Modeling and simulation for PEM fuel cell performance optimization

在各种类型的燃料电池系统中，质子交换膜燃料电池（PEMFC）以其高效、设计简单、低温操作条件等优点而备受关注。由于基于实验的PEMFC设计迭代通常非常昂贵且耗时，计算机建模已成为一个有吸引力的研究方向，揭示有效的热量和水管理策略对于实现PEMFC运行所需的性能和寿命至关重要。我们的初步工作是建立一个全面的三维PEMFC模型，其中考虑了热量和水的管理问题。作为我们正在进行的PEMFC研究工作的延伸，这里提出的项目旨在将PEMFC运行过程中产生的所有重要的物理和电化学过程整合到一个完整的PEMFC模型中，以更真实地解释非等温条件下的多维、多物种和多相传输。为此，我们将特别注意三个新的成分：(a)水的相变；(b)二级电化学动力学；(c)瞬态行为。所得到的模型预计将具有高度非线性和系统级动态性质，其成功的数值解将强烈依赖于先进的数值技术。因此，除了PEMFC模型的发展之外，另一种趋势将是针对复杂的流型和复杂的输运现象，以后验误差估计为指导的三维有限元网格自适应。这将是自适应有限元方法在PEMFC计算机模拟中的首次应用，并有助于在控制质量良好的网格上实现精确的数值解，同时大大减少了计算资源。这两种研究成果将最终合并，然后实现为商业上可用的CFD代码。最终的软件包有望为PEMFC研究人员提供有用的信息，并为PEMFC的设计、性能优化和成本降低提供有价值的见解和指导。

Among various types of fuel cell systems, proton exchange membrane fuel cell (PEMFC) has become promising owing to its high efficiency, simplicity in design, and low-temperature operating condition. Since PEMFC design iterations relying on experiments are usually very expensive and time-consuming, computer modeling has become an attractive research direction, revealing effective heat and water management strategies are of top importance in achieving the required performance and lifetime of PEMFC operation. Our initial efforts have been made to build up a comprehensive 3D PEMFC model with the heat and water management issue taken into account. As an extension of our ongoing PEMFC research work, the project proposed here will be aimed at incorporating all important physical and electrochemical processes arising during the PEMFC operation into a complete PEMFC model to more realistically account for multi-dimensional, multi-species, and multi-phase transport under non-isothermal conditions. For this purpose, our particular attention will be paid to three new ingredients: (a) water phase change; (b) second order electrochemical kinetics; and (c) transient behavior. The resulting model is expected to be of highly nonlinear and system-level dynamic natures, the successful numerical solution of which will strongly rely on advanced numerical techniques. Therefore, in addition to the steam of PEMFC model development, another stream will be unfolding towards 3D finite element mesh adaptation guided by the a posteriori error estimation in response to the complex flow pattern and sophisticated transport phenomena. This will represent the first application of adaptive finite element methods to the PEMFC computer simulation, and help achieve an accurate numerical solution on meshes of well controlled quality using a significantly reduced amount of computational resources. The two streams of research efforts will be eventually merging and then implemented into a commercially available CFD code. The resulting software package is expected to serve for the PEMFC researchers to obtain useful information and gain valuable insight and guidance for design, performance optimization, and cost reduction of PEMFCs.