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

微尺度多孔材料液气两相流热水力学分析模型的开发

基本信息

批准号：
18560206
负责人：
MORI Hideo
金额：
$ 2.45万
依托单位：
Kyushu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2006
资助国家：
日本
起止时间：
2006 至 2007
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18560206/
关键词：
Microporous material liquid and gas two-phase flow Analysis model Fuel cell Diffusion layer

项目摘要

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

为了实现聚合物电解质燃料电池的利用和高性能化，开展了液气两相流通过微米级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，旨在在水、液体、空气和水蒸气两相流流经电极扩散层时得到以下结果： 1．基材和防水材料两部分由扩散层的孔体积分布数据确定每种基础材料和防水材料的空隙百分比。2.基于气体压降的测量确定每种基础材料和防水材料的绝对渗透率。单相流，.3.发现水分含量对气体单相流的压降几乎没有影响。4.基于液体和气体两相流的测量，相对的得出了微孔材料的液相和气相相对渗透率，与常用的Wyllie方程计算的值相比要低得多。 5．根据孔径分布数据估计各相的毛细管压力，可以很好地再现了接触角。 6．测量了每种基础材料和防水材料的接触角。 7．发现在基材和防水材料部分之间的边界处形成水的蒸发，并且由于基材部分的饱和度大而容易阻碍氧的扩散。此外，还表明，尽管基材部分。如果使防水材料的细孔分布接近于基材部的细孔分布，则能够减小部分的饱和度，因此，在高分子电解质膜中无法充分保持水分。