揭示PTFE表面覆盖在控制气体扩散层水含量的作用
Florian Wiesner1,2, James Woodford2, Mayank Sabharwal2
1Chemical Process Engineering, RWTH Aachen University, Forckenbeckstr. 51, Aachen 52074, Germany.
ACS applied materials & interfaces
|June 28, 2024
概括
新的算法模拟了气体扩散层 (GDL) 中的混合湿度,揭示了聚四乙烯 (PTFE) 含量如何影响和和气体运输. 增加PTFE可以改善气体扩散,同时保持水资源管理.
科学领域:
- 材料科学 材料科学 材料科学
- 化学工程是化学工程的重要组成部分.
- 计算机建模 计算建模
背景情况:
- 气体扩散层 (GDL) 需要疏水涂层,以实现最佳的气相和液相平衡,这对于燃料电池等应用中的大规模运输至关重要.
- 现有的数值模型通常通过假设均的材料特性来简化GDL,忽视了像聚四乙烯 (PTFE) 这样的疏水剂的特定影响.
研究的目的:
- 开发和验证新的混合湿度算法,用于预测多材料GDLs的行为.
- 调查不同聚四乙烯 (PTFE) 含量对GDL性能的影响,特别是毛细血管压力,和和气体输送.
主要方法:
- 介绍了两种混合湿度算法,这些算法考虑了接触角度和接近固体表面的位置,以确定孔尺度毛细血管压力.
- 将算法应用于微型计算机断层扫描 (μ-CT) 重建的SGL 39BA和随机重建的Toray 120C GDLs.
- 毛细管压力与和曲线的估计和气体扩散率的模拟.
主要成果:
- 混合湿度模型准确地预测了随着PTFE含量增加而降低和度,与实验数据保持一致.
- 该模型复制了Toray-120C GDLs的低和入侵特征,将PTFE覆盖与特定的湿行为联系起来.
- 增加的PTFE含量导致突破压力更高,突破和度降低,气体扩散率提高.
结论:
- 该研究强调了多材料湿模型对于准确模拟GDL性能至关重要.
- 在GDL中增加PTFE含量可以通过降低突破时的和度来增强气体运输,同时保持水资源管理能力.
- 建议进一步研究GDL和催化剂层内PTFE和离子体的详细分布.
相关概念视频
01:13Excess Pressure Inside a Drop and a Bubble
The shape of a small drop of liquid can be considered spherical, neglecting the effect of gravity. This drop can further be considered as two equal hemispherical drops put together due to surface tension. The forces acting on the spherical drop are due to the pressure of the liquid inside the drop, the pressure due to air outside the drop, and the force due to the surface tension acting on the two hemispherical drops.
01:22Surface Tension of Fluid
Surface tension is a fundamental property of fluids, occurring at the boundary between a liquid and a gas or between two immiscible liquids. This phenomenon arises from the cohesive forces between molecules at the fluid's surface, creating an effect similar to a stretched elastic membrane. Inside each fluid, molecules are equally attracted in all directions by neighboring molecules, but surface molecules experience a net inward force, resulting in surface tension.
Surface tension varies with...
Surface tension varies with...