高性能水电解中微介观气液两相传输机理的数值研究

High-performance water electrolysis technology provides an efficient and sustainable solution for hydrogen production, storage and integrated utilization of energy that is generated from intermittent and renewable power sources. Proton exchange membrane (PEM) water electrolysis technology has great development potential and application prospect in the hydrogen production and large-scale energy storage due to its advantages such as high efficiency, high gas purity, compact structure and high pressure operation. Gas/liquid two-phase transport is an important fundamental scientific issue in PEM water electrolysis and is the key factor controlling its performance. In this project, a numerical simulation method will be used to study the micro/meso-scale two-phase transport phenomena in an advanced PEM water electrolysis cell. The proposed research work mainly includes: A mathematical model, which can accurately describe the behaviors of bubble nucleation and evolution in the catalyst layer, will be established to reveal the mechanisms of bubble nucleation, growth, and detachment on a catalytic reaction surface; a pore-scale gas/liquid two-phase transport model, which is based on the lattice Boltzmann method, will be developed to numerically simulate the gas bubbles transport and gas/liquid two-phase distribution inside a thin diffusion layer, a complex porous diffusion layer, and a micro-channel. This project is intended to obtain a fundamental understanding of the mechanism of micro/meso-scale gas/liquid two-phase transport in PEM water electrolysis, and to provide theoretical basis and technical support for the design and optimization of a high-performance water electrolysis system.

高性能水电解技术为氢能制取及间歇式可再生能源存储、综合利用提供了一种有效可持续的解决方案。质子交换膜水电解技术由于具有高效、气体制取纯度高、结构紧凑、可高压运行等优势在制氢及大规模储能领域表现出巨大的发展潜力和应用前景。气液两相传输是质子交换膜水电解中一个重要基础性科学问题，是影响其性能的关键因素。本项目拟采用数值模拟方法，针对先进的质子交换膜水电解单元运行中涉及的微介观尺度下两相传输问题展开研究，主要包括：构建一种能准确描述催化层气泡成核演变规律的数学模型，揭示催化反应表面气泡成核、生长及脱离机理；基于格子Boltzmann方法，发展一套孔隙尺度下的气液两相传输计算模型，数值模拟超薄扩散层、复杂多孔扩散层以及微流道内气泡传递和气液两相分布规律。项目旨在全面深入的了解质子交换膜水电解中微介观尺度下气液两相传输机理，为高性能水电解系统的设计和优化提供理论依据和技术支撑。

气液两相传输是影响质子交换膜水电解系统性能及设计的关键因素，是发展高性能水电解技术有待解决的重要基础问题。本项目针对单个质子交换膜水电解单元运行期间涉及的气液两相传输问题开展了研究，主要包括：建立了一个催化层内固体表面气泡动力学计算模型，数值模拟了催化反应表面气泡演变特性；基于格子Boltzmann两相流动模型，发展了一套微介观尺度下多孔介质内气液两相传输模型，数值模拟了多孔扩散层内气液两相传输现象，同时也模拟研究了扩散层表面及微流道内气泡传递过程。该研究获得了单个水电解单元催化层内气泡生长、脱离等演变规律，掌握了不同参数下扩散层内及其表面的气泡传输分布规律。项目对质子交换膜水电解单元内微介观尺度下的气液两相传输机理有了清晰的认识，为高性能水电解系统的设计和优化提供了理论和技术支撑。