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过程工程学报 ›› 2023, Vol. 23 ›› Issue (12): 1627-1636.DOI: 10.12034/j.issn.1009-606X.223096

• 研究论文 • 上一篇    下一篇

流固耦合对微尺度下气体扩散层液态水流动的影响

王杰敏1， 张赛1*， 王庆泰1， 王宪军2   

  1. 1. 昆明理工大学机电工程学院，云南 昆明 650500 2. 华能澜沧江水电股份有限公司集控中心，云南 昆明 650214
  • 收稿日期:2023-04-03 修回日期:2023-05-30 出版日期:2023-12-28 发布日期:2024-01-01
  • 通讯作者: 张赛 sai_zh@163.com
  • 基金资助:
    云南省科技厅青年基金项目“基于分形理论的多孔材料热质传递系数与热-质全耦合数学模型”

Effect of fluid-structure interaction on liquid water flow in gas diffusion layer at microscale

Jiemin WANG1,  Sai ZHANG1*,  Qingtai WANG1,  Xianjun WANG2   

  1. 1. College of Mechanical and Electrical Engineering, Kunming University of Science and Technology, Kunming, Yunnan 650500, China 2. Central Control Center of Huaneng Lancang River Hydropower Co., Ltd., Kunming, Yunnan 650214, China
  • Received:2023-04-03 Revised:2023-05-30 Online:2023-12-28 Published:2024-01-01

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摘要： 提出了一种重构碳纤维气体扩散层(GDL)微观结构的新方法，用于研究粗糙孔隙通道内速度场对GDL渗流量的影响。利用粗糙元和分形理论得到GDL内部孔隙通道随机分布模型，通过区分通道壁面亲/疏水性，得出了弥散速度占比、滑移增强系数、黏性增强系数和微尺度效应增强系数四种参数，并以此作为控制因素重构更加准确的内部速度分布，结合Darcy定律得到有效渗流系数模型。对GDL孔隙通道内部液态水的流动过程进行模拟，分析了不同粗糙度和接触角对液态水传输性能的影响。研究结果表明，孔隙通道粗糙元随机分布和不均匀流固耦合作用影响扩散层内部弥散速度、黏性、滑移速度的分布，四种控制因素共同作用于液态水的流动过程并促进液态水排出；相同粗糙度情况下，接触角为0o~180o时，亲水壁面滑移效应的促进作用大于弥散效应和黏性的抑制作用的程度逐渐增加，疏水壁面滑移效应的促进作用大于弥散效应和黏性的抑制作用的程度逐渐减小，流量变化曲线的斜率先显著增加后逐渐减小。新建立的扩散层内部液态水有效渗流系数模型可准确描述GDL内部液态水的流动规律，对GDL内部水管理具有一定的指导意义。

关键词: 微尺度, 滑移效应, 流固耦合作用, 分形, 气体扩散层, 传质

Abstract: This work presents a new method to reconstruct the microstructure of carbon fiber gas diffusion layer (GDL), which is used to study the effect of velocity field in rough channels on GDL seepage. The random distribution model of pore channels in the diffusion layer is obtained by using the rough element and fractal theory. By distinguishing the hydrophilicity/hydrophobicity of the channel wall, four parameters, namely, the dispersion velocity ratio, the slip enhancement coefficient, the viscosity enhancement coefficient, and the microscale effect enhancement coefficient, are obtained. With accurate internal velocity distribution reconstructed as a control factor, and the effective seepage coefficient model is obtained by combining Darcy's law. The flow process of liquid water in GDL duct is simulated, and the influence of different roughness and contact angle on liquid water transmission performance is analyzed. The results show that the distributions of dispersion velocity, viscosity and slip velocity in the diffusion layer are affected by the random distribution of channel roughness elements and the non-uniform fluid solid interaction, and the four control factors act together on the flow process of liquid water and promote the discharge of liquid water. Under the same roughness, when the contact angle is 0o~180o, the promotion of hydrophilic wall slip effect conteracting the inhibition of dispersion effect and viscosity increases, and the promotion of hydrophobic wall slip effect conteracting the inhibition of dispersion effect and viscosity decreases, and the slope of flow change curve increases significantly at first and then decreases gradually. The newly established effective seepage coefficient model of liquid water in the diffusion layer can accurately describe the flow law in GDL, which has certain guiding significance for the internal water management of GDL.

Key words: microscale, slip effect, fluid structure interaction, fractal, gas diffusion layer, mass transfer