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Artículos de revistas sobre el tema "Premixed Combustion"

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Autor: Grafiati

Publicado: 4 de junio de 2021

Última modificación: 1 de febrero de 2022

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1

Steele, Robert C., Luke H. Cowell, Steven M. Cannon y Clifford E. Smith. "Passive Control of Combustion Instability in Lean Premixed Combustors". Journal of Engineering for Gas Turbines and Power 122, n.º 3 (15 de mayo de 2000): 412–19. http://dx.doi.org/10.1115/1.1287166.

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A Solar fuel injector that provides lean premixed combustion conditions has been studied in a combined experimental and numerical investigation. Lean premixed conditions can be accompanied by excessive combustion driven pressure oscillations which must be eliminated before the release of a final combustor design. In order to eliminate the pressure oscillations the location of fuel injection was parametrically evaluated to determine a stable configuration. It was observed that small axial changes in the position of the fuel spokes within the premix duct of the fuel injector had a significant positive effect on decoupling the excitation of the natural acoustic modes of the combustion system. In order to further understand the phenomenon, a time-accurate 2D CFD analysis was performed. 2D analysis was first calibrated using 3D steady-state CFD computations of the premixer in order to model the radial distribution of velocities in the premixer caused by non-uniform inlet conditions and swirling flow. 2D time-accurate calculations were then performed on the baseline configuration. The calculations captured the coupling of heat release with the combustor acoustics, which resulted in excessive pressure oscillations. When the axial location of the fuel injection was moved, the CFD analysis accurately captured the fuel time lag to the flame-front, and qualitatively matched the experimental findings. [S0742-4795(00)01103-0]

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2

Libby, P. A., S. Sivasegaram y J. H. Whitelaw. "Premixed combustion". Progress in Energy and Combustion Science 12, n.º 4 (enero de 1986): 393–405. http://dx.doi.org/10.1016/0360-1285(86)90007-9.

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3

Anand, M. S. y F. C. Gouldin. "Combustion Efficiency of a Premixed Continuous Flow Combustor". Journal of Engineering for Gas Turbines and Power 107, n.º 3 (1 de julio de 1985): 695–705. http://dx.doi.org/10.1115/1.3239791.

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Experimental data in the form of radial profiles of mean temperature, gas composition and velocity at the combustor exit and combustion efficiency are reported and discussed for a swirling flow, continuous combustor. The combustor is composed of two confined, concentric independently swirling jets: an outer, annular air jet and a central premixed fuel-air jet, the fuel being propane or methane. Combustion is stabilized by a swirl-generated central recirculation zone. The primary objective of this research is to determine the effect of fuel substitution and of changes in outer flow swirl conditions on combustor performance. Results are very similar for both methane and propane. Changes in outer flow swirl cause significant changes in exit profiles, but, surprisingly, combustion efficiency is relatively unchanged. A combustion mechanism is proposed which qualitatively explains the results and identifies important flow characteristics and physical processes determining combustion efficiency. It is hypothesized that combustion occurs in a thin sheet, similar in structure to a premixed turbulent flame, anchored on the combustor centerline just upstream of the recirculation zone and swept downstream with the flow. Combustion efficiency depends on the extent of the radial propagation, across mean flow streamtubes, of this reaction sheet. It is concluded that, in general, this propagation and hence efficiency are extremely sensitive to flow conditions.

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4

Brookes, S. J., R. S. Cant, I. D. J. Dupere y A. P. Dowling. "Computational Modeling of Self-Excited Combustion Instabilities". Journal of Engineering for Gas Turbines and Power 123, n.º 2 (1 de enero de 2001): 322–26. http://dx.doi.org/10.1115/1.1362662.

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It is well known that lean premixed combustion systems potentially offer better emissions performance than conventional non-premixed designs. However, premixed combustion systems are more susceptible to combustion instabilities than non-premixed systems. Combustion instabilities (large-scale oscillations in heat release and pressure) have a deleterious effect on equipment, and also tend to decrease combustion efficiency. Designing out combustion instabilities is a difficult process and, particularly if many large-scale experiments are required, also very costly. Computational fluid dynamics (CFD) is now an established design tool in many areas of gas turbine design. However, its accuracy in the prediction of combustion instabilities is not yet proven. Unsteady heat release will generally be coupled to unsteady flow conditions within the combustor. In principle, computational fluid dynamics should be capable of modeling this coupled process. The present work assesses the ability of CFD to model self-excited combustion instabilities occurring within a model combustor. The accuracy of CFD in predicting both the onset and the nature of the instability is reported.

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5

Yang, Yao, Gaofeng Wang, Yuanqi Fang, YIfan Xia y Liang Zhong. "IMAGING DIAGNOSTICS OF COMBUSTION INSTABILITY IN PREMIXED SWIRLING COMBUSTION". Journal of the Global Power and Propulsion Society 4 (22 de mayo de 2020): 80–93. http://dx.doi.org/10.33737/jgpps/120536.

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An experimental study on combustion instability is presented with focus on propane-air premixed swirling flames. Swirling flames under self-excited oscillation are studied by imaging of visible light and OH* chemiluminescence filter under several typical conditions. The dynamical characteristics of swirling flames were analysed by Dynamic Mode Decomposition (DMD) method. Three types of unstable modes in the combustor system were observed, which correspond to typical acoustic resonant modes (LF mode, C1/4 mode and P1/2 mode) of the combustor system. The combustion instability is in the longitudinal mode. Furthermore, the structure of downstream hot burnt gas under stable combustion and unstable combustion is studied by imaging of visible light and near-infrared light. Results show that there is a significant difference in the downstream flow under stable combustion and unstable combustion. The DMD spectrum of the flame and the downstream hot burnt gas obtained is the same, which is close to the characteristic frequency of acoustic pressure captured by the microphone signal. The visible light and near-infrared light imaging observation method adopted in this paper provides a new imaging method for the investigation of thermo-acoustic instability.

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6

Dutta, P., J. P. Gore y P. E. Sojka. "Emissions Characteristics of Liquid-Fueled Pilot Stabilized Lean Premixed Flames in a Tubular Premixer-Combustor". Journal of Engineering for Gas Turbines and Power 119, n.º 3 (1 de julio de 1997): 585–90. http://dx.doi.org/10.1115/1.2817024.

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Global emissions of NOx in a liquid-fueled lean-premixed tubular combustor with a tubular premixer operating under atmospheric pressure are studied experimentally. The effects of equivalence ratio, premixer length, residence time, fuel type, and fuel atomization and dispersion characteristics on NOx emissions are studied. Measurements of exhaust species concentrations are used as the primary indicator of the effectiveness of premixing-prevaporization upstream of the combustor. Qualitative levels of prevaporization-premixing are determined from Mie-scattering signals measured at the exit of the premixer. Emission measurements show that the equivalence ratio is the dominant operating parameter, with premixing length and residence time being less significant within the present operating range. Ultra low NOx operation (<10 ppmv @ 15 percent 02) is feasible for equivalence ratios less than 0.5. More significantly, small drops persist beyond the premixer even for very long premixers, and Mie-scattering measurements show considerable spatial inhomogeneity, while allowing ultralow NOx operation. One-dimensional evaporation calculations for single drop trajectories confirm that complete evaporation for typical drop size distributions is not possible with reasonable premixer lengths under atmospheric pressure. Fuel dispersion is found to be the most critical parameter for high combustion efficiency, and adverse effects of poor fuel dispersion cannot be overcome by using longer premixers.

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7

Chein, Reiyu, Yen-Cho Chen, Jui-Yu Chen y J. N. Chung. "Premixed Methanol–Air Combustion Characteristics in a Mini-scale Catalytic Combustor". International Journal of Chemical Reactor Engineering 14, n.º 1 (1 de febrero de 2016): 383–93. http://dx.doi.org/10.1515/ijcre-2014-0061.

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AbstractMethanol catalytic combustion in a mini-scale tubular quartz-made combustor is investigated in this study. An alumina sphere was employed as the support for the platinum catalyst. The experimental results showed that the combustion can be self-ignited at room temperature. Using the combustor wall temperature to characterize the combustor performance, it was found that the combustion temperature can reach a high value within a short time. The experimental results indicated that the combustor performance depends greatly on the fuel/air supply. A higher temperature can be obtained with a higher fuel/air flow rate. The insulated and non-insulated combustor experimental results indicated that heat loss to the environment is an important factor in governing the combustion characteristics due to the large surface/volume ratio. A higher temperature can also be obtained when the combustor is insulated. Because most of the combustion took place at the combustor entrance region, the experimental result suggested that the combustor length can be shortened, leading to a more compact design allowing the combustor integration with various applications. A simple numerical model was built to provide a greater understanding of the combustion characteristics and examine the heat loss effect on combustor performance.

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8

Clavin, P. "Premixed Combustion and Gasdynamics". Annual Review of Fluid Mechanics 26, n.º 1 (enero de 1994): 321–52. http://dx.doi.org/10.1146/annurev.fl.26.010194.001541.

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9

Correa, S. M., A. J. Dean y I. Z. Hu. "Combustion Technology for Low-Emissions Gas-Turbines:Selected Phenomena Beyond NOx". Journal of Energy Resources Technology 118, n.º 3 (1 de septiembre de 1996): 193–200. http://dx.doi.org/10.1115/1.2793862.

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Since recent reviews cover the issues in NOx formation under gas-turbine canditions, and since regulations essentially dictate use of the premixed mode of combustion for minimum NOx, this review concentrates on phenomena that can arise in premixed combustion. Specifically, 1) the initial unmixedness in a fuel-air premixer has been shown to make overall lean mixtures autoignite sooner than might be expected based on the overall fuel-air ratio, because the richer portions of the mixture lead the process;2) combustion pressure oscillations caused by the interplay between acoustic waves and unsteady heat release in a one-dimensional system can be calculated in good accordance with measured data, and set the stage for multi-dimensional CFD;3) carbon deposition arising from the flow of liquid fuel over metal surfaces such as found in fuel injectors and swirl cups has been described as a function of temperature and of surface composition; and 4) quenching and subsequent emissions of carbon monoxide can be minimized by preservation of a boundary-layer rather than an impingement type of flow over combustor liners.

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10

Wirawan, I. K. G., I. N. G. Wardana, Rudy Soenoko y Slamet Wahyudi. "Premixed Combustion of Coconut Oil on Perforated Burner". International Journal of Renewable Energy Development 2, n.º 3 (30 de octubre de 2013): 133–39. http://dx.doi.org/10.14710/ijred.2.3.133-139.

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Coconut oil premixed combustion behavior has been studied experimentally on perforated burner with equivalence ratio (φ) varied from very lean until very rich. The results showed that burning of glycerol needs large number of air so that the laminar burning velocity (SL) is the highest at very lean mixture and the flame is in the form of individual Bunsen flame on each of the perforated plate hole. As φ is increased the SL decreases and the secondary Bunsen flame with open tip occurs from φ =0.54 at the downstream of perforated flame. The perforated flame disappears at φ = 0.66 while the secondary Bunsen flame still exist with SL increases following that of hexadecane flame trend and then extinct when the equivalence ratio reaches one or more. Surrounding ambient air intervention makes SL decreases, shifts lower flammability limit into richer mixture, and performs triple and cellular flames. The glycerol diffusion flame radiation burned fatty acids that perform cellular islands on perforated hole. Without glycerol, laminar flame velocity becomes higher and more stable as perforated flame at higher φ. At rich mixture the Bunsen flame becomes unstable and performs petal cellular around the cone flame front. Keywords: cellular flame; glycerol; perforated flame;secondary Bunsen flame with open tip; triple flame

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11

Scarinci, Thomas y John L. Halpin. "Industrial Trent Combustor—Combustion Noise Characteristics". Journal of Engineering for Gas Turbines and Power 122, n.º 2 (3 de enero de 2000): 280–86. http://dx.doi.org/10.1115/1.483207.

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Thermoacoustic resonance is a difficult technical problem that is experienced by almost all lean-premixed combustors. The Industrial Trent combustor is a novel dry-low-emissions (DLE) combustor design, which incorporates three stages of lean premixed fuel injection in series. The three stages in series allow independent control of two stages—the third stage receives the balance of fuel to maintain the desired power level—at all power conditions. Thus, primary zone and secondary zone temperatures can be independently controlled. This paper examines how the flexibility offered by a 3-stage lean premixed combustion system permits the implementation of a successful combustion noise avoidance strategy at all power conditions and at all ambient conditions. This is because at a given engine condition (power level and day temperature) a characteristic “noise map” can be generated on the engine, independently of the engine running condition. The variable distribution of heat release along the length of the combustor provides an effective mechanism to control the amplitude of longitudinal resonance modes of the combustor. This approach has allowed the Industrial Trent combustion engineers to thoroughly “map out” all longitudinal combustor acoustic modes and design a fuel schedule that can navigate around regions of combustor thermoacoustic resonance. Noise mapping results are presented in detail, together with the development of noise prediction methods (frequency and amplitude) that have allowed the noise characteristics of the engine to be established over the entire operating envelope of the engine. [S0742-4795(00)00802-4]

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12

Nalim, M. R. "Assessment of Combustion Modes for Internal Combustion Wave Rotors". Journal of Engineering for Gas Turbines and Power 121, n.º 2 (1 de abril de 1999): 265–71. http://dx.doi.org/10.1115/1.2817116.

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Combustion within the channels of a wave rotor is examined as a means of obtaining pressure gain during heat addition in a gas turbine engine. Three modes of combustion are assessed: premixed autoignition (detonation), premixed deflagration, and non-premixed autoignition. The last two will require strong turbulence for completion of combustion in a reasonable time in the wave rotor. The autoignition modes will require inlet temperatures in excess of 800 K for reliable ignition with most hydrocarbon fuels. Examples of combustion mode selection are presented for two engine applications.

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13

Yilmaz, Ilker, Harun Yilmaz y Omer Cam. "An experimental study on premixed CNG/H2/CO2 mixture flames". Open Engineering 8, n.º 1 (13 de marzo de 2018): 32–40. http://dx.doi.org/10.1515/eng-2018-0003.

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Abstract In this study, the effect of swirl number, gas composition and CO2 dilution on combustion and emission behaviour of CNG/H2/CO2 gas mixtures was experimentally investigated in a laboratory scale combustor. Irrespective of the gas composition, thermal power of the combustor was kept constant (5 kW). All experiments were conducted at or near stoichiometric and the local atmospheric conditions of the city of Kayseri, Turkey. During experiments, swirl number was varied and the combustion performance of this combustor was analysed by means of centreline temperature distributions. On the other hand, emission behaviour was examined with respect to emitted CO, CO2 and NOx levels. Dynamic flame behaviour was also evaluated by analysing instantaneous flame images. Results of this study revealed the great impact of swirl number and gas composition on combustion and emission behaviour of studied flames.

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14

Ozturk, Suat. "A Numerical Investigation on Emissions of Partially Premixed Shale Gas Combustion". International Journal of Heat and Technology 38, n.º 3 (15 de octubre de 2020): 745–51. http://dx.doi.org/10.18280/ijht.380319.

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The adiabatic, turbulent, and partially premixed combustions of several shale gases and air in a co-axial type combustor are computationally examined under the effects of different equivalence ratios, inlet temperatures, flow rates, humidity ratios, pressure, oxid inlet temperatures and flow rates, and swirl velocities in this study. Shale gases are extracted from Barnette, New Albany, Fayetteville, and Haynesville areas of USA. ANSYS software is used for numerical calculations of combustion. Results show that the maximum NO emissions for Barnette, New Albany, Fayetteville, and Haynesville shale gas occur at the equivalence ratio of 1.42, 1.41, 1.4, and 1.39. The rising fuel inlet temperature increase NO and reduces CO emissions after 300 K. The increasing humidity ratio causes NO and CO mass fractions to decrease. The ascending pressure raises NO up to 4 bar and lowers CO emissions. The increasing oxid flow rate abates the mass fractions of both NO and CO. The rising swirl velocity escalates NO up to 15 m/s and decreases CO emissions for all the shale gas combustions.

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15

Kim, Jong-Chan, Won-Chul Jung, Ji-Seok Hong y Hong-Gye Sung. "The Effects of Turbulent Burning Velocity Models in a Swirl-Stabilized Lean Premixed Combustor". International Journal of Turbo & Jet-Engines 35, n.º 4 (19 de diciembre de 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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16

Hosseini, Seyed, Evan Owens, John Krohn y James Leylek. "Experimental Investigation into the Effects of Thermal Recuperation on the Combustion Characteristics of a Non-Premixed Meso-Scale Vortex Combustor". Energies 11, n.º 12 (4 de diciembre de 2018): 3390. http://dx.doi.org/10.3390/en11123390.

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In small-scale combustors, the ratio of area to the combustor volume increases and hence heat loss from the combustor’s wall is significantly enhanced and flame quenching occurs. To solve this problem, non-premixed vortex flow is employed to stabilize flames in a meso-scale combustion chamber to generate small-scale power or thrust for propulsion systems. In this experimental investigation, the effects of thermal recuperation on the characteristics of asymmetric non-premixed vortex combustion are studied. The exhaust gases temperature, emissions and the combustor wall temperature are measured to evaluate thermal and emitter efficiencies. The results illustrate that in both combustors (with/without thermal recuperator), by increasing the combustion air mass flowrate, the wall temperature increases while the wall temperature of combustor with thermal recuperator is higher. The emitter efficiency calculated based on the combustor wall temperature is significantly increased by using thermal recuperator. Thermal efficiency of the combustion system increases up to 10% when thermal recuperator is employed especially in moderate Reynolds numbers (combustion air flow rate is 120 mg/s).

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17

Peters, N. "Partially premixed diffusion flamelets in non-premixed turbulent combustion". Symposium (International) on Combustion 20, n.º 1 (enero de 1985): 353–60. http://dx.doi.org/10.1016/s0082-0784(85)80521-x.

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18

Peters, N. y F. A. Williams. "Premixed combustion in a vortex". Symposium (International) on Combustion 22, n.º 1 (enero de 1989): 495–503. http://dx.doi.org/10.1016/s0082-0784(89)80056-6.

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19

Di Benedetto, A., F. S. Marra y G. Russo. "Spontaneous oscillations inlean premixed combustion". Combustion Science and Technology 174, n.º 10 (octubre de 2002): 1–18. http://dx.doi.org/10.1080/00102200290021344.

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20

HENSHAW, PAUL F., TINA D'ANDREA, KENNETH R. C. MANN y DAVID S. K. TING. "PREMIXED AMMONIA-METHANE-AIR COMBUSTION". Combustion Science and Technology 177, n.º 11 (noviembre de 2005): 2151–70. http://dx.doi.org/10.1080/00102200500240695.

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21

Lee, Kangyeop, Hyungmo Kim, Poomin Park, Sooseok Yang y Youngsung Ko. "Effects of CO2 dilution on combustion instabilities in dual premixed flames". Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 227, n.º 11 (11 de febrero de 2013): 2569–81. http://dx.doi.org/10.1177/0954406213475945.

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There has been a rapid increase in the demand for biogas applications in recent years, and dry low NOx and dry low emission gas turbine combustors are promising platforms for such applications. Combustion instability is the most important drawback in dry low NOx gas turbine combustors and has, therefore, attracted considerable research interest lately. As a fundamental study towards the use of biogas in dry low NOx and dry low emission gas turbine combustors, this article investigates the influence of CO2 in surrogate biogas on combustion instability. Tests were conducted using a dry low NOx type, a dual lean premixed gas turbine combustor. For a dual flame with dual swirl, the pilot fuel mass fraction affects the flame structure, and the flame structure, in turn, determines the temperature distribution in the combustion chamber and the combustion instability. The effects of the pilot fuel mass fraction, which is an important parameter of the combustor, and the CO2 dilution rate, which is a major contributor of biogas combustion, on the combustion characteristics and instability are investigated through dynamic pressure signal and phase-resolved OH* images. Combustion instability decreases for higher CO2 dilution rates, whose effects depend on the pilot fuel mass fraction. The instability reaches its maximum at a pilot fuel mass fraction of 0.3. Tests confirm that combustion instability diminishes with CO2 dilution, as it reduces the perturbation in the heat emission, and the flame speed decreases resulting in a greater flame surface or volume. Further, investigation of the Rayleigh Index, which represents the coupling strength of the heat release fluctuation and the natural frequency, shows that CO2 dilution weakens the coupling strength, resulting in less combustion instability.

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22

Ro̸kke, N. A. y A. J. W. Wilson. "Experimental and Theoretical Studies of a Novel Venturi Lean Premixed Prevaporized (LPP) Combustor". Journal of Engineering for Gas Turbines and Power 123, n.º 3 (1 de octubre de 2000): 567–73. http://dx.doi.org/10.1115/1.1377008.

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A new gas turbine engine using a unique layout patented in Norway has a low-emission combustion system under development. The gas generator uses entirely radial rotating components and employs a dual entry LP radial compressor, a radial HP compressor, and a radial HP turbine. The power turbine is of a two-stage axial design, coupled to an epicyclical gear embedded in the exhaust duct. Several combustor concepts have been tested and evaluated during the development of the engine. The engine is targeted for marine, power generation, and train propulsion. For the marine and train application liquid fuel operation is needed, thus the primary focus in the development has been for a lean premixed prevapourised system. An interesting concept utilizing two venturi premixers has been studied intensively. By utilizing venturi premixers the following advantages can be achieved: (1) low overall pressure drop but high injector pressure drop and velocities in the mixing region (throat region), (2) high shear forces and drag imposed on the droplets enhancing droplet shedding and evaporation, and (3) excellent emission behavior at designated load conditions. Although these advantages can benefit gas turbine low-emission combustion, the challenges in using venturi premixers are: (1) venturis are susceptible to separation and thus flame stabilization within the venturi which is detrimental and (2) inlet flow disturbances enhance the tendency for separation in the venturis and must be minimized. Studies were launched to investigate a proposed combustor configuration. These studies included analytical studies, computational fluid dynamics (CFD) calculations of isothermal and combusting flow inside the combustor together with rig tests at atmospheric, medium, and full pressure. Finally, engine tests within the full operating range were conducted with very favorable emission figures for lean premixed prevaporized (LPP) operation. The system was capable of running at below 20 ppm NOx and CO, at elevated power for liquid fuel. Control of part load performance and emissions is by variable fuel staging of the two venturi stages. The paper highlights the features of the venturi combustor development and discusses the characteristics in terms of flow conditions and droplet motion, heat transfer, ignition delay time, and emissions.

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23

Undapalli, Satish, Srikant Srinivasan y Suresh Menon. "LES of premixed and non-premixed combustion in a stagnation point reverse flow combustor". Proceedings of the Combustion Institute 32, n.º 1 (2009): 1537–44. http://dx.doi.org/10.1016/j.proci.2008.06.167.

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24

Deng, Xiaowen, Li Xing, Hong Yin, Feng Tian y Qun Zhang. "Numerical Investigation of Fuel Distribution Effect on Flow and Temperature Field in a Heavy Duty Gas Turbine Combustor". International Journal of Turbo & Jet-Engines 35, n.º 1 (26 de marzo de 2018): 71–80. http://dx.doi.org/10.1515/tjj-2016-0021.

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AbstractMultiple-swirlers structure is commonly adopted for combustion design strategy in heavy duty gas turbine. The multiple-swirlers structure might shorten the flame brush length and reduce emissions. In engineering application, small amount of gas fuel is distributed for non-premixed combustion as a pilot flame while most fuel is supplied to main burner for premixed combustion. The effect of fuel distribution on the flow and temperature field related to the combustor performance is a significant issue. This paper investigates the fuel distribution effect on the combustor performance by adjusting the pilot/main burner fuel percentage. Five pilot fuel distribution schemes are considered including 3 %, 5 %, 7 %, 10 % and 13 %. Altogether five pilot fuel distribution schemes are computed and deliberately examined. The flow field and temperature field are compared, especially on the multiple-swirlers flow field. Computational results show that there is the optimum value for the base load of combustion condition. The pilot fuel percentage curve is calculated to optimize the combustion operation. Under the combustor structure and fuel distribution scheme, the combustion achieves high efficiency with acceptable OTDF and low NOXemission. Besides, the CO emission is also presented.

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25

Onuma, Yoshiaki, Masaharu Morikawa, Junichi Kimura, Shigeto Nakagawa y Tatsuya Ichihashi. "Fuel-Lean Premixed Combustion by a Swirl-Flow Combustor." Transactions of the Japan Society of Mechanical Engineers Series B 61, n.º 584 (1995): 1534–39. http://dx.doi.org/10.1299/kikaib.61.1534.

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26

KIM, H., V. ARGHODE y A. GUPTA. "Combustion characteristics of a lean premixed LPG–air combustor". International Journal of Hydrogen Energy 34, n.º 2 (enero de 2009): 1045–53. http://dx.doi.org/10.1016/j.ijhydene.2008.10.036.

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27

Yamada, H., K. Shimodaira y S. Hayashi. "On-Engine Evaluation of Emissions Characteristics of a Variable Geometry Lean-Premixed Combustor". Journal of Engineering for Gas Turbines and Power 119, n.º 1 (1 de enero de 1997): 66–69. http://dx.doi.org/10.1115/1.2815563.

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The design and on-engine testing of a lean-premixed, low-NOx combustor for a simple-cycle, single-shaft, 250-kW gas turbine engine of a pressure ratio of eight are described. A variable-geometry system composed of butterfly air valves was used to control the combustor air split between combustion and dilution. Fuel was staged to a direct-injection pilot burner, and a lean-premixed main burner was fitted to the combustor liner. The NOx emissions with natural gas fueling were found to be less than 20 ppm (at 15 percent O2) at and near full-load conditions with combustion efficiencies greater than 99.8 percent. Emissions data from early high-pressure rig tests of the combustor hardware are also presented.

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28

Lieuwen, T., H. Torres, C. Johnson y B. T. Zinn. "A Mechanism of Combustion Instability in Lean Premixed Gas Turbine Combustors". Journal of Engineering for Gas Turbines and Power 123, n.º 1 (2 de abril de 2000): 182–89. http://dx.doi.org/10.1115/1.1339002.

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There has been increased demand in recent years for gas turbines that operate in a lean, premixed (LP) mode of combustion in an effort to meet stringent emissions goals. Unfortunately, detrimental combustion instabilities are often excited within the combustor when it operates under lean conditions, degrading performance and reducing combustor life. To eliminate the onset of these instabilities and develop effective approaches for their control, the mechanisms responsible for their occurrence must be understood. This paper describes the results of an investigation of the mechanisms responsible for these instabilities. These studies found that combustors operating in a LP mode of combustion are highly sensitive to variations in the equivalence ratio (ϕ) of the mixture that enters the combustor. Furthermore, it was found that such ϕ variations can be induced by interactions of the pressure and flow oscillations with the reactant supply rates. The ϕ perturbations formed in the inlet duct (near the fuel injector) are convected by the mean flow to the combustor where they produce large amplitude heat release oscillations that drive combustor pressure oscillations. It is shown that the dominant characteristic time associated with this mechanism is the convective time from the point of formation of the reactive mixture at the fuel injector to the point where it is consumed at the flame. Instabilities occur when the ratio of this convective time and the period of the oscillations equals a specific constant, whose magnitude depends upon the combustor design. Significantly, these predictions are in good agreement with available experimental data, strongly suggesting that the proposed mechanism properly accounts for the essential physics of the problem. The predictions of this study also indicate, however, that simple design changes (i.e., passive control approaches) may not, in general, provide a viable means for controlling these instabilities, due to the multiple number of modes that may be excited by the combustion process.

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29

Chorpening, B. T., J. D. Thornton, E. D. Huckaby y K. J. Benson. "Combustion Oscillation Monitoring Using Flame Ionization in a Turbulent Premixed Combustor". Journal of Engineering for Gas Turbines and Power 129, n.º 2 (30 de agosto de 2006): 352–57. http://dx.doi.org/10.1115/1.2431390.

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To achieve very low NOx emission levels, lean-premixed gas turbine combustors have been commercially implemented that operate near the fuel-lean flame extinction limit. Near the lean limit, however, flashback, lean blow off, and combustion dynamics have appeared as problems during operation. To help address these operational problems, a combustion control and diagnostics sensor (CCADS) for gas turbine combustors is being developed. CCADS uses the electrical properties of the flame to detect key events and monitor critical operating parameters within the combustor. Previous development efforts have shown the capability of CCADS to monitor flashback and equivalence ratio. Recent work has focused on detecting and measuring combustion instabilities. A highly instrumented atmospheric combustor has been used to measure the pressure oscillations in the combustor, the OH emission, and the flame ion field at the premix injector outlet and along the walls of the combustor. This instrumentation allows examination of the downstream extent of the combustion field using both the OH emission and the corresponding electron and ion distribution near the walls of the combustor. In most cases, the strongest pressure oscillation dominates the frequency behavior of the OH emission and the flame ion signals. Using this highly instrumented combustor, tests were run over a matrix of equivalence ratios from 0.6 to 0.8, with an inlet reference velocity of 25m∕s(82ft∕s). The acoustics of the fuel system for the combustor were tuned using an active-passive technique with an adjustable quarter-wave resonator. Although several statistics were investigated for correlation with the dynamic pressure in the combustor, the best correlation was found with the standard deviation of the guard current. The data show a monotonic relationship between the standard deviation of the guard current (the current through the flame at the premix injector outlet) and the standard deviation of the chamber pressure. Therefore, the relationship between the standard deviation of the guard current and the standard deviation of the pressure is the most promising for monitoring the dynamic pressure of the combustor using the flame ionization signal. This addition to the capabilities of CCADS would allow for dynamic pressure monitoring on commercial gas turbines without a pressure transducer.

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30

Shi, Junrui, Yang Liu, Yongqi Liu, Mingming Mao, Yongfang Xia, Rui Ma y Youning Xu. "An experimental study on coflow diffusion combustion in a pellet-packed bed with different bed lengths". Royal Society Open Science 5, n.º 8 (agosto de 2018): 172027. http://dx.doi.org/10.1098/rsos.172027.

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In experimental investigations on axial symmetry, over-ventilated CH 4 /air diffusion combustion in a packed bed is executed to study the height, shape and stability of the flame. The combustor is a quartz tube packed with alumina pellets in which a cylindrical fuel stream is surrounded by a coflow air nozzle. The results show that the bed length and pellet diameter have a significant influence on the flame properties. In general, the flame above the pellet surface has axial symmetry, and its shape and colour are similar to those of a conventional diffusion flame when the bed length is smaller. The colour of the flame front varies with the bed length. The changed colour indicates an increased flame front temperature and that the combustion regime above the bed surface may change from non-premixed combustion to partially premixed combustion or even premixed combustion owing to the mix and dispersion effect in the packed bed. In addition, multiple flame behaviours, such as an inclined flame front, isolated reaction zone and oscillatory motion followed by a pulsating sound with a few hertz in a packed bed, are observed experimentally. The possible reasons for these phenomena are discussed.

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31

Bender, Christian y Horst Büchner. "Combustion Noise from Non-premixed and Lean-premixed Swirl Flames". Acta Acustica united with Acustica 95, n.º 3 (1 de mayo de 2009): 402–8. http://dx.doi.org/10.3813/aaa.918164.

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32

Carrier, D. M. y R. J. Wetton. "Prediction of Combustion Performance of Aviation Kerosines Using a Novel Premixed Flame Technique". Journal of Engineering for Gas Turbines and Power 110, n.º 1 (1 de enero de 1988): 100–104. http://dx.doi.org/10.1115/1.3240071.

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A novel method for predicting aviation fuel combustion performance has been developed in which the sooting point of a premixed flame is detected automatically. Comparisons with full-scale combustor data confirm that the technique is a more realistic index of combustion quality than Smoke Point or hydrogen content.

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33

Ju, Yiguang, Kaoru Maruta y Takashi Niioka. "Combustion Limits". Applied Mechanics Reviews 54, n.º 3 (1 de mayo de 2001): 257–77. http://dx.doi.org/10.1115/1.3097297.

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Combustion limits and related flame behaviors are reviewed, especially with regard to fundamental problems. As for premixed flames, after a brief historical overview of research on the flammability limit, recent trends of research on planar propagating flames, curved propagating flames, flame balls, and stretched premixed flames are discussed, and then all types of flames are summarized. Finally, instability and dynamics near limits is discussed. With regard to combustion limits of counterflow diffusion flames and droplet flames, their instability is demonstrated, then an explanation of lifted flames and edge flames is presented. Suggestions for future work are also discussed in the concluding remarks. There are 166 references cited in this review article.

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34

Ozawa, Y., Y. Tochihara, N. Mori, I. Yuri, T. Kanazawa y K. Sagimori. "High Pressure Test Results of a Catalytically Assisted Ceramic Combustor for a Gas Turbine". Journal of Engineering for Gas Turbines and Power 121, n.º 3 (1 de julio de 1999): 422–28. http://dx.doi.org/10.1115/1.2818490.

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A catalytically assisted ceramic combustor for a gas turbine was designed to achieve low NOx emission under 5 ppm at a combustor outlet temperature over 1300°C. This combustor is composed of a burner system and a ceramic liner behind the burner system. The burner system consists of 6 catalytic combustor segments and 6 premixing nozzles, which are arranged in parallel and alternately. The ceramic liner is made up of the layer of outer metal wall, ceramic fiber, and inner ceramic tiles. Fuel flow rates for the catalysts and the premixing nozzles are controlled independently. Catalytic combustion temperature is controlled under 1000°C, premixed gas is injected from the premixing nozzles to the catalytic combustion gas and lean premixed combustion over 1300°C is carried out in the ceramic liner. This system was designed to avoid catalytic deactivation at high temperature and thermal and mechanical shock fracture of the honeycomb monolith of the catalyst. A combustor for a 10 MW class, multican type gas turbine was tested under high pressure conditions using LNG fuel. Measurements of emission, temperature, etc. were made to evaluate combustor performance under various combustion temperatures and pressures. This paper presents the design features and the test results of this combustor.

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35

Hayashi, A. K., Y. Yamazaki, T. Mizuno, S. Ogawa, T. Yamamoto, S. Kagiya y T. Motegi. "Active control of combustion oscillations for premixed combustion systems". Journal de Physique IV (Proceedings) 12, n.º 7 (agosto de 2002): 281–89. http://dx.doi.org/10.1051/jp4:20020295.

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36

Vanoverberghe, K. P., E. V. Van den Bulck, M. J. Tummers y W. A. Hu¨bner. "Multiflame Patterns in Swirl-Driven Partially Premixed Natural Gas Combustion". Journal of Engineering for Gas Turbines and Power 125, n.º 1 (27 de diciembre de 2002): 40–45. http://dx.doi.org/10.1115/1.1520159.

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Five different flame states are identified in a compact combustion chamber that is fired by a 30 kW swirl-stabilized partially premixed natural gas burner working at atmospheric pressure. These flame states include a nozzle-attached tulip shaped flame, a nonattached torroidal-ring shaped flame (SSF) suitable for very low NOx emission in a gas turbine combustor and a Coanda flame (CSF) that clings to the bottom wall of the combustion chamber. Flame state transition is generated by changing the swirl number and by premixing the combustion air with 70% of the natural gas flow. The flame state transition pathways reveal strong hysteresis and bifurcation phenomena. The paper also presents major species concentrations, temperature and velocity profiles of the lifted flame state and the Coanda flame and discusses the mechanisms of flame transition and stabilization.

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37

Sokolov, K. Y., A. G. Tumanovsky, M. N. Gutnik, A. I. Mechanikov, V. P. Reshitko y M. I. Grinshtein. "Experimental Investigation of GTE-115 Combustor With Premixed Burner Unit". Journal of Engineering for Gas Turbines and Power 116, n.º 3 (1 de julio de 1994): 547–53. http://dx.doi.org/10.1115/1.2906854.

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The results of experimental investigation of the basic parameters of one-burner, 1/18 sector of a full-scale annular combustor of the “Turboatom” GTE-115 gas turbine unit are presented. Specifics of fuel burnup and formation of toxic pollutants in premixed combustion using a pilot diffusion burner are presented. Generalized dependences of combustor characteristics versus flow parameters and an optimized algorithm of combustor loading are illustrated.

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38

Ozawa, Y., J. Hirano, M. Sato, M. Saiga y S. Watanabe. "Test Results of Low NOx Catalytic Combustors for Gas Turbines". Journal of Engineering for Gas Turbines and Power 116, n.º 3 (1 de julio de 1994): 511–16. http://dx.doi.org/10.1115/1.2906849.

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Catalytic combustion is an ultralow NOx combustion method, so it is expected that this method will be applied to a gas turbine combustor. However, it is difficult to develop a catalytic combustor because catalytic reliability at high temperature is still insufficient. To overcome this difficulty, we designed a catalytic combustor in which premixed combustion was combined. By this device, it is possible to obtain combustion gas at a combustion temperature of 1300°C while keeping the catalytic temperature below 1000°C. After performing preliminary tests using LPG, we designed two types of combustor for natural gas with a capacity equivalent to one combustor used in a 20 MW class multican-type gas turbine. Combustion tests were conducted at atmospheric pressure using natural gas. As a result, it was confirmed that a combustor in which catalytic combustor segments were arranged alternately with premixing nozzles could achieve low NOx and high combustion efficiency in the range from 1000°C to 1300°C of the combustor exit gas temperature.

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39

Abdel-Raheem, M., S. Ibrahim y W. Malalasekera. "NUMERICAL MODELING OF HYDROGEN PREMIXED COMBUSTION". International Conference on Applied Mechanics and Mechanical Engineering 16, n.º 16 (1 de mayo de 2014): 1–10. http://dx.doi.org/10.21608/amme.2014.35594.

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40

Swaminathan, N. "Flamelet regime in non-premixed combustion". Combustion and Flame 129, n.º 1-2 (abril de 2002): 217–19. http://dx.doi.org/10.1016/s0010-2180(01)00369-8.

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41

Bouma, P. H. y L. P. H. de Goey. "Premixed combustion on ceramic foam burners". Combustion and Flame 119, n.º 1-2 (octubre de 1999): 133–43. http://dx.doi.org/10.1016/s0010-2180(99)00050-4.

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42

Mikami, Masato, Kazuhiro Yamamoto, Osamu Moriue y Naoya Kojima. "Combustion of partially premixed spray jets". Proceedings of the Combustion Institute 30, n.º 2 (enero de 2005): 2021–28. http://dx.doi.org/10.1016/j.proci.2004.08.034.

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43

Boettcher, Philipp A., Shyam K. Menon, Brian L. Ventura, Guillaume Blanquart y Joseph E. Shepherd. "Cyclic flame propagation in premixed combustion". Journal of Fluid Mechanics 735 (23 de octubre de 2013): 176–202. http://dx.doi.org/10.1017/jfm.2013.495.

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AbstractIn experiments of hot surface ignition and subsequent flame propagation, a puffing flame instability is observed in mixtures that are stagnant and premixed prior to ignition. By varying the size of the hot surface, power input, and combustion vessel volume, it was determined that the instability is a function of the interaction of the flame, with the fluid flow induced by the combustion products rather than the initial plume established by the hot surface. Pressure ranges from 25 to 100 kPa and mixtures of n-hexane/air with equivalence ratios between $\phi = 0. 58$ and 3.0 at room temperature were investigated. Equivalence ratios between $\phi = 2. 15$ and 2.5 exhibited multiple flame and equivalence ratios above $\phi = 2. 5$ resulted in puffing flames at atmospheric pressure. The phenomenon is accurately reproduced in numerical simulations and a detailed flow field analysis revealed competition between the inflow velocity at the base of the flame and the flame propagation speed. The increasing inflow velocity, which exceeds the flame propagation speed, is ultimately responsible for creating a puff. The puff is then accelerated upward, allowing for the creation of the subsequent instabilities. The frequency of the puff is proportional to the gravitational acceleration and inversely proportional to the flame speed. A scaling relationship describes the dependence of the frequency on gravitational acceleration, hot surface diameter, and flame speed. This relation shows good agreement for rich n-hexane/air and lean hydrogen/air flames, as well as lean hexane/hydrogen/air mixtures.

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44

Sivashinsky, Gregory I. "Some developments in premixed combustion modeling". Proceedings of the Combustion Institute 29, n.º 2 (enero de 2002): 1737–61. http://dx.doi.org/10.1016/s1540-7489(02)80213-9.

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45

Gonçalves, Cecilia K., Jorge A. S. Tenório, Yiannis A. Levendis y Joel B. Carlson. "Emissions from Premixed Combustion of Polystyrene". Energy & Fuels 22, n.º 1 (enero de 2008): 354–62. http://dx.doi.org/10.1021/ef700431f.

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46

Mandai, Shigemi y Tetsuo Gora. "Study on catalytically ignited premixed combustion". Catalysis Today 26, n.º 3-4 (diciembre de 1995): 359–63. http://dx.doi.org/10.1016/0920-5861(95)00159-3.

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47

Hemawan, K. W., C. L. Romel, S. Zuo, I. S. Wichman, T. A. Grotjohn y J. Asmussen. "Microwave plasma-assisted premixed flame combustion". Applied Physics Letters 89, n.º 14 (2 de octubre de 2006): 141501. http://dx.doi.org/10.1063/1.2358213.

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48

Bell, J., M. Day, A. Almgren, M. Lijewski, C. Rendleman, R. Cheng y I. Shepherd. "Simulation of lean premixed turbulent combustion". Journal of Physics: Conference Series 46 (1 de septiembre de 2006): 1–15. http://dx.doi.org/10.1088/1742-6596/46/1/001.

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49

Chiu, H. H. y C. L. Lin. "Anomalous group combustion of premixed clusters". Symposium (International) on Combustion 26, n.º 1 (enero de 1996): 1653–61. http://dx.doi.org/10.1016/s0082-0784(96)80389-4.

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50

Kawaguchi, Osamu, Takashi Otoh, Sunao Nakamura, Atsushi Todoroki y Yoshio Murayama. "Premixed combustion at a fiber mat". Symposium (International) on Combustion 23, n.º 1 (enero de 1991): 1019–24. http://dx.doi.org/10.1016/s0082-0784(06)80359-0.

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