Flame instability and combustion noise of premixed flames in a backward-facing step burner with a variable configuration

IF 5.9 2区工程技术 Q2 ENERGY & FUELS

Combustion and Flame Pub Date : 2026-05-01 Epub Date: 2026-02-26 DOI:10.1016/j.combustflame.2026.114890

Ji Hun Yeo, Nam Il Kim

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引用次数: 0

Abstract

The effects of configurational length scales on flame instability and combustion noise were investigated using a new backward-facing step (BFS) burner for which the nozzle and step widths can vary. Premixed methane and propane flames could be formed in either an attached mode or a lifted mode. The characteristics of combustion noise were examined in relation to various parameters. It was found that more significant combustion noise occurred in the attached mode when the step width induced a specific velocity gradient. The first harmonic frequency differed from the acoustic resonance, and the flame-flow interactions could be visualized using the ensemble-averaged PIV method. A simultaneous comparison between the flow field and flame behaviors can explain the flame dynamics. Pressure in the combustion space is determined by friction in the channel and is influenced by the fluctuating flame, resulting in oscillations in the nozzle velocity. The Rayleigh criterion could be met by the retarded flame response to the oscillating nozzle flow velocity, which could be explained by flame rolling and growing within the oscillating shear layer. In contrast, in the lifted flame mode, flame oscillation and combustion noise were enhanced at a specific step width of approximately 4 mm. There was a flow recirculation zone, which strongly interacts with the edge of the flames.

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可变结构后向台阶燃烧器中预混火焰的火焰不稳定性和燃烧噪声

采用可改变喷嘴和台阶宽度的后面向台阶（BFS）燃烧器，研究了构型长度尺度对火焰不稳定性和燃烧噪声的影响。甲烷和丙烷的预混火焰可以以附着模式或提升模式形成。研究了燃烧噪声特性与各参数的关系。当阶跃宽度引起特定速度梯度时，附著模式下的燃烧噪声更为显著。一次谐波频率与声共振频率不同，火焰流相互作用可以用集合平均PIV方法可视化。同时比较流场和火焰行为可以解释火焰动力学。燃烧空间的压力由通道内的摩擦决定，并受波动火焰的影响，导致喷嘴速度的振荡。振荡喷嘴流速对火焰响应的延迟可以满足瑞利准则，这可以通过火焰在振荡剪切层内的滚动和生长来解释。而在提升火焰模式下，在约4 mm的特定阶跃宽度处，火焰振荡和燃烧噪声增强。有一个流动再循环区，它与火焰的边缘强烈相互作用。

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.