The 3 rd International Conference on Fuel Cell & Hydrogen Technology (ICFCHT 2011) 22-23 November 2011 Kuala Lumpur, Malaysia 1 DEVELOPMENT OF SINGLE CELL TRANSPARENT VISUALIZATION TEST RIG FOR TWO-PHASE FLOW ANALYSIS OF A PEM FUEL CELL * K.I.Sainan 1 , R.Atan 1,2 , W.A.NajmiW.Mohamed 1,2 , 1 Alternative Energy Research Centre, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia 2 Mechanical Engineering Faculty, Universiti Teknologi MARA, 40450 Shah Alam, Selangor, Malaysia *imransainan@salam.uitm.edu.my Tel: +60355436476 Fax: +60355435160 ABSTRACT A 96cm 2 transparent visualization test rig for single cell Proton Exchange Membrane Fuel Cell (PEMFCs) was developed and studied experimentally. The test rig allows clear visualization of flow field channels, making it practical to analyze two-phase flow and transport of reactants and products in that area. The development of the test rig is reported in detail. The flow field channels were manufactured using stainless steel materials with depths of 0.5mm for both anode and cathode. Both end plates were manufactured using 20mm thickness of transparent acrylic material. Limitations to manufacturing capability allow only two-pass serpentine flow field at the anode and six straight parallel channels at the cathode area. The experimentation were conducted with variations in air flow rates and humidification. The fuel cell performs relatively better under both reactant inlet humidification with larger air flow rates. Images of liquid water formation and behavior are presented graphically. Higher amount of liquid water accumulated at high current density at the end of channel exit compared to the channel inlet area. The voltage performance degrades when the reactants inlet were not humidified. The test rig data were compared with simulations results with good agreement. Keywords: PEMFC, Optical Photography Test Rig, Two-phase Flow, Water Management 1.0 Introduction Proton Exchange Membrane Fuel Cells (PEMFCs) operates at cellular and microscopic level which involves transportation of reactants into and product out from the system by means of convection force inside the intricate flow field passage and diffusion through a porous media of Membrane Electrolyte Assembly (MEA). A PEMFC utilizes hydrogen as the fuel at anode region and oxygen at the cathode region that chemically combines to generate electricity with water and heat as by- products. Principally, water is produced in gas phase; however at high current densities water molecules are formed at higher rates and eventually condenses into liquid, resulting in a two-phase flow condition. The liquid water need to be removed out of the fuel cell effectively or it will block the flow field channel passages, eventually reducing the amount of effective reactant transport. The lack of fuel and oxidant supplied to the system influences the power generated from the fuel cell especially at high current densities. Water management have two conflicting needs; high water molecules causes flooding inside the flow field channel, however less water leads to membrane dehydration .The inlet gases are normally humidified and combined with the water produced by the oxygen reduction rate (ORR) as well as water from electro-osmotic drag provides the necessary membrane humidified conditions. However, excess liquid water accumulation reduces the effective porosity of gas diffusion layer (GDL) by covering up the pores and blocking the active site in the catalyst layer, therefore, preventing oxygen diffusion and eventually lowering the electrochemical reaction rate.