IVAN KORKISCHKO
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Artigo IPEN-doc 28365 Three-dimensional CFD modeling of H2/O2 HT-PEMFC based on H3PO4-doped PBI membranes2021 - PANESI, A.R.Q.; SILVA, R.P.; CUNHA, E.F.; KORKISCHKO, I.; SANTIAGO, E.I.A complete non-isothermal model of a HT-PEMFC setup using a PBI/ H3PO4 membrane was developed, modeled, and solved using COMSOL Multiphysics. Polarization curves were simulated and compared to the corresponding experimental data. In this work, a serpentine flow field and an active area of 5 cm2 have been implemented in a computational fluid dynamics (CFD) application. The model predicts water vapor transport, mass concentration of H3PO4, temperature, and membrane current density distribution. In this model, the anode feed is pure hydrogen, and oxygen is introduced at the cathode side. The heat transfer model was coupled with the electrochemical and mass transport; a particular heating configuration is investigated for temperature distribution, emphasizing the membrane. The models showed consistency and were used to investigate the behavior of H3PO4 concentration and all transport characteristics. The concentration of phosphoric acid decreases with increasing temperature and relative humidity and the diffusive flux of water vapor increases with the decrease of the operating voltage. Two different configurations of inlet and outlet flow channels were analyzed and the results were compared.Artigo IPEN-doc 27739 Performance analysis of a water ejector using Computational Fluid Dynamics (CFD) simulations and mathematical modeling2021 - MARUM, VICTOR J. de O.; REIS, LIVIA B.; MAFFEI, FELIPE S.; RANJBARZADEH, SHAHIN; KORKISCHKO, IVAN; GIORIA, RAFAEL dos S.; MENEGHINI, JULIO R.A quasi-one-dimensional (1D) mathematical model coupled with Computational Fluid Dynamics (CFD) simulations of a water ejector is presented. Using data from CFD simulations, the mathematical model was used to calculate the friction loss coefficients of the ejector components, to predict its maximum efficiency point and to delimit its envelope of operation. The CFD approach was validated with experimental data and employed the finite element method to test the main turbulence models found in the literature (k-ε, k-u and k-u SST) for incompressible-flow ejectors. A set of operational conditions (OP) was tested and results show that the k-u SST turbulence model is the most suitable to capture the ejector flow characteristics in all OP. In addition, for higher entrainment ratio (M) values, it was observed a possible correlation between how well the boundary layer can be solved and how the model is able to capture the ejector efficiency curve. Moreover, for lower M values, another possible correlation may be stated between how the turbulence model is able to capture the velocity profile.Artigo IPEN-doc 26753 Modeling and parametric analysis of PEM fuel cells using computational fluid dynamics2019 - PANESI, RICARDO; BERUSKI, OTAVIO; KORKISCHKO, IVAN; OLIVEIRA NETO, ALMIR; SANTIAGO, ELISABETEThis paper presents a parametric investigation of PEMFC electrochemical models employing computational fluid dynamics (CFD) technique and aims to determine the relative importance of each parameter on the modeling results. A compatible and systematic mathematical model is developed in order to study the effect of these parameters. The model is applied to an isothermal, steady state an single phase to observe the main results by a polarization curve. The results compare well with the experimental polarization data obtained at 80 ºC for ohmic and activation regions. The best match with the experimental data is obtained when the specific active surface area of the catalyst layer is 700 cm2/mg and electrolyte conductivity of 8 S/m.Artigo IPEN-doc 23187 CFD analysis of PEMFC flow channel cross sections2017 - PAULINO, A.L.R.; CUNHA, E.F.; ROBALINHO, E.; LINARDI, M.; KORKISCHKO, I.; SANTIAGO, E.I.This paper presents a study of single-channel proton exchange membrane fuel cells (PEMFCs) using computational modeling and simulation. For this analysis, the commercial software COMSOL Multiphysics was used to build a single-phase isothermal and tridimensional fuel cell model. For the mathematical description of the catalyst layer, the flooded agglomerate model was implemented, and it proved to be more accurate than Butler-Volmer model, which is the pre-built model in the software. Such evidence was verified when comparing the polarization curves obtained using both models with an experimental curve. After definition of the model, the main objective of this study was to analyze the influence of the flow channel cross-section in the water distribution inside the cell, studying rectangular, trapezoidal and hybrid stepped geometries. The fuel cell with stepped channel was equivalent to the trapezoidal cell in all aspects analyzed, and both provided superior water management than the rectangular cell. However, the current generation in the rectangular design was slightly higher. It was noted that the simulation of a tridimensional model provided a better understanding of the regions where higher concentrations of water can occur, and that different flow channel designs can be used to enhance water management.