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The fuel cell is an electrochemical energy converter which converts the chemical energy from a fuel into electricity and heat and has been able to introduce itself as a source of clean power in the world over the past few decades. One of the major technical challenges in the development of PEM fuel cell technology is to achieve high and stable efficiency. One of the key parameters in designing this type of fuel cell is the shape and dimensions of reactors 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. Once the proper dimensions of the obstacle have been determined, different arrangements of the obstacle and their effect on the fuel cell efficiency are investigated, and the best arrangement is selected.

Fuel cells are the technology through which chemical energy can be converted to electricity and heat. They perform the conversion with no contamination. Hence, they have become a significant source of clean power in today's modern life. That being said, it is really crucial that every source of power provides a high and stable amount of efficiency, and it should be considered when it comes to developing PEM fuel cell technology as well. One of the most important parameters in applying such fuel cells is the layout and dimensions of the flow field designed for the reactors on the bipolar plates of the fuel cell and its improvement. In the current research, for the best geometry dimension and arrangement of obstacles, four types of obstacle including triangular, cylindrical, square and trapezoidal are simulated. The obtained results show that the triangular obstacle has the best performance in terms of the produced current density and pressure drop. The results reveal that at the constant voltage of 0.6 V, the current density in the flow field with triangular and square obstacles is increased more than 80% in comparison to cylindrical and trapezoidal types. Finally, the fuel cell with triangular and square obstacles as the optimum flow field is designed, manufactured and tested.