# Multi-Physics Coupling of Rectangular Channels with Different Aspect Ratios in Solid Oxide Electrolysis Cells

## TL;DR

This study examines how different channel shapes in solid oxide electrolysis cells affect performance, finding that medium aspect ratios offer the best balance for various conditions.

## Contribution

The novel contribution is identifying optimal channel aspect ratios for different operational needs in solid oxide electrolysis cells.

## Key findings

- Low and high aspect ratio channels show higher maximum pressure drops compared to medium ones.
- Hydrogen mole fraction decreases as the channel's aspect ratio increases.
- Medium aspect ratio structures provide balanced electrochemical performance suitable for various conditions.

## Abstract

To explore the impact of the aspect ratio of the channels in the flow fields of solid oxide electrolysis cells on the performance of the cell, we developed three-dimensional models for cells with varying aspect ratios. Our findings revealed that channels with low and high aspect ratios exhibit higher maximum pressure drops, whereas those with medium aspect ratios have the lowest pressure drops. Additionally, the mole fraction of the hydrogen decreases as the channel’s aspect ratio increases. We also computed the polarization curves for SOEC operating under three distinct aspect ratio channels. Our results suggest that structures with low aspect ratios exhibit the poorest electrochemical performance, suitable only for brief operations at low current densities; medium aspect ratio structures exhibit a balanced performance, making them suitable for various operating conditions; and high aspect ratio structures are best suited for operations at high current densities. This study on selecting different aspect ratios aids in determining the optimal channel parameters for different operating conditions, ultimately enhancing the performance of solid oxide electrolysis cells.