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Laminar burning velocity and unburnt temperature: Comparative analysis across a broad temperature range of atmospheric NH3+H2 flames

IF 5.8 2区工程技术 Q2 ENERGY & FUELS

Combustion and Flame Pub Date : 2025-03-14 DOI:10.1016/j.combustflame.2025.114117

Xinlu Han , Alexander A. Konnov

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引用次数: 0

Abstract

Ammonia (NH₃) emerges as a promising carbon-free fuel, necessitating an understanding of its fundamental combustion properties, particularly the laminar burning velocity (

S_{L}

), at very high unburnt temperatures (

T_{u}

). Despite this need, a consensus on the relationship between

S_{L}

and

T_{u}

across a broad temperature range has not yet been established. This study investigated the

S_{L}

vs.

T_{u}

relationship from 298 K to above 800 K, analyzing both literature data and simulation results for 40%H₂+60%NH₃+air flames at 1 atm. Seven kinetic models were used in the simulations, among which the models from Shrestha, Stagni, Han, NUIG, and KAUST accurately reproduced the experimental data within uncertainty limits, making them suitable for investigating

S_{L}

vs.

T_{u}

relationship. The analysis revealed that no tested correlation perfectly captures the

S_{L}

vs.

T_{u}

relationship across the entire temperature range with their originally defined constants, because the overall activation energy of the global one-step reaction is indeed increasing rapidly with

T_{u}

. In addition, the much lower reaction sensitivities of the temperature dependence coefficient than

S_{L}

, along with the same effects of elevated temperature and oxygen enrichment on model validations, were found to be valid for temperatures up to 850 K in these simulations, consistent with those previously identified for

T_{u}

< 500 K conditions. Reaction sensitivities were also calculated for the overall activation energy, which exhibits significantly stronger temperature dependence than

S_{L}

, thus more effective for identifying reactions requiring adjustment for improving predictions across wide unburnt temperature ranges. Based on these findings, a feasible strategy was proposed for future investigation of the laminar burning velocities with broad unburnt temperature range, helping with relevant applications.

查看原文本刊更多论文

层流燃烧速度和未燃烧温度：在大气NH3+H2火焰的广泛温度范围内的比较分析

氨（NH3）是一种很有前途的无碳燃料，需要了解其基本燃烧特性，特别是在非常高的未燃烧温度（Tu）下的层流燃烧速度（SL）。尽管有这样的需要，但在广泛的温度范围内，对SL和Tu之间的关系尚未达成共识。本文研究了298k到800k之间的SL和Tu关系，分析了文献数据和1atm时40%H2+60%NH3+空气火焰的模拟结果。模拟中使用了7个动力学模型，其中Shrestha、Stagni、Han、NUIG和KAUST的模型在不确定范围内准确地再现了实验数据，适合研究SL与Tu的关系。分析表明，在整个温度范围内，没有经过检验的相关关系可以很好地描述SL与Tu之间的关系，因为整体一步反应的总活化能确实随着Tu的增加而迅速增加。此外，温度依赖系数的反应灵敏度远低于SL，并且温度升高和富氧对模型验证的影响相同。在这些模拟中发现，在高达850 K的温度下是有效的，与之前确定的Tu <；500k条件。总体活化能的反应灵敏度也被计算出来，它表现出比SL更强的温度依赖性，因此更有效地识别需要调整的反应，以提高在较宽的未燃烧温度范围内的预测。在此基础上，提出了一种可行的研究策略，以进一步研究宽未燃烧温度范围的层流燃烧速度，有助于相关应用。

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.