Modeling and simulation for PEM fuel cell performance optimization

在众多的燃料电池系统中，质子交换膜燃料电池(PEMFC)以其效率高、设计简单、工作温度低等优点而成为最有发展前景的燃料电池。由于基于实验的PEMFC设计迭代通常非常昂贵和耗时，计算机建模已成为一个吸引人的研究方向，揭示了有效的热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3DPEMFC模型，其中考虑了热和水管理问题。作为我们正在进行的PEMFC研究工作的延伸，该项目旨在将PEMFC运行过程中出现的所有重要的物理和电化学过程纳入一个完整的PEMFC模型，以便更真实地考虑非等温条件下的多维、多物种和多相传输。为此，我们将特别关注三个新的成分：(A)水的相变；(B)二级电化学动力学；(C)瞬变行为。所得到的模型将具有高度的非线性和系统级的动态特性，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模型发展的潮流外，针对复杂的流型和复杂的输运现象，在后验误差估计的指导下，另一股潮流将向三维有限元网格自适应发展。这将是自适应有限元方法首次应用于PEMFC计算机模拟，并有助于在使用显著减少的计算资源的情况下实现对质量良好控制的网格的精确数值解。这两种研究努力最终将被合并，然后被实施为商业上可用的CFD代码。所生成的软件包有望为质子交换膜燃料电池的研究人员提供有用的信息，并为质子交换膜燃料电池的设计、性能优化和降低成本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.