Lattice-Based Boltzmann Simulation of a Two-Dimensional Heat Flow Involved in a Solid Oxide Fuel Cell with a Focus on Assessing Entropy Generation Depending on the Channel Shape

Abstract

A 2D numerical model has been created to simulate the gas flow in a porous hydrogen (H2) and air-fed solid oxide fuel cell (SOFC) and analyze the generation of entropy involved via the major key contributing factors. On this basis, flow, thermal, and mass transfers have been numerically handled with a validated lattice Boltzmann method (LBM), including flow channels that have an impact on the entropy generation assessment. Flow, thermal, and mass paths have been simulated throughout the SOFC. It turned out that the ohmic losses are largely predominant compared with those of the other factors (irreversibilities due to fluid friction, heat transfer, mass/chemical transfer, and activation). In addition, under equal current density, the partially obstructed anode channel exhibits lower entropy generation compared with the free (unobstructed) anode channel, thereby indicating higher heat and mass transfer performance. These findings indicate the modeling efficiency considered and the potential of the LBM approach to address the processes involved in a porous H2 SOFC. SOFCs directly convert chemical energy into electrical energy, with high efficiency, strong reliability, and low emissions. SOFCs have become attractive for automotive and aerospace industries due to their energy flexibility. The design of their channels directly affects heat and mass transfer capability and their output performance. For a better view of the thermal performance of any thermal system, aspects such as pressure drop and entropy generation must be considered in addition to heat transfer factors. Entropy generation analysis is one of the most used techniques to refine the SOFC design and investigate their performance. This can be achieved by modifying the anode channel. One option is to partially obstruct the channel with differently shaped obstacles. Further, the numerical simulations can provide a solid reference point for future CFD models and are relevant to thermal dynamics in these devices and chemical-to-electrical energy conversion industries.