Browsing by Author "Liu, Syu-Fang"

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Current density analysis in a molten carbonate fuel cell unit with non-uniform inlet flow and high anode gas utilization
(2007-12-01)
Liu, Syu-Fang
;
Chu, Hsin-Sen
;
機械工程學系
;
Department of Mechanical Engineering
This study investigates the electrical performance of a planar molten carbonate fuel cell unit with cross-flow configuration when both the anode gas utilization gets higher and anode gas inlet flows are non-uniform. A software package in this study solves two-dimensional, simultaneous, partial differential equations of mass, energy, and electro-chemistry' without considering stack direction variation. The results show that the anode gas utilization increases with a decrease in the molar flow rate, and the average current density decreases when the molar flow rate drops. Additionally, non-uniform inlet profile of the anode gas will induce a happening of non-reaction area. This non-reaction area deteriorates the average current density and then deteriorates the electrical performance to -4%.
Effect of inlet flow maldistribution on the thermal and electrical performance of a molten carbonate fuel cell unit
(2006-10-27)
Liu, Syu-Fang
;
Chu, Hsin-Sen
;
Yuan, Ping
;
機械工程學系
;
Department of Mechanical Engineering
This study investigates the temperature and current density distributions in a molten carbonate fuel cell unit when the inlet flows of the anode gas and the cathode gas are mal-distributed in eight patterns. The two-dimensional simultaneous partial differential equations of mass, energy and electrochemistry are solved numerically. The results indicate that the maldistribution of anode and cathode gases dominates the current density field and the cell temperature field, respectively. Moreover, the non-uniform inlet flow slightly affects the mean temperature and mean current density, but worsens the distribution of temperature and current density for most maldistribution patterns. According to the results, the variations of the cell temperature in Pattern G and the current density in Pattern D are 12% and 37% greater than those in the uniform pattern when the deviation of the non-uniform profile is 0.25. Consequently, the effect of non-uniform inlet flow on the temperature and current density distribution on the cell plane is evident, and cannot be neglected. (c) 2006 Elsevier B.V. All rights reserved.
Effects of non-uniform inlet flow on the performance of a molten carbonate fuel cell stack
(2007-06-01)
Liu, Syu-Fang
;
Chu, Hsin-Sen
;
機械工程學系
;
Department of Mechanical Engineering
This study develops a quasi-three dimensional numerical method for analyzing three-dimensional temperature and cell voltage distribution in a ten-layer molten carbonate fuel cell. The authors consider the non-uniform profile as progressively increasing along the stacking direction, and assign it to the anode gas inlet or cathode gas inlet to form four kinds of patterns. Results indicate that the non-uniform molar flow rate of cathode gas obviously changes the temperature field of a molten carbonate fuel cell stack, and highest cell temperature occurs at the cathode gas exit in the layer with the lowest molar flow rate. Moreover, non-uniform anode gas in the stacking direction strongly affects cell voltage distribution in the molten carbonate fuel cell stack. Variation rate of average cell temperature and cell voltage among different layers along the stacking direction are 2% and 40%, apparently larger than the variation rate due to non-uniformity in the transverse direction in our previous research.