Fuel最新文献_第2页

Optimising CNG Premix Ratio in Dual-Fuel Direct Injection Spark Ignition Engine 双燃料直喷式火花点火发动机CNG预混比优化

IF 7.5 1区工程技术 Q2 ENERGY & FUELS

Fuel

Pub Date : 2025-12-12 DOI: 10.1016/j.fuel.2025.137780

Ankur Kalwar, PA Lakshminarayanan, Avinash Kumar Agarwal

Spark-ignition engines fuelled by Compressed Natural Gas (CNG) are popular for low engine-out emissions and high fuel economy. However, it suffers from reduced maximum power output due to a loss in volumetric efficiency. Introducing CNG in the port in dual-fuel mode in a gasoline direct injection (GDI) engine can harness the advantage of maintaining the engine power output while reducing carbon emissions. This study investigated three different premix ratios of CNG (25 %, 50 %, and 75 %) based on energy supply at different engine load and speed conditions to understand the engine characteristics in dual-fuel mode. The remaining combustion energy was supplied by direct injection of gasoline. The results were examined through a detailed analysis of combustion, performance, and emissions characteristics for the dual-fuel engine operations. They were compared with baseline GDI and CNG-only port-injection operations. The regression analysis was also performed to investigate the influence of control parameters on engine characteristics. The addition of CNG showed different effects on gasoline combustion, depending on the engine’s torque output. Under low engine load conditions, improvement in CNG/gasoline dual-fuel combustion was observed with an increase in CNG mass flow rate, mainly characterised by the early combustion stage. However, in the full-load regime, the later combustion phase was delayed, thereby extending the combustion duration in CNG/gasoline dual-fuel combustion. Experimental ignition delay and combustion duration results were predicted well with the correlations provided in the literature. CNG premixing beyond 50 % enhanced the brake thermal efficiency of the engine. Significant reductions in carbon-based emissions, including carbon monoxide (CO), hydrocarbons (HC), and smoke opacity, were observed with a 50 % CNG ratio (C50G50). The regression analysis revealed that ignition delay had a significant influence on HC emissions, while the C/H ratio primarily affected smoke emissions. The oxides of nitrogen (NO_x) emissions did not show considerable variations compared to baseline GDI, except at low load and speed conditions. Overall, C50G50 demonstrated optimal results in maintaining engine performance while achieving significant emissions reduction across all engine operating conditions.

以压缩天然气（CNG）为燃料的火花点火发动机因其低排放和高燃油经济性而广受欢迎。然而，由于体积效率的损失，它的最大功率输出减少。在汽油直喷（GDI）发动机的进气道以双燃料模式引入CNG，可以在保持发动机功率输出的同时减少碳排放。为了了解双燃料模式下发动机的特性，研究了在不同发动机负载和转速条件下，CNG预混比（25%、50%和75%）的变化情况。剩余的燃烧能量由汽油直喷提供。通过对双燃料发动机运行的燃烧、性能和排放特性的详细分析，对结果进行了检验。它们与基线GDI和纯cng端口注入操作进行了比较。通过回归分析研究了控制参数对发动机特性的影响。CNG的加入对汽油燃烧表现出不同的影响，这取决于发动机的扭矩输出。在发动机低负荷工况下，CNG/汽油双燃料燃烧得到改善，CNG质量流量增加，主要表现在燃烧初期。然而，在全负荷工况下，后燃烧阶段被推迟，从而延长了CNG/汽油双燃料燃烧的燃烧时间。实验点火延迟和燃烧持续时间的结果与文献提供的相关关系预测得很好。超过50%的天然气预混能提高发动机的制动热效率。在50%的CNG比例（C50G50）下，观察到碳基排放（包括一氧化碳（CO）、碳氢化合物（HC）和烟雾不透明度）显著减少。回归分析表明，点火延迟对HC排放有显著影响，而C/H比主要影响烟气排放。除了在低负荷和低速条件下，氮氧化物（NOx）排放与基线GDI相比没有显着变化。总体而言，C50G50在保持发动机性能的同时，在所有发动机运行条件下都实现了显著的减排。

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引用次数: 0

Towards a better understanding of the combustion chemistry for prenol and iso-prenol: An ab initio kinetic study on hydrogen abstraction reactions by hydrogen atom 为了更好地理解戊醇和异戊醇的燃烧化学：氢原子吸氢反应的从头算动力学研究

IF 7.5 1区工程技术 Q2 ENERGY & FUELS

Fuel

Pub Date : 2025-12-12 DOI: 10.1016/j.fuel.2025.137941

Yaozong Duan , Dong Han , Fashe Li , Hua Wang

Prenol (3-methyl-2-buten-1-ol) has been considered as a potential additive to gasoline, due to its unique octane hyperboosting feature when blended with commercial gasoline or primary reference fuels. However, such an interesting feature was absent in its isomer counterpart, i.e., iso-prenol (3-methyl-3-buten-1-ol). To reveal the potential reasons of this unique feature, it is essential to gain a better understanding of the combustion chemistry for prenol and iso-prenol. In this work, a comprehensive study on the reaction kinetics of hydrogen abstraction reactions from prenol isomers by hydrogen atom was performed with high-level quantum chemical calculation method. The single point energies for reaction species were calculated at CCSD(T)/CBS level of theory, with optimized geometries of the lowest-energy conformers determined at M06-2X/6–311+G(2df,2p) level of theory. The rate coefficients in 400-2000 K temperatures were calculated using the canonical variational transition state theory with multistructural torsional anharmonicity and small-curvature tunneling corrections. Special attentions were paid to the effects of fuel structures, including the presence and location of C=C bond and hydroxyl moiety, via demonstrating a thorough comparison with the theoretical calculations for iso-pentanol and alkene counterparts of prenol isomers reported in the literature. Temperature-dependent thermochemical parameters of prenol isomers and their fuel radicals were derived from the multistructural partition functions, together with the standard formation enthalpies determined with the isodesmic reaction method. Rate coefficients and thermochemistry were incorporated into the kinetic models of prenol isomers to investigate their influence on the performance of prenol/iso-prenol oxidation and pyrolysis. This study provides a better understanding on the combustion chemistry of prenol isomers and reactions between unsaturated alcohols and H atom.

丙烯醇（3-甲基-2-丁烯-1-醇）被认为是一种潜在的汽油添加剂，因为当与商业汽油或主要参考燃料混合时，它具有独特的辛烷值超增压特性。然而，这种有趣的特征在它的同分异构体，即异戊二醇（3-甲基-3-丁烯-1-醇）中是没有的。为了揭示这种独特特征的潜在原因，有必要更好地了解戊醇和异戊醇的燃烧化学。本文采用高阶量子化学计算方法，对戊二醇同分异构体的氢原子吸氢反应动力学进行了全面研究。在CCSD(T)/CBS理论水平上计算了反应组分的单点能，在M06-2X/ 6-311 +G（2df,2p）理论水平上确定了最低能构象的优化几何形状。利用正则变分过渡态理论计算了400-2000 K温度下的速率系数，并考虑了多结构扭非谐性和小曲率隧穿修正。特别注意燃料结构的影响，包括C=C键和羟基部分的存在和位置，通过与文献中报道的异戊醇和烯烃异构体的理论计算进行彻底的比较。由多结构配分函数推导出了prenol异构体及其燃料自由基的温度相关热化学参数，并用等速反应法测定了标准生成焓。采用速率系数和热化学方法，研究了速率系数和热化学参数对prenol/异prenol氧化热解性能的影响。本研究为进一步了解丙二醇异构体的燃烧化学及不饱和醇与H原子的反应提供了新的思路。

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引用次数: 0

The characteristics of stability and NO formation in lean hydrogen-enriched ammonia premixed flames with varying body force 不同体力下贫氢富氨预混火焰的稳定性及NO生成特性

IF 7.5 1区工程技术 Q2 ENERGY & FUELS

Fuel

Pub Date : 2025-12-12 DOI: 10.1016/j.fuel.2025.138006

Jian Zheng, Haiou Wang, Kun Luo, Jianren Fan

In the present work, direct numerical simulations (DNS) were performed to understand the effect of body force on the stability and NO formation in lean hydrogen-enriched ammonia premixed flames. In the linear regime, two-dimensional DNS were conducted under various body force conditions. It was found that the effect of body force on the linear growth rate is negligible when Fr > 1 and becomes significant when Fr < 1, with Fr being the Froude number defined as

S_{L}^{2} / g δ_{L}

, where

g

is the body force magnitude,

S_{L}

is the laminar flame speed and

δ_{L}

is the flame thickness. In the nonlinear regime, three-dimensional DNS were carried out with two different Froude numbers, i.e. Fr = 10 and Fr = 0.033. Both laminar and turbulent flames were considered. The flame consumption speed in the low Fr cases are much higher than that in the high Fr cases, which is primarily due to the increase of flame area. Under laminar conditions, the flame morphology and flame curvature differ significantly between the high and low Fr cases, while the differences become less pronounced for the turbulent cases. The distributions of flame displacement speed and flame stretch along the flame front were analyzed, which are closely related to the flame curvature. The NO formation characteristics were examined, and it was shown that the mass fraction of NO within the flame brush is higher in the low Fr cases, attributed to a wider range of high-temperature region related to superadiabatic combustion. The diagram of global nitrogen flow was analyzed, revealing that both the body force and turbulence rarely change the shares of various nitrogen pathways. The impact of curvature on NO pathways was also explored, showing that the production rate of various NO pathways is significantly enhanced in positively curved regions compared with that in negatively curved regions.

本文采用直接数值模拟的方法研究了体力对贫氢富氨预混火焰稳定性和NO生成的影响。在线性状态下，在不同的体力条件下进行二维DNS。研究发现，当Fr >； 1时，体力对线性增长率的影响可以忽略不计，当Fr <； 1时，体力对线性增长率的影响变得显著，其中Fr为弗劳德数，定义为SL2/gδL，其中g为体力大小，SL为层流火焰速度，δL为火焰厚度。在非线性状态下，采用Fr = 10和Fr = 0.033两种不同的弗鲁德数进行三维DNS。层流火焰和湍流火焰都被考虑在内。低燃比下的火焰消耗速度远高于高燃比下，这主要是由于火焰面积的增加。在层流条件下，火焰形态和火焰曲率在高Fr和低Fr情况下差异显著，而在湍流情况下差异不明显。分析了火焰位移速度和火焰伸展沿火焰前缘的分布，它们与火焰曲率密切相关。研究了NO的形成特性，结果表明，在低Fr情况下，火焰刷内NO的质量分数更高，这是由于与超绝热燃烧相关的高温区域范围更广。通过对全球氮流图的分析，发现无论是机体力还是湍流都很少改变各种氮通路的份额。我们还探讨了曲率对NO通路的影响，结果表明，与负弯曲区相比，正弯曲区各种NO通路的生成速率显著提高。

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引用次数: 0

Efficient synthesis of ethylene glycol monoacetate via coal chemical feedstocks and feedstock-derived catalyst 煤化工原料及原料衍生催化剂高效合成单乙酸乙二醇

IF 7.5 1区工程技术 Q2 ENERGY & FUELS

Fuel

Pub Date : 2025-12-12 DOI: 10.1016/j.fuel.2025.137964

Sixue Xu , Yuxin Wang , Zhigang Zhang , Jinggang Zhao , Lei Shi

Ethylene glycol monoacetate (EGMA) is an important chemical intermediate and is widely used in polymer dissolution, biodiesel additives and other fields. Based on China’s energy structure of “abundant coal, insufficient oil and scarce natural gas”, this study developed a new route to synthesize EGMA via transesterification of methyl acetate (MA) and ethylene glycol (EG), which are both abundant in coal chemical processes. It also innovatively developed a series of ethylene glycol alkali metal salts derived from EG as catalysts for this reaction. The study systematically investigated the feasibility of reaction thermodynamics, catalyst structure–activity relationship, reaction condition optimization and reaction kinetics. Results show that potassium ethylene glycol (EGK) achieves 64.46% EG conversion and 50.82% EGMA yield under mild conditions (65 °C, 1 min), with excellent catalytic activity and selectivity. Pseudo-homogeneous second-order kinetic studies indicate both two-step reactions are slightly endothermic, and the first step is more likely to occur due to lower activation energy. Furthermore, research has confirmed that the conversion of EGK to potassium acetate due to the MA hydrolysis is an important factor contributing to catalyst deactivation. This eco-friendly route with mild conditions and high-performance EGK provides a basis for EGMA industrialization and coal chemical chain extension.

乙二醇单乙酸酯（EGMA）是一种重要的化工中间体，广泛应用于聚合物溶解、生物柴油添加剂等领域。基于中国“煤多、油少、气少”的能源结构，本研究开发了以煤化工工艺中富集的乙酸甲酯（MA）和乙二醇（EG）为原料，通过酯交换法合成EGMA的新路线。创新开发了一系列由EG衍生的乙二醇碱金属盐作为该反应的催化剂。系统考察了反应热力学、催化剂构效关系、反应条件优化和反应动力学的可行性。结果表明，在温和条件下（65℃，1 min），乙二醇钾（EGK）的EG转化率为64.46%，EGMA产率为50.82%，具有良好的催化活性和选择性。伪均相二级动力学研究表明，两步反应均为微吸热反应，由于活化能较低，第一步反应更容易发生。此外，研究证实，由于MA水解，EGK转化为乙酸钾是导致催化剂失活的重要因素。这条环境温和、EGK高性能的环保路线为EGMA产业化和煤化工链延伸提供了基础。

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引用次数: 0

Atomic scale characterization of oxidation path of active functional groups and formation of by-products in coal regulated by oxygen concentration: Experimental and molecular dynamics simulation 氧浓度调控煤中活性官能团氧化路径和副产物形成的原子尺度表征：实验和分子动力学模拟

IF 7.5 1区工程技术 Q2 ENERGY & FUELS

Fuel

Pub Date : 2025-12-12 DOI: 10.1016/j.fuel.2025.137996

Binrui Li, Tianyu Li, Xin Li, Hongqing Zhu, Haoyu Zhang, Linhao Xie, Baolin Qu

Investigating the influence of environmental factors e.g. O₂ concentration in actual coal mining, on the reaction path of CSC provides the important reference for prevention of coal fire and environmental protection during mining. Therefore, the effects of O₂ concentration on reaction heat and group changes during heating are investigated by TG-DSC and FTIR. The influence mechanism of O₂ concentration on the reaction path and products is investigated at atomic scale by ReaxFF MD. The results indicate that low-oxygen condition suppresses chemical adsorption during oxidation, enhances the self-reaction of groups, thereby facilitating the formation of –CHO and the depletion of –CH₂/CH₃, while inhibiting the generation of –OH and –COOH. ReaxFF MD results indicate that high-oxygen facilitates the initial-stage reactions and chemical adsorption of groups. This provides reaction conditions for formation of the by-products e.g. CO and CO₂.The rapid accumulation of secondary groups results early formation of oxygen-containing intermediates, which promotes C–H and C–C bonds cleavage for alkyl generation. It promotes the condensation reaction of side chain and enhanced the formation of C-O and O–H bonds. In the initial stage, –OH has the highest oxygen sensitivity. In the entire process, the sensitivity of –OH and –COOH is higher than –CHO and –CH₂/CH₃.

研究煤矿实际开采过程中O2浓度等环境因素对CSC反应路径的影响，为煤矿火灾防治和开采环境保护提供重要参考。因此，通过TG-DSC和FTIR研究了O2浓度对反应热和加热过程中基团变化的影响。利用ReaxFF MD在原子尺度上研究了O2浓度对反应路径和产物的影响机理。结果表明，低氧条件抑制了氧化过程中的化学吸附，增强了基团的自反应，从而促进了-CHO的形成和-CH2 /CH3的消耗，同时抑制了-OH和-COOH的生成。ReaxFF MD结果表明，高氧有利于初始反应和基团的化学吸附。这为生成CO和CO2等副产物提供了反应条件。次级基团的快速积累导致含氧中间体的早期形成，促进C-H和C-C键的裂解生成烷基。它促进侧链的缩合反应，促进了C-O和O-H键的形成。在初始阶段，-OH的氧敏感性最高。在整个过程中，-OH和-COOH的敏感性高于-CHO和-CH2 /CH3。

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引用次数: 0

Energy input rate as a key switch: tuning product distribution and carbon structure in waste tire pyrolysis via conventional and microwave heating 能量输入率作为关键开关：通过常规加热和微波加热调整废轮胎热解过程中的产物分布和碳结构

IF 7.5 1区工程技术 Q2 ENERGY & FUELS

Fuel

Pub Date : 2025-12-12 DOI: 10.1016/j.fuel.2025.138003

Peng Liu , Shuxiao Wang , Jing Gu , Rui Shan , Yanzhi Sun , Junqing Pan , Haoran Yuan , Yong Chen

To address the issues of low thermal efficiency, poor product quality, and low value associated with conventional pyrolysis of waste tires, this study comparatively investigated the mechanisms influencing product characteristics under three pyrolysis methods: conventional electric heating (EP), low-power microwave (MP-L), and high-power microwave (MP-H). Using multiple characterization techniques including thermogravimetry, chromatography, Raman spectroscopy, X-ray photoelectron spectroscopy, and nitrogen adsorption, the composition, structure, and properties of the gaseous, liquid, and solid pyrolysis products were systematically analyzed. Results indicate that microwave heating (especially MP-H) significantly promotes the formation of light products (increased gas yield with higher H₂, CH₄, and light oil content); while EP yields gas with higher calorific value due to its greater C2–C6 hydrocarbon content. MP-H promotes carbon black ordering and surface purification at low temperatures (400 °C) but causes pore sintering and decreased specific surface area at high temperatures (800 °C). The carbon black obtained from EP exhibits higher porosity and surface functional group content. This study elucidates the regulatory mechanism of energy input rate on pyrolysis pathways and product characteristics, providing crucial theoretical foundations and practical references for achieving high-value and directed pyrolytic conversion of waste tires.

针对废旧轮胎常规热解存在的热效率低、产品质量差、价值低等问题，对比研究了常规电加热（EP）、低功率微波（MP-L）和大功率微波（MP-H）三种热解方式对产品特性的影响机理。采用热重法、色谱法、拉曼光谱法、x射线光电子能谱法、氮吸附等多种表征技术，系统分析了气态、液态和固态热解产物的组成、结构和性质。结果表明，微波加热（尤其是MP-H）显著促进了轻产物的形成（H2、CH4和轻质油含量增加，产气量增加）；而EP由于其较高的C2-C6烃含量，产生的气体具有较高的热值。MP-H在低温（400°C）下促进炭黑有序和表面净化，但在高温（800°C）下导致孔烧结和比表面积下降。EP制得的炭黑具有较高的孔隙率和表面官能团含量。本研究阐明了能量输入速率对热解途径和产物特性的调控机制，为实现废轮胎高价值定向热解转化提供了重要的理论基础和实践参考。

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引用次数: 0

CPFD simulation study on oxygen-enriched gasification characteristics of biomass in circulating fluidized bed gasifier 循环流化床生物质富氧气化特性的CPFD模拟研究

IF 7.5 1区工程技术 Q2 ENERGY & FUELS

Fuel

Pub Date : 2025-12-12 DOI: 10.1016/j.fuel.2025.137975

Zhiwei Hu, Haodong Fan, Qi Chen, Chun Wang, Shihong Zhang

Biomass has the natural advantage of zero carbon emissions, and the use of its gasification in different industrial sectors has become a new trend. However, biomass gasification syngas is unstable due to the influence of raw materials and operating conditions, and the mechanism for adjusting gasification characteristics as needed is not clear. This study comprehensively analyzed the oxygen enriched gasification characteristics of industrial CFB gasifier using computational particle fluid dynamics (CPFD) method, including gas–solid flow, bed temperature distribution, gas concentration distribution, and gasification characteristics. The study shows that pure oxygen replaces air and maintains a constant oxygen supply, CFB gasifiers exhibit optimal thermochemical performance at an oxygen concentration of 41 %. Assuming that the pyrolysis process occurs uniformly within the particles, the carbon conversion rate and gasification efficiency of gasification products decreased by 3 % and 1 %. The proportion of

H_{2}

and

C O

increased by 8 % and 5 %, and the calorific value increased by 60 %. This study enhances the understanding of oxygen enriched gasification process, and it provides theoretical support for optimizing gasification characteristic regulation.

生物质具有零碳排放的天然优势，在不同工业领域利用其气化已成为一种新的趋势。然而，生物质气化合成气受原料和操作条件的影响不稳定，根据需要调整气化特性的机理尚不明确。本研究采用计算粒子流体动力学（CPFD）方法对工业CFB气化炉富氧气化特性进行了全面分析，包括气固流动、床层温度分布、气体浓度分布、气化特性等。研究表明，纯氧替代空气并保持恒定的氧气供应，CFB气化炉在氧气浓度为41%时表现出最佳的热化学性能。假设热解过程在颗粒内均匀发生，气化产物的碳转化率和气化效率分别下降3%和1%。H2和CO的比例分别提高了8%和5%，热值提高了60%。本研究增强了对富氧气化过程的认识，为优化气化特性调控提供了理论支持。

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引用次数: 0

Study on laminar burning velocity and flame stability of ammonia combustion with methyl formate 甲酸甲酯对氨燃烧层流燃烧速度及火焰稳定性的研究

IF 7.5 1区工程技术 Q2 ENERGY & FUELS

Fuel

Pub Date : 2025-12-12 DOI: 10.1016/j.fuel.2025.137994

Hao Xu , Qian Wang , Yuesheng Wang , Liming Dai , Zhixia He

Blending methyl formate (MeFo) with ammonia (NH₃) was found to significantly improve the combustion rate of NH₃. Laminar burning velocities (LBV) of NH₃/MeFo/air mixtures were measured in a spherical constant-volume combustion chamber using the schlieren method under equivalence ratios of 0.7–1.4, initial pressures of 1–5 bar, and an initial temperature of 353 K, with NH₃ fractions ranging from 0 % to 90 %. The LBV was observed to increase with the MeFo fraction, reaching a peak near an equivalence ratio of 1.1. Kinetic analysis based on a newly developed mechanism, which has been validated against multiple experimental datasets, highlighted strong interactions between NH and CH₃ radicals. Flame stability analysis showed that hydrodynamic instability intensified with increasing MeFo fraction and pressure, and was more pronounced under fuel-rich conditions. Thermo-diffusive instability occurred at lean conditions for trace MeFo addition, but shifted to rich conditions when the MeFo fraction exceeded 10 %. The Markstein length increased with equivalence ratio for pure NH₃, decreased for mixtures containing more than 50 % MeFo, and exhibited a non-monotonic trend for intermediate mixtures. Linear stability analysis further revealed that thermal conduction consistently promoted flame stability, viscosity had only a minor destabilizing effect, and the influence of molecular diffusion strongly depended on both mixture composition and equivalence ratio.

甲酸甲酯（MeFo）与氨（NH3）共混可显著提高NH3的燃烧速率。采用纹影法在等容球形燃烧室中测量了NH3/MeFo/空气混合物的层流燃烧速度（LBV），当量比为0.7 ~ 1.4，初始压力为1 ~ 5 bar，初始温度为353 K， NH3分数为0% ~ 90%。观察到LBV随着MeFo馏分的增加而增加，在等效比为1.1附近达到峰值。基于一个新开发的机制的动力学分析，已经在多个实验数据集上得到验证，强调了NH和CH3自由基之间的强相互作用。火焰稳定性分析表明，流体动力不稳定性随甲醇分数和压力的增加而加剧，且在富燃料条件下更为明显。在微量MeFo添加条件下，热扩散不稳定性发生在贫条件下，但当MeFo添加分数超过10%时，热扩散不稳定性转向富条件。对于纯NH3， Markstein长度随等效比增大而增大，对于MeFo含量大于50%的混合物，Markstein长度减小，对于中间混合物，Markstein长度呈现非单调趋势。线性稳定性分析进一步揭示了热传导对火焰稳定性的促进作用，粘度对火焰稳定性的影响较小，而分子扩散对火焰稳定性的影响主要取决于混合物的组成和当量比。

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引用次数: 0

Experimental analysis of performance and emissions of hydrous ethanol in internal combustion engine and multi-objective optimization based on ABC-ANN-NSGAII 基于ABC-ANN-NSGAII的内燃机含水乙醇性能与排放实验分析及多目标优化

IF 7.5 1区工程技术 Q2 ENERGY & FUELS

Fuel

Pub Date : 2025-12-12 DOI: 10.1016/j.fuel.2025.137959

Zijian Zhang , Wei Guan , Yubao Xie , Hengqiu Huang , Ke Liang , Kaifeng Zhong , Li Li , Mingzhang Pan

As a renewable energy source, ethanol is favored by many researchers and has been widely used in many fields. Enhancing modern ethanol engine performance requires practical methods. Therefore, this study employs experiments and artificial intelligence to investigate the effects of ethanol–water content variations on engine performance and emissions across diverse loads and compression ratios, employing multi-objective optimization. Experimental findings demonstrate that elevated water content in ethanol lowers NO_x emissions, but at the same time it will have adverse effects on HC emissions and specific fuel consumption. Under extreme conditions (water fraction reaches 40 %-50 %), reduction in engine performance metrics, specifically efficiency and power will occur. Based on ABC-ANN method, the functional relationship between the parameters of ethanol engine (NO_x, HC, SFC, Efficiency, Power) and engine operating parameters is established in this paper. This study leverages a hybrid NSGA-II-TOPSIS framework to resolve performance-emission conflicts in ethanol engines, thereby acquiring optimal operational parameters. The optimization results show that compared with the benchmark conditions, the emission of NO_x is reduced by 21.03 %, the emission of HC is reduced by 40.35 %, the fuel consumption rate is reduced by 0.67 %, the efficiency is improved by 0.47 %, and the power is increased by 7.4 %. The running conditions of this result are water fraction 30 %, engine speed 2700 rpm, compression ratio 8.7 and ignition advance 51° BTDC.

乙醇作为一种可再生能源，受到许多研究者的青睐，在许多领域得到了广泛的应用。提高现代乙醇发动机的性能需要实用的方法。因此，本研究采用实验和人工智能技术，采用多目标优化方法，研究不同负载和压缩比下乙醇-水含量变化对发动机性能和排放的影响。实验结果表明，提高乙醇中水分含量可以降低NOx排放，但同时会对HC排放和比油耗产生不利影响。在极端条件下（含水率达到40% - 50%），发动机性能指标，特别是效率和功率将会下降。基于ABC-ANN方法，建立了乙醇发动机参数（NOx、HC、SFC、Efficiency、Power）与发动机运行参数之间的函数关系。本研究利用混合NSGA-II-TOPSIS框架来解决乙醇发动机的性能排放冲突，从而获得最佳操作参数。优化结果表明，与基准工况相比，NOx排放量降低21.03%，HC排放量降低40.35%，燃油消耗率降低0.67%，效率提高0.47%，功率提高7.4%。该结果的运行条件为：水分数30%，发动机转速2700转/分，压缩比8.7，点火提前51°BTDC。

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引用次数: 0

Kinetic equation of water electrolysis at HER in SOEC systems determined from molecular modelling 用分子模型确定SOEC系统中HER的水电解动力学方程

IF 7.5 1区工程技术 Q2 ENERGY & FUELS

Fuel

Pub Date : 2025-12-12 DOI: 10.1016/j.fuel.2025.137988

Francisco Gil Adell, Carlos Sáenz Ezquerro, Álvaro Rodríguez-Cambra, María García-Camprubí

Green hydrogen has been established as an attractive alternative and clean source of energy which would help towards climate neutrality. Among the different technologies that can be used to produce this type of hydrogen, solid oxide electrolysis cell (SOEC) has positioned itself as the most promising technology due to its lower global demand of energy and higher efficiency. The present study aims to determine the kinetics of the hydrogen evolution reaction (HER) produced from the water electrolysis at the cathode of a SOEC system composed of yttria-stabilized zirconia (YSZ) and nickel particles. Representative molecular models of such material system were developed and simulated under reactive molecular dynamics (MD) simulations using the ReaxFF potential. The mechanism of the reaction presented the characteristic Volmer and Tafel steps, by which the water molecules split into atomic hydrogen which finally associated in molecular hydrogen. The reaction order (1.14) and activation energy (65.9 ± 9.2 kJ/mol) were determined through kinetic analysis over the temperature range of 1000–1500 K. The results aligned with data from experimental studies, supporting the validity of the methodology for studying the electrochemistry of SOEC systems.

绿色氢已被确立为一种有吸引力的替代能源和清洁能源，有助于实现气候中和。在可用于生产这种类型的氢的不同技术中，固体氧化物电解电池（SOEC）由于其全球能源需求较低且效率较高而将自己定位为最有前途的技术。本研究旨在确定由钇稳定氧化锆（YSZ）和镍颗粒组成的SOEC体系阴极上电解水产生析氢反应（HER）的动力学。建立了具有代表性的分子模型，并利用ReaxFF电位在反应分子动力学（MD）下进行了模拟。反应机理表现为典型的Volmer - Tafel步骤，水分子分裂成氢原子，最终结合成氢分子。在1000 ~ 1500 K范围内，通过动力学分析确定了反应级数（1.14）和活化能（65.9±9.2 kJ/mol）。结果与实验研究的数据一致，支持了研究SOEC系统电化学方法的有效性。

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