Journal articles: 'Turbulent combustion'

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Alhumairi, Mohammed, and Özgür Ertunç. "Active-grid turbulence effect on the topology and the flame location of a lean premixed combustion." Thermal Science 22, no. 6 Part A (2018): 2425–38. http://dx.doi.org/10.2298/tsci170503100a.

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Lean premixed combustion under the influence of active-grid turbulence was computationally investigated, and the results were compared with experimental data. The experiments were carried out to generate a premixed flame at a thermal load of 9 kW from a single jet flow combustor. Turbulent combustion models, such as the coherent flame model and turbulent flame speed closure model were implemented for the simulations performed under different turbulent flow conditions, which were specified by the Reynolds number based on Taylor?s microscale, the dissipation rate of turbulence, and turbulent kinetic energy. This study shows that the applied turbulent combustion models differently predict the flame topology and location. However, similar to the experiments, simulations with both models revealed that the flame moves toward the inlet when turbulence becomes strong at the inlet, that is, when Re? at the inlet increases. The results indicated that the flame topology and location in the coherent flame model were more sensitive to turbulence than those in the turbulent flame speed closure model. The flame location behavior on the jet flow combustor significantly changed with the increase of Re?.

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MIYAUCHI, Toshio. "Turbulence and Turbulent Combustion." TRENDS IN THE SCIENCES 19, no. 4 (2014): 4_44–4_48. http://dx.doi.org/10.5363/tits.19.4_44.

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d’Adamo, Alessandro, Clara Iacovano, and Stefano Fontanesi. "A Data-Driven Methodology for the Simulation of Turbulent Flame Speed across Engine-Relevant Combustion Regimes." Energies 14, no. 14 (July 12, 2021): 4210. http://dx.doi.org/10.3390/en14144210.

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Turbulent combustion modelling in internal combustion engines (ICEs) is a challenging task. It is commonly synthetized by incorporating the interaction between chemical reactions and turbulent eddies into a unique term, namely turbulent flame speed sT. The task is very complex considering the variety of turbulent and chemical scales resulting from engine load/speed variations. In this scenario, advanced turbulent combustion models are asked to predict accurate burn rates under a wide range of turbulence–flame interaction regimes. The framework is further complicated by the difficulty in unambiguously evaluating in-cylinder turbulence and by the poor coherence of turbulent flame speed (sT) measurements in the literature. Finally, the simulated sT from combustion models is found to be rarely assessed in a rigorous manner. A methodology is presented to objectively measure the simulated sT by a generic combustion model over a range of engine-relevant combustion regimes, from Da = 0.5 to Da = 75 (i.e., from the thin reaction regime to wrinkled flamelets). A test case is proposed to assess steady-state burn rates under specified turbulence in a RANS modelling framework. The methodology is applied to a widely adopted combustion model (ECFM-3Z) and the comparison of the simulated sT with experimental datasets allows to identify modelling improvement areas. Dynamic functions are proposed based on turbulence intensity and Damköhler number. Finally, simulations using the improved flame speed are carried out and a satisfactory agreement of the simulation results with the experimental/theoretical correlations is found. This confirms the effectiveness and the general applicability of the methodology to any model. The use of grid/time resolution typical of ICE combustion simulations strengthens the relevance of the proposed dynamic functions. The presented analysis allows to improve the adherence of the simulated burn rate to that of literature turbulent flames, and it unfolds the innovative possibility to objectively test combustion models under any prescribed turbulence/flame interaction regime. The solid data-driven representation of turbulent combustion physics is expected to reduce the tuning effort in ICE combustion simulations, providing modelling robustness in a very critical area for virtual design of innovative combustion systems.

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Gorev, V. A. "Modes of Explosive Combustion during Emergency Explosions of the Gas Clouds in the Open Space." Occupational Safety in Industry, no. 8 (August 2022): 7–12. http://dx.doi.org/10.24000/0409-2961-2022-8-7-12.

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Emergency explosions of steam clouds in the open space occur in the deflagration combustion mode. Destructive force of the explosive waves is mainly determined by the rate of combustion in the steam cloud. Therefore, the issue of explosive combustion rate is the key one for predicting explosion parameters. To form the waves of destructive force, it is required that the combustion rate of the substance in the cloud increase by 30 or more times compared to laminar. The main and generally recognized mechanism of combustion intensification is turbulization of the process as a result of interaction of the gas flow field with various obstacles located in the area of the exploding cloud. In the work, the analysis focuses on the combustion processes in the obstacles with continuously changing blocking of space. Under such conditions, the combustion is not structured, it smoothly changes its characteristics, and not jerks at the locations of blocking barriers. That is, explosive combustion can be considered as a classic turbulent combustion of a homogeneous mixed mixture. The work gives preference to the analysis of works, in which the turbulent combustion rate is presented as allowing a change in the scale of turbulence. The results of these works are presented in the form of functions ff(U¢/Sl, l/d) of the ratio of the pulsation component of turbulence to the laminar combustion rate, and the ratio of the integral scale of turbulence to the thickness of the laminar flame. The work gives a comparison of the turbulent combustion velocity depending on the U¢/SL ratio for three values l/d = 100, 1000, 10 000. On the basis of the turbulent combustion modes diagram, the zones of applicability of various methods for determining the turbulent combustion rate are shown. The paper expresses preference for the Peters theory as the most universal and giving a realistic value of the turbulent combustion rate at l/d >> 1.

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Peters, Norbert. "Turbulent Combustion." Measurement Science and Technology 12, no. 11 (October 19, 2001): 2022. http://dx.doi.org/10.1088/0957-0233/12/11/708.

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Poinsot, Thierry. "Turbulent Combustion." European Journal of Mechanics - B/Fluids 20, no. 3 (May 2001): 427–28. http://dx.doi.org/10.1016/s0997-7546(01)01134-7.

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Peters, N., and Prof Luc Vervisch. "Turbulent combustion." Combustion and Flame 125, no. 3 (May 2001): 1222–23. http://dx.doi.org/10.1016/s0010-2180(01)00233-4.

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Peters,, N., and AM Kanury,. "Turbulent Combustion." Applied Mechanics Reviews 54, no. 4 (July 1, 2001): B73—B75. http://dx.doi.org/10.1115/1.1383686.

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Giacomazzi, Eugenio, and Donato Cecere. "A Combustion Regime-Based Model for Large Eddy Simulation." Energies 14, no. 16 (August 12, 2021): 4934. http://dx.doi.org/10.3390/en14164934.

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The aim of this work is to propose a unified (generalized) closure of the chemical source term in the context of Large Eddy Simulation able to cover all the regimes of turbulent premixed combustion. Turbulence/combustion scale interaction is firstly analyzed: a new perspective to look at commonly accepted combustion diagrams is provided based on the evidence that actual turbulent flames can experience locally several combustion regimes although global non-dimensional numbers would locate such flames in a single specific operating point of the standard combustion diagram. The deliverable is a LES subgrid scale model for turbulent premixed flames named Localized Turbulent Scales Model (LTSM). This is founded on the estimation of the local reacting volume fraction of a computational cell that is related to the local turbulent and laminar flame speeds and to the local flame thickness.

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Sjeric, Momir, Darko Kozarac, and Rudolf Tomic. "Development of a two zone turbulence model and its application to the cycle-simulation." Thermal Science 18, no. 1 (2014): 1–16. http://dx.doi.org/10.2298/tsci130103030s.

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The development of a two zone k-? turbulence model for the cycle-simulation software is presented. The in-cylinder turbulent flow field of internal combustion engines plays the most important role in the combustion process. Turbulence has a strong influence on the combustion process because the convective deformation of the flame front as well as the additional transfer of the momentum, heat and mass can occur. The development and use of numerical simulation models are prompted by the high experimental costs, lack of measurement equipment and increase in computer power. In the cycle-simulation codes, multi zone models are often used for rapid and robust evaluation of key engine parameters. The extension of the single zone turbulence model to the two zone model is presented and described. Turbulence analysis was focused only on the high pressure cycle according to the assumption of the homogeneous and isotropic turbulent flow field. Specific modifications of differential equation derivatives were made in both cases (single and two zone). Validation was performed on two engine geometries for different engine speeds and loads. Results of the cyclesimulation model for the turbulent kinetic energy and the combustion progress variable are compared with the results of 3D-CFD simulations. Very good agreement between the turbulent kinetic energy during the high pressure cycle and the combustion progress variable was obtained. The two zone k-? turbulence model showed a further progress in terms of prediction of the combustion process by using only the turbulent quantities of the unburned zone.

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Fureby, C. "Large eddy simulation modelling of combustion for propulsion applications." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 367, no. 1899 (July 28, 2009): 2957–69. http://dx.doi.org/10.1098/rsta.2008.0271.

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Predictive modelling of turbulent combustion is important for the development of air-breathing engines, internal combustion engines, furnaces and for power generation. Significant advances in modelling non-reactive turbulent flows are now possible with the development of large eddy simulation (LES), in which the large energetic scales of the flow are resolved on the grid while modelling the effects of the small scales. Here, we discuss the use of combustion LES in predictive modelling of propulsion applications such as gas turbine, ramjet and scramjet engines. The LES models used are described in some detail and are validated against laboratory data—of which results from two cases are presented. These validated LES models are then applied to an annular multi-burner gas turbine combustor and a simplified scramjet combustor, for which some additional experimental data are available. For these cases, good agreement with the available reference data is obtained, and the LES predictions are used to elucidate the flow physics in such devices to further enhance our knowledge of these propulsion systems. Particular attention is focused on the influence of the combustion chemistry, turbulence–chemistry interaction, self-ignition, flame holding burner-to-burner interactions and combustion oscillations.

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Povilaitis, Mantas, and Justina Jaseliūnaitė. "Simulation of Hydrogen-Air-Diluents Mixture Combustion in an Acceleration Tube with FlameFoam Solver." Energies 14, no. 17 (September 3, 2021): 5504. http://dx.doi.org/10.3390/en14175504.

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During a severe accident in a nuclear power plant, hydrogen can be generated, leading to risks of possible deflagration and containment integrity failure. To manage severe accidents, great experimental, analytical, and benchmarking efforts are being made to understand combustible gas distribution, deflagration, and detonation processes. In one of the benchmarks—SARNET H2—flame acceleration due to obstacle-induced turbulence was investigated in the ENACCEF facility. The turbulent combustion problem is overly complex because it involves coupling between fluid dynamics, mass/heat transfer, and chemistry. There are still unknowns in understanding the mechanisms of turbulent flame propagation, therefore many methods in interpreting combustion and turbulent speed are present. Based on SARNET H2 benchmark results, a two-dimensional computational fluid dynamics simulation of turbulent hydrogen flame propagation in the ENACCEF facility was performed. Four combustible mixtures with different diluents concentrations were considered—13% H2 and 0%/10%/20%/30% of diluents in air. The aim of this numerical simulation was to validate the custom-built turbulent combustion OpenFOAM solver based on the progress variable model—flameFoam. Furthermore, another objective was to perform parametric analysis in relation to turbulent speed correlations and turbulence models and interpret the k-ω SST model blending function F1 behavior during the combustion process. The obtained results show that in the simulated case all three turbulent speed correlations behave similarly and can be used to reproduce observable flame speed; also, the k-ε model provides more accurate results than the k-ω SST turbulence model. It is shown in the paper that the k-ω SST model misinterprets the sudden parameter gradients resulting from turbulent combustion.

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Benim, Ali Cemal, and Björn Pfeiffelmann. "Comparison of Combustion Models for Lifted Hydrogen Flames within RANS Framework." Energies 13, no. 1 (December 28, 2019): 152. http://dx.doi.org/10.3390/en13010152.

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Within the framework of a Reynolds averaged numerical simulation (RANS) methodology for modeling turbulence, a comparative numerical study of turbulent lifted H2/N2 flames is presented. Three different turbulent combustion models, namely, the eddy dissipation model (EDM), the eddy dissipation concept (EDC), and the composition probability density function (PDF) transport model, are considered in the analysis. A wide range of global and detailed combustion reaction mechanisms are investigated. As turbulence model, the Standard k-ε model is used, which delivered a comparatively good accuracy within an initial validation study, performed for a non-reacting H2/N2 jet. The predictions for the lifted H2/N2 flame are compared with the published measurements of other authors, and the relative performance of the turbulent combustion models and combustion reaction mechanisms are assessed. The flame lift-off height is taken as the measure of prediction quality. The results show that the latter depends remarkably on the reaction mechanism and the turbulent combustion model applied. It is observed that a substantially better prediction quality for the whole range of experimentally observed lift-off heights is provided by the PDF model, when applied in combination with a detailed reaction mechanism dedicated for hydrogen combustion.

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Cemal Benim, Ali, and Björn Pfeiffelmann. "Validation of Combustion Models for Lifted Hydrogen Flame." E3S Web of Conferences 128 (2019): 01014. http://dx.doi.org/10.1051/e3sconf/201912801014.

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Within a Reynolds Averaged Numerical Simulation (RANS) approach for turbulence modelling, a computational investigation of a turbulent lifted H2/N2 flame is presented. Various turbulent combustion models are considered including the Eddy Dissipation Model (EDM), the Eddy Dissipation Concept (EDC), and the composition Probability Density Function transport model (PDF) in combination with different detailed and global reaction mechanisms. Turbulence is modelled using the Standard k-ɛ model, which has proven to offer a good accuracy, based on a preceding validation study for an isothermal H2/N2 jet. Results are compared with the published measurements for a lifted H2/N2 flame, and the relative performance ofthe turbulent combustion models are assessed. It is observed that the prediction quality can vary largely depending on the reaction mechanism and the turbulent combustion model. The best and quite satisfactory agreement with experiments is provided by two detailed reaction mechanisms applied with a PDF model.

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Kim, Jong-Chan, Won-Chul Jung, Ji-Seok Hong, and Hong-Gye Sung. "The Effects of Turbulent Burning Velocity Models in a Swirl-Stabilized Lean Premixed Combustor." International Journal of Turbo & Jet-Engines 35, no. 4 (December 19, 2018): 365–72. http://dx.doi.org/10.1515/tjj-2016-0053.

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Abstract The effects of turbulent burning velocities in a turbulent premixed combustion simulation with a G-equation are investigated using the 3D LES technique. Two turbulent burning velocity models – Kobayashi model, which takes into account the burning velocity pressure effect, and the Pitsch model, which considers the flame regions on the premixed flame structure – are implemented. An LM6000 combustor is employed to validate the turbulent premixed combustion model. The results show that the flame structures in front of the injector have different shapes in each model because of the different turbulent burning velocities. These different flame structures induce changes in the entire combustor flow field, including in the recirculation zone. The dynamic mode decomposition (DMD) method and linear acoustic analysis provide the dominant acoustic mode.

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Yang, Li, Wubin Weng, Yanqun Zhu, Yong He, Zhihua Wang, and Zhongshan Li. "Investigation of Hydrogen Content and Dilution Effect on Syngas/Air Premixed Turbulent Flame Using OH Planar Laser-Induced Fluorescence." Processes 9, no. 11 (October 23, 2021): 1894. http://dx.doi.org/10.3390/pr9111894.

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Syngas produced by gasification, which contains a high hydrogen content, has significant potential. The variation in the hydrogen content and dilution combustion are effective means to improve the steady combustion of syngas and reduce NOx emissions. OH planar laser-induced fluorescence technology (OH-PLIF) was applied in the present investigation of the turbulence of a premixed flame of syngas with varied compositions of H2/CO. The flame front structure and turbulent flame velocities of syngas with varied compositions and turbulent intensities were analyzed and calculated. Results showed that the trend in the turbulent flame speed with different hydrogen proportions and dilutions was similar to that of the laminar flame speed of the corresponding syngas. A higher hydrogen proportion induced a higher turbulent flame speed, higher OH concentration, and a smaller flame. Dilution had the opposite effect. Increasing the Reynolds number also increased the turbulent flame speed and OH concentration. In addition, the effect of the turbulence on the combustion of syngas was independent of the composition of syngas after the analysis of the ratio between the turbulent flame speed and the corresponding laminar flame speed, for the turbulent flames under low turbulent intensity. These research results provide a theoretical basis for the practical application of syngas with a complex composition in gas turbine power generation.

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Reis, J. C., and C. H. Kruger. "Turbulence suppression in combustion-driven magnetohydrodynamic channels." Journal of Fluid Mechanics 188 (March 1988): 147–57. http://dx.doi.org/10.1017/s0022112088000679.

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The effects of a magnetic field on core turbulence, mean-velocity boundary-layer profiles, turbulence-intensity boundary-layer profiles and turbulent spectral-energy distributions have been experimentally determined for combustion-driven magneto-hydrodynamic (MHD) flows. The turbulence suppression of the core was found to be similar to that of liquid-metal MHD flows, even though the turbulent structure was entirely different. The mean-velocity and turbulence-intensity boundary-layer profiles were affected much less than those of liquid-metal flows, primarily because the low-temperature thermal boundary layer reduced the electrical conductivity near the wall. No spectral dependence of turbulence suppression was observed in the core.

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Hossain, Mohammad A., Ahsan Choudhuri, and Norman Love. "Design of an optically accessible turbulent combustion system." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 233, no. 1 (February 8, 2018): 336–49. http://dx.doi.org/10.1177/0954406218757565.

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In order to design the next generation of gas turbine combustors and rocket engines, understanding the flame structure at high-intensity turbulent flows is necessary. Many experimental studies have focused on flame structures at relatively low Reynolds and Damköhler numbers, which are useful but do not help to provide a deep understanding of flame behavior at gas turbine and rocket engine operating conditions. The current work is focused on the presentation of the design and development of a high-intensity (Tu = 15–30%) turbulent combustion system, which is operated at compressible flow regime from Mach numbers of 0.3 to 0.5, preheated temperatures up to 500 K, and premixed conditions in order to investigate the flame structure at high Reynolds and Damköhler numbers in the so-called thickened flame regime. The design of an optically accessible backward-facing step stabilized combustor was designed for a maximum operating pressure of 0.6 MPa. Turbulence generator grid was introduced with different blockage ratios from 54 to 67% to generate turbulence inside the combustor. Optical access was provided via quartz windows on three sides of the combustion chamber. Extensive finite element analysis was performed to verify the structural integrity of the combustor at rated conditions. In order to increase the inlet temperature of the air, a heating section is designed and presented in this paper. Separate cooling subsystem designs are also presented. A 10 kHz time-resolved particle image velocimetry system and a 3 kHz planer laser-induced fluorescence system are integrated with the system to diagnose the flow field and the flame, respectively. The combustor utilizes a UNS 316 stainless steel with a minimum wall thickness of 12.5 mm. Quartz windows were designed with a maximum thickness of 25.4 mm resulting in an overall factor of safety of 3.5.

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Liao, S. Y., D. M. Jiang, J. Gao, and K. Zeng. "Turbulence effects on accelerating turbulent premixed combustion." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 218, no. 9 (September 2004): 1035–40. http://dx.doi.org/10.1243/0954407041856845.

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Veynante, Denis, and Luc Vervisch. "Turbulent combustion modeling." Progress in Energy and Combustion Science 28, no. 3 (March 2002): 193–266. http://dx.doi.org/10.1016/s0360-1285(01)00017-x.

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Borghi, R. "Turbulent combustion modelling." Progress in Energy and Combustion Science 14, no. 4 (January 1988): 245–92. http://dx.doi.org/10.1016/0360-1285(88)90015-9.

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Евсеев, Сергей Анатольевич, Дмитрий Викторович Козел, and Игорь Федорович Кравченко. "ПОВЫШЕНИЕ ТОЧНОСТИ РАСЧЕТА ПОЛЯ ТЕМПЕРАТУР ГАЗА НА ВЫХОДЕ ИЗ КАМЕРЫ СГОРАНИЯ ГТД МЕТОДОМ ТРЕХМЕРНОГО КОМПЬЮТЕРНОГО МОДЕЛИРОВАНИЯ." Aerospace technic and technology, no. 5 (August 29, 2020): 74–82. http://dx.doi.org/10.32620/aktt.2020.5.10.

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The problem of numerical simulation of the gas flow with the combustion of atomized liquid fuel was solved (the equilibrium combustion model pdf was used along with the partially mixed mixture model) in the annular combustion chamber of a gas turbine engine. Numerical modeling was performed in Ansys Fluent calculation complex. The purpose of the calculations was to simulate the radial and circumferential unevenness of the gas temperature pattern at the outlet of the combustion chamber. As a result of the calculations, it was found that the accuracy of modeling the radial and circumferential unevenness of the gas temperature pattern at the outlet of the combustion chamber is unsatisfactory when using the k–e turbulence model with the initial settings for the Ansys Fluent calculation complex. Moreover, the maximum value of the radial non-uniformity of the gas temperature pattern at the outlet of the combustion chamber exceeded the value obtained in the experiment by 12.61 %, and the maximum value of the circumferential non-uniformity by 12.69 %. To improve the accuracy of modeling the temperature pattern non-uniformity at the outlet of the combustion chamber, a numerical experiment was conducted to study the effect of the degree of turbulent diffusion of gas components on the value of temperature pattern non-uniformity. To reduce the non-uniformity of the temperature pattern at the outlet of the combustion chamber, the degree of turbulent diffusion of gas components was increased with respect to the initial version of the calculation, performed using the k–e model of turbulence with the initial settings for the Ansys Fluent calculation complex, by reducing the turbulent Schmidt number Sc in the turbulence model. For the initial settings of the k–e turbulence model in the Ansys Fluent calculation complex, the turbulent Schmidt number Sc = 0.85. A numerical experiment was performed for the values of Sc = 0.6, Sc = 0.4, and Sc = 0.2. The results of a numerical experiment confirmed the influence of the turbulent Schmidt number Sc on the result of calculating the gas temperature pattern at the outlet of the combustion chamber; as the value of Sc decreases, the level of the circumferential and radial non-uniformities of the gas temperature pattern decreases. However, the degree of reduction of radial and circumferential irregularities with a decrease in Sc is different. Therefore, to ensure high accuracy in calculating both the circumferential and radial non-uniformities of the gas temperature pattern, it was proposed to use a variable value of the turbulent Schmidt number Sc depending on the gas temperature instead of a constant value. The functional dependence of the turbulent Schmidt number Sc on the gas temperature was implemented in the Ansys Fluent calculation complex using the user function (UDF). The results of modeling the gas temperature pattern using the proposed UDF function for the turbulent Schmidt number Sc are in satisfactory agreement with the experimental data for both radial and circumferential non-uniformities of the gas temperature pattern at the outlet of the combustion chamber.

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Pan, J. C., W. J. Schmoll, and D. R. Ballal. "Turbulent Combustion Properties Behind a Confined Conical Stabilizer." Journal of Engineering for Gas Turbines and Power 114, no. 1 (January 1, 1992): 33–38. http://dx.doi.org/10.1115/1.2906304.

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Turbulence properties were investigated in and around the recirculation zone produced by a 45 deg conical flame stabilizer of 25 percent blockage ratio confined in a pipe supplied with a turbulent premixed methane-air mixture at a Reynolds number of 5.7×104. A three-component LDA system was used for measuring mean velocities, turbulence intensities, Reynolds stresses, skewness, kurtosis, and turbulent kinetic energy. It was found that wall confinement elongates the recirculation zone by accelerating the flow and narrows it by preventing mean streamline curvature. For confined flames, turbulence production is mainly due to shear stress-mean strain interaction. In the region of maximum recirculation zone width and around the stagnation point, the outer stretched flame resembles a normal mixing layer and gradient-diffusion closure for velocity holds. However, and in the absence of turbulent heat flux data, countergradient diffusion cannot be ruled out. Finally, and because of the suppression of mean streamline curvature by confinement, in combusting flow, the production of turbulence is only up to 33 percent of its damping due to dilatation and dissipation.

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Lackmann, Tim, Andreas Nygren, Anders Karlsson, and Michael Oevermann. "Investigation of turbulence–chemistry interactions in a heavy-duty diesel engine with a representative interactive linear eddy model." International Journal of Engine Research 21, no. 8 (December 5, 2018): 1469–79. http://dx.doi.org/10.1177/1468087418812319.

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Simulations of a heavy-duty diesel engine operated at high-load and low-load conditions were compared to each other, and experimental data in order to evaluate the influence of turbulence–chemistry interactions on heat release, pressure development, flame structure, and temperature development are quantified. A recently developed new combustion model for turbulent diffusion flames called representative interactive linear eddy model which features turbulence–chemistry interaction was compared to a well-stirred reactor model which neglects the influence of turbulent fluctuations on the mean reaction rate. All other aspects regarding the spray combustion simulation like spray break-up, chemical mechanism, and boundary conditions within the combustion chamber were kept the same in both simulations. In this article, representative interactive linear eddy model is extended with a progress variable, which enables the model to account for a flame lift-off and split injection, when it is used for diffusion combustion. In addition, the extended version of representative interactive linear eddy model offers the potential to treat partially premixed and premixed combustion as well. The well-stirred reactor model was tuned to match the experimental results, thus computed pressure and apparent heat release are in close agreement with the experimental data. Representative interactive linear eddy model was not tuned specifically for the case and thus the computed results for pressure and heat release are in reasonable agreement with experimental data. The computational results show that the interaction of the turbulent flow field and the chemistry reduce the peak temperatures and broaden up the turbulent flame structure. Since this is the first study of a real combustion engine (metal engine) with the newly developed model, representative interactive linear eddy model appears as a promising candidate for predictions of spray combustion in engines, especially in combustion regimes where turbulence–chemistry interaction plays an even more important role like, example given, in low-temperature combustion or combustion with local extinction and re-ignition.

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Ballal, D. R., T. H. Chen, and W. J. Schmoll. "Fluid Dynamics of a Conical Flame Stabilizer." Journal of Engineering for Gas Turbines and Power 111, no. 1 (January 1, 1989): 97–102. http://dx.doi.org/10.1115/1.3240234.

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Turbulence measurements were performed on a 45 deg conical flame stabilizer with a 31 percent blockage ratio, mounted coaxially at the mouth of a circular pipe and supplied with a turbulent premixed methane-air mixture at a Reynolds number of 2.85 × 104. A two-component LDA system was used in the measurement of mean velocities, turbulence intensities, Reynolds stresses, skewness, and kurtosis. It was found that combustion accelerates mean-flow velocities but damps turbulence intensity via the processes of turbulent dilatation and viscous dissipation due to heat release. Measurements in the axial direction showed that the length of the recirculation zone was nearly doubled as a result of combustion. Also, the region around the downstream stagnation point where streamlines meet and velocities change direction was found to be highly turbulent. Skewness and kurtosis data indicated that large-scale eddies carrying fresh combustible mixture are entrained into the high-shear region surrounding the recirculation zone. Finally, a discussion of turbulence-combustion interaction is presented to explain these experimental results.

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Ga, Bui Van, Nguyen Van Dong, and Bui Van Hung. "Turbulent burning velocity in combustion chamber of SI engine fueled with compressed biogas." Vietnam Journal of Mechanics 37, no. 3 (August 25, 2015): 205–16. http://dx.doi.org/10.15625/0866-7136/37/3/5939.

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Turbulent burning velocity is the most important parameter in analyzing pre-mixed combustion simulation of spark ignition engines. It depends on the laminar burning velocity and turbulence intensity in the combustion chamber. The first term can be predicted if one knows fuel composition, physico chemical properties of the fluid. The second term strongly depends on the geometry of the combustion chamber and fluid movement during the combustion process. One cannot suggest a general expression for different cases of engine. Thus, for accuracy modeling, one should determine turbulent burning velocity in the combustion chamber of each case of engine individually. In this study, the turbulent burning velocity is defined by a linear function of laminar burning velocity in which the proportional constant is defined as the turbulent burning velocity coefficient. This coefficient was obtained by analyzing the numerical simulation results and experimental data and this is applied to a concrete case of a Honda Wave motorcycle engine combustion chamber that fueled with compressed biogas. The results showed that the turbulent burning velocity coefficient in this case is around 1.3 when the average engine revolutions is in the range of 3000 rpm to 6000 rpm with biogas containing 80% Methane. We can then predict the effects of different parameters on the performance of the engine fueled with compressed biogas by simulation.

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Zimont, V. L. "Gas premixed combustion at high turbulence. Turbulent flame closure combustion model." Experimental Thermal and Fluid Science 21, no. 1-3 (March 2000): 179–86. http://dx.doi.org/10.1016/s0894-1777(99)00069-2.

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de Lemos, Marcelo J. S., and Maximilian S. Mesquita. "Comparison of Four Thermo-Mechanical Models for Simulating Reactive Flow in Porous Materials." Defect and Diffusion Forum 297-301 (April 2010): 1493–501. http://dx.doi.org/10.4028/www.scientific.net/ddf.297-301.1493.

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The objective of this paper is to present numerical simulations of combustion of an air/methane mixture in porous materials using a model that considers the intra-pore levels of turbulent kinetic energy. Transport equations are written in their time-and-volume-averaged form and a volume-based statistical turbulence model is applied to simulate turbulence generation due to the porous matrix. Four different thermo-mechanical models are compared, namely Laminar, Laminar with Radiation Transport, Turbulent, Turbulent with Radiation Transport. Combustion is modeled via a unique simple closure. Preliminary testing results indicate that a substantially different temperature distribution is obtained depending on the model used. In addition, for high excess air peak gas temperature are reduced.

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Ershadi, Ali, and Mehran Rajabi-Zargarabadi. "Application of higher-order heat flux model for predicting turbulent methane-air combustion." Thermal Science, no. 00 (2019): 415. http://dx.doi.org/10.2298/tsci181110415e.

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The present study addresses a new effort to improve the prediction of turbulent heat transfer and NO emission in non-premixed methane-air combustion. In this regard, a symmetric combustion chamber in a stoichiometric condition is numerically simulated using the Reynolds averaged Navier-Stokes equations. The Realizable k-? model and Discreate Ordinate are applied for modeling turbulence and radiation, respectively. Also, the eddy dissipation model is adopted for predicting the turbulent chemical reaction rate. Zeldovich mechanism is applied for estimating the NO emission. Higher-order generalized gradient diffusion hypothesis (HOGGDH) is employed for predicting the turbulent heat flux in turbulent reactive flows. Results show that the HOGGDH model is capable of predicting temperature distribution in good agreement with the available experimental data. Comparison of the results obtained by the simple eddy diffusivity (SED) and HOGGDH models shows that applying the HOGGDH significantly improves the over-prediction of NO emission. Finally, the average turbulent Prandtl number for the non-premixed methane-air combustion has been calculated.

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Lipatnikov, Andrei N., and Vladimir A. Sabelnikov. "Karlovitz Numbers and Premixed Turbulent Combustion Regimes for Complex-Chemistry Flames." Energies 15, no. 16 (August 11, 2022): 5840. http://dx.doi.org/10.3390/en15165840.

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The structure of premixed turbulent flames and governing physical mechanisms of the influence of turbulence on premixed burning are often discussed by invoking combustion regime diagrams. In the majority of such diagrams, boundaries of three combustion regimes associated with (i) flame preheat zones broadened locally by turbulent eddies, (ii) reaction zones broadened locally by turbulent eddies, and (iii) local extinction are based on a Karlovitz number Ka, with differently defined Ka being used to demarcate different combustion regimes. The present paper aims to overview different definitions of Ka, comparing them, and suggesting the most appropriate choice of Ka for each combustion regime boundary. Moreover, since certain Karlovitz numbers involve a laminar flame thickness, the influence of complex combustion chemistry on the thickness and, hence, on various Ka and relations between them is explored based on results of complex-chemistry simulations of unperturbed (stationary, planar, and one-dimensional) laminar premixed flames, obtained for various fuels, equivalence ratios, pressures, and unburned gas temperatures.

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Madia, M., G. Cicalese, and L. Dalseno. "Hydrogen, methane and one of their fuel blends combustion: CFD analysis and numerical-experimental comparisons of fixed and mobile applications." Journal of Physics: Conference Series 2648, no. 1 (December 1, 2023): 012080. http://dx.doi.org/10.1088/1742-6596/2648/1/012080.

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Abstract The capabilities of Computational Fluid Dynamics (CFD) coupled with detailed chemistry simulations are examined in both steady jet diffusion flames and in an internal combustion engine case fuelled with hydrogen. Different approaches to turbulence-chemistry interaction such as the “Laminar Flame Concept” the “Eddy Dissipation Concept” and the “Turbulent Flame Speed Closure” are considered and tested. The results are compared with the experimental data available. Concerning the jet diffusion flames, the combustion processes of hydrogen, methane and one of their fuel blends are investigated on two burner geometries. Different sensitivities (i.e. mesh, turbulence model, turbulent Schmidt number, chemical mechanism) are performed. The study demonstrates that despite the burner geometry considered and the chemical composition of the fuel, the Complex Chemistry with “Eddy Dissipation Concept” is the model that better describes the behaviour of the turbulent flames. On the other hand, the “Laminar Flame Concept” sub-model is characterized by an higher fuel consumption rate, which causes an overestimation of the temperature peak. As for the in-cylinder unsteady simulations, the hydrogen combustion process is better described by the “Turbulent Flame Speed Closure” sub-model, which, unlike the other two, requires the specification of both laminar and turbulent flame speed. Despite different variations being considered, the “Laminar Flame Concept” adoption leads to an unphysically high burning rate, while the Eddy Dissipation Concept sub-model is characterized by an underestimation of the apparent heat release rate, and thus of the pressure peak inside the combustion chamber.

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Krishnan, Abin, R. I. Sujith, Norbert Marwan, and Jürgen Kurths. "On the emergence of large clusters of acoustic power sources at the onset of thermoacoustic instability in a turbulent combustor." Journal of Fluid Mechanics 874 (July 9, 2019): 455–82. http://dx.doi.org/10.1017/jfm.2019.429.

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In turbulent combustors, the transition from stable combustion (i.e. combustion noise) to thermoacoustic instability occurs via intermittency. During stable combustion, the acoustic power production happens in a spatially incoherent manner. In contrast, during thermoacoustic instability, the acoustic power production happens in a spatially coherent manner. In the present study, we investigate the spatiotemporal dynamics of acoustic power sources during the intermittency route to thermoacoustic instability using complex network theory. To that end, we perform simultaneous acoustic pressure measurement, high-speed chemiluminescence imaging and particle image velocimetry in a backward-facing step combustor with a bluff body stabilized flame at different equivalence ratios. We examine the spatiotemporal dynamics of acoustic power sources by constructing time-varying spatial networks during the different dynamical states of combustor operation. We show that as the turbulent combustor transits from combustion noise to thermoacoustic instability via intermittency, small fragments of acoustic power sources, observed during combustion noise, nucleate, coalesce and grow in size to form large clusters at the onset of thermoacoustic instability. This nucleation, coalescence and growth of small clusters of acoustic power sources occurs during the growth of pressure oscillations during intermittency. In contrast, during the decay of pressure oscillations during intermittency, these large clusters of acoustic power sources disintegrate into small ones. We use network measures such as the link density, the number of components and the size of the largest component to quantify the spatiotemporal dynamics of acoustic power sources as the turbulent combustor transits from combustion noise to thermoacoustic instability via intermittency.

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Gerke, Udo, and Konstantinos Boulouchos. "Three-dimensional computational fluid dynamics simulation of hydrogen engines using a turbulent flame speed closure combustion model." International Journal of Engine Research 13, no. 5 (April 10, 2012): 464–81. http://dx.doi.org/10.1177/1468087412438796.

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The mixture formation and combustion process of a hydrogen direct-injection internal combustion engine is computed using a modified version of a commercial three-dimensional computational fluid dynamics code. The aim of the work is the evaluation of hydrogen laminar flame speed correlations and turbulent flame speed closures with respect to combustion of premixed and stratified mixtures at various levels of air-to-fuel equivalence ratio. Heat-release rates derived from in-cylinder pressure traces are used for the validation of the combustion simulations. A turbulent combustion model with closures for a turbulent flame speed is investigated. The value of the computed heat-release rates mainly depends on the quality of laminar burning velocities and standard of turbulence quantities provided to the combustion model. Combustion simulations performed with experimentally derived laminar flame speed data give better results than those using laminar flame speeds obtained from a kinetic scheme. However, experimental data of hydrogen laminar flame speeds found in the literature are limited regarding the range of pressures, temperatures and air-to-fuel equivalence ratios, and do not comply with the demand of high-pressure engine-relevant conditions.

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Song, Ruitao, Gerald Gentz, Guoming Zhu, Elisa Toulson, and Harald Schock. "A control-oriented model of turbulent jet ignition combustion in a rapid compression machine." Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering 231, no. 10 (November 13, 2016): 1315–25. http://dx.doi.org/10.1177/0954407016670303.

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Turbulent jet ignition combustion is a promising concept for achieving high thermal efficiency and low NOx (nitrogen oxides) emissions. A control-oriented turbulent jet ignition combustion model with satisfactory accuracy and low computational effort is usually a necessity for optimizing the turbulent jet ignition combustion system and developing the associated model-based turbulent jet ignition control strategies. This article presents a control-oriented turbulent jet ignition combustion model developed for a rapid compression machine configured for turbulent jet ignition combustion. A one-zone gas exchange model is developed to simulate the gas exchange process in both pre- and main-combustion chambers. The combustion process is modeled by a two-zone combustion model, where the ratio of the burned and unburned gases flowing between the two combustion chambers is variable. To simulate the influence of the turbulent jets on the rate of combustion in the main-combustion chamber, a new parameter-varying Wiebe function is proposed and used for the mass fraction burned calculation in the main-combustion chamber. The developed model is calibrated using the least-squares fitting and optimization procedures. Experimental data sets with different air-to-fuel ratios in both combustion chambers and different pre-combustion chamber orifice areas are used to calibrate and validate the model. The simulation results show good agreement with the experimental data for all the experimental data sets. This indicates that the developed combustion model is accurate for developing and validating turbulent jet ignition combustion control strategies. Future work will extend the rapid compression machine combustion model to engine applications.

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Mahammedi, Abdelkder, Naas Toufik Tayeb, D. Medjahed, and Telha Mostefa. "Numerical Modeling of Turbulent Biogas Combustion." All Sciences Abstracts 1, no. 2 (July 25, 2023): 4. http://dx.doi.org/10.59287/as-abstracts.1194.

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The primary purpose of this research is to investigate the combustion properties of three different types of biogas using a 300 KW BERL combustor. Biogas is a renewable type of this fossil fuel; it is an intelligent fuel that offers an incredibly environmentally beneficial alternative to existing fuels.In order to study the impact of the biogas compositions on the flow field prediction, we perform the calculation using the FLUENT code, which has been used to present the numerical modeling of turbulent diffusion flames by using the realizable k-–ε model of turbulent flow interacting with a two-dimensional PDF combustion scheme. Some comparisons of biogas performance in turbulent diffusion flame mode and methane performance in conventional mode are shown, in addition to the 9-steps, GRI 2.11 mechanisms and experiment data are used to validate the case investigated.

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Pekkan, K., and M. R. Nalim. "Two-Dimensional Flow and NOx Emissions in Deflagrative Internal Combustion Wave Rotor Configurations." Journal of Engineering for Gas Turbines and Power 125, no. 3 (July 1, 2003): 720–33. http://dx.doi.org/10.1115/1.1586315.

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A wave rotor is proposed for use as a constant volume combustor. A novel design feature is investigated as a remedy for hot gas leakage, premature ignition, and pollutant emissions that are possible in this class of unsteady machines. The base geometry involves fuel injection partitions that allow stratification of fuel/oxidizer mixtures in the wave rotor channel radially, enabling pilot ignition of overall lean mixture for low NOx combustion. In this study, available turbulent combustion models are applied to simulate approximately constant volume combustion of propane and resulting transient compressible flow. Thermal NO production histories are predicted by simulations of the STAR-CD code. Passage inlet/outlet/wall boundary conditions are time-dependent, enabling the representation of a typical deflagrative internal combustor wave rotor cycle. Some practical design improvements are anticipated from the computational results. For a large number of derivative design configurations, fuel burn rate, two-dimensional flow and emission levels are evaluated. The sensitivity of channel combustion to initial turbulence levels is evaluated.

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Benim, Ali Cemal, Sohail Iqbal, Franz Joos, and Alexander Wiedermann. "Numerical Analysis of Turbulent Combustion in a Model Swirl Gas Turbine Combustor." Journal of Combustion 2016 (2016): 1–12. http://dx.doi.org/10.1155/2016/2572035.

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Turbulent reacting flows in a generic swirl gas turbine combustor are investigated numerically. Turbulence is modelled by a URANS formulation in combination with the SST turbulence model, as the basic modelling approach. For comparison, URANS is applied also in combination with the RSM turbulence model to one of the investigated cases. For this case, LES is also used for turbulence modelling. For modelling turbulence-chemistry interaction, a laminar flamelet model is used, which is based on the mixture fraction and the reaction progress variable. This model is implemented in the open source CFD code OpenFOAM, which has been used as the basis for the present investigation. For validation purposes, predictions are compared with the measurements for a natural gas flame with external flue gas recirculation. A good agreement with the experimental data is observed. Subsequently, the numerical study is extended to syngas, for comparing its combustion behavior with that of natural gas. Here, the analysis is carried out for cases without external flue gas recirculation. The computational model is observed to provide a fair prediction of the experimental data and predict the increased flashback propensity of syngas.

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KATSUKI, Masashi, Yukio MIZUTANI, Toshihiko YASUDA, and Tetsuyuki YOSHIDA. "Turbulence and Mixing in Turbulent Premixed Flames. 3rd Report. Turbulent Combustion Model." Transactions of the Japan Society of Mechanical Engineers Series B 58, no. 551 (1992): 2261–67. http://dx.doi.org/10.1299/kikaib.58.2261.

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Rutkuniene, Zivile. "LES modeling gas particle dispersion and thermal characteristics in a reacting turbulent low." Physical Sciences and Technology 11, no. 1-2 (2024): 76–84. http://dx.doi.org/10.26577/phst2024v11i1a9.

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This paper presents the results of a 3D computer simulation of the combustion processes of gas particles (methane) in turbulent flow by applying numerical methods for calculating complex turbulent flows. The numerical model for calculating turbulent reacting flow is based on the filtered equations of conservation of mass, momentum, and internal energy using a spatial filter for calculating and modeling complex vortex structures. Aerodynamic, temperature and thermal characteristics of the flow were obtained based on the study on the influence of the Sauter mean radius of methane particles on its distribution and combustion processes. 3D visualization of the reacting flow was obtained considering the degree of its turbulence and the intensity of methane particle collision on the area of its distribution. The obtained results can be used for a deep understanding of the theory of gas combustion, in combustion chambers of various thermophysical objects and as an alternative to liquid hydrocarbon fuels due to safety and low harmful load of methane on the environment.

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YAMAMOTO, Kazuhiro, Satoshi INOUE, Hiroshi YAMASHITA, Daisuke SHIMOKURI, Satoru ISHIZUKA, and Yoshiaki ONUMA. "PIV Measurement and Turbulence Scale in Turbulent Combustion." Transactions of the Japan Society of Mechanical Engineers Series B 71, no. 711 (2005): 2741–47. http://dx.doi.org/10.1299/kikaib.71.2741.

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Yamamoto, Kazuhiro, Satoshi Inoue, Hiroshi Yamashita, Daisuke Shimokuri, Satoru Ishizuka, and Yoshiaki Onuma. "PIV measurement and turbulence scale in turbulent combustion." Heat Transfer—Asian Research 35, no. 7 (2006): 501–12. http://dx.doi.org/10.1002/htj.20129.

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Шайкин, А. П., and И. Р. Галиев. "О связи ширины зоны турбулентного горения с составом топлива, давлением, скоростью распространения и электропроводностью пламени." Журнал технической физики 90, no. 7 (2020): 1064. http://dx.doi.org/10.21883/jtf.2020.07.49437.65-19.

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The results of an experimental study of the relationship between the width turbulent combustion zone (TCZ) and composition of the composite fuel (hythane), the maximum pressure in combustion chamber of variable volume, the propagation velocity and electrical conductivity of the turbulent flame are presented. It was revealed that the width TCZ has a characteristic dependence on the composition of hythane. It was experimentally found that, despite a change coefficient of excess air, hydrogen concentration in the fuel, turbulence intensity and type of fuel (hythane and gasoline), the dependences of width TCZ on the turbulent flame propagation velocity and electrical conductivity of the flame, as well as the dependence maximum pressure on width, remain unchanged TCZ. The results of the work can be used in the design and development of energy-efficient and low-emission combustion chambers.

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James, S., M. S. Anand, M. K. Razdan, and S. B. Pope. "In Situ Detailed Chemistry Calculations in Combustor Flow Analyses." Journal of Engineering for Gas Turbines and Power 123, no. 4 (March 1, 1999): 747–56. http://dx.doi.org/10.1115/1.1384878.

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In the numerical simulation of turbulent reacting flows, the high computational cost of integrating the reaction equations precludes the inclusion of detailed chemistry schemes, therefore reduced reaction mechanisms have been the more popular route for describing combustion chemistry, albeit at the loss of generality. The in situ adaptive tabulation scheme (ISAT) has significantly alleviated this problem by facilitating the efficient integration of the reaction equations via a unique combination of direct integration and dynamic creation of a look-up table, thus allowing for the implementation of detailed chemistry schemes in turbulent reacting flow calculations. In the present paper, the probability density function (PDF) method for turbulent combustion modeling is combined with the ISAT in a combustor design system, and calculations of a piloted jet diffusion flame and a low-emissions premixed gas turbine combustor are performed. It is demonstrated that the results are in good agreement with experimental data and computations of practical turbulent reacting flows with detailed chemistry schemes are affordable.

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Arpaci, V. "Microscales of turbulent combustion." Progress in Energy and Combustion Science 21, no. 2 (1995): 153–71. http://dx.doi.org/10.1016/0360-1285(95)00002-y.

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Riley, James J. "Book Review: Turbulent combustion." Journal of Turbulence 2 (January 2001): N19. http://dx.doi.org/10.1088/1468-5248/2/1/701.

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GIBSON, CARL H. "THE FIRST TURBULENT COMBUSTION." Combustion Science and Technology 177, no. 5-6 (April 2005): 1049–71. http://dx.doi.org/10.1080/00102200590926987.

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Karpov, V. P., G. G. Politenkova, and E. S. Severin. "Turbulent combustion of alcohols." Combustion, Explosion, and Shock Waves 22, no. 4 (1987): 397–99. http://dx.doi.org/10.1007/bf00862879.

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Xu, Guoqing, Yuri Martin Wright, Michele Schiliro, and Konstantinos Boulouchos. "Characterization of combustion in a gas engine ignited using a small un-scavenged pre-chamber." International Journal of Engine Research 21, no. 7 (September 12, 2018): 1085–106. http://dx.doi.org/10.1177/1468087418798918.

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Prechamber ignition technology receives increasing attention due to its considerable improvement on engine combustion efficiency and stability. However, fundamental knowledge concerning flame propagation inside the pre-chamber and jet formation in the main chamber is still quite scarce. In this study, a small (<0.5% VTDC) un-scavenged pre-chamber was tested in a medium size gas engine with pressure transducers installed in both pre- and main chamber. Three-dimensional computational reactive fluid dynamics Reynolds-averaged Navier–Stokes simulations were carried out using a level-set combustion model –G-equation – towards improved understanding of the combustion processes occurring inside the pre and main chamber. The characteristics of the turbulence and the flame at locations just ahead of the propagating turbulent flame front were recorded and analysed by means of the well-known Borghi–Peters diagram. The results revealed that the characteristics of the flame inside the pre-chamber differed greatly from those inside the main chamber due to considerably reduced turbulent length scales. In addition, a wide range of turbulence intensity and length scales are covered throughout the combustion event, presenting a significant challenge to modelling of flame–turbulence interaction. Various turbulent flame speed ( ST) closures widely used in internal combustion engine simulation were therefore assessed and the ranges of their respective model constants explored. A correlation for ST is subsequently proposed by blending two formulations of Gülder developed for small and large scale turbulence, respectively, and compared to the well-known Peters correlation. With appropriate model constants, both successfully reproduce the pre and main chamber combustion for the reference case in terms of evolutions of cylinder pressure, heat release rate and pressure difference between pre and main chamber. Following successful calibration of the reference operating condition, variations in engine speed, load, spark timing and lambda were calculated using both correlations, demonstrating encouraging predictive capabilities of the proposed modelling strategy.

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Toman, Rastislav, and Jan Macek. "Evaluation of the Predictive Capabilities of a Phenomenological Combustion Model for Natural Gas SI Engine." Journal of Middle European Construction and Design of Cars 15, no. 2 (December 20, 2017): 37–48. http://dx.doi.org/10.1515/mecdc-2017-0007.

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Abstract The current study evaluates the predictive capabilities of a new phenomenological combustion model, available as a part of the GT-Suite software package. It is comprised of two main sub-models: 0D model of in-cylinder flow and turbulence, and turbulent SI combustion model. The 0D in-cylinder flow model (EngCylFlow) uses a combined K-k-ε kinetic energy cascade approach to predict the evolution of the in-cylinder charge motion and turbulence, where K and k are the mean and turbulent kinetic energies, and ε is the turbulent dissipation rate. The subsequent turbulent combustion model (EngCylCombSITurb) gives the in-cylinder burn rate; based on the calculation of flame speeds and flame kernel development. This phenomenological approach reduces significantly the overall computational effort compared to the 3D-CFD, thus allowing the computation of full engine operating map and the vehicle driving cycles. Model was calibrated using a full map measurement from a turbocharged natural gas SI engine, with swirl intake ports. Sensitivity studies on different calibration methods, and laminar flame speed sub-models were conducted. Validation process for both the calibration and sensitivity studies was concerning the in-cylinder pressure traces and burn rates for several engine operation points achieving good overall results.

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Gilmanov, Anvar, Ponnuthurai Gokulakrishnan, and Michael S. Klassen. "Development and Validation of a Compressible Reacting Gas-Dynamic Flow Solver for Supersonic Combustion." Dynamics 4, no. 1 (February 11, 2024): 135–56. http://dx.doi.org/10.3390/dynamics4010008.

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An approach based on the OpenFOAM library has been developed to solve a high-speed, multicomponent mixture of a reacting, compressible flow. This work presents comprehensive validation of the newly developed solver, called compressibleCentralReactingFoam, with different supersonic flows, including shocks, expansion waves, and turbulence–combustion interaction. The comparisons of the simulation results with experimental and computational data confirm the fidelity of this solver for problems involving multicomponent high-speed reactive flows. The gas dynamics of turbulence–chemistry interaction are modeled using a partially stirred reactor formulation and provide promising results to better understand the complex physics involved in supersonic combustors. A time-scale analysis based on local Damköhler numbers reveals different regimes of turbulent combustion. In the core of the jet flow, the Damköhler number is relatively high, indicating that the reaction time scale is smaller than the turbulent mixing time scale. This means that the combustion is controlled by turbulent mixing. In the shear layer, where the heat release rate and the scalar dissipation rate have the highest value, the flame is stabilized due to finite rate chemistry with small Damköhler numbers and a limited fraction of fine structure. This solver allows three-dimensional gas dynamic simulation of high-speed multicomponent reactive flows relevant to practical combustion applications.

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Journal articles on the topic 'Turbulent combustion'

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