovery of O2 from metabolic CO2 at the International Space Station (ISS)

The International Space Station (ISS) is presently equipped with an elaborate, heavy, and high-power consuming system that recovers approximately 50% of O2 from metabolic CO2 as part of the atmospheric revitalization (AR) at the ISS habitat. Future long-duration missions will require a more sustainable and efficient system capable of yielding a minimum of 75% O2 recovery to reach the self-sufficiency required for long-duration space missions beyond Earth’s low orbit. A Microfluidic Electrochemical Reactor (MFECR) technology development effort is currently underway at NASA Marshall Space Flight Center (MSFC) to not only increase significantly current O2 recovery efficiency, improving self-sufficiency on AR at the ISS habitat and future long-duration missions, but also reduce system complexity. The authors have developed and deployed a comprehensive 3D multiphysics model that thoroughly replicates the actual configuration and fluid/material domains of the MFECR. The coupled physics in this multiphysics model include multicomponent-multiphase electrochemical-driven reactions, non-ideal mass transport mechanism, free and porous flow, heat transfer, CO2 solubility on alkaline electrolyte, water condensation on porous medium, and DC electrical current generation along with Joule heating effect. This model is aimed to conduct qualitative benchmark on three different MFECR layouts, one without serpentine paths (plain) and two with serpentines leading to four and twelve paths respectively. Once experimental data is generated via a test matrix of 200 tests, the model will be validated to conduct MFECR process optimization and revalidate the qualitative benchmark on three different MFECR layouts.