ABSTRACT

The gas-water separator is an important auxiliary component of the hydrogen recirculation subsystem for the proton exchange membrane fuel cell (PEMFC) system. This study investigated three baffle separators with different structures used for a 75 kW PEMFC system by computational fluid dynamics (CFD) simulation and experimental validation. An Euler-Lagrange two-phase simulation model was established to investigate the gas-phase flow characteristics and the droplets trajectory and film distribution in separators. Moreover, an experimental bench was set up to test the overall performance of the separators. The results showed that the CFD model can predict the performance of the gas-water separator accurately. Through the comparison of air and mixed hydrogen, it was found that the density of the gas phase fluid has a great influence on the pressure drop. The local gas flow at the baffle bottom where the film fall directly is at high velocity in separator A, resulting in that the liquid film is broken easily to cause more fine droplets being entrained again into the outflow. Besides, thicker liquid film still formed in the top part of the separators A and B compared with separator C, which is not conducive for high separation performance. Thus, the separator C is preferred to be suggested for PEMFC systems.

抽象的

气水分离器是质子交换膜燃料电池（PEMFC）系统氢气再循环子系统的重要辅助组件。本研究通过计算流体动力学（CFD）模拟和实验验证，研究了用于75 kW PEMFC系统的三种结构不同的隔板分离器。建立了Euler-Lagrange两相模拟模型，以研究气相流动特性以及分离器中的液滴轨迹和膜分布。此外，建立了一个试验台来测试分离器的整体性能。结果表明，CFD模型可以准确预测气水分离器的性能。通过比较空气和混合氢，已经发现，气相流体的密度对压降具有很大的影响。膜直接下落的挡板底部的局部气流在分离器A中处于高速状态，导致液膜容易破裂，导致更多的细小液滴再次被夹带到流出物中。此外，与隔板C相比，在隔板A和B的顶部仍形成较厚的液膜，这不利于高分离性能。因此，对于PEMFC系统，建议使用隔板C。与隔板C相比，在隔板A和B的顶部仍形成较厚的液膜，这不利于高分离性能。因此，对于PEMFC系统，建议使用隔板C。与隔板C相比，在隔板A和B的顶部仍形成较厚的液膜，这不利于高分离性能。因此，对于PEMFC系统，建议使用隔板C。