Pub Date : 2025-02-13DOI: 10.1016/j.combustflame.2025.114011
Alessandro Giannotta , Matthew Yoko , Stefania Cherubini , Pietro De Palma , Matthew P. Juniper
<div><div>We perform twenty experiments on an acoustically-forced laminar premixed Bunsen flame and assimilate high-speed footage of the natural emission into a physics-based model containing seven parameters. The experimental rig is a ducted Bunsen flame supplied by a mixture of methane and ethylene. A high-speed camera captures the natural emission of the flame, from which we extract the position of the flame front. We use Bayesian inference to combine this experimental data with our prior knowledge of this flame’s behaviour. This prior knowledge is expressed through (i) a model of the kinematics of a flame front moving through a model of the perturbed velocity field, and (ii) <em>a priori</em> estimates of the parameters of the above model with quantified uncertainties. We find the most probable <em>a posteriori</em> model parameters using Bayesian parameter inference, and quantify their uncertainties using Laplace’s method combined with first-order adjoint methods. This is substantially cheaper than other common Bayesian inference frameworks, such as Markov Chain Monte Carlo. This process results in a quantitatively-accurate physics-based reduced-order model of the acoustically forced Bunsen flame for injection velocities ranging from <span><math><mrow><mn>1</mn><mo>.</mo><mn>75</mn><mspace></mspace><mtext>m/s</mtext></mrow></math></span> to <span><math><mrow><mn>2</mn><mo>.</mo><mn>99</mn><mspace></mspace><mtext>m/s</mtext></mrow></math></span> and equivalence ratio values ranging from 1.26 to 1.47, using seven parameters. We use this model to evaluate the heat release rate between experimental snapshots, to extrapolate to different experimental conditions, and to calculate the flame transfer function and its uncertainty for all the flames. Since the proposed model relies on only seven parameters, it can be trained with little data and successfully extrapolates beyond the training dataset. Matlab code is provided so that the reader can apply it to assimilate further flame images into the model.</div><div><strong>Novelty and Significance Statement</strong> Thermoacoustic systems tend to be extremely sensitive to small parameter changes, which makes them difficult to model <em>a priori</em> from existing models in the literature. This means, however, that thermoacoustic models tend to be easy to train using data-driven methods because, with well-chosen experiments, their parameters can be easily observed from experimental data. This paper presents a novel use of Bayesian inference to combine experimental measurements, numerical simulations, and prior knowledge about flame behaviour. We outline our methodology and demonstrate its effectiveness using a laminar premixed Bunsen flame. Our approach yields a quantitatively-accurate physics-based model that predicts the expected value and uncertainty bounds of the flame transfer function between velocity and heat release rate perturbations. The proposed model contains only seven physical parameters,
{"title":"Bayesian inference of physics-based models of acoustically-forced laminar premixed conical flames","authors":"Alessandro Giannotta , Matthew Yoko , Stefania Cherubini , Pietro De Palma , Matthew P. Juniper","doi":"10.1016/j.combustflame.2025.114011","DOIUrl":"10.1016/j.combustflame.2025.114011","url":null,"abstract":"<div><div>We perform twenty experiments on an acoustically-forced laminar premixed Bunsen flame and assimilate high-speed footage of the natural emission into a physics-based model containing seven parameters. The experimental rig is a ducted Bunsen flame supplied by a mixture of methane and ethylene. A high-speed camera captures the natural emission of the flame, from which we extract the position of the flame front. We use Bayesian inference to combine this experimental data with our prior knowledge of this flame’s behaviour. This prior knowledge is expressed through (i) a model of the kinematics of a flame front moving through a model of the perturbed velocity field, and (ii) <em>a priori</em> estimates of the parameters of the above model with quantified uncertainties. We find the most probable <em>a posteriori</em> model parameters using Bayesian parameter inference, and quantify their uncertainties using Laplace’s method combined with first-order adjoint methods. This is substantially cheaper than other common Bayesian inference frameworks, such as Markov Chain Monte Carlo. This process results in a quantitatively-accurate physics-based reduced-order model of the acoustically forced Bunsen flame for injection velocities ranging from <span><math><mrow><mn>1</mn><mo>.</mo><mn>75</mn><mspace></mspace><mtext>m/s</mtext></mrow></math></span> to <span><math><mrow><mn>2</mn><mo>.</mo><mn>99</mn><mspace></mspace><mtext>m/s</mtext></mrow></math></span> and equivalence ratio values ranging from 1.26 to 1.47, using seven parameters. We use this model to evaluate the heat release rate between experimental snapshots, to extrapolate to different experimental conditions, and to calculate the flame transfer function and its uncertainty for all the flames. Since the proposed model relies on only seven parameters, it can be trained with little data and successfully extrapolates beyond the training dataset. Matlab code is provided so that the reader can apply it to assimilate further flame images into the model.</div><div><strong>Novelty and Significance Statement</strong> Thermoacoustic systems tend to be extremely sensitive to small parameter changes, which makes them difficult to model <em>a priori</em> from existing models in the literature. This means, however, that thermoacoustic models tend to be easy to train using data-driven methods because, with well-chosen experiments, their parameters can be easily observed from experimental data. This paper presents a novel use of Bayesian inference to combine experimental measurements, numerical simulations, and prior knowledge about flame behaviour. We outline our methodology and demonstrate its effectiveness using a laminar premixed Bunsen flame. Our approach yields a quantitatively-accurate physics-based model that predicts the expected value and uncertainty bounds of the flame transfer function between velocity and heat release rate perturbations. The proposed model contains only seven physical parameters, ","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"274 ","pages":"Article 114011"},"PeriodicalIF":5.8,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395262","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-13DOI: 10.1016/j.combustflame.2025.114045
Jay Patel, Arindrajit Chowdhury, Neeraj Kumbhakarna
The primary objective of the current research is to develop and validate a detailed reaction mechanism for the condensed-phase decomposition of ammonium perchlorate (AP), which is crucial for understanding the combustion behavior of AP-based propellants that are extensively used in solid rocket propulsion systems. Quantum mechanics calculations were performed at the B3LYP/6–311++G(d,p) level of theory to investigate the elementary reactions in the condensed phase, utilizing the Integral Equation Formalism of the Polarizable Continuum Model (IEFPCM) to simulate these reactions. Transition state theory was employed to determine the kinetic parameters, while the CBS-QB3 method was used to calculate the thermodynamic properties of the reactions. Experimental validation was achieved by comparing the computational results with data from laser pyrolysis and Fourier-transform infrared spectroscopy (FTIR) experiments, conducted at four isothermal conditions (410 °C, 430 °C, 450 °C, and 470 °C) in terms of mass loss and gas-phase mole fraction profiles. The computational model, incorporating a detailed reaction mechanism and product evaporation, closely matched experimental observations, with minor deviations attributed to experimental uncertainties. The model assumes that 40 % of AP undergoes sublimation, forming NH₃ and HClO₄ in the gas phase, while the remaining 60 % reacts in the condensed phase, producing species such as H₂O, HCl, NO₂, N₂O, ClO₂, HNO₃, and Cl₂, which evaporate into the gas phase. This validated reaction mechanism represents a significant advancement in modeling AP decomposition, providing valuable insights for safety and performance assessments in industrial applications.
{"title":"Development and validation of a detailed reaction mechanism for the condensed phase decomposition of ammonium perchlorate","authors":"Jay Patel, Arindrajit Chowdhury, Neeraj Kumbhakarna","doi":"10.1016/j.combustflame.2025.114045","DOIUrl":"10.1016/j.combustflame.2025.114045","url":null,"abstract":"<div><div>The primary objective of the current research is to develop and validate a detailed reaction mechanism for the condensed-phase decomposition of ammonium perchlorate (AP), which is crucial for understanding the combustion behavior of AP-based propellants that are extensively used in solid rocket propulsion systems. Quantum mechanics calculations were performed at the B3LYP/6–311++G(d,p) level of theory to investigate the elementary reactions in the condensed phase, utilizing the Integral Equation Formalism of the Polarizable Continuum Model (IEFPCM) to simulate these reactions. Transition state theory was employed to determine the kinetic parameters, while the CBS-QB3 method was used to calculate the thermodynamic properties of the reactions. Experimental validation was achieved by comparing the computational results with data from laser pyrolysis and Fourier-transform infrared spectroscopy (FTIR) experiments, conducted at four isothermal conditions (410 °C, 430 °C, 450 °C, and 470 °C) in terms of mass loss and gas-phase mole fraction profiles. The computational model, incorporating a detailed reaction mechanism and product evaporation, closely matched experimental observations, with minor deviations attributed to experimental uncertainties. The model assumes that 40 % of AP undergoes sublimation, forming NH₃ and HClO₄ in the gas phase, while the remaining 60 % reacts in the condensed phase, producing species such as H₂O, HCl, NO₂, N₂O, ClO₂, HNO₃, and Cl₂, which evaporate into the gas phase. This validated reaction mechanism represents a significant advancement in modeling AP decomposition, providing valuable insights for safety and performance assessments in industrial applications.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"274 ","pages":"Article 114045"},"PeriodicalIF":5.8,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395261","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}
Pub Date : 2025-02-13DOI: 10.1016/j.combustflame.2025.114028
Ignacio Trueba-Monje, Jeffrey A. Sutton
An important issue for conversion of measured filtered Rayleigh scattering (FRS) signals into temperature in combustion systems is the degree to which the local chemical state needs to be known or approximated. To avoid the need for simultaneous multi-species measurements, Part I of this paper series introduced a framework based on state relationships from one-dimensional laminar flame simulations to account for composition effects. Following the demonstration of accurate and reliable FRS-based thermometry under laminar flame conditions (Part I), this paper uses both computational and experimental data to evaluate the accuracy of this methodology in turbulent premixed flames. First, synthetic results from direct numerical simulations (DNS) of CH4/air flames under varying turbulence levels are used to directly evaluate the proposed FRS approach. Results demonstrate accurate temperature determination using the proposed FRS methodology with uncertainties of less than 3%. Analysis shows that, even when the local species composition fluctuates significantly in space and time, the conditional relationship between a given species and temperature shows relatively little scatter compared to the most probable value. Furthermore, there exists an apparent stable behavior where the under-prediction of some species by the presumed state relationship is counter-balanced by an over-prediction of other species in such a manner that the composition-dependent portion of the FRS signal-temperature relationship remains relatively unchanged and well represented by the laminar flame state relationship, regardless of temperature or turbulence level. Experimental results are also presented in a series of turbulent premixed flames with variations in reactant composition, equivalence ratio, and Reynolds numbers. Simultaneous laser Rayleigh scattering (LRS) and FRS measurements converge to common temperatures, indicating accuracy of the proposed FRS methodology within turbulent premixed flames. Overall, results demonstrate that laminar flame state relationships sufficiently capture the net effect of species formation, mixing, and transport with respect to their influence on the local FRS signal. This allows accurate FRS-based temperature measurements in turbulent premixed flames without the need for additional species measurements.
{"title":"Filtered Rayleigh scattering thermometry in premixed flames, Part II: Implementation and accuracy in turbulent flames","authors":"Ignacio Trueba-Monje, Jeffrey A. Sutton","doi":"10.1016/j.combustflame.2025.114028","DOIUrl":"10.1016/j.combustflame.2025.114028","url":null,"abstract":"<div><div>An important issue for conversion of measured filtered Rayleigh scattering (FRS) signals into temperature in combustion systems is the degree to which the local chemical state needs to be known or approximated. To avoid the need for simultaneous multi-species measurements, Part I of this paper series introduced a framework based on state relationships from one-dimensional laminar flame simulations to account for composition effects. Following the demonstration of accurate and reliable FRS-based thermometry under laminar flame conditions (Part I), this paper uses both computational and experimental data to evaluate the accuracy of this methodology in turbulent premixed flames. First, synthetic results from direct numerical simulations (DNS) of CH<sub>4</sub>/air flames under varying turbulence levels are used to directly evaluate the proposed FRS approach. Results demonstrate accurate temperature determination using the proposed FRS methodology with uncertainties of less than 3%. Analysis shows that, even when the local species composition fluctuates significantly in space and time, the conditional relationship between a given species and temperature shows relatively little scatter compared to the most probable value. Furthermore, there exists an apparent stable behavior where the under-prediction of some species by the presumed state relationship is counter-balanced by an over-prediction of other species in such a manner that the composition-dependent portion of the FRS signal-temperature relationship remains relatively unchanged and well represented by the laminar flame state relationship, regardless of temperature or turbulence level. Experimental results are also presented in a series of turbulent premixed flames with variations in reactant composition, equivalence ratio, and Reynolds numbers. Simultaneous laser Rayleigh scattering (LRS) and FRS measurements converge to common temperatures, indicating accuracy of the proposed FRS methodology within turbulent premixed flames. Overall, results demonstrate that laminar flame state relationships sufficiently capture the net effect of species formation, mixing, and transport with respect to their influence on the local FRS signal. This allows accurate FRS-based temperature measurements in turbulent premixed flames without the need for additional species measurements.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"274 ","pages":"Article 114028"},"PeriodicalIF":5.8,"publicationDate":"2025-02-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395260","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}
Pub Date : 2025-02-12DOI: 10.1016/j.combustflame.2025.114025
John H. Kim , Andrew B. Mansfield , Miles A. Burnett , Robert S. Tranter , Margaret S. Wooldridge
The effects of trimethylsilanol (TMSO) and hexamethyldisiloxane (HMDSO) addition on OH time histories during syngas (H2 and CO) ignition were investigated using the University of Michigan rapid compression facility. Experiments spanned temperatures of 1010–1080 K, at a pressure of approximately 5 atm. Syngas mixtures of 1.2 % H2/2.8 % CO/20 % O2 by volume (balance N2 and Ar) provided a baseline for comparison with mixtures that included 100, 200, and 1000 ppm of the TMSO and 100 ppm of HMDSO. Narrow-line ultraviolet laser-absorption was used to measure OH mole-fraction during ignition. The addition of TMSO and HMDSO significantly shifted the OH time-histories earlier in time, by up to 51 %, compared with the baseline syngas mixture. The value of the maximum OH mole fraction was consistent between the 100 and 200 ppm TMSO mixtures and the 100 ppm HMDSO mixtures, but the maximum OH increased significantly with the 1000 ppm TMSO mixtures. The OH data indicate TMSO and HMDSO were not direct sources of OH radicals. Analysis further indicates the TMSO and HMDSO decompose rapidly followed by reactions that enhance the production of H atoms, and the increased reactivity observed is via the H + O2 = OH + O reaction.
{"title":"Time-resolved measurements of OH during auto-ignition of syngas with trimethylsilanol and hexamethyldisiloxane","authors":"John H. Kim , Andrew B. Mansfield , Miles A. Burnett , Robert S. Tranter , Margaret S. Wooldridge","doi":"10.1016/j.combustflame.2025.114025","DOIUrl":"10.1016/j.combustflame.2025.114025","url":null,"abstract":"<div><div>The effects of trimethylsilanol (TMSO) and hexamethyldisiloxane (HMDSO) addition on OH time histories during syngas (H<sub>2</sub> and CO) ignition were investigated using the University of Michigan rapid compression facility. Experiments spanned temperatures of 1010–1080 K, at a pressure of approximately 5 atm. Syngas mixtures of 1.2 % H<sub>2</sub>/2.8 % CO/20 % O<sub>2</sub> by volume (balance N<sub>2</sub> and Ar) provided a baseline for comparison with mixtures that included 100, 200, and 1000 ppm of the TMSO and 100 ppm of HMDSO. Narrow-line ultraviolet laser-absorption was used to measure OH mole-fraction during ignition. The addition of TMSO and HMDSO significantly shifted the OH time-histories earlier in time, by up to 51 %, compared with the baseline syngas mixture. The value of the maximum OH mole fraction was consistent between the 100 and 200 ppm TMSO mixtures and the 100 ppm HMDSO mixtures, but the maximum OH increased significantly with the 1000 ppm TMSO mixtures. The OH data indicate TMSO and HMDSO were not direct sources of OH radicals. Analysis further indicates the TMSO and HMDSO decompose rapidly followed by reactions that enhance the production of H atoms, and the increased reactivity observed is via the <em>H</em> + O<sub>2</sub> = OH + O reaction.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"274 ","pages":"Article 114025"},"PeriodicalIF":5.8,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387874","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}
Pub Date : 2025-02-12DOI: 10.1016/j.combustflame.2025.114027
Ignacio Trueba-Monje, Jeffrey A. Sutton
Filtered Rayleigh scattering (FRS) is a proven laser-based measurement technique that can be used to determine gas-phase properties in the presence of interference from unwanted surface or particulate scattering. In combustion environments, an important issue for conversion of measured FRS signals into temperature is the strong dependence on the local gas mixture composition. Previously, the importance of accurately characterizing the local chemical state has not been systematically evaluated in terms of FRS-based thermometry. Simultaneous quantitative measurements of all pertinent species are quite challenging and involve complex and expensive experimental setups. Thus, there have been previous FRS-specific approaches developed to approximate species composition that circumvent additional multi-scalar measurements. This paper is one of a two-part series that first seeks to evaluate the sensitivity of derived temperature estimates to the local composition and assess existing simplifying assumptions for approximating the unknown composition in laminar premixed flames. This paper uses a combination of simulations and experiments in laminar premixed flames of various fuels and equivalence ratios to understand the importance of composition knowledge/approximation for accurate FRS thermometry results. In general, results show that there is a need to reliably represent the most abundant species and their associated Rayleigh–Brillouin scattering spectral contributions. Approximations of the local composition by a single species lead to significant error (up to 50%) and non-physical results over a broad range of flame conditions. Finally, a simple but robust framework based on state relations from laminar flame calculations is recommended for accounting for composition effects. This approach leads to accurate (2% error) and reliable FRS-based temperature results in laminar premixed flames without the need for simultaneous species concentration measurements.
{"title":"Filtered Rayleigh scattering thermometry in premixed flames—Part I: Laminar flames and the effects of mixture composition approximation","authors":"Ignacio Trueba-Monje, Jeffrey A. Sutton","doi":"10.1016/j.combustflame.2025.114027","DOIUrl":"10.1016/j.combustflame.2025.114027","url":null,"abstract":"<div><div>Filtered Rayleigh scattering (FRS) is a proven laser-based measurement technique that can be used to determine gas-phase properties in the presence of interference from unwanted surface or particulate scattering. In combustion environments, an important issue for conversion of measured FRS signals into temperature is the strong dependence on the local gas mixture composition. Previously, the importance of accurately characterizing the local chemical state has not been systematically evaluated in terms of FRS-based thermometry. Simultaneous quantitative measurements of all pertinent species are quite challenging and involve complex and expensive experimental setups. Thus, there have been previous FRS-specific approaches developed to approximate species composition that circumvent additional multi-scalar measurements. This paper is one of a two-part series that first seeks to evaluate the sensitivity of derived temperature estimates to the local composition and assess existing simplifying assumptions for approximating the unknown composition in laminar premixed flames. This paper uses a combination of simulations and experiments in laminar premixed flames of various fuels and equivalence ratios to understand the importance of composition knowledge/approximation for accurate FRS thermometry results. In general, results show that there is a need to reliably represent the most abundant species and their associated Rayleigh–Brillouin scattering spectral contributions. Approximations of the local composition by a single species lead to significant error (up to 50%) and non-physical results over a broad range of flame conditions. Finally, a simple but robust framework based on state relations from laminar flame calculations is recommended for accounting for composition effects. This approach leads to accurate (<span><math><mo><</mo></math></span>2% error) and reliable FRS-based temperature results in laminar premixed flames without the need for simultaneous species concentration measurements.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"274 ","pages":"Article 114027"},"PeriodicalIF":5.8,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387880","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}
Pub Date : 2025-02-11DOI: 10.1016/j.combustflame.2025.114002
Bin Dong , Yushen Yu , Qingbo Zhu , Bingzhi Liu , Kuiwen Zhang , Jun Fang , Longhua Hu , Zhandong Wang
Ethylene carbonate (EC) is a major component of the widely used lithium-ion battery (LIB) electrolytes, therefore it is of great importance for the risk assessment of LIB fires. In this work, the pyrolysis and oxidation of EC (equivalence ratio of 0.5) was investigated in a jet-stirred reactor (JSR) coupled to synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS) and gas chromatography at atmospheric pressure, with initial EC mole fraction of 0.0021 and residence time of 2 s. The mole fraction profiles of reaction products measured in this work, including hydrogen, water, carbon monoxide, carbon dioxide, C1C2 hydrocarbons, formaldehyde, acetaldehyde, ketene and etc., were utilized to validate the recently proposed electrolyte surrogate models in the literatures. The results showed that the prediction of ketene yield in EC pyrolysis, as well as the prediction of EC reactivity in EC oxidation, are poor using the previous models. Therefore, based on reaction pathway analysis and sensitivity analysis in JSR, the kinetic model of EC in the literature was improved by updating and tuning the rate constants of some key reactions related to the formation and consumption of formyl methyl radical (ĊH2CHO) and ketene. The updated model could predict EC consumption and the yield of major species better than those predicted by models in the literatures. In addition, from the oxidation results of EC, we found that the reactivity of EC could be significantly enhanced by hydroxyl radical (ȮH) produced by the reaction of formyl methyl radical with oxygen.
{"title":"Experimental study of ethylene carbonate (EC) pyrolysis and oxidation in jet-stirred reactor by SVUV-PIMS","authors":"Bin Dong , Yushen Yu , Qingbo Zhu , Bingzhi Liu , Kuiwen Zhang , Jun Fang , Longhua Hu , Zhandong Wang","doi":"10.1016/j.combustflame.2025.114002","DOIUrl":"10.1016/j.combustflame.2025.114002","url":null,"abstract":"<div><div>Ethylene carbonate (EC) is a major component of the widely used lithium-ion battery (LIB) electrolytes, therefore it is of great importance for the risk assessment of LIB fires. In this work, the pyrolysis and oxidation of EC (equivalence ratio of 0.5) was investigated in a jet-stirred reactor (JSR) coupled to synchrotron vacuum ultraviolet photoionization mass spectrometry (SVUV-PIMS) and gas chromatography at atmospheric pressure, with initial EC mole fraction of 0.0021 and residence time of 2 s. The mole fraction profiles of reaction products measured in this work, including hydrogen, water, carbon monoxide, carbon dioxide, C<sub>1<img></sub>C<sub>2</sub> hydrocarbons, formaldehyde, acetaldehyde, ketene and etc., were utilized to validate the recently proposed electrolyte surrogate models in the literatures. The results showed that the prediction of ketene yield in EC pyrolysis, as well as the prediction of EC reactivity in EC oxidation, are poor using the previous models. Therefore, based on reaction pathway analysis and sensitivity analysis in JSR, the kinetic model of EC in the literature was improved by updating and tuning the rate constants of some key reactions related to the formation and consumption of formyl methyl radical (ĊH<sub>2</sub>CHO) and ketene. The updated model could predict EC consumption and the yield of major species better than those predicted by models in the literatures. In addition, from the oxidation results of EC, we found that the reactivity of EC could be significantly enhanced by hydroxyl radical (ȮH) produced by the reaction of formyl methyl radical with oxygen.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"274 ","pages":"Article 114002"},"PeriodicalIF":5.8,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143387873","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}
Pub Date : 2025-02-11DOI: 10.1016/j.combustflame.2025.114023
Zhenyang Li , Bo Yin , Qifu Lin , Yifei Zhu , Yun Wu
<div><div>The kinetics of plasma assisted low temperature oxidation of <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>3</mn></mrow></msub><msub><mrow><mi>H</mi></mrow><mrow><mn>8</mn></mrow></msub><mo>/</mo><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>/</mo><mi>A</mi><mi>r</mi></mrow></math></span> mixtures have been studied in a wide specific deposited energy with the help of nanosecond repetitively pulsed discharge. Two types of nanosecond pulsed plasma sources, the nanosecond capillary discharge (nCD) and dielectric barrier discharge (DBD) combined with the synchrotron photoionization mass spectrometry are investigated. The electron impact reaction rate of propane dissociation and some combustion chemical reactions rate constants are updated according to the nCD and DBD experiment results, and uncertainty of the reactions are analyzed in detail. Compared to the existing model, the updated model’s prediction accuracy has great improvement in species <span><math><mrow><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>O</mi></mrow></math></span>, <span><math><mrow><mi>C</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math></span>, <span><math><mrow><mi>C</mi><msub><mrow><mi>H</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></math></span>, <span><math><mrow><mi>C</mi><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>O</mi></mrow></math></span>, <span><math><mrow><mi>C</mi><msub><mrow><mi>H</mi></mrow><mrow><mn>3</mn></mrow></msub><mi>O</mi><mi>H</mi></mrow></math></span>, <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math></span>, <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>H</mi></mrow><mrow><mn>6</mn></mrow></msub></mrow></math></span>, <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>H</mi></mrow><mrow><mn>5</mn></mrow></msub><mi>O</mi><mi>H</mi></mrow></math></span>, <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>H</mi></mrow><mrow><mn>5</mn></mrow></msub><mi>O</mi><mi>O</mi><mi>H</mi></mrow></math></span>, <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>3</mn></mrow></msub><msub><mrow><mi>H</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></math></span>-<span><math><mi>A</mi></math></span>, <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>3</mn></mrow></msub><msub><mrow><mi>H</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></math></span>-<span><math><mi>P</mi></math></span>, <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>H</mi></mrow><mrow><mn>5</mn></mrow></msub><mi>C</mi><mi>H</mi><mi>O</mi></mrow></math></span>, <span><math><mi>i</mi></math></span>-<span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>3</mn></mrow></msub><msub><mrow><mi>H</mi></mrow><mrow><mn>7</mn>
{"title":"Kinetic development of low-temperature propane oxidation in a repetitively-pulsed nanosecond discharge","authors":"Zhenyang Li , Bo Yin , Qifu Lin , Yifei Zhu , Yun Wu","doi":"10.1016/j.combustflame.2025.114023","DOIUrl":"10.1016/j.combustflame.2025.114023","url":null,"abstract":"<div><div>The kinetics of plasma assisted low temperature oxidation of <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>3</mn></mrow></msub><msub><mrow><mi>H</mi></mrow><mrow><mn>8</mn></mrow></msub><mo>/</mo><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub><mo>/</mo><mi>A</mi><mi>r</mi></mrow></math></span> mixtures have been studied in a wide specific deposited energy with the help of nanosecond repetitively pulsed discharge. Two types of nanosecond pulsed plasma sources, the nanosecond capillary discharge (nCD) and dielectric barrier discharge (DBD) combined with the synchrotron photoionization mass spectrometry are investigated. The electron impact reaction rate of propane dissociation and some combustion chemical reactions rate constants are updated according to the nCD and DBD experiment results, and uncertainty of the reactions are analyzed in detail. Compared to the existing model, the updated model’s prediction accuracy has great improvement in species <span><math><mrow><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>O</mi></mrow></math></span>, <span><math><mrow><mi>C</mi><msub><mrow><mi>O</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math></span>, <span><math><mrow><mi>C</mi><msub><mrow><mi>H</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></math></span>, <span><math><mrow><mi>C</mi><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub><mi>O</mi></mrow></math></span>, <span><math><mrow><mi>C</mi><msub><mrow><mi>H</mi></mrow><mrow><mn>3</mn></mrow></msub><mi>O</mi><mi>H</mi></mrow></math></span>, <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></math></span>, <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>H</mi></mrow><mrow><mn>6</mn></mrow></msub></mrow></math></span>, <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>H</mi></mrow><mrow><mn>5</mn></mrow></msub><mi>O</mi><mi>H</mi></mrow></math></span>, <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>H</mi></mrow><mrow><mn>5</mn></mrow></msub><mi>O</mi><mi>O</mi><mi>H</mi></mrow></math></span>, <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>3</mn></mrow></msub><msub><mrow><mi>H</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></math></span>-<span><math><mi>A</mi></math></span>, <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>3</mn></mrow></msub><msub><mrow><mi>H</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></math></span>-<span><math><mi>P</mi></math></span>, <span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>2</mn></mrow></msub><msub><mrow><mi>H</mi></mrow><mrow><mn>5</mn></mrow></msub><mi>C</mi><mi>H</mi><mi>O</mi></mrow></math></span>, <span><math><mi>i</mi></math></span>-<span><math><mrow><msub><mrow><mi>C</mi></mrow><mrow><mn>3</mn></mrow></msub><msub><mrow><mi>H</mi></mrow><mrow><mn>7</mn>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"274 ","pages":"Article 114023"},"PeriodicalIF":5.8,"publicationDate":"2025-02-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143379058","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}
Pub Date : 2025-02-09DOI: 10.1016/j.combustflame.2025.114008
Matteo Impagnatiello, Sergey Shcherbanev, Bayu Dharmaputra, Nicolas Noiray
<div><div>This study experimentally investigates the coupling between thermoacoustic instabilities and autoignition kernel formation in Constant Pressure Sequential Combustors (CPSCs). Two fuel types are examined: a less reactive methane–hydrogen blend (<span><math><msub><mrow><mi>F</mi></mrow><mrow><msub><mrow><mi>CH</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></msub></math></span>) and pure hydrogen (<span><math><msub><mrow><mi>F</mi></mrow><mrow><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></msub></math></span>). By increasing the thermal power of the first stage, thermoacoustic instabilities arise in both configurations, albeit with distinct behaviors. <span><math><msub><mrow><mi>F</mi></mrow><mrow><msub><mrow><mi>CH</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></msub></math></span> exhibits a gradual onset of instability, whereas <span><math><msub><mrow><mi>F</mi></mrow><mrow><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></msub></math></span> undergoes a subcritical Hopf bifurcation, characterized by abrupt, intermittent transitions between a linearly stable state and limit cycles at intermediate first-stage power. Distinct acoustic pressure spectra are observed during instability: <span><math><msub><mrow><mi>F</mi></mrow><mrow><msub><mrow><mi>CH</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></msub></math></span> features a single dominant peak around 290 Hz, while <span><math><msub><mrow><mi>F</mi></mrow><mrow><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></msub></math></span> displays multiple high-amplitude peaks corresponding to harmonics of the fundamental frequency near 400 Hz. Analysis of acoustic pressure and OH* chemiluminescence during instability reveals a strong coupling between acoustic fluctuations and autoignition kernel formation. With <span><math><msub><mrow><mi>F</mi></mrow><mrow><msub><mrow><mi>CH</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></msub></math></span>, the temporal evolution of the OH* chemiluminescence associated with these kernels follows a quasi-sinusoidal profile at the instability frequency, whereas with <span><math><msub><mrow><mi>F</mi></mrow><mrow><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></msub></math></span>, it consists of sharp pulses synchronized with the fundamental acoustic mode. Although existing Low-Order Models (LOMs) successfully capture the experimental behavior in <span><math><msub><mrow><mi>F</mi></mrow><mrow><msub><mrow><mi>CH</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></msub></math></span>, they fail to replicate the complex dynamics of <span><math><msub><mrow><mi>F</mi></mrow><mrow><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></msub></math></span>. To address this, a novel LOM incorporating a strongly nonlinear Heat Release Rate (HRR) feedback term is developed, specifically tailored for configurations with significant coupling between autoignition and thermoacousti
{"title":"Nonlinear dynamics and thermoacoustic intermittency of a hydrogen-powered sequential combustor","authors":"Matteo Impagnatiello, Sergey Shcherbanev, Bayu Dharmaputra, Nicolas Noiray","doi":"10.1016/j.combustflame.2025.114008","DOIUrl":"10.1016/j.combustflame.2025.114008","url":null,"abstract":"<div><div>This study experimentally investigates the coupling between thermoacoustic instabilities and autoignition kernel formation in Constant Pressure Sequential Combustors (CPSCs). Two fuel types are examined: a less reactive methane–hydrogen blend (<span><math><msub><mrow><mi>F</mi></mrow><mrow><msub><mrow><mi>CH</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></msub></math></span>) and pure hydrogen (<span><math><msub><mrow><mi>F</mi></mrow><mrow><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></msub></math></span>). By increasing the thermal power of the first stage, thermoacoustic instabilities arise in both configurations, albeit with distinct behaviors. <span><math><msub><mrow><mi>F</mi></mrow><mrow><msub><mrow><mi>CH</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></msub></math></span> exhibits a gradual onset of instability, whereas <span><math><msub><mrow><mi>F</mi></mrow><mrow><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></msub></math></span> undergoes a subcritical Hopf bifurcation, characterized by abrupt, intermittent transitions between a linearly stable state and limit cycles at intermediate first-stage power. Distinct acoustic pressure spectra are observed during instability: <span><math><msub><mrow><mi>F</mi></mrow><mrow><msub><mrow><mi>CH</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></msub></math></span> features a single dominant peak around 290 Hz, while <span><math><msub><mrow><mi>F</mi></mrow><mrow><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></msub></math></span> displays multiple high-amplitude peaks corresponding to harmonics of the fundamental frequency near 400 Hz. Analysis of acoustic pressure and OH* chemiluminescence during instability reveals a strong coupling between acoustic fluctuations and autoignition kernel formation. With <span><math><msub><mrow><mi>F</mi></mrow><mrow><msub><mrow><mi>CH</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></msub></math></span>, the temporal evolution of the OH* chemiluminescence associated with these kernels follows a quasi-sinusoidal profile at the instability frequency, whereas with <span><math><msub><mrow><mi>F</mi></mrow><mrow><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></msub></math></span>, it consists of sharp pulses synchronized with the fundamental acoustic mode. Although existing Low-Order Models (LOMs) successfully capture the experimental behavior in <span><math><msub><mrow><mi>F</mi></mrow><mrow><msub><mrow><mi>CH</mi></mrow><mrow><mn>4</mn></mrow></msub></mrow></msub></math></span>, they fail to replicate the complex dynamics of <span><math><msub><mrow><mi>F</mi></mrow><mrow><msub><mrow><mi>H</mi></mrow><mrow><mn>2</mn></mrow></msub></mrow></msub></math></span>. To address this, a novel LOM incorporating a strongly nonlinear Heat Release Rate (HRR) feedback term is developed, specifically tailored for configurations with significant coupling between autoignition and thermoacousti","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"274 ","pages":"Article 114008"},"PeriodicalIF":5.8,"publicationDate":"2025-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143376547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-07DOI: 10.1016/j.combustflame.2025.114007
Tingquan Tian , Haiou Wang , Jacqueline H. Chen , Zhongshan Li , Marcus Aldén , Kun Luo , Jianren Fan
In the present study, three-dimensional direct numerical simulations (DNS) of experimental ammonia/air premixed jet flames with different turbulent intensities were performed. The DNS results were first compared to the measurements with good agreements. Based on the DNS data, the turbulent flame structure, stabilization mechanism and NO emission characteristics of the flames were investigated. It was found that the flame with higher turbulent intensity exhibits a higher degree of wrinkling and an increased flame surface area. In addition, turbulent eddies can enter into the reaction zone and disrupt the distributions of NH and temperature more strongly for the flame with higher turbulent intensity. It was shown that the heat release rate of the turbulent flame can be approximated by the results of strained laminar flames to some extent. Enhanced heat release rates were observed in the regions of negative curvature near the reactant side and in the regions of positive curvature near the product side, which is due to the local enhancement of radicals such as NH and NH that contribute significantly to the heat release. To understand the flame stabilization mechanism of the turbulent flames, corresponding one-dimensional unstrained and strained unsteady laminar flames were simulated. It was found that auto-ignition initially occurs and the reaction front transitions into a propagating front following the ignition process for both the unstrained and strained laminar flames. The ignition characteristics of the turbulent flames are largely consistent with those of the laminar flames. The study also revealed the NO formation characteristics. NO is consumed in the reaction zone and produced in the product side. The maximum NO mass fraction increases with increasing axial distance. Analysis of NO pathway suggests that this phenomenon is due to the enhanced NO production in the downstream regions, which is related to the accumulation of radicals such as OH, O and H.
Novelty and significance
This research reports the first direct numerical simulations of laboratory-scale ammonia/air turbulent premixed jet flames with varying turbulent intensities. The novelty of this research is that the flame structure, flame stabilization and NO emission characteristics of ammonia/air jet flames are explored using detailed DNS data, which are crucial for improved understanding of ammonia combustion. Furthermore, the present work provides high-fidelity DNS data of turbulent ammonia combustion for the development of combustion models.
{"title":"Direct numerical simulations of laboratory-scale NH3/air jet flames: Analysis of flame structure, flame stabilization and NO emission characteristics","authors":"Tingquan Tian , Haiou Wang , Jacqueline H. Chen , Zhongshan Li , Marcus Aldén , Kun Luo , Jianren Fan","doi":"10.1016/j.combustflame.2025.114007","DOIUrl":"10.1016/j.combustflame.2025.114007","url":null,"abstract":"<div><div>In the present study, three-dimensional direct numerical simulations (DNS) of experimental ammonia/air premixed jet flames with different turbulent intensities were performed. The DNS results were first compared to the measurements with good agreements. Based on the DNS data, the turbulent flame structure, stabilization mechanism and NO emission characteristics of the flames were investigated. It was found that the flame with higher turbulent intensity exhibits a higher degree of wrinkling and an increased flame surface area. In addition, turbulent eddies can enter into the reaction zone and disrupt the distributions of NH and temperature more strongly for the flame with higher turbulent intensity. It was shown that the heat release rate of the turbulent flame can be approximated by the results of strained laminar flames to some extent. Enhanced heat release rates were observed in the regions of negative curvature near the reactant side and in the regions of positive curvature near the product side, which is due to the local enhancement of radicals such as NH and NH<span><math><msub><mrow></mrow><mrow><mn>2</mn></mrow></msub></math></span> that contribute significantly to the heat release. To understand the flame stabilization mechanism of the turbulent flames, corresponding one-dimensional unstrained and strained unsteady laminar flames were simulated. It was found that auto-ignition initially occurs and the reaction front transitions into a propagating front following the ignition process for both the unstrained and strained laminar flames. The ignition characteristics of the turbulent flames are largely consistent with those of the laminar flames. The study also revealed the NO formation characteristics. NO is consumed in the reaction zone and produced in the product side. The maximum NO mass fraction increases with increasing axial distance. Analysis of NO pathway suggests that this phenomenon is due to the enhanced NO production in the downstream regions, which is related to the accumulation of radicals such as OH, O and H.</div><div><strong>Novelty and significance</strong></div><div>This research reports the first direct numerical simulations of laboratory-scale ammonia/air turbulent premixed jet flames with varying turbulent intensities. The novelty of this research is that the flame structure, flame stabilization and NO emission characteristics of ammonia/air jet flames are explored using detailed DNS data, which are crucial for improved understanding of ammonia combustion. Furthermore, the present work provides high-fidelity DNS data of turbulent ammonia combustion for the development of combustion models.</div></div>","PeriodicalId":280,"journal":{"name":"Combustion and Flame","volume":"274 ","pages":"Article 114007"},"PeriodicalIF":5.8,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143349904","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}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：