Journal articles: 'Adiabatic Flame Temperature'

1

Sakhrieh, Ahmad. "The adiabatic flame temperature and laminar flame speed of methane premixed flames at varying pressures." Acta Periodica Technologica, no. 50 (2019): 220–27. http://dx.doi.org/10.2298/apt1950220s.

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This paper studies the influence of equivalence ratio, pressure and initial temperature on adiabatic flame temperature and laminar flame speed of methane-air mixture. The results indicate that adiabatic flame temperature is weakly correlated with pressure. The adiabatic flame temperature increases only by about 50?C as a result of 30 bar pressure increase. The flame speed is inversely proportional to pressure. The maximum adiabatic flame temperature and flame speed occur at the stoichiometric ratio, ?=1. The percent increase in the flame speed was about 400% when the initial temperature of the mixture is increased from 25?C to 425?C.

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Lee, Dae-Hee, and B. Bollinger. "The Development of Combustion Laboratory Test Apparatus for Mechanical Engineers." International Journal of Mechanical Engineering Education 24, no. 1 (January 1996): 1–10. http://dx.doi.org/10.1177/030641909602400101.

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A combustion laboratory test apparatus has been developed and put to use in the mechanical engineering measurement course at the California State University, Sacramento. The objectives of this apparatus are to study the characteristics of a premixed flame for a range if air/propane mixtures (from near stoichiometric to rich to highly rich) and to examine the principles of chemical thermodynamics of combustion by comparing the calculated adiabatic flame temperature to the measured adiabatic flame temperature, and by doing an energy balance on the flame. The apparatus consists of a burner that is used to ignite a regulated air/propane mixture. A thin wire thermocouple is used to measure both the flame temperature profiles and the adiabatic flame temperatures for two different air/propane mixtures (rich and highly rich). Furthermore, a copper tank containing water is heated by a near-stoichiometric mixture flame, causing heat transfer from the flame to the water. The results show that approximately 83% of the heat released from the near stoichiometric flame is transferred to the water in the copper tank.

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Conroy, P. J., P. Weinacht, and M. J. Nusca. "Parametric Erosion Investigation: Propellant Adiabatic Flame Temperature." Defence Science Journal 52, no. 1 (January 1, 2002): 77–85. http://dx.doi.org/10.14429/dsj.52.2152.

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Shehata, Mohamed S., Mohamed M. ElKotb, and Hindawi Salem. "Combustion Characteristics for Turbulent Prevaporized Premixed Flame Using Commercial Light Diesel and Kerosene Fuels." Journal of Combustion 2014 (2014): 1–17. http://dx.doi.org/10.1155/2014/363465.

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Experimental study has been carried out for investigating fuel type, fuel blends, equivalence ratio, Reynolds number, inlet mixture temperature, and holes diameter of perforated plate affecting combustion process for turbulent prevaporized premixed air flames for different operating conditions. CO2, CO, H2, N2, C3H8, C2H6, C2H4, flame temperature, and gas flow velocity are measured along flame axis for different operating conditions. Gas chromatographic (GC) and CO/CO2infrared gas analyzer are used for measuring different species. Temperature is measured using thermocouple technique. Gas flow velocity is measured using pitot tube technique. The effect of kerosene percentage on concentration, flame temperature, and gas flow velocity is not linearly dependent. Correlations for adiabatic flame temperature for diesel and kerosene-air flames are obtained as function of mixture strength, fuel type, and inlet mixture temperature. Effect of equivalence ratio on combustion process for light diesel-air flame is greater than for kerosene-air flame. Flame temperature increases with increased Reynolds number for different operating conditions. Effect of Reynolds number on combustion process for light diesel flame is greater than for kerosene flame and also for rich flame is greater than for lean flame. The present work contributes to design and development of lean prevaporized premixed (LPP) gas turbine combustors.

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Ugarte, Orlando J., and V’yacheslav Akkerman. "Computational Study of Premixed Flame Propagation in Micro-Channels with Nonslip Walls: Effect of Wall Temperature." Fluids 6, no. 1 (January 11, 2021): 36. http://dx.doi.org/10.3390/fluids6010036.

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This investigation evaluates the propagation of premixed flames in narrow channels with isothermal walls. The study is based on the numerical solution of the set of fully-compressible, reacting flow equations that includes viscosity, diffusion, thermal conduction and Arrhenius chemical kinetics. Specifically, channels and pipes with one extreme open and one extreme closed are considered such that a flame is sparked at the closed extreme and propagates towards the open one. The isothermal channel walls are kept at multiple constant temperatures in the range from Tw=300 K to 1200 K. The impact of these isothermal walls on the flame dynamics is studied for multiple radii of the channel (R) and for various thermal expansion ratios (Θ), which approximate the thermal behavior of different fuel mixtures in the system. The flame dynamics in isothermal channels is also compared to that with adiabatic walls, which were previously found to produce exponential flame acceleration at the initial stage of the burning process. The results show that the heat losses at the walls prevent strong acceleration and lead to much slower flame propagation in isothermal channels as compared to adiabatic ones. Four distinctive regimes of premixed burning in isothermal channels have been identified in the Θ−Tw−R space: (i) flame extinction; (ii) linear flame acceleration; (iii) steady or near-steady flame propagation; and (iv) flame oscillations. The physical processes in each of these regimes are discussed, and the corresponding regime diagrams are presented.

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JU, YIGUANG, HONGSHENG GUO, KAORU MARUTA, and FENGSHAN LIU. "On the extinction limit and flammability limit of non-adiabatic stretched methane–air premixed flames." Journal of Fluid Mechanics 342 (July 10, 1997): 315–34. http://dx.doi.org/10.1017/s0022112097005636.

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Extinction limits and the lean flammability limit of non-adiabatic stretched premixed methane–air flames are investigated numerically with detailed chemistry and two different Planck mean absorption coefficient models. Attention is paid to the combined effect of radiative heat loss and stretch at low stretch rate. It is found that for a mixture at an equivalence ratio lower than the standard lean flammability limit, a moderate stretch can strengthen the combustion and allow burning. The flame is extinguished at a high stretch rate due to stretch and is quenched at a low stretch rate due to radiation loss. A O-shaped curve of flame temperature versus stretch rate with two distinct extinction limits, a radiation extinction limit and a stretch extinction limit respectively on the left- and right-hand sides, is obtained. A C-shaped curve showing the flammability limit of the stretched methane–air flame is obtained by plotting these two extinction limits in the mixture strength coordinate. A good agreement is shown on comparing the predicted results with the experimental data. For equivalence ratio larger than a critical value, it is found that the O-shaped temperature curve opens up in the middle of the stable branch, so that the stable branch divides into two stable flame branches; a weak flame branch and a normal flame branch. The weak flame can survive between the radiation extinction limit and the opening point (jump limit) while the normal flame branch can survive from its stretch extinction limit to zero stretch rate. Finally, a G-shaped curve showing both extinction limits and jump limits of stretched methane–air flames is presented. It is found that the critical equivalence ratio for opening up corresponds to the standard flammability limit measured in microgravity. Furthermore, the results show that the flammability limit (inferior limit) of the stretched methane–air flame is lower than the standard flammability limit because flames are strengthened by a moderate stretch at Lewis number less than unity.

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Jeon, Min-Kyu, and Nam Il Kim. "Fuel pyrolysis and its effects on soot formation in non-premixed laminar jet flames of methane, propane, and DME." Mathematical Modelling of Natural Phenomena 13, no. 6 (2018): 56. http://dx.doi.org/10.1051/mmnp/2018052.

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High-temperature combustion techniques have recently attracted interest with regard to the improvement of the thermal efficiency of combustion systems. Fuel pyrolysis is an important factor, as it can affect such flame structures at high temperatures. In this study, the pyrolysis of methane, propane, and dimethyl ether (DME) was measured and the results were compared with theoretical predictions. Pyrolyzed fuels were quenched to room temperature before being introduced onto the burner. Thus, the pyrolysis effects on laminar non-premixed jet flames could be distinguished from many other complex thermal effects. It was found that the flame length was not notably extended in spite of the great increase in the volumetric flow rates resulting from the pyrolysis. In contrast, fuel pyrolysis could significantly affect the soot formation process,and the number of smoke points could be sharply reduced depending on the pyrolysis temperature. Distributions of the luminous intensity and scattering intensity levels in the soot region were discussed in terms of the soot temperatures obtained with a two-color method. Although the adiabatic flame temperatures of the pyrolyzed fuels were theoretically increased, the actual soot temperatures could be reduced when the soot particles were excessively formulated, as in the case with propane flames.

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Aljerf, Loai, and Nuha AlMasri. "Flame Propagation Model and Combustion Phenomena: Observations, Characteristics, Investigations, Technical Indicators, and Mechanisms." Journal of Energy Conservation 1, no. 1 (July 30, 2018): 31–40. http://dx.doi.org/10.14302/issn.2642-3146.jec-18-2232.

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Critical conditions are usually obtained for ignition in a self-heating solid system consisting of two components generating heat independently, one component being inexhaustible and the other exhaustible by either simple first order or autocatalytic reaction. Ignition depends upon whether the exhaustible component can cause a temperature rise in excess of the upper stationary, but unstable, value possible for the inexhaustible component reacting alone. The system provides a theoretical model for some commonly occurring examples of self-heating and ignition in porous solids containing oxidisable oils. It is shown that: (a) the ignition criterion of the model, which involves a nonarbitrary critical temperature increase, has a high degree of physical reality; (b) the model is, in principle, capable of predicting ignition from primary kinetic and thermal data; (c) it is likely to be possible often to make a reliable prediction of critical size for self-ignition in a two-component system at ordinary atmospheric temperatures by a simple extrapolation from small-scale ignition data, obtained at higher temperatures, in the same way as for ignition due to a single reaction. Examination of both adiabatic and non-adiabatic flame theories showed that a 'steady state' exists only under the special condition that a heat sink exists at the initial temperature. For the general case of freely propagating, non-adiabatic flames only a quasi-steady state can be achieved.

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Abe, Keisuke, Ade Kurniawan, Masafumi Sanada, Takahiro Nomura, and Tomohiro Akiyama. "Combustion Synthesis Ironmaking: Investigation on Required Carbon Amount in Raw Material from the Viewpoint of Adiabatic Flame Temperature Calculation." Indonesian Journal of Chemistry 19, no. 3 (May 29, 2019): 696. http://dx.doi.org/10.22146/ijc.38359.

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Combustion synthesis (CS) is a simple and very fast method to synthesize a target material. New ironmaking method via the CS using carbon-infiltrated iron ore was proposed, and the possible conditions for the method were investigated. Adiabatic flame temperatures (Tad) of the CS reaction, maximum reachable temperatures in an adiabatic system, were calculated to estimate the sample temperature during the CS. To reach the adiabatic temperature of 1811 K, 23.9, 27.9, and 29.3 wt.%-C were required for Fe2O3, Fe3O4, and FeO, respectively. When the carbon amount is higher than the calculated one, molten iron which is separated from slag components should be obtained via the CS.

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10

Yue, Meng, Mao-Zhao Xie, Jun-Rui Shi, Hong-Sheng Liu, Zhong-Shan Chen, and Ya-Chao Chang. "Numerical and Experimental Investigations on Combustion Characteristics of Premixed Lean Methane–Air in a Staggered Arrangement Burner with Discrete Cylinders." Energies 13, no. 23 (December 3, 2020): 6397. http://dx.doi.org/10.3390/en13236397.

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Premixed combustion of lean methane–air in an artificial porous media burner with staggered alumina cylinders was experimentally and numerically performed. Numerical simulations were conducted at gas mixture velocities of 0.43–0.86 m/s and equivalence ratios of 0.162 and 0.243, respectively. Through comparison with experimental results, temperature distribution, peak temperature and flame propagation velocity are analyzed and discussed in detail. The numerical calculated temperature profile over the axis of the combustor coincided well with test data in the post-flame zone, however a certain deviation was found in the preheated zone. A two-dimensional flame shape was observed and the flame thickness was the size of cylinder diameter. The peak temperature increased with the gas mixture inlet velocity at the certain equivalence ratio, and its peak value was about 1.8–2.16 times higher than the adiabatic combustion temperature under the desired equivalence ratio, which indicates that super-adiabatic combustion was the case for all the numerical simulations. The flame propagating velocity had a positive correlation with the gas mixture inlet velocity.

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LAW, C., A. MAKINO, and T. LU. "On the off-stoichiometric peaking of adiabatic flame temperature." Combustion and Flame 145, no. 4 (June 2006): 808–19. http://dx.doi.org/10.1016/j.combustflame.2006.01.009.

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12

BACONNEAU, OLIVIER, JAN BOUWE VAN DEN BERG, CLAUDE-MICHEL BRAUNER, and JOSEPHUU HULSHOF. "Multiplicity and stability of travelling wave solutions in a free boundary combustion-radiation problem." European Journal of Applied Mathematics 15, no. 1 (February 2004): 79–102. http://dx.doi.org/10.1017/s0956792503005333.

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We study travelling wave solutions of a one-dimensional two-phase Free Boundary Problem, which models premixed flames propagating in a gaseous mixture with dust. The model combines diffusion of mass and temperature with reaction at the flame front, the reaction rate being temperature dependent. The radiative effects due to the presence of dust account for the divergence of the radiative flux entering the equation for temperature. This flux is modelled by the Eddington equation. In an appropriate limit the divergence of the flux takes the form of a nonlinear heat loss term. The resulting reduced model is able to capture a hysteresis effect that appears if the amount of fuel in front of the flame, or equivalently, the adiabatic temperature is taken as a control parameter.

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13

Gu¨lder, O¨ L. "Flame Temperature Estimation of Conventional and Future Jet Fuels." Journal of Engineering for Gas Turbines and Power 108, no. 2 (April 1, 1986): 376–80. http://dx.doi.org/10.1115/1.3239914.

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An approximate formula is presented by means of which the adiabatic flame temperature of jet fuel-air systems can be calculated as functions of pressure, temperature, equivalence ratio, and hydrogen to carbon atomic ratio of the fuel. The formula has been developed by fitting of the data from a detailed chemical equilibrium code to a functional expression. Comparisons of the results from the proposed formula with the results obtained from a chemical equilibrium code have shown that the average error in estimated temperatures is around 0.4 percent, the maximum error being less than 0.8 percent. This formula provides a very fast and easy means of predicting flame temperatures as compared to thermodynamic equilibrium calculations, and it is also applicable to diesel fuels, gasolines, pure alkanes, and aromatics as well as jet fuels.

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14

Zhang, Qingguo, David R. Noble, and Tim Lieuwen. "Characterization of Fuel Composition Effects in H2∕CO∕CH4 Mixtures Upon Lean Blowout." Journal of Engineering for Gas Turbines and Power 129, no. 3 (December 26, 2006): 688–94. http://dx.doi.org/10.1115/1.2718566.

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This paper describes measurements of the dependence of lean blowout limits upon fuel composition for H2∕CO∕CH4 mixtures. Blowout limits were obtained at fixed approach flow velocity, reactant temperature, and combustor pressure at several conditions. Consistent with prior studies, these results indicate that the percentage of H2 in the fuel dominates the mixture blowout characteristics. That is, flames can be stabilized at lower equivalence ratios, adiabatic flame temperatures, and laminar flame speeds with increasing H2 percentage. In addition, the blowoff phenomenology qualitatively changes with hydrogen levels in the fuel, being very different for mixtures with H2 levels above and below about 50%. It is shown that standard well stirred reactor based correlations, based upon a Damköhler number with a diffusivity ratio correction, can capture the effects of fuel composition variability on blowoff limits.

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Okano, Yasushi, and Akira Yamaguchi. "Theoretical Adiabatic Temperature and Chemical Composition of Sodium Combustion Flame." Nuclear Technology 144, no. 3 (December 2003): 388–99. http://dx.doi.org/10.13182/nt03-a3453.

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16

Mishra, S. "Adiabatic flame temperature of hydrogen in combination with gaseous fuels." International Journal of Hydrogen Energy 14, no. 11 (1989): 839–44. http://dx.doi.org/10.1016/0360-3199(89)90021-9.

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Masum, B. M., M. A. Kalam, H. H. Masjuki, and S. M. Palash. "Study on the Effect of Adiabatic Flame Temperature on NOx Formation Using Ethanol Gasoline Blend in SI Engine." Advanced Materials Research 781-784 (September 2013): 2471–75. http://dx.doi.org/10.4028/www.scientific.net/amr.781-784.2471.

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Active research and development on using ethanol fuel in gasoline engine had been done for few decades since ethanol served as a potential of infinite fuel supply. This paper discussed analytically and provides data on the effects of compression ratio, equivalence ratio, inlet temperature, inlet pressure and ethanol blend in cylinder adiabatic flame temperature (AFT) and nitrogen oxide (NO) formation of a gasoline engine. Olikara and Borman routines were used to calculate the equilibrium products of combustion for ethanol gasoline blended fuel. The equilibrium values of each species were used to predict AFT and the NO formation of combustion chamber. The result shows that both adiabatic flame temperature and NO formation are lower for ethanol-gasoline blend than gasoline fuel.

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Berning, Torsten, and Søren Knudsen Kær. "A Thermodynamic Analysis of an Air-Cooled Proton Exchange Membrane Fuel Cell Operated in Different Climate Regions." Energies 13, no. 10 (May 20, 2020): 2611. http://dx.doi.org/10.3390/en13102611.

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A fundamental thermodynamic analysis of an air-cooled fuel cell, where the reactant air stream is also the coolant stream, is presented. The adiabatic cell temperature of such a fuel cell is calculated in a similar way as the adiabatic flame temperature in a combustion process. Diagrams that show the dependency of the cathode outlet temperature, the stoichiometric flow ratio and the operating cell voltage are developed. These diagrams can help fuel cell manufacturers to identify a suitable blower and a suitable operating regime for their fuel cell stacks. It is found that for standard conditions, reasonable cell temperatures are obtained for cathode stoichiometric flow ratios of ξ = 50 and higher, which is in very good agreement with manufacturer’s recommendations. Under very cold ambient conditions, the suggested stoichiometric flow ratio is only in the range of ξ = 20 in order to obtain a useful fuel cell operating temperature. The outside relative humidity only plays a role at ambient temperatures above 40 °C, and the predicted stoichiometric flow ratios should be above ξ = 70 in this region. From a thermodynamic perspective, it is suggested that the adiabatic outlet temperature is a suitable definition of the fuel cell operating temperature.

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Nehru, L. C., and C. Sanjeeviraja. "Microwave-Assisted Combustion Synthesis of Nanocrystalline ZnO Powders Using Zinc Nitrate and Various Amount of Organic Fuels as Reactants: Influence of Reactant Parameters - A Status Review." Nano Hybrids 6 (February 2014): 75–110. http://dx.doi.org/10.4028/www.scientific.net/nh.6.75.

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Nanocrystalline ZnO powders have been synthesized by a novel and simple microwave-assisted combustion synthesis method using urea, glycine, carbohydrazine and citric acid as fuels and zinc nitrate as oxidant. The starting materials were directly mixed and a slurry precursor with high homogeneity was formed due to the hygroscopicity of the reactants. The precursor could be ignited at room temperature, resulting in dry, loose and voluminous ZnO powders. An interpretation based on an adiabatic flame temperature, amount of gases produced during reaction for various fuel-to-oxidizer molar ratios (ψ), has been proposed for the nature of combustion and its correlation with the characteristics of as-synthesized product. The variation of adiabatic flame temperature (Tad) with the ψ value was calculated theoretically according to the thermodynamic concept. The reaction process of the precursor was investigated by XRD techniques.

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20

Y. Lethwala , Nishant Sharma, Y. Lethwala ,. Nishant Sharma. "Relation of Adiabatic Flame Temperature with Varying Insulation of Octane Fuel." International Journal of Automobile Engineering Research and Development 8, no. 2 (2018): 9–16. http://dx.doi.org/10.24247/ijauerddec20182.

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21

Zhou, Minyong, and J. E. Donald Gauthier. "A new method for adiabatic flame temperature estimations of hydrocarbon fuels." Fuel 78, no. 4 (March 1999): 471–78. http://dx.doi.org/10.1016/s0016-2361(98)00093-3.

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22

Gregor, Mark Aurel, and Andreas Dreizler. "A quasi-adiabatic laminar flat flame burner for high temperature calibration." Measurement Science and Technology 20, no. 6 (May 1, 2009): 065402. http://dx.doi.org/10.1088/0957-0233/20/6/065402.

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Jabbar, Tahseen A. "Effect the Dissociation of H2O and CO2 on Adiabatic Flame Temperature." Thi-Qar University Journal for Engineering Sciences 9, no. 1 (May 2018): 42–50. http://dx.doi.org/10.31663/tqujes.9.1.257(2018).

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24

Foley, Christopher, Ianko Chterev, Bobby Noble, Jerry Seitzman, and Tim Lieuwen. "Shear layer flame stabilization sensitivities in a swirling flow." International Journal of Spray and Combustion Dynamics 9, no. 1 (August 19, 2016): 3–18. http://dx.doi.org/10.1177/1756827716653426.

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A variety of different flame configurations and heat release distributions exist in high swirl, annular flows, due to the existence of inner and outer shear layers as well a vortex breakdown bubble. Each of these different configurations, in turn, has different thermoacoustic sensitivities and influences on combustor emissions, nozzle durability, and liner heating. This paper presents findings on the sensitivities of the outer shear layer- stabilized flames to a range of parameters, including equivalence ratio, bulkhead temperature, flow velocity, and preheat temperature. There is significant hysteresis for flame attachment/detachment from the outer shear layer and this hysteresis is also described. Results are also correlated with extinction stretch rate calculations based on detailed kinetic simulations. In addition, we show that the bulkhead temperature near the flame attachment point has significant impact on outer shear layer detachment. This indicates that understanding the heat transfer between the edge flame stabilized in the shear layer and the nozzle hardware is needed in order to predict shear layer flame stabilization limits. Moreover, it shows that simulations cannot simply assume adiabatic boundary conditions if they are to capture these transitions. We also show that the reference temperature for correlating these transitions is quite different for attachment and local blow off. Finally, these results highlight the deficiencies in current understanding of the influence of fluid mechanic parameters (e.g. velocity, swirl number) on shear layer flame attachment. For example, they show that the seemingly simple matter of scaling flame transition points with changes in flow velocities is not understood.

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PEREIRA, F. M., A. A. M. OLIVEIRA, and F. F. FACHINI. "Theoretical analysis of ultra-lean premixed flames in porous inert media." Journal of Fluid Mechanics 657 (June 10, 2010): 285–307. http://dx.doi.org/10.1017/s0022112010001461.

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The structure of stationary adiabatic premixed flames within porous inert media under intense interphase heat transfer is investigated using the asymptotic expansion method. For the pore sizes of interest for combustion in porous inert media, this condition is reached for extremely lean mixtures where lower flame velocities are found. The flame structure is analysed in three distinct regions. In the outer region (the solid-phase diffusion length scale), both phases are in local thermal equilibrium and the problem formulation is reduced to the one-equation model for the energy conservation. In the first inner region (the gas-phase diffusion length scale), there is local thermal non-equilibrium and two equations for the energy conservation are required. In this region, the gas-phase temperature at the flame is limited by the interphase heat transfer. In the second inner region (the reaction length scale), the chemical reaction occurs in a very thin zone where the highest gas-phase temperature is found. The results showed that superadiabatic effects are reduced for leaner mixtures, smaller pore sizes and smaller fuel Lewis numbers. The results also show that there is a minimum superadiabatic temperature for the flame propagation to be possible, which corresponds to the lean flammability limit for the premixed combustion in porous inert media. A parameter that universalizes the leading-order flame properties is identified and discussed.

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Sattelmayer, T., W. Polifke, D. Winkler, and K. Do¨bbeling. "NOx-Abatement Potential of Lean-Premixed GT Combustors." Journal of Engineering for Gas Turbines and Power 120, no. 1 (January 1, 1998): 48–59. http://dx.doi.org/10.1115/1.2818087.

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The influence of the structure of perfectly premixed flames on NOx formation is investigated theoretically. Since a network of reaction kinetics modules and model flames is used for this purpose, the results obtained are independent of specific burner geometries. Calculations are presented for a mixture temperature of 630 K, an adiabatic flame temperature of 1840 K, and 1 and 15 bars combustor pressure. In particular, the following effects are studied separately from each other: • molecular diffusion of temperature and species; • flame strain; • local quench in highly strained flames and subsequent reignition; • turbulent diffusion (no preferential diffusion); • small scale mixing (stirring) in the flame front. Either no relevant influence or an increase in NOx production over that of the one-dimensional laminar flame is found. As a consequence, besides the improvement of mixing quality, a future target for the development of low-NOx burners is to avoid excessive turbulent stirring in the flame front. Turbulent flames that exhibit locally and instantaneously near laminar structures (“flamelets”) appear to be optimal. Using the same methodology, the scope of the investigation is extended to lean-lean staging, since a higher NOx-abatement potential can be expected in principle. As long as the chemical reactions of the second stage take place in the boundary between the fresh mixture of the second stage and the combustion products from upstream, no advantage can be expected from lean-lean staging. Only if the primary burner exhibits much poorer mixing than the second stage can lean-lean staging be beneficial. In contrast, if full mixing between the two stages prior to afterburning can be achieved (lean-mix-lean technique), the combustor outlet temperature can in principle be increased somewhat without NO penalty. However, the complexity of such a system with a larger flame tube area to be cooled will increase the reaction zone temperatures, so that the full advantage cannot be realized in an engine. Of greater technical relevance is the potential of a lean-mixlean combustion system within an improved thermodynamic cycle. A reheat process with sequential combustion is perfectly suited for this purpose, since, first, the required low inlet temperature of the second stage is automatically generated after partial expansion in the high pressure turbine, second, the efficiency of the thermodynamic cycle has its maximum and, third, high exhaust temperatures are generated, which can drive a powerful Rankine cycle. The higher thermodynamic efficiency of this technique leads to an additional drop in NOx emissions per power produced.

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Brückner, Clemens, Sushant Sunil Pandurangi, Panagiotis Kyrtatos, Michele Bolla, Yuri Martin Wright, and Konstantinos Boulouchos. "NOx emissions in direct injection diesel engines – part 1: Development of a phenomenological NOx model using experiments and three-dimensional computational fluid dynamics." International Journal of Engine Research 19, no. 3 (April 24, 2017): 308–28. http://dx.doi.org/10.1177/1468087417704312.

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There exists a well-established correlation of exhaust NOx emissions arising from diesel engines with the adiabatic flame temperature, in particular for conventional (i.e. short ignition delay, diffusion combustion-dominated) operating conditions. Most published NOx emission models rely on this correlation. However, numerous experimental studies have identified operating conditions where this correlation fails to capture the exhaust NOx trend. In this work, a novel phenomenological NOx model concept is introduced, including a first successful validation against experimental data. The model development is based on experimental observations and is supported by three-dimensional computational fluid dynamics computations, strengthening the understanding of the underlying mechanisms leading to the discrepancy between the adiabatic flame temperature and exhaust NOx trend. For long ignition delay operating conditions, the improved mixture preparation before ignition leads to reduced mixing rates during and after combustion. Both the improved mixture preparation before ignition and the instantaneous increase of mass observed above 2000 K after start of combustion are due to compression heating of the burned gases. Key features of the model are improved description of mixture distribution at start of combustion, NOx formed in products of premixed burn, different physical treatments of premixed and diffusion sourced products, and inherent consideration of burned gas compression heating. Model results capture the NOx emissions for conventional diesel combustion, as well as for operating conditions where the NOx emissions do not follow the adiabatic flame temperature trend. Moreover, the results show that the contribution of NOx from products from premixed burn and the consideration of compression heating effects on burned (post-flame) gases are essential to capture the NOx emissions under the latter conditions.

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Bidabadi, M., A. Shabani Shahrbabaki, M. Jadidi, and S. Montazerinejad. "An analytical study of radiation effects on the premixed laminar flames of aluminium dust clouds." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 224, no. 8 (August 1, 2010): 1679–95. http://dx.doi.org/10.1243/09544062jmes1919.

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A new analytical model of a quasi one-dimensional non-adiabatic dust flame is developed with the assumption that the particle burning rate in the flame front is controlled by the process of oxygen diffusion. In this model, the flame propagation mechanism is considered to be radiation, conduction, and convection. Algebraic equations defining the laminar flame speed were obtained in two limiting cases: lean and rich mixtures. The flame structure is assumed to consist of a preheat zone, a reaction zone, and a postflame zone for lean mixtures and a preheat zone and a reaction zone for rich mixtures. Under the lean mixture approximation, values of the flame speed, lean limit, and flame temperature were calculated by adding the radiation term; flame temperature in the preheat zone increased, while it decreased in the postflame zone. This phenomenon may be attributed to the radiative heat transfer from the postflame zone to the preheat zone. Also, when the radiation term was considered, the flame speed increased but the lean limit decreased. In addition, radiation in the rich mixture resulted in the increase of the flame speed and the gas phase temperature in the preheat zone, whereas in the flame zone, the gas phase temperature decreased. Calculated values of the flame speed and flame temperature are in a good agreement with the experimental data in the literature.

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Dixon-Lewis, Graham. "Laminar premixed flame extinction limits. II Combined effects of stretch and radiative loss in the single flame unburnt-to-burnt and the twin-flame unburnt-to-unburnt opposed flow configurations." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 462, no. 2066 (November 29, 2005): 349–70. http://dx.doi.org/10.1098/rspa.2005.1549.

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Numerical methods have been used to examine the effects of (a) stretch alone, and (b) a combination of stretch and radiative loss, on the properties and extinction limits of methane–air flames near the lean flammability limit. Two axisymmetric opposed flow configurations were examined: (i) a single flame, unburnt-to-burnt (UTB) system in which fresh reactant is opposed by a stream of its own combustion products at the unburnt temperature, and (ii) a symmetric unburnt-to-unburnt (UTU) configuration where twin flames are supported back to back, one on each side of the stagnation plane. The maximum temperatures achieved in the UTB system are always away from the stagnation plane. For a fixed sufficiently sub-adiabatic product stream temperature, increasing flame stretch or gaseous radiative emissivity, or a combination of both, will augment downstream conductive heat loss, leading to a reduction in T max and eventually to an abrupt extinction if the loss rate is sufficiently large. The UTU system is more complex, and offers the additional possibility of purely stretch-induced extinctions where the flames are forced together back-to-back so that radiative loss is restricted to upstream of the maximum temperature. Extinction in these cases occurs by straightforward truncation of the hot sides of the reaction zones. At sufficiently low stretch, near and at the standard flammability limit, radiative loss makes a major contribution to the overall extinction mechanism in both configurations. The detailed effects of flame stretch on extinction behaviour depend on the diffusion characteristics within the near-limit mixtures, in particular the Lewis number, Le, of the deficient component. The effect of high stretch is always to attenuate the composition range of flammability. However, for Le<1 this range is extended at low to moderate stretch, particularly in the UTU situations where downstream radiative loss is not present at extinction. Lewis number effects for a global methane–air chemistry, and with assumed Le≥1, are discussed in the light of numerical results previously presented by Ju et al . ( Ju et al . 1998 Combust. Flame 113 , 603–614).

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VAN MAAREN, A., D. S. THUNG, and L. R. H. DE GOEY. "Measurement of Flame Temperature and Adiabatic Burning Velocity of Methane/Air Mixtures." Combustion Science and Technology 96, no. 4-6 (January 1994): 327–44. http://dx.doi.org/10.1080/00102209408935360.

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SZWAJA, Stanisław, Wojciech TUTAK, Karol GRAB-ROGALIŃSKI, Arkadiusz JAMROZIK, and Arkadiusz KOCISZEWSKI. "Selected combustion parameters of biogas at elevated pressure–temperature conditions." Combustion Engines 148, no. 1 (February 1, 2012): 40–47. http://dx.doi.org/10.19206/ce-117050.

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Results from tests conducted in several RTD centers lead to conclusion that biogas as a potential fuel for the internal combustion (IC) spark ignited (SI) engine features with its satisfactory combustion predisposition causing smooth engine run without accidental misfiring or knock events. This good predisposition is obtained due to carbon dioxide (CO2) content in the biogas. On the other hand, carbon dioxide as incombustible gas contribute to decrease in the brake power of the biogas fueled engine. To analyze mutual CO2 and CH4 content on biogas burning the combustion parameters as follows: adiabatic combustion temperature, laminar flame speed and ignition delay of biogas with various methane content were determined and presented in the paper. Additionally, these parameters for pure methane were also included in order to make comparison between each other. As computed, ignition delay, which has is strongly correlated with knock resistance, can change several times with temperature increase, but does not change remarkably with increase in methane content. Adiabatic combustion temperature does not also ought to influence on engine performance or increase in engine cooling and exhaust losses due to its insignificant changes. The largest change was observed in laminar flame speed, that can influence on development of the first premixed combustion phase.

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Mitu, Maria, Venera Giurcan, Codina Movileanu, Domnina Razus, and Dumitru Oancea. "Propagation of CH4-N2O-N2 Flames in a Closed Spherical Vessel." Processes 9, no. 5 (May 12, 2021): 851. http://dx.doi.org/10.3390/pr9050851.

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Flammable fuel-N2O mixtures raise safety and environmental protection issues in areas where these mixtures are used (such as: industry, research, internal combustion engines). Therefore, it is important to know their laminar combustion velocities and propagation speeds—important safety parameters for design of active protection devices against gas explosions and corresponding safety recommendations. In this paper, the laminar combustion velocities of N2-diluted CH4-N2O flames, obtained in experiments on outwardly propagating flames, at various initial pressures (within 0.5–2.0 bar) and room temperature, are reported. The experiments were made in a 0.5 L spherical cell with central ignition. The laminar combustion velocities were calculated from the constants of cubic law of flame propagation during the early stage of closed cell explosions and the expansion coefficients of unburned flammable mixtures, using the adiabatic model of the flame propagation. The expansion coefficients were determined from equilibrium calculations on flames propagating under isobaric conditions. The laminar combustion velocities were compared with data reported in the literature. Using the laminar combustion velocities and the expansion coefficients, the propagation speeds of N2-diluted CH4-N2O flames were calculated. Both laminar combustion velocities and propagation speeds decrease with the initial pressure increase.

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Steinbacher, Thomas, Max Meindl, and Wolfgang Polifke. "Modelling the generation of temperature inhomogeneities by a premixed flame." International Journal of Spray and Combustion Dynamics 10, no. 2 (November 14, 2017): 111–30. http://dx.doi.org/10.1177/1756827717738139.

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The response of a laminar, premixed flame to perturbations of upstream equivalence ratio is investigated and modelled, with emphasis on the generation of ‘entropy waves’, i.e. entropic inhomogeneities of downstream temperature. Transient computational fluid dynamics simulations of two adiabatic lean methane-air flames of different Péclet numbers provide guidance and validation data for subsequent modelling. The respective entropy transfer functions, which describe the production of temperature inhomogeneities, as well as transfer functions for the variation of the heat release, are determined from the computational fluid dynamics time series data by means of system identification. The processes governing the dynamics of the entropy transfer functions are segregated into two sub-problems: (1) heat release due to chemical reaction at the flame front and (2) advective and diffusive transport. By adopting a formulation in terms of a mixture fraction variable, these two sub-problems can be treated independently from each other. Models for both phenomena are derived and analysed using simple 0- and 1-dimensional configurations. The heat release process (1) is represented by a fast-reaction-zone model, which takes into account variations of the specific heat capacity with equivalence ratio in order to evaluate the magnitude of downstream temperature fluctuations with quantitative accuracy. For the transport processes (2), two types of models based on mean field data from the computational fluid dynamics simulation are proposed: A semi-analytical, low-order formulation based on stream lines, and a state-space formulation, which is constructed by Finite Elements discretisation of the transport equation for mixture fraction. Model predictions for the entropy transfer functions are found to agree well with the computational fluid dynamics reference data at very low computational costs.

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34

Sherikar, Baburao N., and A. M. Umarji. "Effect of Adiabatic Flame Temperature on Nano Alumina Powders during Solution Combustion Process." Transactions of the Indian Ceramic Society 70, no. 3 (July 2011): 167–72. http://dx.doi.org/10.1080/0371750x.2011.10600166.

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Hancock, Robert D., Kenneth E. Bertagnolli, and Robert P. Lucht. "Nitrogen and hydrogen CARS temperature measurements in a hydrogen/air flame using a near-adiabatic flat-flame burner." Combustion and Flame 109, no. 3 (May 1997): 323–31. http://dx.doi.org/10.1016/s0010-2180(96)00191-5.

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36

Huang, Zhejun, Harvinder Sidhu, Isaac Towers, Zlatko Jovanoski, and Simon Watt. "On the route to extinction in non-adiabatic flames from competitive exothermic reactions." Mathematical Modelling of Natural Phenomena 13, no. 6 (2018): 49. http://dx.doi.org/10.1051/mmnp/2018047.

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We consider non-adiabatic combustion waves arising from two-step competitive exothermic reaction schemes. A numerical method is employed to study the behaviour of this system and we show that the inclusion of heat loss can lead to a period-doubling route to the termination of the propagating flame front. The nature of oscillations becomes more complex with increasing loss of heat until the system can no longer sustain a propagating front. In other words, beyond some critical value of heat loss, extinction of the combustion reaction would occur. For the non-adiabatic case, particularly close to the extinction threshold, large excursions in temperature and wave speed above those observed for the adiabatic case can occur. Such behaviour close to extinction may have implications for safety or industrial processes.

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37

Kotob, Mostafa Raafat, Tianfeng Lu, and Seddik S. Wahid. "Experimental Study of Direct Water Injection Effect on NOx Reduction from The Gas Fuel." Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 76, no. 3 (October 29, 2020): 92–108. http://dx.doi.org/10.37934/arfmts.76.3.92108.

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Direct Water Injection (DWI) is commonly used in many nitrogen oxides (NOx) emissions control applications due to its effect to reduce the adiabatic flame temperature. In this paper an experimental test rig is designed to study the effect of water injection spray inside a simulated gas turbine combustor from the gas fuel. The practical work introduced by the chemical reaction methodology followed by the experiment which was presented and discussed carefully. Results are obtained in term of the exhaust gas temperature and different injection parameters including position, direction and fuel mass flow rate on the nitrogen oxide emission value in PPM (Parts per Million) at different conditions. The results showed that the best water injection effect was obtained at 45° degree inside the primary air zone. Injection location has a major effect on the NOx reduction as the best injected location is the Primary air zone compared with the direct fuel nozzle tip due to the increase of the water droplets residence time inside the combustor and perform a vortex that will affect the reduction of exhaust gas temperature and NOx emission respectively. The huge impact was observed at LPG (Liquefied Petroleum gas) flowrate 2.7L/min and water to fuel ratio about 0.4 as the NOx value was decreased about 73% from almost 381 PPM to 73 PPM. The chemical reaction arrangement order methodology presented good agreement with the experimental results at different fuel flow rate and equivalence ratio. The chemical Reaction equations were implemented to calculate the different adiabatic flame temperatures which is experimentally known as the exhaust gas temperature and impacted directly the NOx emission results.

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Glaude, Pierre-Alexandre, René Fournet, Roda Bounaceur, and Michel Molière. "Adiabatic flame temperature from biofuels and fossil fuels and derived effect on NOx emissions." Fuel Processing Technology 91, no. 2 (February 2010): 229–35. http://dx.doi.org/10.1016/j.fuproc.2009.10.002.

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Hindasageri, Vijaykumar, Rajendra P. Vedula, and Siddini V. Prabhu. "A novel method of estimation of adiabatic wall temperature for impinging premixed flame jets." International Journal of Heat and Mass Transfer 77 (October 2014): 185–93. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2014.05.015.

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40

Warren, D. L., and P. O. Hedman. "Differential Mass and Energy Balances in the Flame Zone From a Practical Fuel Injector in a Technology Combustor." Journal of Engineering for Gas Turbines and Power 119, no. 2 (April 1, 1997): 352–61. http://dx.doi.org/10.1115/1.2815582.

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This paper presents further analysis of experimental results from an Air Force program conducted by researchers at Brigham Young University (BYU), Wright-Patterson Air Force Base (WPAFB), and Pratt and Whitney Aircraft Co. (P&W) (Hedman et al., 1994a, 1995). These earlier investigations of the combustion of propane in a practical burner installed in a technology combustor used: (1) digitized images from video and still film photographs to document observed flame behavior as fuel equivalence ratio was varied, (2) sets of LDA data to quantify the velocity flow fields existing in the burner, (3) CARS measurements of gas temperature to determine the temperature field in the combustion zone, and to evaluate the magnitude of peak temperature, and (4) two-dimensional PLIF images of OH radical concentrations to document the instantaneous location of the flame reaction zones. This study has used the in situ velocity and temperature measurements from the earlier study, suitably interpolated, to determine local mass and energy balances on differential volume elements throughout the flame zone. The differential mass balance was generally within about ±10 percent with some notable exceptions near regions of very high shear and mixing. The local differential energy balance has qualitatively identified the regions of the flame where the major heat release is occurring, and has provided quantitative values on the rate of energy release (up to −400 kJ/m3s). The velocity field data have also been used to determine Lagrangian pathlines through the flame zone. The local velocity and temperature along selected pathlines have allowed temperature timelines to be determined. The temperature generally achieves its peak value, often near the adiabatic flame temperature, within about 10 ms. These temperature timelines, along with the quantitative heat release data, may provide a basis for evaluating kinetic combustion models.

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41

Kalb, Jochen R., and Thomas Sattelmayer. "Lean Blowout Limit and NOx Production of a Premixed Sub-ppm NOx Burner With Periodic Recirculation of Combustion Products." Journal of Engineering for Gas Turbines and Power 128, no. 2 (March 1, 2004): 247–54. http://dx.doi.org/10.1115/1.2061267.

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The technological objective of this work is the development of a lean-premixed burner for natural gas. Sub-ppm NOx emissions can be accomplished by shifting the lean blowout limit (LBO) to slightly lower adiabatic flame temperatures than the LBO of current standard burners. This can be achieved with a novel burner concept utilizing spatially periodic recirculation of combustion products: Hot combustion products are admixed to the injected premixed fresh mixture with a mass flow rate of comparable magnitude, in order to achieve self-ignition. The subsequent combustion of the diluted mixture again delivers products. A fraction of these combustion products is then admixed to the next stream of fresh mixture. This process pattern is to be continued in a cyclically closed topology, in order to achieve stable combustion of, for example, natural gas in a temperature regime of very low NOx production. The principal ignition behavior and NOx production characteristics of one sequence of the periodic process was modeled by an idealized adiabatic system with instantaneous admixture of partially or completely burnt combustion products to one stream of fresh reactants. With the CHEMKIN-II package, a reactor network consisting of one perfectly stirred reactor (PSR, providing ignition in the first place) and two plug flow reactors (PFR) has been used. The effect of varying burnout and the influence of the fraction of admixed flue gas has been evaluated. The simulations have been conducted with the reaction mechanism of Miller and Bowman and the GRI-Mech 3.0 mechanism. The results show that the high radical content of partially combusted products leads to a massive decrease of the time required for the formation of the radical pool. As a consequence, self-ignition times of 1 ms are achieved even at adiabatic flame temperatures of 1600 K and less, if the flue gas content is about 50–60% of the reacting flow after mixing is complete. Interestingly, the effect of radicals on ignition is strong, outweighs the temperature deficiency and thus allows stable operation at very low NOx emissions.

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Grenkin, Gleb V., Alexander Yu Chebotarev, Valeri I. Babushok, and Sergey S. Minaev. "Determination of global kinetic parameters by optimization procedure using burning velocity measurements." Mathematical Modelling of Natural Phenomena 13, no. 6 (2018): 50. http://dx.doi.org/10.1051/mmnp/2018048.

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The optimization procedure was developed to derive the global kinetic parameters using experimental dependence of burning velocity on the equivalence ratio. The simple model of laminar premixed flame propagation with assumed constant parameters was used to demonstrate the features of the suggested procedure. The suggested method allows finding optimal parameters for the defined functional dependence of the reaction rate on the temperature and reactant concentrations. The dependence of combustion adiabatic temperature on equivalence ratio is assumed to be known from the flame equilibrium calculations. The global kinetic parameters of combustion reaction were determined for methane, ethylene and propane mixtures with air on the basis of experimental data on burning velocity as function of the equivalence ratio. The calculated overall kinetic parameters are compared with parameters obtained by other methods within similar global model.

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SHERIKAR, BABURAO N., and A. M. UMARJI. "SYNTHESIS OF DIOPSIDE BY SOLUTION COMBUSTION PROCESS USING GLYCINE FUEL." International Journal of Modern Physics: Conference Series 22 (January 2013): 217–23. http://dx.doi.org/10.1142/s2010194513010155.

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Nano ceramic Diopside ( CaMgSi 2 O 6) powders are synthesized by Solution Combustion Process(SCS) using Calcium nitrate, Magnesium nitrate as oxidizer and glycine as fuel, fumed silica as silica source. Ammonium nitrate (AN) is used as extra oxidizer. Effect of AN on Diopside phase formation is investigated. The adiabatic flame temperatures are calculated theoretically for varying amount of AN according to thermodynamic concept and correlated with the observed flame temperatures. A “Multi channel thermocouple setup connected to computer interfaced Keithley multi voltmeter 2700” is used to monitor the thermal events during the process. An interpretation based on maximum combustion temperature and the amount of gases produced during reaction for various AN compositions has been proposed for the nature of combustion and its correlation with the characteristics of as synthesized powder. These powders are characterized by XRD, SEM showing that the powders are composed of polycrystalline oxides with crystallite size of 58nm to 74nm.

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Zhang, Xiang, and Fan Zhang. "Preparation and Performance of a Novel Intumescent Flame Retardant." Advanced Materials Research 415-417 (December 2011): 424–28. http://dx.doi.org/10.4028/www.scientific.net/amr.415-417.424.

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A novel phosphor-nitrogen intumescent flame retardant was prepared by dry method (without adding any solvent) using H3PO4, P2O5, pentaerythritol and melamine as raw materials. IR analysis found that the synthetic flame retardants had the P=O and P-O-C double-ring structures, the same to phosphate ester melamine salts. The reaction temperature, time and the ratio of raw materials had significant effect on the esterification reaction. The esterification reaction temperature should be controlled between 120°C and 130°C, and the reaction time should be 2.5 hours. The conversion rate of esterification could be improved by adding P2O5 to the reaction, and preferential mole rate between H3PO4 and P2O5 should be 2:1. Thermogravimetric analysis showed that the starting decomposition temperature of the flame retardant was 190°C, and at 700°C, the residual char rate was about 30%. The expansion ratio of the flame retardant after heated was about 30 to 50 times, SEM analysis found that the exteral surface of the expansion char layer was continuous and smooth, and the interior of the expansion char layer was uniformly porous structures, and the aperture size was about 150-200 μm, such porous structures could provide better adiabatic effect.

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45

Cheng, Zhe, Wen Jun Wang, Wen Qing Shen, Ai Wu Fan, and Wei Liu. "Flame Stability of Methane/Air Mixture in a Heat-Recirculating-Type Mesoscale Channel with a Bluff-Body." Applied Mechanics and Materials 325-326 (June 2013): 12–15. http://dx.doi.org/10.4028/www.scientific.net/amm.325-326.12.

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To extend the stable combustion range of micro-combustor, a heat-recirculating-type planar micro-combustor fitted with a bluff-body was proposed in the present work. Numerical simulation on CH4/air premixed combustion in this combustor was performed and the stable combustion range was determined, which showed that the blow-off limit increases with the equivalence ratio and the lower flammability limit was extended. Effect of the equivalence ratio and inlet velocity on combustion efficiency and maximum temperature were investigated. The numerical results showed that combustion efficiencies were higher than 99%, and the maximum temperatures were larger than the corresponding adiabatic flame temperature due to the excess enthalpy combustion effect. However, flashback emerged when the inlet velocity was too small and the equivalence ratio is relatively high.

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Jiang, Xudong, Yihao Tang, Zhaohui Liu, and Venkat Raman. "Computational Modeling of Boundary Layer Flashback in a Swirling Stratified Flame Using a LES-Based Non-Adiabatic Tabulated Chemistry Approach." Entropy 23, no. 5 (May 2, 2021): 567. http://dx.doi.org/10.3390/e23050567.

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When operating under lean fuel–air conditions, flame flashback is an operational safety issue in stationary gas turbines. In particular, with the increased use of hydrogen, the propagation of the flame through the boundary layers into the mixing section becomes feasible. Typically, these mixing regions are not designed to hold a high-temperature flame and can lead to catastrophic failure of the gas turbine. Flame flashback along the boundary layers is a competition between chemical reactions in a turbulent flow, where fuel and air are incompletely mixed, and heat loss to the wall that promotes flame quenching. The focus of this work is to develop a comprehensive simulation approach to model boundary layer flashback, accounting for fuel–air stratification and wall heat loss. A large eddy simulation (LES) based framework is used, along with a tabulation-based combustion model. Different approaches to tabulation and the effect of wall heat loss are studied. An experimental flashback configuration is used to understand the predictive accuracy of the models. It is shown that diffusion-flame-based tabulation methods are better suited due to the flashback occurring in relatively low-strain and lean fuel–air mixtures. Further, the flashback is promoted by the formation of features such as flame tongues, which induce negative velocity separated boundary layer flow that promotes upstream flame motion. The wall heat loss alters the strength of these separated flows, which in turn affects the flashback propensity. Comparisons with experimental data for both non-reacting cases that quantify fuel–air mixing and reacting flashback cases are used to demonstrate predictive accuracy.

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Hsu, P. F., J. R. Howell, and R. D. Matthews. "A Numerical Investigation of Premixed Combustion Within Porous Inert Media." Journal of Heat Transfer 115, no. 3 (August 1, 1993): 744–50. http://dx.doi.org/10.1115/1.2910746.

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A numerical investigation of premixed combustion within a highly porous inert medium is reported. Specifically, results of a numerical model using detailed chemical kinetics and energy exchange between the flowing gas and the porous solid are presented. The current formulation differs from prior models of this type of combustion in that multistep kinetics is used and a better description of the thermophysical properties of the solid is applied in the present model. It was found that the preheating effect increases strongly with increasing convective heat transfer and with increasing effective thermal conductivity of the solid. The convective heat transfer is expected to increase with increasing number of cells per unit length of porous matrix but the absorption coefficient decreases with increasing cell size and decreasing cell density. Numerical simulations using baseline properties indicate that the lean limit can be extended to an equivalence ratio of about 0.36 for a methane–air flame and that the peak flame temperature is generally higher than the adiabatic flame temperature. The latter effect is predicted to be more pronounced at lower equivalence ratios.

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Jarungthammachote, Sompop. "Simplified model for estimations of combustion products, adiabatic flame temperature and properties of burned gas." Thermal Science and Engineering Progress 17 (June 2020): 100393. http://dx.doi.org/10.1016/j.tsep.2019.100393.

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49

Zayoud, Azd, P. Mahanta, and U. K. Saha. "Pure Oxy-Fuel Circulating Fluidized Bed Combustion by Controlling Adiabatic Flame Temperature Using Fuel Staging." Current Science 113, no. 08 (October 25, 2017): 1560. http://dx.doi.org/10.18520/cs/v113/i08/1560-1567.

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Abdelhafez, Ahmed, Medhat A. Nemitallah, Sherif S. Rashwan, and Mohamed A. Habib. "Adiabatic Flame Temperature for Controlling the Macrostructures and Stabilization Modes of Premixed Methane Flames in a Model Gas-Turbine Combustor." Energy & Fuels 32, no. 7 (June 17, 2018): 7868–77. http://dx.doi.org/10.1021/acs.energyfuels.8b01133.

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Journal articles on the topic 'Adiabatic Flame Temperature'

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