燃料电池流道内液滴流动建模与分析

Modeling and analysis of droplet dynamics in gas channel of PEMFC

在燃料电池运行过程中,流道内液态水不能迅速排出将导致电堆进出口压差增大,性能下降,甚至失效。基于液滴存在于通道内造成的流速变化,建立了液滴流动的力平衡模型,推导了液态水累积极限半径。针对液滴累计过程的半径变化周期,对流道的进出口压差建立积分平均模型,获得液滴存在导致的通道进出口压差增长预测。采用两相流仿真验证模型合理性,通过模型分析了关键参数的影响。结果表明,由积水带来的压差提升效应在更深的流道中相对明显,随着流速和接触角的增加则呈先增大后减小的趋势。

During the PEMFC (proton exchange membrane fuel cell) operation, the accumulation of water will result in the increase of pressure drop, performance degradation and even the failure of the stack. A model of the droplet dynamics was established based on the flow velocity variation and the force balance condition. The accumulative maximum radius of water droplet was derived. According to the radius change period in accumulation process, the integral average model was established for the pressure drop of the gas channel. The growth prediction of the pressure drop caused by the liquid droplet was evaluated. The model was verified by two phase flow simulation and the influence of the key parameters was analyzed by the model. The results show that the effect of pressure drop caused by water accumulation is relatively obvious in deeper channels, and it increases first and then decreases with the increase of velocity and contact angle.