Redesign for channel width to improve temperature distribution: Investigation of minimum guaranteed channel width effects

Abstract

Due to the high-temperature environment of solid oxide fuel cells (SOFCs), heat dissipation and uniform heat distribution within the cell are crucial for stable operation and prevention of degradation. In this study, instead of introducing obstacles increasing the average cell temperature, method for optimizing channel width is proposed to improve flow uniformity (Γ) and temperature distribution. The width calculation for redesign in this study is derived from the Hagen–Poiseuille equation and the Reynolds number formula. To prevent excessive variations in channel width and account for the unpredictable flow environment within the interconnect, a minimum guaranteed channel width (wmg) is incorporated. The optimization is evaluated using computational fluid dynamics simulations for the 1-inlet-1-outlet and 2-inlet-1-outlet configurations. The analysis considers varying mass flow rates (0.5m·, m·, 2m·, 4m·) and different current densities (6000, 8000, and 10000 A/m2) to assess these conditions' effects on wmg. Consequently, the Γ improves to 88–95 % across all operating conditions, leading to a more uniform temperature distribution near the edges and a reduction in the mean temperature of the positive electrode-electrolyte-negative electrode layer compared to the original model. Additionally, the optimal model is defined as 1-inlet-1-outlet configuration with wmg of 0.25 mm, ensuring uniformity over 80 % under all conditions. For optimal model, the power density considering blower input work is compared, resulting in up to approximately 7 % improvement in the net power density at concentration loss region. These results demonstrate that channel width redesign with wmg offers a novel solution for enhancing power density and temperature distribution in SOFCs.

Keywords

• Solid oxide fuel cell
• Internal manifold
• Optimization
• Channel width