Flow analysis of internal manifold-type SOFC stacks based on electrical capacity

To investigate flow uniformity within individual unit cells in internal manifold-type solid oxide fuel cell stacks with respect to electrical capacity and stack height variations, numerical analyses using computational fluid dynamics techniques were conducted on SOFC stack models with capacities of 1 kWe, 2 kWe, and 3 kWe. The results of these calculations reveal that while the inlet flow rate increases with an increase in the number of unit cells, the flow rate supplied to each unit cell remains largely consistent, resulting in a nearly uniform pressure drop in the core region. Nonetheless, the flow rate in the pipe and manifold regions increases proportionally to the inlet flow rate for 1 kWe, 2 kWe, and 3 kWe models, leading to a corresponding increase in pressure drop. Furthermore, the patterns of mass flow rate and pressure drop within unit cells are comparable. Particularly, the pressure drop within unit cell channels is primarily influenced by the pressure distributions in the outlet manifold regions. In summary, as the stack height increases, the uniformity of pressure and flow rate distributions among unit cells decreases. This effect is more pronounced in the cathode with a higher flow rate than the anode, and it has implications for achieving uniform flow rates while minimizing flow rates in individual unit cells.