Numerical and experimental study on designs and performances of multi-serpentine flow field with bend-area block for proton exchange membrane fuel cell

The geometric modification of the flow field is an effective measure to improve the performance of proton exchange membrane fuel cell (PEMFC) and the mass transfer ability of reactants. In this paper, serpentine channels with geometric parameters containing various blocks to generate gas forced convection at the U-bends are established and numerically studied. Setting blocks at different angles at U-bends has different effects at the corners, offering a more flexible and variable region of active gas diffusion in the vertical direction. The area of high vertical velocity is increased by the Angle-Height combination design with low pressure drop and uniform temperature distribution. It is demonstrated that a vertical velocity of 0.4 m s−1 can be achieved around the block in the 135° series with half-height corner blocks, proving the existence of the mass transfer enhancement. Subsequently, experimental testing is conducted to verify the feasibility of the optimized flow field. The experimental results support the trend of block height influencing cell performance, with a maximum power density increase of 3.4 %. Modifying the U-bend corner structure has proven to be an effective technique for improving the overall performance of PEMFC, which can serve an important guidance for future flow field design.