Numerical Study of The Effectsof Liquid Water Accumulation In A Pem Fuel Cell Gas Channel
Fuel cells are a promising clean energy technology for use as a source of heat and electricity for buildings, and as an electrical power source for electric motors propelling vehicles. Water management is an effective way of improving Proton Exchange Membrane (PEM) fuel cell performance and durability. Changing the wettability of gas channel walls and gas diffusion layer (GDL) is an effective way of controlling water management in a fuel cell for its influence on liquid water dynamic behavior. Volume-of-fluid (VOF) numerical method is commonly used to study the two-phase flow in PEM fuel cell gas channels. The method is unique in the way it shows the interface of different phases in a multi-phase flow. In the current study, liquid water accumulation was investigated in a channel representative of a fuel cell gas channel under various operating and boundary conditions using the VOF method. The numerical work is carried out to investigate the effects of operating conditions on water saturation in the channel at steady state, time to reach steady state, and air pressure drop along the channel at steady state. Water saturation in the channel and the time to reach steady state were affected by the change of air velocity, the change in water velocity, and the sidewalls wettability. Water saturation in the channel decreased when air inlet velocity and wall contact angle were increased while it increased when water inlet velocity was increased.
Keywords - PEM Fuel Cell, Two-phase Flows, VOF Method, Water Accumulation