Experimental and numerical investigation of obstacle effect on the performance of PEM fuel cell

Abstract

Fuel cells are an alternative energy technology that generates electric energy through the reaction between hydrogen and oxygen. These devices are particularly interesting due to high efficiencies relative to traditional combustion engines and low emissions, producing only heat and water as waste products. One of the key parameters in designing this type of fuel cell is the shape and dimensions of gas flow field channels on the bipolar plates. In this research, the obstacle is simulated by selecting the obstacle geometry in the channel path, and after choosing the best range (height), the best obstacle width is analyzed to have better performance. The simulation is done for the non-obstacle case and obstacles with 0.5, 1, 1.5 and 2 mm heights and 0.9, 1.8, 2.7 and 3.6 mm widths, respectively. The obtained results for PEMFC show that the height of 1.5 mm and the width of 3.6 mm have the highest impact on the fuel cell efficiency regarding species consumption, pressure drop and current density. Furthermore, for the best geometry dimension and arrangement of obstacles four types of obstacle including triangular, cylindrical, square and trapezoidal are simulated. Finally fuel cell with triangular and square obstacles as optimum flow field is designed, manufactured and tested. The results have shown that using a triangular obstacle at a voltage of 0.6 V, the current density is increased by more than 50% compared to unobstructed.