YANYAN "LAURIE" ZHANG
Ph.D in Mechanical Engineering, March, 2007
Advanced Materials and Technologies Laboratory
University of Connecticut

Presently with General Motors Fuel Cell Activities Research Center

 

1). Effects of Operating Parameters on the Uniformity of Current Density Distribution in Proton Exchange Membrane (PEM) Fuel Cells.

In the fuel cell, the variation of the current density increases the possibility of the damages due to sharp temperature and stress gradients on certain points. This project investigated the effects of the operating conditions on the uniformity of the current density distribution and identified the optimum operating conditions which led to the uniform current density distribution while maximizing the power density and minimizing anode stoichiometry. To this end, a two-dimensional PEM fuel cell modeling was developed. Systematic parametric studies were implemented to investigate the effects the operating conditions and the design windows were constructed to determine the optimum operating conditions.

2). Analysis and design on passive air breathing PEM fuel cell.

Passive air-breathing fuel cell is promising portable energy source as an alternative to dry-cell battery. The objective of this research is to investigate the performance of the passive PEM fuel cell and its stack under different operating conditions and different orientations with different geometry parameters. A two dimensional nonisothermal multi-components modeling with natural convection air supply was developed. The investigation of the performance of single passive fuel cell was completed by implementing parametric studies for the effects of operating conditions and studying temperature and species distributions across the cell under different orientations. The performance of the passive fuel cell stack is decided by a few factors including the geometry parameters and operating parameters. The effect of geometry parameters including the gap between the cells, the height between the stack and the bottom board and the length of the cell were investigated and the design window were created to determine the optimum design parameters under certain requirements for the stack.

3). Optimum porosity and catalyst loading distribution in the PEM fuel cell.

To improve the uniformity of current density distribution by choosing certain operating conditions is limited and thus less effective under certain conditions. A novel approach to improve the uniformity of the current density distribution is to change the structure or material properties of the cell. The objective of this project is to decrease the variation of the current density by investigating nonuniform porosity of the gas diffusion layer and nonuniform catalyst loading in the catalyst layer. The effects of the shape of the channel will be also investigated.

Publications

C-05-01: Y. Zhang, A. Mawardi, and R. Pitchumani, “Analysis and Design of Proton Exchange Membrane Fuel Cells For Maximum Power Density and Uniform Current Density Distritbution,” First European Fuel Cell Technology and Applications Conference , December 14–16, 2005, Rome , Italy .

J-06-06: [Abstract | Request Reprint] Y. Zhang, A. Mawardi, and R. Pitchumani, “Effects of Operating Parameters on the Uniformity of Current Density Distribution in Proton Exchange Membrane Fuel Cells,” ASME Journal of Fuel Cell Science and Technology, 3(4), pp. 464-476, 2006.

J-07-02: [Abstract | Request Reprint] Y. Zhang and R. Pitchumani, “Numerical Studies on an Air-breathing Proton Exchange Membrane (PEM) Fuel Cell,” International Journal of Heat and Mass Transfer, 50(23-24), pp. 4698-4712, 2007.

J-07-03: [Abstract | Request Reprint] Y. Zhang, A. Mawardi, and R. Pitchumani, “Numerical Studies on an Air-breathing Proton Exchange Membrane (PEM) Fuel Cell Stack,” Journal of Power Sources, 173, pp. 264-276, 2007.