Effects of U-type and Z-type configurations on proton exchange membrane fuel cell stack performances considering non-uniform flow distribution phenomena

ABSTRACT

To investigate the proton exchange membrane fuel cell stack performance heterogeneity, a pseudo two-dimensional stack model integrating non-uniform flow distributions is developed. The frictional and local pressure drop losses in stack manifolds as well as detailed transport processes inside every fuel cell are considered. After being validated against experimental data under different tested conditions, effects of U-type and Z-type configurations, manifold cross-sectional area, and fuel cell number on stack performances are investigated. It is observed that the cell voltage consistency of U-type stack is significantly better than that of Z-type stack. Besides, smaller manifold cross-sectional area is required for the U-type stack, which contributes to the decrease of overall stack geometric dimensions. As the manifold cross-sectional area increases, the uniformity of cell voltage and reactant distribution improve obviously in both configurations. Meanwhile, temperature differences between U-type and Z-type configurations are significantly reduced, which mainly results from improved reactant flow distributions and enhanced performance homogeneity. For large-scale commercial stacks, it is inferred that the voltage distribution follows a decrease-increase trend in the Z-type stack while it is likely to follow a decreasing trend in the U-type stack.

KEYWORDS:

• PEMFC stack
• non-uniform flow distributions
• Z-type and U-type configurations
• manifold cross-sectional area
• voltage distribution trend

Nomenclature

Table

Acknowledgments

The study is supported by CATARC Key Research Project (No.19223402) and National Engineering Laboratory for Mobile Source Emission Control Technology (No. NELMS2019A10).

Disclosure statement

There is no conflict of interest.

Highlights

1. A pseudo 2D stack model integrating non-uniform flow distributions is developed.

2. The model is validated against experimental data under different tested conditions.

3. Cell voltage consistency of U-type stack is significantly better than Z-type stack.

4. U-type stack contributes to the decrease of overall stack geometric dimensions.

5. Stack configuration becomes vitally important for large-scale commercial stacks.

Additional information

Funding

This work was supported by the CATARC Key Research Project [No.19223402]; National Engineering Laboratory for Mobile Source Emission Control Technology [No. NELMS2019A10].