المؤلفون: Chunkan Yu, Sudhi Shashidharan, Shuyang Wu, Felipe Minuzzi, Viatcheslav Bykov

المصدر: Modelling, Vol 4, Iss 4, Pp 470-484 (2023)

مصطلحات موضوعية: ignition problem, chemical kinetics, model reduction, reduced chemistry, GQL, hydrogen, Engineering design, TA174

الوصف: The global quasi-linearization (GQL) is used as a method to study and to reduce the complexity of mathematical models of mechanisms of chemical kinetics. Similar to standard methodologies, such as the quasi-steady-state assumption (QSSA), the GQL method defines the fast and slow invariant subspaces and uses slow manifolds to gain a reduced representation. It does not require empirical inputs and is based on the eigenvalue and eigenvector decomposition of a linear map approximating the nonlinear vector field of the original system. In the present work, the GQL-based slow/fast decomposition is applied for different combustion systems. The results are compared with the standard QSSA approach. For this, an implicit implementation strategy described by differential algebraic equations (DAEs) systems is suggested and used, which allows for treating both approaches within the same computational framework. Hydrogen–air (with 9 species) and ethanol–air (with 57 species) combustion systems are considered representative examples to illustrate and verify the GQL. The results show that 4D GQL for hydrogen–air and 14D GQL ethanol–air slow manifolds outperform the standard QSSA approach based on a DAE-based reduced computation model.

وصف الملف: electronic resource

العلاقة: https://www.mdpi.com/2673-3951/4/4/27Test; https://doaj.org/toc/2673-3951Test

الوصول الحر: https://doaj.org/article/8b7d79271c89428eb0a52168ae8b6d01Test

المؤلفون: Le Boursicaud, Marc, Zhao, Song, Consalvi, Jean-Louis, Boivin, Pierre

المساهمون: Laboratoire de Mécanique, Modélisation et Procédés Propres (M2P2), Aix Marseille Université (AMU)-École Centrale de Marseille (ECM)-Centre National de la Recherche Scientifique (CNRS), Institut universitaire des systèmes thermiques industriels (IUSTI), Aix Marseille Université (AMU)-Centre National de la Recherche Scientifique (CNRS), ANR-20-CE05-0009,MALBEC,Méthodes Avancées Lattice-Boltzmann En Combustion(2020)

المصدر: ISSN: 0010-2180 ; Combustion and Flame ; https://hal.science/hal-04169558Test ; Combustion and Flame, 2023, 256, pp.112938. ⟨10.1016/j.combustflame.2023.112938⟩.

مصطلحات موضوعية: Auto-ignition, Hydrogen, Hydrogen safety, reduced chemistry, [SPI.FLUID]Engineering Sciences [physics]/Reactive fluid environment

الوصف: International audience ; With an increasing interest in hydrogen as an alternative fuel for transportation, there is a need to develop tools for the prediction of ignition events. A cost-effective passive scalar formulation has been recently developed to predict hydrogen auto-ignition. A single scalar advection-diffusion-reaction equation is used to reproduce the chain-branched ignition process, where the scalar represents the radical pool responsible of ignition (H, O, OH, HO2 , H2O2). The scalar reaction rate is analytically deduced from the Jacobian matrix associated to hydrogen ignition chemistry. This method was found to reproduce with good accuracy the ignition delays obtained by detailed chemistry for temperature where the branching is the leading process. For temperature close or below the crossover temperature, where other phenomenon such as the thermal runaway are important, the scalar approach fails to predict correctly ignition events. Thus, an extension of the scalar source term formulation is proposed to extend its validity over the entire temperature range. In addition, a simple way to approximate the diffusion properties of the scalar is introduced: the radical pool composition may vary drastically, with molecules having very different diffusion properties (e.g. H and HO2). The complete modified framework is presented and its capability is assessed in canonical scenarios and more complex simulations relevant to hydrogen safety.

العلاقة: hal-04169558; https://hal.science/hal-04169558Test; https://hal.science/hal-04169558/documentTest; https://hal.science/hal-04169558/file/An%20improved%20passive%20scalar%20model%20for%20hydrogen%20hazardous%20ignition%20prediction%20PREPRINT.pdfTest

الإتاحة: https://doi.org/10.1016/j.combustflame.2023.112938Test
https://hal.science/hal-04169558Test
https://hal.science/hal-04169558/documentTest
https://hal.science/hal-04169558/file/An%20improved%20passive%20scalar%20model%20for%20hydrogen%20hazardous%20ignition%20prediction%20PREPRINT.pdfTest

المؤلفون: Yu, Chunkan, Cai, Liming, Chopra, Lovish, Minuzzi, Felipe, Maas, Ulrich

المصدر: Journal of the Brazilian Society of Mechanical Sciences and Engineering, 45 (10), Art.Nr.: 525 ; ISSN: 1678-5878, 1806-3691

مصطلحات موضوعية: Probability density function (PDF), Turbulent combustion, Reduced chemistry, Methane flame, ddc:600, Technology, info:eu-repo/classification/ddc/600

الوصف: The present work focuses on the five different chemical mechanisms coupled with probability density function (PDF) model to represent the local extinction and re-ignition flame characteristics of the well-known Sandia Flames D–F. These five mechanisms span from the Foundational Fuel Chemistry Model (FFCM) mechanism involving 38 species to the Glarborg mechanism involving 150 species. The coupled computational fluid dynamics (CFD) and transported-PDF method are used for the turbulence modeling, and the reaction–diffusion manifolds (REDIMs) are used as an advanced technique for the simplification of chemical kinetics and to speed up the numerical computation. It is demonstrated that these chemical mechanisms have an ability to represent the degree of local extinction and re-ignition accurately. Furthermore, the sensitivity analysis shows that the degree of local extinction is very sensitive to only several key elementary reactions, and an analysis on the turbulence–chemistry interaction investigates the influence of these elementary reactions.

وصف الملف: application/pdf

العلاقة: info:eu-repo/semantics/altIdentifier/wos/001068354800001; info:eu-repo/semantics/altIdentifier/issn/1678-5878; info:eu-repo/semantics/altIdentifier/issn/1806-3691; https://publikationen.bibliothek.kit.edu/1000162664Test; https://publikationen.bibliothek.kit.edu/1000162664/151407791Test; https://doi.org/10.5445/IR/1000162664Test

الإتاحة: https://doi.org/10.5445/IR/1000162664Test
https://doi.org/10.1007/s40430-023-04444-yTest
https://publikationen.bibliothek.kit.edu/1000162664Test
https://publikationen.bibliothek.kit.edu/1000162664/151407791Test

المؤلفون: Shastry, Varun, Riber, Eleonore, Gicquel, Laurent, Cuenot, Bénédicte, Bodoc, Virginel

المساهمون: Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique (CERFACS), DMPE, ONERA, Université de Toulouse Toulouse, ONERA-PRES Université de Toulouse

المصدر: ISSN: 1540-7489.

مصطلحات موضوعية: Large Eddy Simulation, Spray flames, Analytically reduced chemistry, Multicomponent evaporation, Sustainable Aviation Fuel, [SPI.FLUID]Engineering Sciences [physics]/Reactive fluid environment

الوصف: International audience ; Large Eddy Simulations of the realistic liquid fueled gas turbine combustor LOTAR operated at ONERA are performed for two fuels; a conventional JetA-1 and an alternative alcohol to jet fuel At-J, each modeled by a 3component formulation. JetA-1 is composed of n-dodecane, methyl-cyclohexane and xylene each corresponding to the major hydrocarbon families found in real fuel. At-J is a synthetic drop in fuel composed of only branched chain alkanes, iso-octane, iso-dodecane and iso-hexadecane. Analytically reduced chemistry and multicomponent spray evaporation model coupled to the dynamic thickened flame turbulent combustion model are employed to understand the processes involved in turbulent spray flames in the LOTAR configuration. The objectives are to predict and understand the potential effects of staged vapourisation and consumption of the fuel components, and their impact on the spray flame structures. Simulations confirm the role of preferential evaporation in establishing and stabilising the reaction zone. JetA-1 evaporation zones extend deep into the rich burnt gasses resulting in a combustion regime with the possibility of droplet clusters burning individually. At-J which is more volatile, leads to complete combustion with the majority occurring due to the premixed lean reactions of the smaller pyrolysed components. The need to further include models capable of identifying and handling combustion regimes encountered in such spray flames is hence highlighted. This work is intended as a starting point for improving multicomponent spray modelling and requires additional experimental data for validation.

العلاقة: hal-04105312; https://hal.science/hal-04105312Test; https://hal.science/hal-04105312/documentTest; https://hal.science/hal-04105312/file/DMPE22150.1684939261_postprint.pdfTest

الإتاحة: https://doi.org/10.1016/j.proci.2022.08.059Test
https://hal.science/hal-04105312Test
https://hal.science/hal-04105312/documentTest
https://hal.science/hal-04105312/file/DMPE22150.1684939261_postprint.pdfTest

المؤلفون: Capurso, T., Laera, D., Riber, E., Cuenot, B.

المساهمون: Polytechnic University of Bari / Politecnico di Bari, Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique (CERFACS), Laboratoire d'Ingénierie des Fluides et des Systèmes Énergétiques (LIFSE), Conservatoire National des Arts et Métiers CNAM (CNAM), HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)-Arts et Métiers Sciences et Technologies, HESAM Université - Communauté d'universités et d'établissements Hautes écoles Sorbonne Arts et métiers université (HESAM)

المصدر: ISSN: 0010-2180 ; Combustion and Flame ; https://cnam.hal.science/hal-04164183Test ; Combustion and Flame, 2023, 248, pp.1-15. ⟨10.1016/j.combustflame.2022.112581⟩.

مصطلحات موضوعية: Hydrogen/air combustion NO, Large Eddy simulation, Reduced chemistry, Conjugate heat transfer, [SPI]Engineering Sciences [physics], [CHIM]Chemical Sciences, [INFO.INFO-MO]Computer Science [cs]/Modeling and Simulation, [PHYS.MECA.THER]Physics [physics]/Mechanics [physics]/Thermics [physics.class-ph], [SPI.NRJ]Engineering Sciences [physics]/Electric power

الوصف: International audience ; Today’s climate and energy challenges are driving the use of decarbonised and renewable alternative fuels in power generation and transportation. Hydrogen as a fuel is a good candidate to meet these requirements, as it offers no carbon emissions and can play the role of an energy carrier to store excess energy produced by renewable energy. Nonetheless, the production of NO needs to be assessed. For this reason, this study proposes high-fidelity Large Eddy Simulations (LES) with detailed NO analyzes of a partially premixed lean swirling H-air flame. The chosen configuration is the technically premix hydrogen injector measured at the Berlin Institute of Technology (TUB) in Germany. A novel kinetic scheme for H-air comprising 15 species and 47 reactions is developed to take into account all NO pathways. To accurately solve the combustion process and the NO production level, static mesh refinement (SMR) and conjugate heat transfer (CHT) are applied to the LES modeling and their impact on the numerical predictions is evaluated. A detailed analysis of the preferential diffusion and formation of NO is presented, demonstrating that the proposed numerical model, combined with the novel chemical kinetic scheme, is able to correctly predict complex transport phenomena observed in lean turbulent hydrogen flames and to predict their NO dynamic formation accounting for both primary and secondary (NO and NNH) NO pathways.

العلاقة: hal-04164183; https://cnam.hal.science/hal-04164183Test; https://cnam.hal.science/hal-04164183/documentTest; https://cnam.hal.science/hal-04164183/file/Capurso_Comb_Flame_AR_CFD_23_2.pdfTest

الإتاحة: https://doi.org/10.1016/j.combustflame.2022.112581Test
https://cnam.hal.science/hal-04164183Test
https://cnam.hal.science/hal-04164183/documentTest
https://cnam.hal.science/hal-04164183/file/Capurso_Comb_Flame_AR_CFD_23_2.pdfTest

المؤلفون: Millán Merino, Alejandro, Fernández Tarrazo, Eduardo Antonio, Sánchez Sanz, Mario

المساهمون: Ministerio de Economía y Competitividad (España)

مصطلحات موضوعية: Auto-ignition, Ethanol droplet combustion, Humidity, Reduced chemistry, Ingeniería Industrial, Ingeniería Mecánica

الوصف: Results of time-dependent, spherically symmetrical computations of the vaporization and combustion of ethanol and ethanol/water droplets are reported. Mixture-average transport was employed, along with a systematically reduced chemical-kinetic mechanism involving 15 overall steps among 17 chemical species, to speed the computations by a factor of about 100 over what would be required if full detailed chemistry had been used. Absorption of water from the gas surrounding the droplet and its diffusive transport within the liquid phase were taken into account, providing excellent agreement with previous experimental and computational results for the combustion of ethanol droplets in air. On the other hand, the assumption of rapid liquid-phase mixing produced very poor agreement when water condensation on the droplet surface or hydrous ethanol are considered. To characterize autoignition, we define the critical autoignition temperature Tc ∞ as the critical ambient temperature below which autoignition is not observed. Computations for autoignition of cold ethanol/water droplets in air showed that Tc ∞ decreases with increasing initial droplet diameters. In the range of parameters under consideration, ignition was found to take place always before complete vaporization of the droplet, and the ignition time was found to become longer with the increasing initial water content of the liquid ethanol droplet. On the contrary, addition of water vapor to the initial air atmosphere was found to shorten the ignition time, increasing ethanol vaporization rate as a consequence of the extra heat release associated with water absorption into the liquid. ; The authors want to express their gratitude to Professor Forman Williams in the conception and guidance of this work, in particular, and all the ongoing work on ethanol droplet vaporization and combustion. This work was supported by the projects ENE2015-65852-C2-1-R and PID2019-108592RB-C41 (MINECO/FEDER,UE).

العلاقة: Gobierno de España. ENE2015-65852-C2-1-R; Gobierno de España. PID2019-108592RB-C41; Millán-Merino, A., Fernández-Tarrazo, E. & Sánchez-Sanz, M. (2021). Numerical analysis of the autoignition of isolated wet ethanol droplets immersed in a hot and humid air atmosphere. Combustion and Flame, 226, 42–52.; http://hdl.handle.net/10016/34208Test; https://doi.org/10.1016/j.combustflame.2020.11.023Test; 42; 52; Combustion and Flame; 226; AR/0000028668

الإتاحة: https://doi.org/10.1016/j.combustflame.2020.11.023Test
http://hdl.handle.net/10016/34208Test

المؤلفون: Efimov, Denis V., de Goey, Philip, van Oijen, Jeroen A.

المصدر: Efimov , D V , de Goey , P & van Oijen , J A 2020 , ' QFM : quenching flamelet-generated manifold for modelling of flame–wall interactions ' , Combustion Theory and Modelling , vol. 24 , no. 1 , pp. 72-104 . https://doi.org/10.1080/13647830.2019.1658901Test

مصطلحات موضوعية: additional chemical time scales, flame modelling, flamelet-generated manifold (FGM), flame–wall interaction, prediction of emissions, reduced chemistry, side-wall quenching, flame-wall interaction

الوصف: This work introduces a new method to improve the accuracy of the flamelet-generated manifold (FGM) method under conditions of flame–wall interactions (FWI). Special attention is given to the prediction of the pollutant CO. In existing FGM methods, in order to account for heat loss, usually flamelets with constant enthalpy are utilised. These constant enthalpy flamelets used to generate the manifold, do not include the effects of wall heat loss on the manifold composition, resulting in simulation inaccuracies in the near-wall region, where large enthalpy gradients are present. To address this issue, the idea to utilise 1D head on quenching (HOQ) flamelets for tabulated chemistry is adopted and applied here in the context of the FGM method. The HOQ qualitatively resembles the general phenomena of FWI. However, the rates of wall heat loss and the accompanied effects on the chemical species composition may quantitatively differ between various FWI configurations. In addition, the magnitude of heat transfer rate may vary in space and time in general configurations. Therefore, in this work, a method is introduced to generate a 3D manifold, based on multiple HOQ-like flamelets, that includes the variation of the rate of heat loss as an extra table dimension. This dimension is parametrised by a second reaction progress variable for which a transport equation is solved next to the equations for enthalpy and the first progress variable. The new developed method, referred to as Quenching Flamelet-generated Manifold (QFM), is described in this work. Further, the method is validated against detailed chemistry simulations of a two-dimensional premixed laminar side-wall quenching of a methane-air flame. A comparison is presented, analysing the performance obtained using the existing 2D FGM method, a 2D QFM that is based on a single HOQ flamelet which does not account for a varying rate of wall heat loss and a 3D QFM, which does. Finally, it is shown that the 3D QFM tabulated chemistry simulation yields a very good level of ...

وصف الملف: application/pdf

العلاقة: https://research.tue.nl/en/publications/d5caa749-6b2a-4d48-9541-621ed77c50d6Test

الإتاحة: https://doi.org/10.1080/13647830.2019.1658901Test
https://research.tue.nl/en/publications/d5caa749-6b2a-4d48-9541-621ed77c50d6Test
https://pure.tue.nl/ws/files/146921683/QFM_quenching_flamelet_generated_manifold_for_modelling_of_flame_wall_interactions.pdfTest
https://pure.tue.nl/ws/files/148302755/QFM_quenching_flamelet_generated_manifold_for_modelling_of_flame_wall_interactions.pdfTest
http://www.scopus.com/inward/record.url?scp=85071333732&partnerID=8YFLogxKTest

المؤلفون: Maio, Giampaolo, Cailler, Mélody, Cuoci, Alberto, Fiorina, Benoît

المساهمون: Laboratoire d'Énergétique Moléculaire et Macroscopique, Combustion (EM2C), CentraleSupélec-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Safran Tech, Politecnico di Milano Milan (POLIMI)

المصدر: ISSN: 1364-7830.

مصطلحات موضوعية: Nitric oxide, virtual chemistry, laminar flames, reduced chemistry, [SPI]Engineering Sciences [physics]

الوصف: International audience ; A reduced order kinetic model for NO (Nitric Oxide) prediction, based on the virtual chemistry methodology [1], is developed and applied. Virtual chemistry aims to optimize thermochemical properties and kinetic rate parameters of a network of virtual species and reactions. A virtual main chemical mechanism is dedicated to temperature and heat release prediction and is coupled with the flow governing equations, whereas satellite sub-mechanisms are designed to predict pollutants formation. Two virtual chemistry mechanisms are here employed: a main mechanism for calculating the temperature and heat release rate and a second mechanism dedicated to NO prediction. To recover the chemical structure of multi-mode combustion, both premixed and non-premixed flamelets are included in the learning database used to optimize the virtual NO mechanism. A multi-zone optimization procedure is developed to accurately capture both fast and slow NO chemistry that include prompt, thermal and reburning pathways. The proposed NO sub-mechanism and optimization methodology are applied to CH4/air combustion. Laminar 1-D premixed and non-premixed flamelet configurations are first tested. The approach is then further assessed in 2-D CFD laminar flame simulations, by providing a direct comparison against detailed chemistry. 2-D premixed, non-premixed and partially premixed flame configurations are numerically investigated. For all cases, the virtual mechanism fairly captures temperature and NOx chemistry with only 12 virtual species and 8 virtual reactions with a drastic CPU time reduction compared to detailed chemistry.

العلاقة: hal-03419970; https://hal.science/hal-03419970Test; https://hal.science/hal-03419970/documentTest; https://hal.science/hal-03419970/file/Maio_et_al_CTM_2019.pdfTest

الإتاحة: https://doi.org/10.1080/13647830.2020.1772509Test
https://hal.science/hal-03419970Test
https://hal.science/hal-03419970/documentTest
https://hal.science/hal-03419970/file/Maio_et_al_CTM_2019.pdfTest

المؤلفون: Millán Merino, Alejandro, Fernández Tarrazo, Eduardo Antonio, Sánchez Sanz, Mario, Williams, Forman Arthur

المساهمون: Ministerio de Economía y Competitividad (España)

مصطلحات موضوعية: Combustion chemistry, Ethanol combustion, Reduced chemistry, Ingeniería Industrial, Ingeniería Mecánica

الوصف: We present in this short communication a modification to our previous ethanol reduced combustion chemistry (Millán-Merino, 2018) that eliminates nonphysical values of the species concentrations which we discovered in applying the mechanism to the combustion of an isolated ethanol droplet. This unsteady test is reported here to check the multipurpose character of the reduced mechanism for a problem that combines non-homogeneous autoignition, rich and lean premixed-flame propagation, and the development of a diffusion flame, as well as a the presence of a cold moving boundary at the droplet surface. During the computations, production and consumption rates of the alfa-hydroxyethyl (CH3CHOH) intermediary radical became unbalanced, invalidating its steady-state hypothesis, which was used during the derivation of the reduced scheme. This difficulty is removed here by taking CH3CHOH out of steady state, thereby augmenting slightly the reduced mechanism. ; This work was supported by the project ENE2015-65852-C2-1-R (MINECO/FEDER,UE).

العلاقة: Gobierno de España. ENE2015-65852-C2-1-R; Combustion and flame, Vo. 215, May 2020, Pp. 221-223; 1556-2921 (online); http://hdl.handle.net/10016/34468Test; https://doi.org/10.1016/j.combustflame.2020.02.003Test; 221; 223; COMBUSTION AND FLAME; 215; AR/0000025733

الإتاحة: https://doi.org/10.1016/j.combustflame.2020.02.003Test
http://hdl.handle.net/10016/34468Test

المؤلفون: Cellier, A., Duchaine, F., Poinsot, Thierry, Okyay, G., Leyko, M., Pallud, M.

المساهمون: Centre Européen de Recherche et de Formation Avancée en Calcul Scientifique (CERFACS), Institut de mécanique des fluides de Toulouse (IMFT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT), SAFT Bordeaux, Société des accumulateurs fixes et de traction (SAFT), TotalEnergies

المصدر: ISSN: 0010-2180 ; Combustion and Flame ; https://hal.science/hal-04047601Test ; Combustion and Flame, 2023, 250, pp.112648. ⟨10.1016/j.combustflame.2023.112648⟩.

مصطلحات موضوعية: Lithium-Ion cell fire, Thermal runaway, Analytically reduced chemistry, Large eddy simulation, [SPI]Engineering Sciences [physics]

الوصف: International audience ; The recent evolution of Lithium-Ion cells toward increasing energy-to-weight ratios makes them prone to critical events such as Thermal Runaway. Flammable and toxic gases are suddenly produced from the decomposition of internal components. To avoid an uncontrolled opening of the cell casing, the gases are vented out, which can potentially lead to fire. In this paper, six gaseous mixtures sampled experimentally, based on four different cathode materials are first compared for commonly observed 0D and 1D combustion processes. A single Analytically Reduced Chemistry scheme is derived for the six mixtures to lower computational cost and allow 3D high fidelity simulations. In comparison to the root detailed scheme, the reduced scheme offers low errors and an average speed up of 5.5 when computing targeted 1D flames, making it suitable for a 3D reactive Large Eddy Simulation of a burning so called “18650”-type cell. Such 3D simulations show a true potential to study simple safety design choices prior to any experimental investigation, reducing development costs. Under the same venting conditions, the number of venting holes is predicted to play a crucial role on flame intrinsic behavior.

العلاقة: hal-04047601; https://hal.science/hal-04047601Test

الإتاحة: https://doi.org/10.1016/j.combustflame.2023.112648Test
https://hal.science/hal-04047601Test