A comparative analysis of plasma and hydrogen effects on premixed ammonia combustion

IF 5.8 2区工程技术 Q2 ENERGY & FUELS

Combustion and Flame Pub Date : 2025-06-19 DOI:10.1016/j.combustflame.2025.114300

Mohammad Shahsavari , Nilanjan Chakraborty , Alexander A. Konnov , Shenghui Zhong , Agustin Valera-Medina , Mehdi Jangi

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引用次数: 0

Abstract

In this study, we use direct numerical simulations to investigate turbulent premixed ammonia flames assisted by non-equilibrium nanosecond plasma discharges and hydrogen addition. The results reveal the coupling effects of turbulence, the hydrogen concentration in the fuel blend, and plasma discharges on the microscopic structure of the flame and chemical pathways. It is found that the flame front assisted by plasma is more distributed, whilst 58 % less stretched when compared to the hydrogen-enriched un-assisted flame. Additionally, turbulence has more pronounced effects on the hydrogen-enriched flame, broadening the flame brush. A comparison of the reaction pathways contributing to the heat release indicates that turbulence shifts the key reactions producing heat from HNO+H⬄NO+H₂ and OH+H₂⬄H + H₂O to NH₂ dissociation reactions. Additionally, NOx emissions are more influenced by thermal effects in the hydrogen-enriched flame, with NO concentration being 35 % higher than in the plasma-assisted flame. The higher NOx emissions in the hydrogen-enriched flame are attributed to the higher concentration of H radicals, which react with HNO and produce NO.

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等离子体和氢气对预混合氨燃烧影响的比较分析

在这项研究中，我们使用直接数值模拟研究了非平衡纳秒等离子体放电和加氢辅助下的湍流预混氨火焰。结果揭示了湍流、混合燃料中氢浓度和等离子体放电对火焰微观结构和化学路径的耦合效应。结果表明，等离子体辅助火焰锋面比无助火焰锋面分布更均匀，而拉伸量减少58%。此外，湍流对富氢火焰的影响更为明显，使火焰刷变宽。通过对产生热量的反应途径的比较表明，湍流将产生热量的关键反应从HNO+H⬄NO+H2和OH+H2⬄H + H2O转变为NH2解离反应。此外，在富氢火焰中，NOx排放更受热效应的影响，其中NO浓度比等离子体辅助火焰高35%。富氢火焰中较高的NOx排放量是由于高浓度的H自由基与HNO反应生成NO。

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.