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首页> 外文期刊>International Journal of Heat and Mass Transfer >Non-isothermal melting of ice in the gas-diffusion layer of a proton-exchange-membrane fuel cell
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Non-isothermal melting of ice in the gas-diffusion layer of a proton-exchange-membrane fuel cell

机译：质子交换膜燃料电池气体扩散层中冰的非等温融化

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摘要

Non-isothermal ice melting in the fibrous gas-diffusion layer (GDL) of a proton-exchange-membrane fuel cell (PEMFC) is investigated using differential scanning calorimetry (DSC). Non-isothermal ice-melting rates and ice-melting times are obtained from heat-flow measurements in water-saturated Toray GDLs at heating rates of 1, 2.5, 5, 10, and 25 K/min. In all cases, ice-melting times decrease nonlinearly with increasing heating rate. Nevertheless, melting temperatures remain at 272.9 ± 0.5 and 272.7 ± 0.4 K for bulk ice and ice within the GDL, respectively, reiterating that melting is thermodynamic-based at a rate limited by heat transfer. The slight GDL ice melting-point depression is consistent with the Gibbs-Thom-son equation for equilibrium melting using an average pore diameter of 30 μm. Ice-melting endotherms are predicted from overall DSC energy balances coupled with a moving-boundary Stefan problem, where an ice-melting front within a GDL propagates with volume-averaged properties through an effective medium. Agreement between DSC experiment and theory is excellent. The proposed model accurately predicts ice-melting endotherms for Toray GDLs with two ice saturations and for bulk ice. Further, a pseudo-steady-state analysis obtains an analytical expression for ice-melting time, which is controlled by the time for heat addition to the propagating solid/liquid interface. Significantly, the new expression elucidates parameters controlling ice melting and allows for better design of both GDL materials and heating strategies to enhance the success of PEMFC cold-start.
机译：使用差示扫描量热法（DSC）研究了质子交换膜燃料电池（PEMFC）的纤维气体扩散层（GDL）中的非等温冰融化。非等温冰的融化速率和融化时间可通过在水饱和的Toray GDL中以1、2.5、5、10和25 K / min的加热速率进行热流测量获得。在所有情况下，冰的融化时间都随着加热速率的增加而非线性降低。尽管如此，散装冰和GDL中冰的融化温度分别保持在272.9±0.5和272.7±0.4 K，重申融化是基于热力学的，受传热限制。 GDL的轻微冰点熔点降低与使用30μm平均孔径进行平衡融化的Gibbs-Thom-son方程式一致。从整体DSC能量平衡与移动边界Stefan问题一起预测融冰的吸热，在该区域中，GDL中的融冰前沿以体积平均的方式传播通过有效介质。 DSC实验与理论之间的一致性非常好。提出的模型可准确预测具有两个冰饱和度的Toray GDL和散装冰的融冰吸热曲线。此外，拟稳态分析获得了融冰时间的解析表达式，该表达式由加到传播的固/液界面的热量的时间控制。重要的是，新表达式阐明了控制冰融化的参数，并允许对GDL材料和加热策略进行更好的设计，以增强PEMFC冷启动的成功率。

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    TJ. Dursch; G.J. Trigub; J.F. Liu; C.J. Radke; A.Z. Weber;

  • 作者单位

    Chemical and Biomolecular Engineering Department, University of California. Berkeley, CA 94720, United States,Environmental Energy Technology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States;

    Chemical and Biomolecular Engineering Department, University of California. Berkeley, CA 94720, United States;

    Chemical and Biomolecular Engineering Department, University of California. Berkeley, CA 94720, United States;

    Chemical and Biomolecular Engineering Department, University of California. Berkeley, CA 94720, United States,Earth Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States;

    Environmental Energy Technology Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

    Stefan; Melting; Fuel cell; Gas-diffusion layer; Differential scanning calorimetry; Ice;

    机译：斯特凡融化;燃料电池;气体扩散层;差示扫描量热法;冰;

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