Study on Gas-Liquid Two Phase Flow in Polymer Electrolyte Fuel Cell

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Flow measurement techniques in a single cell channel were examined and the relationship between the supplied gas property and the fuel cell performance was investigated for technology development of Polymer Electrolyte Fuel Cell (PEFC). First, three types of single cell channel models simulating PEFC flow channels with different aspect ratios were manufactured, then pressure distribution along the internal flow channel was measured while inlet pressure and flow rate of supplied air were varied. As a result, it was found difficult to clearly separate the bend loss from the friction loss in the straight part of the channel by acquiring pressure data from a lot of measuring points on a straight line and a bend. However, it was found possible to evaluate the bend loss without any serious problems by acquiring pressure data from several measuring points located in the center of each straight line and by using a relatively accurate prediction formula for friction loss prediction. Second, a s … More ingle cell of PEFC with gas channels similar to those used in the aforementioned air flow measurement was manufactured, then generator performance was measured with air and hydrogen (in dead-end system) supplied. Varied parameters were air utility rate (20%-80%), with/without humidification, supplied gas pressure (50kPa, 100kPa). Air utility rate had the strongest influence on generator performance as far as the experiment was concerned. Generator performance, such as voltage, power and efficiency was higher in higher air utility rate, without humidification and in higher gas pressure. For further study, it will be necessary to investigate influence of other parameters on fuel cell performance as well as to clarify the performance dominating mechanism by measuring internal resistance in detail. On the other hand, it will be also important to measure internal flow while electricity is generated because a lot is still to be clarified in the flow behavior in the channel as seen in flooding. Less