Soot formation in iso-octane counterflow diffusion flames

IF 6.2 2区工程技术 Q2 ENERGY & FUELS

Combustion and Flame Pub Date : 2025-09-29 DOI:10.1016/j.combustflame.2025.114513

Petros Vlavakis , Fabian P. Hagen , Alexandra Loukou, Dimosthenis Trimis

{"title":"Soot formation in iso-octane counterflow diffusion flames","authors":"Petros Vlavakis , Fabian P. Hagen , Alexandra Loukou, Dimosthenis Trimis","doi":"10.1016/j.combustflame.2025.114513","DOIUrl":null,"url":null,"abstract":"<div><div>This study investigates soot formation in laminar iso-octane counterflow diffusion flames (CDFs) under varying strain rates and fuel mass fractions. Spatially resolved measurements of temperature, major and minor gas-phase species, including polycyclic aromatic hydrocarbons (PAHs) up to three fused aromatic rings, as well as properties of the formed soot particles, such as volume fractions, primary particle sizes, and optical properties, i.e., refractive-index function for absorption in the near-infrared spectral region <span><math><mrow><mi>E</mi><mo>(</mo><mrow><mi>m</mi><mo>,</mo><msub><mi>λ</mi><mrow><mi>N</mi><mi>I</mi><mi>R</mi></mrow></msub></mrow><mo>)</mo></mrow></math></span>, were conducted using both intrusive and non-intrusive diagnostics. With increasing fuel mass fraction, the concentrations of C<sub>1</sub> to C<sub>3</sub> hydrocarbons and soot precursor molecules increase. This in turn results in higher soot volume fractions and larger particle sizes in the investigated CDFs of iso-octane. The evolution of the nanostructure and maturity of soot particles can be tracked via <span><math><mrow><mi>E</mi><mo>(</mo><mrow><mi>m</mi><mo>,</mo><msub><mi>λ</mi><mrow><mi>N</mi><mi>I</mi><mi>R</mi></mrow></msub></mrow><mo>)</mo></mrow></math></span>, which increases with rising fuel mass fractions and indicates extended basic structural units and a decreasing carbon-to-hydrogen ratio. Similarly, increasing strain rate reduces PAH concentrations, thereby affecting soot volume fractions, particle sizes, and maturity due to shortened residence times. The unique dataset aims to better understand the effects of alkane branching on soot formation by systematically investigating laminar iso-octane CDFs, and to elucidate the transition from precursor molecules to primary soot particles, including their molecular fine structure. In addition, the dataset is intended to contribute to the validation and development of kinetic mechanisms and soot models.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"282 ","pages":"Article 114513"},"PeriodicalIF":6.2000,"publicationDate":"2025-09-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Combustion and Flame","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0010218025005504","RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"ENERGY & FUELS","Score":null,"Total":0}

引用次数: 0

Abstract

This study investigates soot formation in laminar iso-octane counterflow diffusion flames (CDFs) under varying strain rates and fuel mass fractions. Spatially resolved measurements of temperature, major and minor gas-phase species, including polycyclic aromatic hydrocarbons (PAHs) up to three fused aromatic rings, as well as properties of the formed soot particles, such as volume fractions, primary particle sizes, and optical properties, i.e., refractive-index function for absorption in the near-infrared spectral region

E (m, λ_{N I R})

, were conducted using both intrusive and non-intrusive diagnostics. With increasing fuel mass fraction, the concentrations of C₁ to C₃ hydrocarbons and soot precursor molecules increase. This in turn results in higher soot volume fractions and larger particle sizes in the investigated CDFs of iso-octane. The evolution of the nanostructure and maturity of soot particles can be tracked via

E (m, λ_{N I R})

, which increases with rising fuel mass fractions and indicates extended basic structural units and a decreasing carbon-to-hydrogen ratio. Similarly, increasing strain rate reduces PAH concentrations, thereby affecting soot volume fractions, particle sizes, and maturity due to shortened residence times. The unique dataset aims to better understand the effects of alkane branching on soot formation by systematically investigating laminar iso-octane CDFs, and to elucidate the transition from precursor molecules to primary soot particles, including their molecular fine structure. In addition, the dataset is intended to contribute to the validation and development of kinetic mechanisms and soot models.

查看原文本刊更多论文

异辛烷逆流扩散火焰中烟灰的形成

本文研究了不同应变速率和燃料质量分数下层状异辛烷逆流扩散火焰（CDFs）中烟灰的形成。采用侵入式和非侵入式两种诊断方法，对温度、主要气相和次要气相物质（包括多环芳烃（PAHs），最多三个融合的芳烃环）以及形成的煤烟颗粒的性质（如体积分数、初级粒径和光学性质，即近红外光谱区E（m,λNIR）的吸收折射率函数）进行了空间分辨测量。随着燃料质量分数的增加，C1 ~ C3烃和油烟前体分子的浓度增加。这反过来又导致在所研究的异辛烷的CDFs中更高的烟灰体积分数和更大的颗粒尺寸。通过E（m,λNIR）可以跟踪烟尘颗粒的纳米结构和成熟度的演变，随着燃料质量分数的增加而增加，表明基本结构单元延长，碳氢比降低。同样，增加应变速率会降低多环芳烃浓度，从而影响烟尘的体积分数、粒径和成熟度，因为停留时间缩短。该独特的数据集旨在通过系统地研究层流异辛烷CDFs，更好地了解烷烃分支对烟灰形成的影响，并阐明从前体分子到初级烟灰颗粒的转变，包括其分子精细结构。此外，该数据集旨在为动力学机制和烟灰模型的验证和发展做出贡献。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

求助全文

约1分钟内获得全文求助全文

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.