Liquid water management is one of the key research topics for the development and commercialization of proton exchange membrane fuel cells (PEMFCs) as it greatly affects their performance and durability. Natureinspired designs show their prominent characteristics such as low pressure drops and effective fluid distribution. Those designs with branched configurations similar to leaves allow more efficient water management; therefore, provide better fuel cell performance than the conventional ones. The air-liquid water transport phenomena are studied for the first time for a leaf-like biomimetic flow field design with a channel configuration mimicking the branching of veins in leaves. The study is conducted using a 3D two-phase air-liquid flows transient numerical simulation. The simulation utilizes the volume of fluid (VOF) method to track the gas-liquid interface with the validated dynamic contact angle (DCA) model is implemented for better accuracy. The fundamental understanding of the liquid water transportation behaviors inside this type of biomimetic flow field is made. Observations such as the effect of the branching on the liquid water drainage could be used for the improvement of flow field designs. For the given boundary conditions, the liquid amount in the flow field becomes stable at 1.5 Â 10 À4 kg after the start-up time, while the pressure drop fluctuates about 3.25 kPa.
Novelty StatementA leaf-like biomimetic flow field is designed with a channel configuration mimicking the branching of veins in leaves. A 3D CFD multiphase numerical simulation utilizing the validated volume of fluid and dynamic contact angle method is employed for investigating the air-liquid water transport process. Pressure, water, and velocity distribution, and the effect of the branching on the liquid water drainage, which could be used for the improvement of flow field designs, are observed. K E Y W O R D S biomimetic flow field, flow field design, fuel cell, PEMFC, volume of fluid method