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Acetaldehyde reactivity at engine-relevant conditions: An experimental and kinetic modeling study 乙醛在发动机相关条件下的反应性:实验和动力学模型研究
IF 5.2 2区 工程技术
Proceedings of the Combustion Institute Pub Date : 2025-01-01 Epub Date: 2025-09-20 DOI: 10.1016/j.proci.2025.105828
Jesus Caravaca-Vilchez, Malte Döntgen, Karl Alexander Heufer
{"title":"Acetaldehyde reactivity at engine-relevant conditions: An experimental and kinetic modeling study","authors":"Jesus Caravaca-Vilchez,&nbsp;Malte Döntgen,&nbsp;Karl Alexander Heufer","doi":"10.1016/j.proci.2025.105828","DOIUrl":"10.1016/j.proci.2025.105828","url":null,"abstract":"<div><div>Understanding the combustion chemistry of acetaldehyde, a carcinogenic by-product formed during the low-temperature oxidation of various hydrocarbons, is essential for reducing harmful emissions in engines. Previous acetaldehyde experimental works have largely focused on low-pressure conditions, with a few exceptions. Some studies report a clear negative temperature coefficient (NTC) behavior for acetaldehyde and highlight the need for further low-temperature, high-pressure experiments to fully characterize it. In this context, acetaldehyde ignition delay times were measured using a rapid compression machine and a shock tube over a wide range of conditions (580–1410 K, 10–40 bar, and equivalence ratios of 0.5–1.5), significantly extending the very limited IDT data available in the literature at 10 bar. At low temperatures, the most comprehensive kinetic models of acetaldehyde greatly underestimate its reactivity, even those that show reasonable performance for flow reactor species measurements from the literature in the same temperature regime. At high temperatures, model predictions were generally in better agreement with the measured data. To improve prediction accuracy, refinements were made within GalwayMech1.0 model, incorporating recently calculated thermochemistry from the literature and modified reaction rate parameters based on direct analogies and literature information. The resulting chemistry revealed that the acetyl peroxy radical is the primary driver of low-temperature reactivity at high pressures through a closed-loop fuel consumption pathway. Further adjustments in the peroxyl radicals chemistry, which is less relevant under low-pressure conditions, successfully separate first-stage and main ignition in the NTC region. At high temperatures, revised H-atom abstraction by <span><math><mover><mrow><mi>H</mi></mrow><mrow><mo>̇</mo></mrow></mover></math></span> and O<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> rates improved high-temperature predictions. Overall, the proposed model outperforms existing mechanisms over a wide range of conditions, but retains uncertainties in the formation of a few minor intermediates. This work highlights the importance of using high-pressure validation targets for comprehensive kinetic modeling and provides a solid foundation for future studies on acetaldehyde oxidation.</div></div>","PeriodicalId":408,"journal":{"name":"Proceedings of the Combustion Institute","volume":"41 ","pages":"Article 105828"},"PeriodicalIF":5.2,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145104440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Dynamic behaviors of flame and molten insulation in electrical wire fire under applied electric field 外加电场作用下电线着火火焰和熔融绝缘的动态行为
IF 5.2 2区 工程技术
Proceedings of the Combustion Institute Pub Date : 2025-01-01 Epub Date: 2025-09-17 DOI: 10.1016/j.proci.2025.105862
Jeong Park , Chun Sang Yoo , Suk Ho Chung
{"title":"Dynamic behaviors of flame and molten insulation in electrical wire fire under applied electric field","authors":"Jeong Park ,&nbsp;Chun Sang Yoo ,&nbsp;Suk Ho Chung","doi":"10.1016/j.proci.2025.105862","DOIUrl":"10.1016/j.proci.2025.105862","url":null,"abstract":"<div><div>This study reviews recent findings on the dynamic behaviors of flame and molten insulation material observed in spreading flames over electrical wires under applied electric fields, which is a relevant scenario in electrical wire safety. The important roles of various unique dynamic behaviors in flame spreads are discussed, including fuel-vapor jet ejection from molten polyethylene (PE) surface, internal circulation of molten PE driven by Marangoni convection, dripping of molten PE, electrospray ejecting multiple small droplets from molten PE surface, and lateral dielectrophoresis by migrating a part of main molten PE toward the burnt wire side by forming a secondary molten PE or a liquid film of molten PE and sometimes leading to a formation of splitting flame. Additional behaviors such as vibration/rotation of molten PE due to a vertical dielectrophoresis, flame-leaning toward the burnt wire side caused by ionic wind, and magnetic field induced flame vortices near flame edges are also reviewed. The physical mechanisms of these dynamic behaviors are explained. Various regimes are identified depending on the occurrence of abovementioned phenomena. The dependence of flame spread rate on relevant physical parameters is reviewed, revealing a non-monotonic response to applied AC voltage and frequency, due to the intricate interactions among various dynamic phenomena. Phenomenological correlations are established for the FSR using key physical parameters including wire diameter, wire core diameter, applied voltage and frequency, and radial electric field gradient. To better understand the dynamic behaviors of molten insulation, the combustion of a droplet suspended on a wire was investigated, isolating the effects of solid-to-liquid phase change and the asymmetric distribution of molten PE between the burnt and unburned sides of the wire. The dynamic behaviors of such burning droplets under applied electric fields, along with their underlying mechanisms, are also reviewed and discussed.</div></div>","PeriodicalId":408,"journal":{"name":"Proceedings of the Combustion Institute","volume":"41 ","pages":"Article 105862"},"PeriodicalIF":5.2,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145104448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Experimental investigation of turbulent premixed H2-jet flames at high exhaust gas recirculation 高排气再循环条件下湍流预混h2射流火焰的实验研究
IF 5.2 2区 工程技术
Proceedings of the Combustion Institute Pub Date : 2025-01-01 Epub Date: 2025-10-04 DOI: 10.1016/j.proci.2025.105866
Maurus Bauer , Björn Stelzner , Peter Habisreuther , Michael Schneider , Christof Weis , Dimosthenis Trimis
{"title":"Experimental investigation of turbulent premixed H2-jet flames at high exhaust gas recirculation","authors":"Maurus Bauer ,&nbsp;Björn Stelzner ,&nbsp;Peter Habisreuther ,&nbsp;Michael Schneider ,&nbsp;Christof Weis ,&nbsp;Dimosthenis Trimis","doi":"10.1016/j.proci.2025.105866","DOIUrl":"10.1016/j.proci.2025.105866","url":null,"abstract":"<div><div>This study presents an experimental investigation of a turbulent premixed hydrogen jet flame operating under high exhaust gas recirculation (EGR) rates. Experiments were conducted at a Reynolds number of 10<!--> <!-->000, exploring flames ranging from pure H<sub>2</sub>–air mixtures to cases with an EGR rate of 0.67. The flames were carefully adjusted to maintain similar laminar burning velocities, enabling consistent comparisons and revealing a systematic increase in the equivalence ratio (<span><math><mi>Φ</mi></math></span>) with higher EGR rates. These operating conditions were derived through a detailed 1D analysis of H<sub>2</sub>–air–EGR laminar flames using comprehensive chemical kinetics, complemented with measurements of the laminar burning velocities of premixed H<sub>2</sub>–air–EGR flames. The flow field of the model burner setup and nozzle design was characterized under both non-reactive and reactive conditions using particle image velocimetry (PIV). OH* chemiluminescence imaging did not reveal significant changes in the overall structure of the flame, even as the equivalence ratio varied from <span><math><mi>Φ</mi></math></span> = 0.4 (pure H<sub>2</sub>–air flame) to near-stoichiometric conditions (<span><math><mi>Φ</mi></math></span> = 0.77). Selected cases were further investigated using OH planar laser-induced fluorescence (OH-LIF), offering detailed visualization of the flame structure and corroborating the observations from OH* chemiluminescence. NO<sub>X</sub> emissions remained low across all investigated EGR rates, demonstrating robust emission control. These findings enhance the understanding of hydrogen combustion dynamics under high EGR conditions and provide valuable insights for developing low-emission, high-stability combustion strategies.</div></div>","PeriodicalId":408,"journal":{"name":"Proceedings of the Combustion Institute","volume":"41 ","pages":"Article 105866"},"PeriodicalIF":5.2,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145262475","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Detonation chemistry and propagation characteristics in partially cracked ammonia 部分裂解氨的爆轰化学与传播特性
IF 5.2 2区 工程技术
Proceedings of the Combustion Institute Pub Date : 2025-01-01 Epub Date: 2025-10-08 DOI: 10.1016/j.proci.2025.105910
Jie Sun , Salim M. Shaik , Van Bo Nguyen , Huangwei Zhang
{"title":"Detonation chemistry and propagation characteristics in partially cracked ammonia","authors":"Jie Sun ,&nbsp;Salim M. Shaik ,&nbsp;Van Bo Nguyen ,&nbsp;Huangwei Zhang","doi":"10.1016/j.proci.2025.105910","DOIUrl":"10.1016/j.proci.2025.105910","url":null,"abstract":"<div><div>Ammonia has relatively low reactivity, making it difficult to initiate and maintain a stable detonation wave. Cracking ammonia into hydrogen and nitrogen can enhance the detonability of the mixture. This study evaluates the influence of ammonia cracking ratio (<em>κ</em>) on the detonation characteristics of partially cracked ammonia and oxygen mixtures (NH<sub>3</sub>/H<sub>2</sub>/O<sub>2</sub>/N<sub>2</sub>) by numerical simulations considering detailed chemistry. It aims to explain how the initial hydrogen generated from ammonia cracking affects the detonation. First, steady ZND structures and reaction flux paths are analyzed for different <em>κ</em>. The results show that NH<sub>3</sub> is primarily consumed via pyrolysis. The initial hydrogen reacts through reactions R3 (O+H<sub>2</sub>→OH+H), R4 (OH+H<sub>2</sub>→H+H<sub>2</sub>O) and R160 (NH<sub>3</sub>+H→NH<sub>2</sub>+H<sub>2</sub>), which releases heat and shortens the induction time. As <em>κ</em> increases, R3 and R4 replace R160 to dominate the initial hydrogen consumption. Besides, increasing <em>κ</em> also favors the pyrolysis of NH<sub>3</sub> by NH<sub>3</sub>→NH<sub>2</sub>→NH due to more H and OH radicals generated from the initial hydrogen reactions. Subsequently, unsteady pulsating and cellular detonations are simulated. Detonation waves propagate more stably as <em>κ</em> increases. Two re-initiation modes are identified for pulsating detonations. When <em>κ</em> is small, unburned mixture pockets are observed behind the leading shock. The mixtures within the pockets burn, creating pressure waves to interact with the leading shock. The interactions induce new reaction fronts to re-initiate the detonation. As κ increases, the reactivity of the shocked mixture increases, reshaping the reactivity gradient and causing the re-initiation mode to transition to the acceleration of the original reaction front. For cellular detonation, similar unburned gas pockets caused by the decoupling of transverse detonation waves are also observed. As κ increases, more initial hydrogen reacts and enhances the mixture reactivity behind the incident shock waves, leading to transverse detonation waves to propagate without decoupling. Hence the detonation waves become more stable.</div></div>","PeriodicalId":408,"journal":{"name":"Proceedings of the Combustion Institute","volume":"41 ","pages":"Article 105910"},"PeriodicalIF":5.2,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145262473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Clustering-based data-driven multi-fidelity reduced order modeling of ammonia combustion 基于聚类的数据驱动多保真度氨燃烧降阶建模
IF 5.2 2区 工程技术
Proceedings of the Combustion Institute Pub Date : 2025-01-01 Epub Date: 2025-10-08 DOI: 10.1016/j.proci.2025.105881
Aysu Özden , Riccardo Malpica Galassi , Francesco Contino , Alessandro Parente
{"title":"Clustering-based data-driven multi-fidelity reduced order modeling of ammonia combustion","authors":"Aysu Özden ,&nbsp;Riccardo Malpica Galassi ,&nbsp;Francesco Contino ,&nbsp;Alessandro Parente","doi":"10.1016/j.proci.2025.105881","DOIUrl":"10.1016/j.proci.2025.105881","url":null,"abstract":"<div><div>This study presents a multi-fidelity reduced-order modeling (MF-ROM) framework that uses unsupervised clustering to identify and separately model distinct combustion regimes within the training data. This regime-specific approach allows enhancing computational efficiency while maintaining high predictive accuracy. The proposed MF-ROM framework leverages Proper Orthogonal Decomposition (POD) for dimensionality reduction, manifold alignment for optimal data fusion, and Co-Kriging regression to incorporate both high-fidelity (HiFi) and low-fidelity (LoFi) datasets effectively. First, global clustering is applied to segment the design space into combustion regimes, significantly improving MF-ROM accuracy while reducing the number of required HiFi simulations. Additionally, localized clustering is explored within specific subsets of the design space, demonstrating further refinement in predictive performance. Ammonia combustion is selected as the benchmark case because it is carbon-free and a promising candidate for the energy transition. Moreover, its chemical characteristics make it particularly suitable for the clustering-based MF-ROM approach, as they facilitate the generation of a very diverse training dataset. Results show that the clustering-based MF-ROM achieves the same accuracy as the model without clustering with significantly fewer HiFi simulations, leading to a sixfold reduction in computational cost while maintaining predictive reliability. Moreover, local clustering enhances interpolation capabilities, particularly in regions where combustion characteristics exhibit strong variability. A comparative analysis of temperature and NO emissions confirms that the clustering-driven approach improves both accuracy and efficiency, which can lead to an increase in prediction accuracy up to 50%. The methodology offers a scalable and adaptable approach for optimizing MF-ROMs in reacting flows, supporting the development of low-emission combustion technologies.</div></div>","PeriodicalId":408,"journal":{"name":"Proceedings of the Combustion Institute","volume":"41 ","pages":"Article 105881"},"PeriodicalIF":5.2,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145262471","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Investigating the use of ammonia- and methanol-diesel blends in reactivity controlled compression ignition mode for marine engines 研究氨和甲醇-柴油混合物在船舶发动机反应性控制压缩点火模式中的应用
IF 5.2 2区 工程技术
Proceedings of the Combustion Institute Pub Date : 2025-01-01 Epub Date: 2025-08-22 DOI: 10.1016/j.proci.2025.105813
Aneesh Vijay Kale, Harsh Darshan Sapra, Saurabh Kumar Gupta, Reed Hanson, Sage Kokjohn
{"title":"Investigating the use of ammonia- and methanol-diesel blends in reactivity controlled compression ignition mode for marine engines","authors":"Aneesh Vijay Kale,&nbsp;Harsh Darshan Sapra,&nbsp;Saurabh Kumar Gupta,&nbsp;Reed Hanson,&nbsp;Sage Kokjohn","doi":"10.1016/j.proci.2025.105813","DOIUrl":"10.1016/j.proci.2025.105813","url":null,"abstract":"<div><div>There is a need to adopt low-carbon fuels such as ammonia and methanol to decarbonize the marine fleet. The higher autoignition temperatures of ammonia and methanol make it challenging to use these fuels in conventional diesel engines. Previous studies have demonstrated that operating a conventional diesel engine in the Reactivity Controlled Compression Ignition (RCCI) mode has the potential to utilize low-carbon fuels without compromising engine performance or emissions. This study comprehensively compares the RCCI engine characteristics when methanol-diesel and ammonia-diesel are used as fuels. Experiments were conducted in a 6.7 L Cummins ISB engine for the methanol-diesel RCCI. A 3D CFD numerical engine model was developed in the Converge software and validated with experimental data. The ammonia-diesel RCCI was studied by replacing the methanol-diesel blend with the ammonia-diesel blend for the same fuel energy. The premixed energy ratio was varied from 5 % to 95 % for the constant fuel energy, keeping all other engine operating parameters the same. Best cases for RCCI combustion were chosen based on maximum gross indicated thermal efficiency and minimum greenhouse gas emissions. The maximum gross indicated thermal efficiency for the methanol-diesel RCCI (obtained by substituting 83 % diesel mass with methanol) was 20 % higher than that of ammonia-diesel RCCI (obtained by substituting 65 % diesel mass with ammonia) and 13 % higher than that of conventional diesel combustion. Overall, this study provides directions on using methanol and ammonia as sustainable fuels for marine engines, selecting the optimal premixed energy ratios to achieve efficient RCCI combustion.</div></div>","PeriodicalId":408,"journal":{"name":"Proceedings of the Combustion Institute","volume":"41 ","pages":"Article 105813"},"PeriodicalIF":5.2,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144886774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Experimental evidence for indene formation from o-methylphenyl radical + C2H2/C2H4 reactions 邻甲基苯基自由基+ C2H2/C2H4反应生成茚的实验证据
IF 5.2 2区 工程技术
Proceedings of the Combustion Institute Pub Date : 2025-01-01 Epub Date: 2025-09-22 DOI: 10.1016/j.proci.2025.105859
Zhaohan Chu , Zhongkai Liu , Changyang Wang , Long Zhao , Bin Yang
{"title":"Experimental evidence for indene formation from o-methylphenyl radical + C2H2/C2H4 reactions","authors":"Zhaohan Chu ,&nbsp;Zhongkai Liu ,&nbsp;Changyang Wang ,&nbsp;Long Zhao ,&nbsp;Bin Yang","doi":"10.1016/j.proci.2025.105859","DOIUrl":"10.1016/j.proci.2025.105859","url":null,"abstract":"<div><div>An experimental study was conducted to investigate the weight growth routes from <em>o</em>-methylphenyl radical (<em>o</em>-CH<sub>3</sub>C<sub>6</sub>H<sub>4</sub>) to indene. <em>o</em>-Nitrosotoluene served as the precursor for <em>o</em>-methylphenyl radicals in this study. Co-pyrolysis of <em>o</em>-methylphenyl radical/C<sub>2</sub>H<sub>2</sub> and <em>o</em>-methylphenyl radical/C<sub>2</sub>H<sub>4</sub> was investigated utilizing the chemical microreactor and synchrotron vacuum ultraviolet photoionization mass spectrometry. Sampled mass-specific photoionization efficiency (PIE) curves were employed to identify the aromatic species, elucidating interactions between <em>o</em>-methylphenyl radicals and C<sub>2</sub> species. The species detected at <em>m/z</em> = 116 and 118, essential for understanding the reaction mechanism, were identified via matching photoionization cross-sections and adiabatic ionization energies with literature and theoretical values. Specifically, indene and its isomer <em>o</em>-methylphenylacetylene (<em>m/z</em> = 116) were determined in the reaction of <em>o</em>-methylphenyl radical with C<sub>2</sub>H<sub>2</sub>, while indene and <em>o</em>-methylstyrene (<em>m/z</em> = 118) were identified in the reaction of <em>o</em>-methylphenyl radical with C<sub>2</sub>H<sub>4</sub>. By combining the identified intermediate species with previous literature basis, the formation pathways for indene, originating from <em>o</em>-methylphenyl radical were discussed in both reaction systems, providing further insights for understanding the indene formation pathways.</div></div>","PeriodicalId":408,"journal":{"name":"Proceedings of the Combustion Institute","volume":"41 ","pages":"Article 105859"},"PeriodicalIF":5.2,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145109371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Ignition dynamics of a hydrogen-fueled annular combustor 氢燃料环形燃烧室的点火动力学
IF 5.2 2区 工程技术
Proceedings of the Combustion Institute Pub Date : 2025-01-01 Epub Date: 2025-10-15 DOI: 10.1016/j.proci.2025.105893
Nicolas Vaysse, Daniel Durox, Ronan Vicquelin, Sébastien Candel, Antoine Renaud
{"title":"Ignition dynamics of a hydrogen-fueled annular combustor","authors":"Nicolas Vaysse,&nbsp;Daniel Durox,&nbsp;Ronan Vicquelin,&nbsp;Sébastien Candel,&nbsp;Antoine Renaud","doi":"10.1016/j.proci.2025.105893","DOIUrl":"10.1016/j.proci.2025.105893","url":null,"abstract":"<div><div>Hydrogen is currently considered as a possible fuel substitute for gas turbines and aeroengines in the context of decarbonizing transportation and energy industries. However, its combustion raises scientific challenges due to its broad flammability domain and propensity to combustion instabilities. To ensure safe operation of hydrogen fueled systems, it is mandatory to study hydrogen combustion in industrially-relevant annular configurations that are typically found in applications. The present investigation is carried out in the MICCA facility equipped with 16 hydrogen injection units. In each injector, hydrogen is delivered in cross-flow in a swirled air flow. The aim of this investigation is to study the light-round ignition dynamics of a hydrogen-fueled annular combustor. The ignition sequence is observed with a high-speed camera equipped with an OH<span><math><msup><mrow></mrow><mrow><mo>∗</mo></mrow></msup></math></span> filter. The light-round delays are determined for a range of injection velocities and for equivalence ratios between 0.29 to 0.72. The relatively short light-round delays (from 18 ms to 35 ms), are considerably lower than those found for hydrocarbon flames. It is also found that at low equivalence ratios, the light-round proceeds but does not establish all the flames. The light-round delay is shown to decrease when the equivalence ratio is increased, and also when the inlet velocity is augmented at constant equivalence ratio. A link is made between the average flame displacement velocity and the turbulent burning velocity taking into account the thermal expansion. It is found that this can be achieved with a model combining two expressions for the turbulent burning velocity, corresponding to high and low values of the laminar burning velocity. The model captures the influence of injection velocity and equivalence ratio on the flame displacement velocity during light round. It is thus possible to derive a correlation for the reduced light-round delay that suitably retrieves experimental data.</div></div>","PeriodicalId":408,"journal":{"name":"Proceedings of the Combustion Institute","volume":"41 ","pages":"Article 105893"},"PeriodicalIF":5.2,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145319801","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Influence of soot oxidation reaction time scale on soot break-through 煤烟氧化反应时间尺度对煤烟突破的影响
IF 5.2 2区 工程技术
Proceedings of the Combustion Institute Pub Date : 2025-01-01 Epub Date: 2025-10-15 DOI: 10.1016/j.proci.2025.105930
Gandolfo Scialabba , Antonio Attili , Heinz Pitsch
{"title":"Influence of soot oxidation reaction time scale on soot break-through","authors":"Gandolfo Scialabba ,&nbsp;Antonio Attili ,&nbsp;Heinz Pitsch","doi":"10.1016/j.proci.2025.105930","DOIUrl":"10.1016/j.proci.2025.105930","url":null,"abstract":"<div><div>A previous Direct Numerical Simulation (DNS) study is extended to assess the influence of the soot oxidation reaction time scale on soot break-through in turbulent non-premixed flames. In such cases, soot is formed in rich regions and then pushed toward the flame, where it is often completely oxidized without escaping to the lean region and hence the environment. However, a fast relative drift of soot particles with respect to the oxidation layer paired with local flame extinction can lead to soot break-through (soot leakage), even when the total equivalence ratio is lean. These conditions are met when turbulence levels are sufficiently high, leading to a smoking flame behavior. The baseline configuration consists of a turbulent non-premixed temporal jet where significant soot break-through is observed due to local extinction and mixing. A soot oxidation Damköhler number is defined as the ratio of the flow and soot oxidation reaction time scales. A parametric variation of the soot oxidation Damköhler number is performed by varying the oxidation time scale, i.e., rescaling the soot oxidation rate coefficients, while keeping the flow time scale constant. The relative influence on soot break-through of OH and O<sub>2</sub>-based soot oxidation reaction time scales at varying soot oxidation Damköhler numbers (<span><math><msub><mrow><mi>Da</mi></mrow><mrow><mi>Ox,OH</mi></mrow></msub></math></span> and <span><math><msub><mrow><mi>Da</mi></mrow><mrow><mi>Ox</mi><mo>,</mo><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></msub></math></span>) is quantified. Soot and gas-phase statistics are collected along Lagrangian trajectories to evaluate the relative impact of partial soot oxidation events. A modest change in peak soot mass is observed for both variations. An even smaller impact is found for soot mass break-through, which is only marginally affected by the soot oxidation reaction time scales, as it mainly occurs in regions with strong local extinctions. The results imply that, to capture soot break-through events in reduced-order models, an accurate description of local flame extinction is likely more important than the values of soot oxidation reaction rates.</div></div>","PeriodicalId":408,"journal":{"name":"Proceedings of the Combustion Institute","volume":"41 ","pages":"Article 105930"},"PeriodicalIF":5.2,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145319800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
Title Page 标题页
IF 5.2 2区 工程技术
Proceedings of the Combustion Institute Pub Date : 2025-01-01 Epub Date: 2025-12-18 DOI: 10.1016/S1540-7489(25)00203-2
{"title":"Title Page","authors":"","doi":"10.1016/S1540-7489(25)00203-2","DOIUrl":"10.1016/S1540-7489(25)00203-2","url":null,"abstract":"","PeriodicalId":408,"journal":{"name":"Proceedings of the Combustion Institute","volume":"41 ","pages":"Article 105989"},"PeriodicalIF":5.2,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145786766","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
引用次数: 0
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