高压氢气泄漏自燃特性及机理研究

Spontaneous ignition of pressurized hydrogen release is one of the biggest obstacles in hydrogen storage, which has become a huge obstacle in the development and popularization of hydrogen energy. In order to understand the spontaneous combustion characteristics of pressured hydrogen release and its dynamic mechanism, and to seek safe hydrogen storage means, this project will systematically study the basic law of spontaneous combustion of high pressured hydrogen by integrating experiment and numerical results. First, the main factors that influence the spontaneous combustion characteristics and the detailed process of flame formation and development are obtained by means of experiment based on the typical leakage cases. Then, the detailed process, flame structure and composition distribution of the spontaneous combustion of hydrogen at high pressure under different leakage modes and dilution conditions are obtained by means of direct numerical simulation using the detailed chemical reaction mechanism. Finally, through the analysis of the experimental and numerical results, the basic rules of spontaneous combustion characteristics and detailed dynamic process of high pressure hydrogen leakage are obtained. The results of this project will provide an effective method and rich data for the deep understanding of the spontaneous combustion characteristics and mechanism of high pressure hydrogen leakage, provide analytical tools and theoretical guidance for seeking safe high pressure hydrogen storage and novel combustion device, provide a new solution for the analysis of complex reaction flow, and contribute to the development the basic theory of turbulence combustion.

泄漏自燃是高压储氢的重大安全隐患，已成为氢能发展和推广应用中的巨大障碍。为了深刻认识高压氢气泄漏的自燃特性及其动力学机理，寻求安全的储氢手段，本课题将采用实验与数值模拟相结合的方法系统地研究高压氢气泄漏自燃过程的基本规律。首先，以典型泄漏模式为基础，通过实验的手段获得影响氢气高压泄漏自燃特性的主要因素及火焰形成及发展的详细过程。然后，采用适用于高压燃烧动力学特性计算的氢气详细化学反应机理，通过直接数值模拟的方法获得不同泄漏模式和稀释条件下的高压氢气泄漏自燃的详细过程、火焰结构和组分分布。最后,通过对实验与模拟结果的分析，获得高压氢气泄漏自燃特性及详细动力学过程的基本规律。本课题将为高压氢气泄漏自燃特性及机理的深入认识提供有效的方法和丰富的数据，为寻求安全的高压储氢手段和新型燃烧设备提供分析工具和理论指导；将为复杂反应流的分析提供新的解决思路，并有助于发展湍流燃烧的基础理论。

为了满足高压氢气及富氢燃气泄漏自燃特性及动力学机制研究的需要，提出了以提高下游空气真空度实现高压力比燃气泄漏自燃的等效实验方法，并自主研发了面向超音速流动、火焰传播、动力学过程等问题的反应流二维瞬态模拟程序SURMS(supersonic reacting-flow modeling system)。通过实验和数值模拟相结合的方法，研究了不同压比、不同燃料成分、不同流道结构等条件下氢气及富氢燃气泄漏自燃特性。研究结果表明：燃气的组分与激波马赫数是影响燃气高压泄漏自燃特性的关键因素，富氢燃气中低活性组分严重影响H自由基的反应路径。.受限空间高压氢气泄漏研究表明，激波强度大小是决定自燃发生与否最重要的因素，当激波强度足够高时，将在氢气/空气混合层内靠近空气侧的贫燃区发生自燃。氢气/空气混合层内的链分支反应H+O2<=>O+OH与链终止反应H+O2(+M)<=>HO2(+M)的竞争决定了受限空间高压氢气泄漏自燃火焰结构与着火延迟时间。高压氢气在开放空间泄漏将形成正激波和半球型衍射激波，且在超声速氢气射流中心着火，并沿混合层向射流两侧传播。H+O2+M<=>HO2+M、H2+OH<=>H+H2O、H2+O<=>H+OH、H+O2<=>O+OH和H2+O2<=>H+HO2是影响开放空间氢气泄漏自燃的关键反应。.以CH4/H2混合气、虚拟燃料为对象，研究了掺混对高压泄漏自燃特性的影响，并从激波强度、混合层温度、反应活性、物质输运与反应耦合关系等方面揭示了通过添加低活性组分抑制高压氢气泄漏自燃的内在机制。研究结果表明：低活性组分的添加可显著延长高压氢气泄漏自燃延迟时间，低活性组分的掺混极大地降低了泄漏过程的激波强度及火焰锋面处自由基的积累速率，而掺混降低高压氢气泄漏自燃风险的本质是对混合燃料摩尔质量的提高以及对燃料/空气混合层内自由基输运损失的增强。.提出的高压比等效泄漏自燃实验方法为燃气高压泄漏自燃实验数据的获取提供了新的思路，研发的二维瞬态模拟程序SURMS为反应流高精度数值研究提供了强有力的分析工具，对高压氢气及富氢燃气泄漏自燃特性、关键反应路径、流动与反应相互作用机制的揭示有效促进了对泄漏自燃本质的认识，并为发展高压燃气安全储存技术提供了理论支撑。