Numerical study of a bamboo-like micro-tubular solid oxide fuel cell

Abstract

An innovative structure of segmented-in-series tubular solid oxide fuel cell, the bamboo-like optimized the current collection and achieve higher power density compared with that of the cell with the same axial length. In this study, a comprehensive three-dimensional (3D) numerical model of a bamboo-like micro-tubular solid oxide fuel cell (uT-SOFC) coupling the electrochemical reactions and mass, momentum, heat transfer processes and thermal stress, is developed by using the finite element method for the first time. Investigating the internal conditions under steady-state conditions to understand mass transfer, heat transfer processes, and mechanical states of the bamboo-like uT-SOFCs. The steam flow exhibits limited diffusion in the region of the anode at the internal end of the interconnector, creating a concentration gradient of H₂O that adversely affects the cell performance. The maximum mole fraction of H₂O in this region of two-cells and three-cells in series is increased by 185 % and 112 % respectively compared to the overall average of the cells. The interconnector shortens the current transmission path of the cells, and exhibits high current collection efficiency. This structure achieves a lower temperature while attaining higher power density compared to the same axial length cell at 973 K. The temperature of three-cells in series decreased by 3 K–5 K compared with two-cells in series. The thermal stress induced by the interconnector on the cells is minor, and the thermal expansion displacement caused by the interconnector is only approximately 7 μm–8 μm. This study revealed its internal conditions, and provides an insight into the bamboo-like structure.