... was the main objective of the tests. Four crucial parameters for fuel cell operation were chosen; relative humidity (RH), temperature, pressure, and stoichiometry at varying current density. Furthermore, procedures for polarization curve recording were also tested both in ascending and descending current...

... the surface. In this way the CO desorption kinetic constant was calculated, regardless of other possible reactions taking place in the fuel cell anode compartment. The desorption of isotopic carbon monoxide was monitored at different relative humidity levels. As expected, relatively more 13 CO...

... corresponding to the inception of two-phase flow, called the threshold current density, is found to be a function of the channel length and height, GDL thickness, velocity, and relative humidity of the air at the inlet and cell temperature. Thus, for given design and operating conditions, the analytical model...

... were 2/5, 2/4, 2/3, 1.5/3.5, and 1.5/4. Once the spectra were recorded, the physical parameters (stack temperature of 65 ° C , stoichiometry rates, current) related to the durability test were set again and the aging experiment in low humidity conditions could immediately continue...

... when a small amount of water vapor was added to the air supplied to a cathode. Therefore, it is suggested that a moderate humidity in air supplied to a cathode may accelerate cathode reactions, while higher humidity causes voltage drop especially at lower operational temperatures. Water vapor...

... distribution of the entire module as well as of the oxygen concentration and relative humidity at a specific cell. Airflow near the cathode in a single cell was also visualized. It was concluded that the power breakdown was probably caused by flooding in the anode of one of the most downstream cells...

... as a function of temperature and humidity is proposed. To this end, the G’Sell–Jonas (1979, “Determination of the Plastic Behavior of Solid Polymers at Constant True Strain Rate,” J. Mater. Sci., 14, pp. 583–591) constitutive model for semicrystalline polymers is extended by incorporating, in addition...

... of 25 cm 2 with Nafion ® 117 membrane. Triple serpentine designs for the flow fields with two different flow depths were used in this research. The experimental results indicated that the relative humidity and temperature play an important role with respect to fuel cell performance. The fuel cell needs...

...Fabio Rinaldi; Renzo Marchesi The aim of this work is the performance study of a polimeric electrolyte membrane stack. Extreme conditions of temperature and relative humidity, such as those that may be found in practical situations (i.e., automotive), have been considered. The research has been...

... geometry test cell with serpentine channels and counter flow. Subsequently, the model is applied to explore cell temperature effects in the cell environment with different relative humidity of inlet. The numerical model is validated and agreed well with the experimental data. The nonuniformity of thermal...

... is useful in investigating the current density distribution in a single cell as well as a stack, which carries the information about the local reactant activity over the electrode area. It was found that the current density close to the gas inlets is strongly influenced by the reactants' relative humidity...

... and membrane Ohmic overpotential. Overall, good agreements between the simulated results and the experimental data were obtained. However, at large current densities, with high relative humidity reactant inputs, the simulation under-predicted the fuel cell performance due to the single-phase assumption...

... heat generation. In the anode channel, on the other hand, the phase change is less likely to occur even if the inlet hydrogen is humidified with a high relative humidity value. The model is partially validated using the experimental data from open literature. A series of analyses are carried out...

...-osmotic drag and diffusion depends not only on operating conditions, such as current density and relative humidity at the membrane boundaries, but also on design parameters, such as membrane thickness and membrane material. Computed water fluxes for different humidity boundary conditions indicate...