In present study, a numerical model is employed to investigate the effects of different operating parameters and channel geometry on the performance of membrane humidifier. Simulations are performed by a commercial CFD code and based on user defined functions. Three-dimensional counter-flow humidifier model for a gas-to-gas case is considered. Results show that an increase in porosity or permeability leads to better humidification. Moreover, increase in inlet temperature of dry and wet channels as well as inlet mass flowrate of water vapor would enhance humidifying process. On the other hand, by reduction in inlet mass flowrate of gas channel and thickness of the porous medium in membrane, better humidifier performance would be achieved. To investigate the geometric parameters, three different channel types including stepped, sinusoidal and zigzag are considered. It is found that stepped geometry has the best performance in humidifying.

中文翻译：

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PEM燃料电池系统平面多孔膜加湿器加湿过程的数值预测，以评估操作和几何参数的影响

在本研究中，采用数值模型来研究不同操作参数和通道几何形状对膜加湿器性能的影响。仿真是通过商业CFD代码并基于用户定义的功能执行的。考虑了气对气情况的三维逆流加湿器模型。结果表明，孔隙率或渗透率的增加导致更好的增湿。此外，增加干，湿通道的入口温度以及水蒸气的入口质量流量将增强加湿过程。另一方面，通过减少气体通道的入口质量流量和膜中多孔介质的厚度，可以实现更好的加湿器性能。为了研究几何参数，三种不同的通道类型包括阶梯形，考虑正弦曲线和锯齿形。发现阶梯状几何形状在加湿方面具有最佳性能。