Influence of pulsating flow on droplet flow characteristics in cathode channel of proton exchange membrane fuel cell using multiple-relaxation time lattice Boltzmann method

The production and discharge balance of water significantly affects the reaction efficiency and system stability of the proton exchange membrane fuel cells (PEMFCs). Efficient water management is crucial for improving PEMFC performance. In this paper, the two-phase and multiple-relaxation time lattice Boltzmann (LB) model is developed to investigate the influence of waveform, frequency, amplitude and temperature on droplet removal in cathode channel of a PEMFC. The droplet morphology is characterized by analyzing the dynamic coverage and height of the droplets. The results indicate that pulsating flow enhances droplet removal, with square wave flow being the most effective. Additionally, the efficiency of droplet removal improves as the frequency and amplitude of the pulsating flow increase. The dynamic behavior of droplets at 353 K and 296 K is compared, and the lower surface tension of the droplet at high temperature leads to a drastic morphological variation during purging, resulting in decreased efficiency of droplet removal. This study elucidates the mechanism of pulsating flow on liquid droplet removal in the channel and determines the influence of various pulsating flow parameters on this process. It provides valuable insights for enhancing the water management strategy of PEMFCs.