Development of an Analysis Model for Thermal Hydraulics on a Liquid and Gas Two-phase Flow through a Microscale Porous Material

为了实现聚合物电解质燃料电池的实用化和高性能化，针对含氧空气和水蒸汽的水液气两相流流经电极扩散层，进行了微尺度多孔材料的压降实验和行为观察，并基于物理模型进行了数值分析。得到以下结果.为了估算压降，需要将扩散层分为构成扩散层的基材和防水材料两部分，根据扩散层的孔隙体积分布数据，求出基材和防水材料各自的孔隙率.基于气体单相流的压降的测量，确定每种基础材料和防水材料的绝对渗透率。结果表明，含水率对纤维的强度几乎没有影响 关于我们 e气体单相流的压降。通过对气液两相流的测量，得到了气液两相的相对渗透率。与传统的Wyllie方程计算值相比，微尺度多孔材料的相对渗透率要低得多.根据孔径分布数据估算各相的毛细管压力，用Burdine方程较好地再现了基体和憎水部分的液相和气相相对渗透率.测量每种基础材料和防水材料的接触角。作为数值分析的结果，发现水的蒸发形成在基底和防水材料部分之间的边界上，并且由于基底材料部分的大饱和度，氧的扩散容易被阻挡。此外，表明尽管通过使防水材料的孔分布接近基部的孔分布可以使基部饱和度小，但是在聚合物电解质膜中保持足够的水分变得不可能。少

For utilization and high-performance of a polymer electrolyte fuel cell, experiments on pressure drop and observation of behavior were carried out for liquid and gas two-phase flow through a microscale porous material and beside a numerical analysis was performed based on physical model, aimed at the two-phase flow of water liquid and gas of air and steam containing oxygen which flows through an electrode diffusion layer. The following results were obtained.1. For the estimation of the pressure drop, it is necessary to divide the diffusion layer into two parts of base material and water repellent material constituting it. Percentage of void for each of base and water repellent materials was determined from pore volume distribution data of the diffusion layer.2. Absolute permeability was determined for each of base and water repellent materials based on measurements of the pressure drop of a gas single-phase flow,.3. It was found that there was almost no effect of moisture content on th … More e pressure drop of the gas single-phase flow.4. Based on measurements of a liquid and gas two-phase flow, relative permeabilities of liquid and gas phases were obtained. Then, relative permeability of microscale porous material was found to be quite lower compared with the value calculated by the Wyllie equation used well conventionally.5. Relative permeabilities of liquid and gas phases for base and water repellent parts were reproduced well by the Burdine equation with capillary pressure of each phase estimated from the pore size distribution data.6. Contact angle was measured for each of base and water repellent materials.7. As the results of numerical analysis, it was found that evaporation of water was formed on the boundary between base and water repellent material parts, and that diffusion of the oxygen was easily blocked due to large saturation of the base material part. In addition, it was shown that, although the base part saturation could be made small by bringing pore distribution of the water repellent material close to that of the base part, it becomes impossible to hold moisture sufficient in the polymer electrolyte film. Less