Hydrogen addition effect on the structure of the lean premixed flame stabilized on a high-temperature bluff-body

IF 5.8 2区工程技术 Q2 ENERGY & FUELS

Combustion and Flame Pub Date : 2025-05-10 DOI:10.1016/j.combustflame.2025.114229

Siqi Cai, Jianlong Wan

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引用次数: 0

Abstract

It has been confirmed that the High-temperature bluff-body (HTB) can significantly improve the Lean premixed flame (LPF) stabilization. To further improve the HTB stabilized LPF performance and reduce the CO₂ emission, the hydrogen-methane is employed. This study investigates the hydrogen addition effect on the LPF structure stabilized on the HTB by the means of the numerical simulation. A new non-equidistant central difference method is employed to identify the normal vector of the flame front accurately. When the percentage α of hydrogen in the mixed fuel increases, the flame thickness significantly decreases and its base shifts upstream. In the case of α=0, the flame base immerses in the Recirculation zone (RZ), and the flame base anchors at the boundary of the RZ in the case of α=0.15 and 0.30. The transport path and magnitude of the reactants are visualized. It is interestingly observed that the hydrogen addition can promote the transport magnitude of methane to the flame. When α increases, the peak values of the net reaction rates of hydrogen and methane increase, and the corresponding locations shift upstream. The three source terms of the energy equation are visualized quantitatively employing the real specific heat rather than the conventional constant equivalent specific heat. The increase in the α value enlarges the magnitudes of the aforementioned three source terms significantly. For the downstream flame front, it is interestingly observed that the weight of the convection term is large in the case of α=0 while it is small in the case of α=0.30. The heat release rate structure can be classified into the adiabatic zone, the excess reaction zone, and the weak reaction zone. To the best of our knowledge, such detailed analysis of the HTB stabilized LPF structure of hydrogen-enriched methane has not been reported yet. This work offers new insights into the LPF dynamics stabilized on the HTB.

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加氢对高温崖体稳定贫预混火焰结构的影响

实验证明，高温崖体（HTB）能显著提高Lean预混火焰（LPF）的稳定性。为了进一步提高HTB稳定LPF的性能并降低CO2排放，采用了甲烷氢。本文采用数值模拟的方法研究了加氢对HTB上稳定LPF结构的影响。采用一种新的非等距中心差分法准确地识别火焰锋面法向量。随着混合燃料中氢的百分比α的增加，火焰厚度显著减小，火焰底部向上游移动。α=0时，火焰基浸没在再循环区（RZ）内，α=0.15和0.30时，火焰基锚定在RZ边界处。传递路径和反应物的大小是可视化的。有趣的是，氢的加入可以提高甲烷向火焰的输运幅度。当α增大时，氢和甲烷的净反应速率峰值增大，且相应位置上移。能量方程的三个源项采用实际比热而不是传统的常数等效比热进行定量可视化。α值的增加使上述三个源项的幅度显著增大。对于下游火焰锋面，有趣的是，当α=0时对流项的权重较大，而当α=0.30时对流项的权重较小。放热速率结构可分为绝热区、过量反应区和弱反应区。据我们所知，对HTB稳定富氢甲烷LPF结构的详细分析尚未见报道。这项工作为HTB上稳定的LPF动力学提供了新的见解。

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.