چكيده به لاتين
Polymer electrolyte membrane fuel cells thanks to lack of emission of harmful exhaust gases, short start up time and low operating temperatures have been considered by car makers as one of the alternatives for internal combustion engines. One of the issues that is discussed in the water management of this type of fuel cell is the two-phase flow analysis which is generated within the channel of the reactant gases, especially in high current densities. In addition, the rate of heat generation in the PEM fuel cell increases with increasing the current density (decreasing the fuel cell voltage), which poses a major challenge in the cooling of the PEM fuel cell stacks, especially the automotive fuel cell stacks that need high current density for high power density. The PEMFCs have an operating temperature of 60 to 80 oC. With considering the low temperature difference between the stack and the ambient, thermal management and optimal operation of the cooling system play a key role in optimal performance and durability of the fuel cell stack.
The present study was carried out by using a 3D non-isothermal two-phase model in ANSYS Fluent software. Initially, in this study, the effect of operating parameters such as relative humidity of the reactive gases, operating temperature, operating pressure and inlet air velocity on the cathode side were investigated on the performance of the fuel cell (polarization curve) and two-phase flow, and then in the thermal analysis of the PEM fuel cell, a cooling channel was added on the cathode side so that besides the cooling investigation, its effect on the two-phase flow is evaluated.
Based on the obtained results in this study, the operating pressure has the greatest effect on the two-phase flow within the channel of the reactant gases in the PEMFC and it has been observed that cooling also affects the two-phase flow analysis.
