Measurements of NO in the post-flame region of laminar premixed ammonia/methane-air flames using laser-induced fluorescence

IF 6.2 2区工程技术 Q2 ENERGY & FUELS

Combustion and Flame Pub Date : 2025-09-15 DOI:10.1016/j.combustflame.2025.114450

M. Richter , J. Lill , R.S. Barlow , A. Dreizler , J.R. Dawson , D. Geyer

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引用次数: 0

Abstract

Cofiring of ammonia (NH₃) with methane (CH₄) offers a promising route to enhance the combustion characteristics of pure ammonia while partially decarbonizing methane-based energy systems. However, the presence of fuel-bound nitrogen in ammonia leads to elevated NOx emissions. Although NO measurements in NH₃-containing flames have been reported, there is a notable lack of validation datasets for NH₃/CH₄ cofiring based on non-intrusive diagnostics. In this communication, a laser-induced fluorescence (LIF) approach recently developed for post-flame NO measurements is applied to NH₃/CH₄-air flames with CH₄ contents ranging from 50 vol.-% to 80 vol.-% in the fuel mixture. The LIF signal processing includes corrections for laser absorption, signal trapping, and pulse energy fluctuations. Thermochemical differences between calibration and target flames are addressed through corrections for number density, Boltzmann fraction, spectral line overlap, and electronic quenching. The results show good agreement with recent chemical kinetic models over a broad range of conditions. Within the tested range, increasing the NH₃ content results in a notable reduction of NO emissions under fuel-rich conditions, while the opposite trend is observed under fuel-lean conditions. The observed NO trends are interpreted using normalized radical pool indicators for

and O/H/OH species.

Novelty and Significance

Quantitative data on NO emissions from ammonia-based fuels remain limited, especially those obtained using non-intrusive diagnostics. In this paper, we extend a previously presented laser-induced fluorescence (LIF) method to measure post-flame NO concentrations in NH₃/CH₄-air flames across a broad range of equivalence ratios and fuel compositions. The dataset covers CH₄ contents from 50 to 80 vol.%. By introducing normalized radical pool indicators for

and O/H/OH species, the work helps to interpret observed NO trends. The results provide a basis for refining chemical kinetic models with respect to NO formation.

查看原文本刊更多论文

用激光诱导荧光法测量层流氨/甲烷-空气预混火焰火焰后区域NO

氨（NH3）与甲烷（CH4）的共烧为提高纯氨的燃烧特性，同时使甲烷能源系统部分脱碳提供了一条有前途的途径。然而，氨中存在的燃料结合氮会导致氮氧化物排放增加。虽然在含NH3火焰中测量NO已经有报道，但明显缺乏基于非侵入式诊断的NH3/CH4共燃验证数据集。在本通讯中，激光诱导荧光（LIF）方法最近开发用于火焰后NO测量应用于NH3/CH4-空气火焰，燃料混合物中CH4含量从50 vol.-%到80 vol.-%。LIF信号处理包括激光吸收、信号捕获和脉冲能量波动的校正。校准和目标火焰之间的热化学差异通过修正数密度，玻尔兹曼分数，谱线重叠和电子淬火来解决。结果表明，在广泛的条件下，与最近的化学动力学模型很好地吻合。在测试范围内，在富油工况下，增加NH3含量会显著减少NO排放，而在贫油工况下，则相反。使用归一化自由基池指标对和O/H/OH物种解释观察到的NO趋势。关于氨基燃料NO排放的定量数据仍然有限，特别是那些使用非侵入式诊断方法获得的数据。在本文中，我们扩展了先前提出的激光诱导荧光（LIF）方法，以在广泛的等效比和燃料成分范围内测量NH3/ ch4 -空气火焰中的燃烧后NO浓度。数据集涵盖了CH4含量的50 - 80 vol.%。通过引入标准化的自由基池指标和O/H/OH物种，该工作有助于解释观测到的NO趋势。研究结果为完善NO生成的化学动力学模型提供了依据。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Combustion and Flame 工程技术-工程：化工

CiteScore

9.50

自引率

20.50%

发文量

631

审稿时长

3.8 months

期刊介绍： The mission of the journal is to publish high quality work from experimental, theoretical, and computational investigations on the fundamentals of combustion phenomena and closely allied matters. While submissions in all pertinent areas are welcomed, past and recent focus of the journal has been on: Development and validation of reaction kinetics, reduction of reaction mechanisms and modeling of combustion systems, including: Conventional, alternative and surrogate fuels; Pollutants; Particulate and aerosol formation and abatement; Heterogeneous processes. Experimental, theoretical, and computational studies of laminar and turbulent combustion phenomena, including: Premixed and non-premixed flames; Ignition and extinction phenomena; Flame propagation; Flame structure; Instabilities and swirl; Flame spread; Multi-phase reactants. Advances in diagnostic and computational methods in combustion, including: Measurement and simulation of scalar and vector properties; Novel techniques; State-of-the art applications. Fundamental investigations of combustion technologies and systems, including: Internal combustion engines; Gas turbines; Small- and large-scale stationary combustion and power generation; Catalytic combustion; Combustion synthesis; Combustion under extreme conditions; New concepts.