Development of high performance and low‐cost solid oxide fuel cell stacks: Numerical optimization of flow channel geometry

Abstract

Summary Solid oxide fuel cell (SOFC) stacks with small volume and weight are essential to obtain higher specific and volumetric power densities as an alternative to conventional SOFC stacks with interconnectors having machined flow channels. This can be achieved by employing thin sheet interconnectors with flow channels formed by stamping methods rather than conventional machining of thick bulk materials. Besides the determination of process parameters providing defect free manufacturing of the desired channel design, the channel geometry is also significant for the cell performance. This study, therefore, focuses on the performance based parametric optimization of those flow channels in SOFCs by numerical simulations. In this respect, the effects of rib width, channel depth and rib angle on the cell performance are numerically investigated after the model validation with experimental results. The optimum rib width, channel depth and rib angle are determined to be 0.5 mm, 0.5 mm and 90°, respectively, within the parameter ranges considered in this study. In addition, the rib width is turned out to be the most effective parameter on the cell performance, while the cell performance almost remains unchanged for different channel depths.

Performance evaluation of a trapezoidal interconnector configuration of solid oxide fuel cell: A numerical study

“…The only attribute that changed is the channel configuration. Instead of a straight parallel channel, a taper of 75° is given to the vertical edge of the channels making it a trapezoidal channel with a wider channel width of 1.5 mm and narrow rib width of 0.5 mm 27 . The taper angle of 75° is chosen from the work reported by R. M. Manglik and Y. N. Magar, 28 where triangular channel, a trapezoidal channel with internal inclination angles ( θ ) of 60° and 75°, and rectangular channel were studied and it was reported that (a) As θ increases, the heat transfer or Nusselt characteristics increases from θ = 45° to 90° with a significant change observed when θ changes from 60° to 75° for a trapezoidal channel.…”

“…Instead of a straight parallel channel, a taper of 75 is given to the vertical edge of the channels making it a trapezoidal channel with a wider channel width of 1.5 mm and narrow rib width of 0.5 mm. 27 The taper angle of 75 is chosen from the work reported by R. M. Manglik and Y. N. Magar, 28 where triangular channel, a trapezoidal channel with internal inclination angles (θ) of 60 and 75 , and rectangular channel were studied and it was reported that (a) As θ increases, the heat transfer or Nusselt characteristics increases from θ = 45 to 90 with a significant change observed when θ changes from 60 to 75 for a trapezoidal channel. (b) The ratio Nu/fRe which was used as a measure of the relative surface-area compactness or increased convective heat transfer surfacearea density showed a drastic increase for θ = 60 to 75 after which the change is almost linear with an increase in θ up to 90 .…”