考虑水膜结构的PEMFC团聚体二相流模型

Two-phase Flow Model of Proton Exchange Membrane Fuel Cell Based on Agglomerate Catalyst Layer with Liquid Water Membrane

液态水对催化层的影响是目前PEMFC的研究热点之一。团聚体模型是催化层研究中广泛采用的一种复杂模型,但目前的研究多集中在液态水对催化层孔隙率的影响,对团聚体模型的影响却很少。本文引入液态水对团聚体自身结构的影响,建立了能更加准确反映催化层结构参数影响的二维、气液二相变的阴极模型。计算分析结果显示液态水在团聚体表面形成水膜会阻碍氧气的扩散,从而导致在大电流密度(>5000A/m2)时,PEMFC极化曲线会快速下降,同时极限电流密度减小。

The effect of liquid water on the catalyst layer is one of the hot spots of PEMFC. The agglomerate model is widely used in complex models. However,the current research focused on the effect of liquid water on the porosity of the catalyst layer,but little impact on the agglomerate model. In this paper,the effect of liquid water on the structure of agglomerate is introduced,a two dimensional gas liquid two-phase flow with structure parameters of agglomerate catalyst cathode model is established. The results show that the water film that surrounding the agglomerate surface can hinder the diffusion of oxygen, which leads to the rapid decrease of the output voltage of PEMFC polarization curve at high current density（5000A/m2） and the limited current density will be drop.