The volume of fluid method is used to investigate the behavior of a liquid water slug in a PEMFC trapezoidal gas channel(GC) with a open angle of 60 degrees. To evaluate the effect of the contact angle of the top and side walls, the gas diffusion layer water coverage ratio(GWCR) and water volume fraction(WVF) in a inspection control volume are analyzed. As the contact angle increases, GWCR increases and WVF decreases. The cases with the GC contact angle of 60 and 80 degrees show the more favorable water removal characteristics compared to the other cases in a GC flooding condition.

In a PEMFC gas channel with a trapezoidal cross-section, the effect of air and water inlet velocities on water removal characteristics is numerically studied via the volume of fluid(VOF) method. When the channel wall contact angle is 60 degrees, the air inlet velocities higher than 2.5 m/s are advantageous to obtain lower GDL surface water coverage ratio(WCR). The WCR increases as the wall contact angle increases to 90 or 120 degrees due to the relatively lower surface tension force. In overall, WCR decreases as the air inlet velocity increases and WCR increases as the water inlet velocity increases.

The water removal characteristics in a PEMFC trapezoidal gas channel are investigated with the volume of fluid (VOF) method. For the case of wall contact angle of 60 degree, liquid water attaches on the top wall and moves toward the exit. In contrast, liquid water moves along the channel side corner or GDL surface irregularly for the higher wall contact angles. The hydrophillic wall contact angle of 60 degrees provides more favorable diffusion of reactants to cathode reaction sites as the GDL surface water coverage ratio approaches zero even if the water flow rate increases.

The effect of PEMFC trapezoidal channel wall contact angle on water removal characteristics is investigated with the volume of fluid (VOF) method. Two different contact angles 60 and 90 degrees are selected. In the case of the side and top wall contact angle of 60 degrees, stable semi-spherical droplets move along the top wall slowly. In contrast, complex shaped droplets move along the lower edge in the case of 90 degrees. Moreover, it is shown that very complex interaction patterns between different droplets which introduced into the channel at different times.

The lattice Boltzmann method (LBM) is applied to study the behavior of liquid droplet inside a PEMFC gas channel. To validate the fluid-fluid interaction model, the relationship between the pressure jump across the interface and the bubble radius is investigated for a static bubble to confirm the Laplace’s law. To evaluate the fluid-solid interaction model, static contact angle is calculated by changing the interaction parameter. Also, a constant gravitational force is applied to study the temporal evolution of liquid droplet placed on the bottom wall in a three dimensional periodic channel.

The volume of fluid method is applied to study the effects of the gas channel wall contact angle on the removal characteristics of a water slug in a right angle PEMFC gas channel. While maintaining the same GDL surface contact angle, two different contact angle distributions on the control area in the corner region are compared via the water coverage ratio and water volume fraction. The water coverage ratios of the hydrophobic channel corner case mainly show smaller values than that of the hydrophilic case except around 27 ms. The water volume fraction of the hydrophobic corner case is supposed to drop down quickly around 27 ms due to the dynamic movement of the liquid water compared to the hydrophilic case. In overall, the hydrophobic corner case shows better water slug removal characteristics.

The volume of fluid (VOF) method is applied to study the effects of the gas channel cross-section shape on the removal characteristics of a water slug in a trapezoidal PEMFC gas channel. Two different open angles 50 and 60 degrees are selected to investigate the effect of cross-section shape on the behavior of a liquid water slug. In comparison to the 50 degrees case, the water slug is removed slightly faster for the 60 degrees case.

To study the effects of the gas channel wall contact angle on the behavior of a liquid water slug, numerical simulations are performed with the volume of fluid (VOF) method. Two different contact angle combinations on the side and top channel walls are selected. In comparison to the reference case, the water slug is removed faster when the hydrophobic contact angle is applied selectively in the corner section.

Numerical simulations of liquid water droplets interacting with gas channel walls in a polymer electrolyte membrane fuel cell are performed with the volume of fluid (VOF) method. To investigate the effect of channel wall wettability, the contact angles of gas diffusion layer (GDL) and the side/top walls are varied as 45, 90, and 140 degrees. Two different water injection inlet locations are selected to investigate the interactions of liquid water with the different gas channel walls. As the GDL contact angle increases, the GDL surface water coverage ratio and the water volume ratio decrease. When the water injection hole is located near the side wall, the GDL surface water coverage ratio decreases and the water volume ratio increases as the contact angle of the side and top walls decreases. In conclusion, the GDL surface water coverage ratio and the water volume ratio may compete with each other to determine the fuel cell performance.

The dynamic interaction of liquid droplets emerging from the gas diffusion layer surface is modeled to study the behavior of liquid water inside the gas channel of a polymer electrolyte membrane fuel cell with the volume of fluid (VOF) formulation. The surface contact angle of gas diffusion layer is varied as 45, 90, and 140 degrees. The air inlet velocity in the gas channel is varied as 5, 10, and 15 m/s. The water inlet velocity from micro pores is varied as 0.5, 1, and 2 m/s. As the contact angle increases, water coverage ratio increases. As the air inlet velocity and the water inlet velocity increase, water droplets move faster toward the channel exit as evidenced from the water front location plots. In summary, the hydrophobic wall contact angle and higher air/water inlet velocities provide better water removal characteristics.

In this paper, a three dimensional numerical analysis tool was applied to study the PEMFC performance characteristics. The porosity and electrical conductivity of GDL and CL as well as the relative humidity of anode and cathode channel gas were selected as simulation parameters. As the porosity of GDL and CL increases, current density and temperature increase because reactant gases diffuse well. As the electrical conductivity of GDL and CL increases, current density and temperature increase due to increased electron transfer rate. As anode relative humidity increases, current density and temperature increase. Unlike anode, current density and temperature increase when cathode relative humidity increases from 0 percent to 60 percent. Then current density and temperature decrease when cathode relative humidity increases from 60 percent to 100 percent.