Understanding Turbulent Hydrogen Flames and Instability via Measurements and Simulations

通过测量和模拟了解湍流氢火焰和不稳定性

• 批准号: EP/W034700/1
• 负责人: Simone Hochgreb
• 金额: $ 59.35万
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FW034700%2F1
• 关键词: Understanding; Turbulent; Hydrogen; Flames; Instability

Hydrogen is the simplest fuel, yet it has very different characteristics compared to common hydrocarbons: (a) high energy release per unit mass, (b) very high diffusivity, and (c) high reactivity. These three factors result in high flame speeds, which peak at around ten times those of hydrocarbons, and extremely wide flammability limits, from 3 to 95 percent in air. Hydrogen also has a propensity to form unstable flame surfaces owing to thermo-diffusive instabilities associated with the very light nature of hydrogen molecules, which form long finger-like leading edges, and very thick reaction zones, which means that the way in which we describe the physics of flames for other hydrocarbons does not work well for hydrogen. In this project we aim to develop simulations and experiments that will unveil quantitatively how these instabilities affect the reaction rate and local species formation, allowing the development of models that can be used in new carbon-free engines and gas turbines. The project will use direct numerical simulations and experiments of a stabilised hydrogen flame at atmospheric pressure and temperature, for a range of hydrogen/oxygen ratios and dilution. The experimental database will for the first time generate reconstructed 3D flame surfaces and velocities, joint two-dimensional temperature, OH radical measurements and one-dimensional hydrogen species concentrations. The numerical database will produce simulations overlapping with the experiments, as well as an extension of conditions inaccessible to experiments to higher pressures of up to 5 times atmospheric. The combination of matched experimental and numerical data will enable direct comparison, to explore the instability behaviour and dependence on reactant conditions, confirm numerical predictions, and use more complete DNS data to extrapolate from lower-fidelity experimental data.The particular issues of thermodiffusive instabilities are also relevant to other potential reactive mixtures, and some of the findings may be generalisable to other physical situations. More immediately, the research is also supported by industrial partners at the leading edge of development of hydrogen-based land and air propulsion, and findings from the proposed research will be immediately incorporated into models for turbulent combustion used at the collaborating facilities.

氢是最简单的燃料，但是与常见的碳氢化合物相比，它具有非常不同的特性：（a）单位质量的高能量释放，（b）非常高的扩散率和（c）高反应性。这三个因素导致高火速度，碳氢化合物的峰值约为十倍，而易燃性极高的速度从3％到95％的空气中达到了峰值。氢还具有形成不稳定的火焰表面的倾向，这是由于与氢分子非常轻的性质相关的热性不稳定，从而形成了长手指状的前缘，并且反应区非常厚，这意味着我们描述了其他氢碳碳的火焰物理学的方式，对氢气无效。在该项目中，我们旨在开发模拟和实验，以定量地推出这些不稳定性如何影响反应速率和局部物种形成，从而开发可用于新的无碳发动机和燃气轮机的模型。该项目将在大气压力和温度下使用稳定的氢火焰的直接数值模拟以及一系列氢/氧比和稀释的实验。实验数据库将首次产生重建的3D火焰表面和速度，关节二维温度，OH激进测量和一维氢物质浓度。数值数据库将产生与实验重叠的模拟，以及对实验无法访问的条件扩展到高达大气上的5倍的高压。匹配的实验数据和数值数据的组合将使直接比较，探索不稳定性行为和对反应物条件的依赖，确认数值预测，并使用更完整的DNS数据从较低的实验实验数据中推断出来。热源不足的特定问题也与其他潜在的反应混合物以及其他可能的物质相关，以及其他可能的情况，与其他可能的相关性相关。更立即，这项研究还得到了工业伙伴的支持，在基于氢的土地和空气推进的领先地位的领先地位，拟议研究的发现将立即纳入合作设施中使用的湍流燃烧模型中。