The laminar and turbulent flame speed of methanol/ammonia/air, ethyl-acetate/ammonia/air, and dimethoxymethane/ammonia/air under atmospheric and elevated pressures

IF 5.8 2区工程技术 Q2 ENERGY & FUELS

Combustion and Flame Pub Date : 2025-04-18 DOI:10.1016/j.combustflame.2025.114187

Shixing Wang , Ayman M. Elbaz , Zhihua Wang , William L. Roberts

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引用次数: 0

Abstract

Experiments of the laminar and turbulent flame speed of typical E-fuels blended with ammonia: methanol/ammonia/(CH₃OH/NH₃)/air, ethyl-acetate/ammonia/(EA/NH₃)/air, and dimethoxymethane/ammonia/(DMM/NH₃)/air under atmospheric and elevated pressures (1 and 3 atm) are conducted in a fan-stirred constant volume combustion chamber, with initial temperature of 373 K. The results show that turbulent flame speed (S_T) follow the same ranking order as laminar flame speed (S_L) at fuel-lean side from high to low as: DMM, CH₃OH, and EA; while with ammonia addition, CH₃OH/NH₃ and EA/NH₃ have similar S_L and S_T values; and at fuel-rich side, DMM and EA show increasing S_T and S_T/S_L values than at fuel-lean side Meanwhile, the measured Markstein length (L_b) is decreasing towards the fuel-rich side and even becomes negative for EA. Ammonia addition enhances the turbulent flame wrinkling and deformation from the morphology analyses, and this leads to E-fuel/NH₃ blends always having higher normalized turbulent flame speed (S_T/S_L) than pure E-fuel. Next, we test several different turbulent flame speed correlations composed of (u'/S_L) and (l_T/l_F), it is found that the power exponents of (u'/S_L) and (l_T/l_F) do not necessarily have to be equal; they change as the turbulent regime varies in different zones. S_T/S_L/Ka = a(Da/Le)^b performs best among all correlation types with 0.5 ≤ b ≤ 1 corresponding to the Damköhler's two limits. Comparing three types of Lewis number, it is found that volume based Le_V has the best fitting goodness in the correlation of S_T/S_L/Ka = a(Da/Le)^b. Taking into account the developing flame brush thickness, wrinkling ratio and integral length scale as a function of radius, the flame radius based Da_R correlations are proposed: S_T/S_L/γ = a(Da_R/Le)^b where 0.5 ≤ b ≤ 1 which can unify present experimental data with Lewis number larger than unity and previous data with Lewis number less than unity.

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甲醇/氨/空气、乙酸乙酯/氨/空气和二甲氧基甲烷/氨/空气在常压和高压下的层流和湍流火焰速度

在初始温度为 373 K 的风扇搅拌式恒容燃烧室中，对甲醇/氨/(CH3OH/NH3)/空气、乙酸乙酯/氨/(EA/NH3)/空气和二甲氧基甲烷/氨/(DMM/NH3)/空气等典型掺氨电子燃料在大气压和高压（1 atm 和 3 atm）下的层流和湍流火焰速度进行了实验。结果表明，在燃料贫乏侧，湍流火焰速度（ST）与层流火焰速度（SL）从高到低的顺序相同：同时，测得的马克斯坦长度（Lb）在燃料富裕侧逐渐减小，EA 甚至变为负值。从形态分析来看，氨的加入增强了湍流火焰的起皱和变形，这导致 E-燃料/NH3 混合物的归一化湍流火焰速度（ST/SL）始终高于纯 E-燃料。接下来，我们测试了由（u'/SL）和（lT/lF）组成的几种不同的湍流火焰速度相关性，发现（u'/SL）和（lT/lF）的功率指数并不一定相等；它们会随着不同区域湍流机制的变化而变化。ST/SL/Ka = a(Da/Le)b 在所有相关类型中表现最佳，0.5 ≤ b ≤ 1 对应于达姆克勒的两个极限。比较三种路易斯数发现，基于体积的 LeV 在 ST/SL/Ka = a(Da/Le)b 的相关性中拟合效果最好。考虑到发展中火焰刷厚度、皱褶率和整体长度尺度与半径的函数关系，提出了基于火焰半径的 DaR 相关性：ST/SL/γ = a(DaR/Le)b 其中 0.5 ≤ b ≤ 1 可以统一目前路易斯数大于一的实验数据和以前路易斯数小于一的数据。

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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.