Experimental Analysis of Operating Modes Effect of Opend-end and Dead-end on Watermanagement in H2/O2 PEMFC Stack

The management of consumption the reactive gas in PEMFC is classified into three types: open-end, recirculation and dead-end. In dead-end mode, reactant gasses due to accumulating of water and inert gas should be purged alternatively. In this paper a PEMFC stack with transparent end plates and a unique design for investigation of water management is designed, manufactured and fabricated. In this paper, for the first time, the discussion of water management in a dead-end anode and cathode PEMFC stack with details of form and remove of water has been investigated. The results have shown that at the current density lower than 200 mA/cm2 the produced water is in the form of separate droplets and there is no film flow and slug flow of water in the channel. Also, as expected, the accumulation of droplets and film flow in the lower half was more than the upper half and therefore the reduction of the number of channels to increase gas speed and effective water removal in this part was essential. The results have shown that for steady-state operation, the maximum time possible for closing the output valves is 5 seconds and the minimum time required to open it is 5 seconds.