Insights into the scalar structures in turbulent diffusion flames with progressive H2 addition using 1D spontaneous Raman scattering and simultaneous PIV-OH PLIF

IF 5.8 2区工程技术 Q2 ENERGY & FUELS

Combustion and Flame Pub Date : 2025-03-27 DOI:10.1016/j.combustflame.2025.114129

Kuppuraj Rajamanickam , Ariff Magdoom Mahuthannan , Corine Lacour , Said Idlahcen , Armelle Cessou , David Honoré , Bertrand Lecordier

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引用次数: 0

Abstract

This paper examined the effect of H₂ enrichment in a primary fuel (CH₄) on turbulent flame features using 1D spontaneous Raman scattering (SRS) and simultaneous particle Image Velocimetry (PIV), OH-Planar Laser Induced Fluorescence (PLIF) measurements. The experiments are conducted in a canonical non-premixed bluff body burner operating under typical central fuel jet-dominated flow mode. Downstream of the bluff body, the flow exhibits complex patterns, and it can be globally categorized into three successive zones: recirculation, neck, and jet-like zones. The flame undergoes local extinction in the neck zone, where the local flow-induced hydrodynamic strain rate (κ_hyd) is much higher than the flame extinction strain rate (κ_ext). It is well known that H₂ enrichment increases κ_ext and thus modifies the probability of localized flame extinctions in the neck zone. Additionally, recent studies have shown the significance of preferential diffusion effects of H₂ in H₂ + CH₄ bluff body stabilized premixed and turbulent jet diffusion flames. Although 1D SRS measurements in canonical jet and bluff body stabilized non-premixed flames were studied extensively, to the best of our knowledge, differential diffusion has not been reported earlier in the non-premixed bluff body burner fueled with progressive H₂ addition. To better understand this phenomenon, five H₂ enrichment levels are considered: 0 %, 10 %, 30 %, 50 % and 80 % (in vol.). The simultaneous PIV and OH-PLIF measurements revealed the presence of local extinctions in the cases of H₂ enrichment ≤ 30 %, while local extinctions are not witnessed for H₂ = 50, 80 %. The conditional PDFs of the temperature in mixture fraction space obtained from the 1D SRS further confirmed this observation. Furthermore, the local instantaneous hydrogen/methane mass fraction ratio has been estimated to evaluate the differential diffusion effects. The results showed the dominance of the differential diffusion in the burner's near field, while the strong turbulence mixing effect weakens the differential diffusion in the far field.

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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.