Local heat generation management for temperature gradient reduction in tubular solid oxide fuel cells

Reducing the temperature gradient in solid oxide fuel cells could improve their working stability. In this study, we have constructed a 2D-axisymmetric model to investigate the effect of the heat generation management on the temperature gradient reduction in a micro-tubular solid oxide fuel cell. The local heat generation is controlled by placing separators in the fuel channel, which could affect the fuel concentration distribution and the associated exothermic electrochemical reactions in the porous anode. We compared the electrochemical and thermal performance of the solid oxide fuel cells with tubular separators and flanged separators. We demonstrated both separators could effectively reduce the cell temperature gradient, but the flanged separator caused a more uniform temperature profile. A 25 mm long flanged separator could reduce the highest cell temperature gradient from 50 ℃/cm to 18.7 ℃/cm. The spatial temperature gradient diagram was proposed to evaluate the influence of different geometric parameters of the separator on its overall performance. It showed that the radius and length of tubular separators both affected the cell temperature profile while the length of flanged separators was the primary factor affecting the cell performance. This study helps improve our understanding about the thermal management of solid oxide fuel cells through the local heat generation control and build a foundation for the flow channel design.