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1
Pham, Vu Thanh Nam. "AN IMAGE PROCESSING APPROACH FOR DETERMINING THE SPRAY CONE ANGLE OF A PRESSURE SWIRL INJECTOR EQUIPPED IN A GAS-TURBINE ENGINE". Journal of Science and Technique 16, nr 2 (29.08.2022): 33–47. http://dx.doi.org/10.56651/lqdtu.jst.v16.n02.265.
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This paper adopts the directionality tool provided by the ImageJ package to determine the spray cone angle of a gas-turbine engine’s injector. An imaging experiment system has been developed in this study to image a spray of a practical gas-turbine injector under injection pressure conditions varying from 2 to 6 bars. The results show that the reliability of the measurement is achieved when analyzing at least 500 images. Preferably, using 1500 images shows the uncertainty of less than 0.5% (approximately corresponding with 0.2° of the angle). The average spray cone angle varies between 100° and 128.15° when the injection pressure increases from 2 to 6 bars. An accurate determination of the spray cone angle helps to improve the quality of research on micro and macro spray characteristics including the droplet concentration and distribution. The results could also be utilized to develop a diagnostic technique for gas-turbine injectors.
2
McGuirk, J. J. "The aerodynamic challenges of aeroengine gas-turbine combustion systems". Aeronautical Journal 118, nr 1204 (czerwiec 2014): 557–99. http://dx.doi.org/10.1017/s0001924000009386.
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Abstract The components of an aeroengine gas-turbine combustor have to perform multiple tasks – control of external and internal air distribution, fuel injector feed, fuel/air atomisation, evaporation, and mixing, flame stabilisation, wall cooling, etc. The ‘rich-burn’ concept has achieved great success in optimising combustion efficiency, combustor life, and operational stability over the whole engine cycle. This paper first illustrates the crucial role of aerodynamic processes in achieving these performance goals. Next, the extra aerodynamic challenges of the ‘lean-burn’ injectors required to meet the ever more stringent NO x emissions regulations are introduced, demonstrating that a new multi-disciplinary and ‘whole system’ approach is required. For example, high swirl causes complex unsteady injector aerodynamics; the threat of thermo-acoustic instabilities means both aerodynamic and aeroacoustic characteristics of injectors and other air admission features must be considered; and high injector mass flow means potentially strong compressor/combustor and combustor/turbine coupling. The paper illustrates how research at Loughborough University, based on complementary use of advanced experimental and computational methods, and applied to both isolated sub-components and fully annular combustion systems, has improved understanding and identified novel ideas for combustion system design.
3
So, Younseok, Yeoungmin Han i Sejin Kwon. "Combustion Characteristics of Multi-Element Swirl Coaxial Jet Injectors under Varying Momentum Ratios". Energies 14, nr 13 (5.07.2021): 4064. http://dx.doi.org/10.3390/en14134064.
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The combustion characteristics of a staged combustion cycle engine with an oxidizer-rich preburner were experimentally studied at different momentum ratios of multi-element injectors. Propellants were simultaneously supplied as a liquid–liquid–liquid system, and an injector was designed in which a swirl coaxial jet is sprayed. The injector burned the propellants in the inner chamber which had a temperature greater than 2000 K. To cool the combustion gas, a liquid oxidizer was supplied to the cooling channel outside the injector. To prevent the turbine blades from melting, the temperature of the combustion gas was maintained below 700 K. To confirm the combustion characteristics at different momentum ratios of the high-temperature combustion gas inside the injector and the low-temperature liquid oxidizer outside the injector, three types of injectors were designed and manufactured with different momentum ratios: MR 3.0, MR 3.3, and MR 3.7. In this study, the results of the combustion test for each type were compared for 30 s. For ORPB-A, a combustion pressure of 18.5 MPaA, fuel mass flow rate of 0.26 kg/s, oxidizer mass flow rate of 15.3 kg/s, and turbine inlet temperature of 686 K were obtained in the combustion stability period of 29.0–29.5 s. The combustion efficiency was 98% for MR 3.0 (ORPB-A), which was superior to that for other momentum ratios. In addition, during the combustion test for MR 3.0, the fluctuations in the characteristic velocity, combustion pressure, and propellant mass flow rate were low, indicating that combustion was stable. The three types of combustion instability were all less than 0.8%, thus confirming that the combustion stability was excellent.
4
WANG, SHANWU, VIGOR YANG, GEORGE HSIAO, SHIH-YANG HSIEH i HUKAM C. MONGIA. "Large-eddy simulations of gas-turbine swirl injector flow dynamics". Journal of Fluid Mechanics 583 (4.07.2007): 99–122. http://dx.doi.org/10.1017/s0022112007006155.
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A comprehensive study on confined swirling flows in an operational gas-turbine injector was performed by means of large-eddy simulations. The formulation was based on the Favre-filtered conservation equations and a modified Smagorinsky treatment of subgrid-scale motions. The model was then numerically solved by means of a preconditioned density-based finite-volume approach. Calculated mean velocities and turbulence properties show good agreement with experimental data obtained from the laser-Doppler velocimetry measurements. Various aspects of the swirling flow development (such as the central recirculating flow, precessing vortex core and Kelvin–Helmholtz instability) were explored in detail. Both co- and counter-rotating configurations were considered, and the effects of swirl direction on flow characteristics were examined. The flow evolution inside the injector is dictated mainly by the air delivered through the primary swirler. The impact of the secondary swirler appears to be limited.
5
Woo, Seongphil, Jungho Lee, Yeoungmin Han i Youngbin Yoon. "Experimental Study of the Combustion Efficiency in Multi-Element Gas-Centered Swirl Coaxial Injectors". Energies 13, nr 22 (19.11.2020): 6055. http://dx.doi.org/10.3390/en13226055.
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The effects of the momentum-flux ratio of propellant upon the combustion efficiency of a gas-centered-swirl-coaxial (GCSC) injector used in the combustion chamber of a full-scale 9-tonf staged-combustion-cycle engine were studied experimentally. In the combustion experiment, liquid oxygen was used as an oxidizer, and kerosene was used as fuel. The liquid oxygen and kerosene burned in the preburner drive the turbine of the turbopump under the oxidizer-rich hot-gas condition before flowing into the GCSC injector of the combustion chamber. The oxidizer-rich hot gas is mixed with liquid kerosene passed through combustion chamber’s cooling channel at the injector outlet. This mixture has a dimensionless momentum-flux ratio that depends upon the dispensing speed of the two fluids. Combustion tests were performed under varying mixture ratios and combustion pressures for different injector shapes and numbers of injectors, and the characteristic velocities and performance efficiencies of the combustion were compared. It was found that, for 61 gas-centered swirl-coaxial injectors, as the moment flux ratio increased from 9 to 23, the combustion-characteristic velocity increased linearly and the performance efficiency increased from 0.904 to 0.938. In addition, excellent combustion efficiency was observed when the combustion chamber had a large number of injectors at the same momentum-flux ratio.
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Lezsovits, Ferenc, Sándor Könczöl i Krisztián Sztankó. "CO emission reduction of a HRSG duct burner". Thermal Science 14, nr 3 (2010): 845–54. http://dx.doi.org/10.2298/tsci1003845l.
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A heat-recovery steam generator was erected after a gas-turbine with a duct burner into the district heat centre. After commissioning, the CO emissions were found to be above the acceptable level specified in the initial contract. The Department of Energy Engineering of the BME was asked for their expert contribution in solving the problem of reducing these CO emissions. This team investigated the factors that cause incomplete combustion: the flue-gas outlet of the gas-turbine has significant swirl and rotation, the diffuser in between the gas-turbine and heat-recovery steam generator is too short and has a large cone angle, the velocity of flue-gas entering the duct burner is greater than expected, and the outlet direction of the flammable mixture from the injector of the duct burner was not optimal. After reducing the flow swirl of flue-gas and modifying the nozzle of the duct burner as suggested by the Department of Energy Engineering of the BME, CO emissions have been reduced to an acceptable level. The method involves the application of CFD modeling and studying images of the flames which proved to be very informative.
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Durbin, M. D., M. D. Vangsness, D. R. Ballal i V. R. Katta. "Study of Flame Stability in a Step Swirl Combustor". Journal of Engineering for Gas Turbines and Power 118, nr 2 (1.04.1996): 308–15. http://dx.doi.org/10.1115/1.2816592.
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A prime requirement in the design of a modern gas turbine combustor is good combustion stability, especially near lean blowout (LBO), to ensure an adequate stability margin. For an aeroengine, combustor blow-off limits are encountered during low engine speeds at high altitudes over a range of flight Mach numbers. For an industrial combustor, requirements of ultralow NOx emissions coupled with high combustion efficiency demand operation at or close to LBO. In this investigation, a step swirl combustor (SSC) was designed to reproduce the swirling flow pattern present in the vicinity of the fuel injector located in the primary zone of a gas turbine combustor. Different flame shapes, structure, and location were observed and detailed experimental measurements and numerical computations were performed. It was found that certain combinations of outer and inner swirling air flows produce multiple attached flames, aflame with a single attached structure just above the fuel injection tube, and finally for higher inner swirl velocity, the flame lifts from the fuel tube and is stabilized by the inner recirculation zone. The observed difference in LBO between co- and counterswirl configurations is primarily a function of how the flame stabilizes, i.e., attached versus lifted. A turbulent combustion model correctly predicts the attached flame location(s), development of inner recirculation zone, a dimple-shaped flame structure, the flame lift-off height, and radial profiles of mean temperature, axial velocity, and tangential velocity at different axial locations. Finally, the significance and applications of anchored and lifted flames to combustor stability and LBO in practical gas turbine combustors are discussed.
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Sung, Hong-Gye. "Combustion dynamics in a model lean-premixed gas turbine with a swirl stabilized injector". Journal of Mechanical Science and Technology 21, nr 3 (marzec 2007): 495–504. http://dx.doi.org/10.1007/bf02916311.
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Mardani, Amir, Rezapour Rastaaghi i Fazlollahi Ghomshi. "Liquid petroleum gas flame in a double-swirl gas turbine model combustor: Lean blow-out, pollutant, preheating". Thermal Science, nr 00 (2020): 139. http://dx.doi.org/10.2298/tsci190623139m.
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In this paper, lean blow-out (LBO) limits in a double swirl gas turbine model combustor were investigated experimentally for Liquid Petroleum Gas (LPG) fuel. The LBO curve was extracted for different combustor configurations. While burner could operate reasonably under ultra-lean conditions, two different sets of operating conditions, one with a low flow rate (LFR) and another one with high flow rate (HFR), are identified and studied in terms of LBO and pollutant. Results showed that while the flame structure was similar in both cases, the chamber responses to geometrical changes and also preheating are minimal at the LFR. That means confinement and injector type have desirable effects on stability borders but not for the LFR. The channeled injector shifted down the LBO limit around 28 percent at HFR. Measurements on the combustor exhaust gas composition and temperature indicate a region with relatively complete combustion and reasonable temperature and a very low level of exhaust NOx pollutants (i.e., below ten ppm) at about 25-50% above the LBO. In this operating envelope, a burner power increment led to a higher exhaust average temperature and combustion efficiency, while NOx formation decreased. Preheating the inlet air up to 100?C results in an improvement in burner stability in about 10 percent, but NOx production intensifies more than three times. Results indicate that the LBO limit is configured more by the burner design and aerodynamic aspects rather than the fuel type.
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Cheng, R. K., D. Littlejohn, P. A. Strakey i T. Sidwell. "Laboratory investigations of a low-swirl injector with H2 and CH4 at gas turbine conditions". Proceedings of the Combustion Institute 32, nr 2 (2009): 3001–9. http://dx.doi.org/10.1016/j.proci.2008.06.141.
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Choi, Myeung Hwan, Jeongwoo An i Jaye Koo. "Breakup Mechanism of a Jet in the L-Shape Crossflow of a Gas Turbine Combustor". Energies 15, nr 9 (5.05.2022): 3360. http://dx.doi.org/10.3390/en15093360.
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Experimental investigations are conducted to determine the mechanism and characteristics of a jet in an L-shape crossflow simulating the radial swirl injector of a lean premixed-prevaporized (LPP) combustor. To simplify the radial flow of the actual injector while ignoring the centrifugal effect, the L-shaped 2D-channel is used for the crossflow, and water is used as a fuel simulant. The jet breakup is captured using a high-speed camera, and the density gradient magnitude is post-processed to clarify the spray. The Sauter mean diameter (SMD) of the spray is measured via a laser diffraction method with a helium–neon laser optical system (HELOS). The characteristics of the jet in the L-shape crossflow are compared with the characteristics of the jet in a typical crossflow through the flat channel. The results for different outlet heights of the L-shape channel (H/d0) and different injector positions (L/d0) are presented. A dimensionless number (τ) consisting of a time ratio is introduced to describe the jet characteristics. In a previous work, the spraying tendency was demonstrated for different injector positions. In addition, the effect of the recirculation area on H/d0 was empirically shown. H/d0 determines the size of the recirculation area, and the range of τ determines the jet breakup mechanism inside the L-shape channel. The results of this study present the breakup mechanism of the jet in the L-shape channel flow, which simulates a jet in a radial swirler injector for gas turbine engines. It is expected that these results can be used to assist in designing gas turbine engines with more combustion efficiency.
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Cao, Cheng, Yaping Gao, Shaolin Wang, Fuqiang Liu, Cunxi Liu, Yong Mu, Deqing Mei i Gang Xu. "Numerical Investigation on Mechanism of Swirling Flow of the Prefilming Air-Blast Fuel Injector". Energies 16, nr 2 (5.01.2023): 650. http://dx.doi.org/10.3390/en16020650.
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Prefilming air-blast atomizers are widely used in modern gas turbine combustors. Due to insufficient awareness of the coupling mechanism of multi-stage swirling flow in gas turbines, there is a lack of effective methods for flow field optimization in combustor. In this study, the effect of some critical parameters on the flow field of a prefilming air-blast atomizer was analyzed with CFD. The parameters include the angle and number of the first swirler blades, the angle of the second swirler blades and the angle of sleeve. Furthermore, the coupling mechanism of two-stage swirling airflows of prefilming air-blast atomizer was discussed. Moreover, the influence of the interaction between two-stage counter swirling airflows on the characteristics of flow field was explained. The results show that with the increase in SNi, the axial length of the primary recirculation zone decreased, while the radial width increased. The starting position of primary recirculation zone (PRZ) moves forward with the increase in SNo. Reducing the sleeve angle β helps to form the primary recirculation zone. The results indicate that it is the transition of tangential velocity of airflow to radial velocity that promotes the formation of the PRZ. These results provide theoretical support for optimization of the flow field in swirl combustor.
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Ford, C. L., J. F. Carrotte i A. D. Walker. "The application of porous media to simulate the upstream effects of gas turbine injector swirl vanes". Computers & Fluids 77 (kwiecień 2013): 143–51. http://dx.doi.org/10.1016/j.compfluid.2013.03.001.
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Littlejohn, D., i R. K. Cheng. "Fuel effects on a low-swirl injector for lean premixed gas turbines". Proceedings of the Combustion Institute 31, nr 2 (styczeń 2007): 3155–62. http://dx.doi.org/10.1016/j.proci.2006.07.146.
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Baba-Ahmadi, M. H., i G. R. Tabor. "Inlet Conditions for Large Eddy Simulation of Gas-Turbine Swirl Injectors". AIAA Journal 46, nr 7 (lipiec 2008): 1782–90. http://dx.doi.org/10.2514/1.35259.
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Daniels, W. A., B. V. Johnson, D. J. Graber i R. J. Martin. "Rim Seal Experiments and Analysis for Turbine Applications". Journal of Turbomachinery 114, nr 2 (1.04.1992): 426–32. http://dx.doi.org/10.1115/1.2929161.
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An experimental investigation was conducted to determine the sealing effectiveness and the aerodynamic characteristics of four rim seal models for a number of flow conditions. The experiments were conducted to obtain an extended data base for advanced turbine rim seal design. The class of rim seals investigated are those found on the downstream side of the rotor where the boundary layer on the disk is pumped directly into the seal gap. The experiments were conducted at disk tangential Reynolds numbers up to 5.1 × 106 with a simulated gas path flow across the top of the seal. The simulated gas path flow was injected with various amounts of swirl to determine the effect of swirl on the seal effectiveness. The radial gap and the axial overlap of the seal were varied and results compared with a baseline configuration. A rim seal configuration intended to prevent disk pumping directly into the seal gap was also investigated. A mass transfer analogy was used to characterize the rim seal ingestion characteristics and the trace gas chosen for this technique was CO2. The results of this investigation indicate that decreasing the radial gap of the seal produces a better improvement in seal effectiveness than increasing the axial overlap of the seal, that seal effectiveness increases only modestly as the swirl across the top of the seal decreases, and that the trace gas technique employed to determine seal effectiveness is an accurate alternative to pressure measurement or flow visualization techniques used by other investigators. The results of this investigation were compared with results from a boundary layer model for rim seals with axial gap geometries.
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Tolpadi, A. K., D. L. Burrus i R. J. Lawson. "Numerical Computation and Validation of Two-Phase Flow Downstream of a Gas Turbine Combustor Dome Swirl Cup". Journal of Engineering for Gas Turbines and Power 117, nr 4 (1.10.1995): 704–12. http://dx.doi.org/10.1115/1.2815456.
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The two-phase axisymmetric flow field downstream of the swirl cup of an advanced gas turbine combustor is studied numerically and validated against experimental Phase-Doppler Particle Analyzer (PDPA) data. The swirl cup analyzed is that of a single annular GE/SNECMA CFM56 turbofan engine that is comprised of a pair of coaxial counterswirling air streams together with a fuel atomizer. The atomized fuel mixes with the swirling air stream, resulting in the establishment of a complex two-phase flow field within the swirl chamber. The analysis procedure involves the solution of the gas phase equations in an Eulerian frame of reference using the code CONCERT. CONCERT has been developed and used extensively in the past and represents a fully elliptic body-fitted computational fluid dynamics code to predict flow fields in practical full-scale combustors. The flow in this study is assumed to be nonreacting and isothermal. The liquid phase is simulated by using a droplet spray model and by treating the motion of the fuel droplets in a Lagrangian frame of reference. Extensive PDPA data for the CFM56 engine swirl cup have been obtained at atmospheric pressure by using water as the fuel (Wang et al., 1992a). The PDPA system makes pointwise measurements that are fundamentally Eulerian. Measurements have been made of the continuous gas phase velocity together with discrete phase attributes such as droplet size, droplet number count, and droplet velocity distribution at various axial stations downstream of the injector. Numerical calculations were performed under the exact inlet and boundary conditions as the experimental measurements. The computed gas phase velocity field showed good agreement with the test data. The agreement was found to be best at the stations close to the primary venturi of the swirler and to be reasonable at later stations. The unique contribution of this work is the formulation of a numerical PDPA scheme for comparing droplet data. The numerical PDPA scheme essentially converts the Lagrangian droplet phase data to the format of the experimental PDPA. Several sampling volumes (bins) were selected within the computational domain. The trajectories of various droplets passing through these volumes were monitored and appropriately integrated to obtain the distribution of the droplet characteristics in space. The calculated droplet count and mean droplet velocity distributions were compared with the measurements and showed very good agreement in the case of larger size droplets and fair agreement for smaller size droplets.
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Vandervort, C. L. "9 ppm NOx/CO Combustion System for “F” Class Industrial Gas Turbines". Journal of Engineering for Gas Turbines and Power 123, nr 2 (1.01.2001): 317–21. http://dx.doi.org/10.1115/1.1362661.
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The Dry Low NOx (DLN) -2.6 combustion system has achieved emission rates of lower than 9 ppm NOx (dry, corrected to 15 percent O2) and CO from 50 to 100 percent load for the GE MS7001FA industrial gas turbine on natural gas. The system uses lean premixed combustion with fuel staging for low load stability. The first unit achieved commercial operation in March of 1996 with a firing temperature of 2350°F. As of September 9, 1999, it has accumulated over 11,800 hours of operation in peaking and base load service. Sixteen more units have since entered commercial service. Emissions data are shown for operation on natural gas. The DLN-2.6 system can operate on liquid fuel with water injection for NOx abatement. Power augmentation with steam injection is allowable while operating on natural gas. The premixed gas nozzles utilize swirl for flame stabilization. Aerodynamically shaped natural gas injectors are applied for flashback or flame-holding resistance.
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Kim, Lina, Ji-Seok Hong, Won Cheol Jeong, Kwang-Hee Yoo, Jong-Chan Kim i Hong-Gye Sung. "Turbulent Combustion Characteristics of a Swirl Injector in a Gas Turbine Annular Combustor Using LES and Level-set Flamelet". Journal of the Korean Society of Propulsion Engineers 18, nr 2 (1.04.2014): 1–9. http://dx.doi.org/10.6108/kspe.2014.18.2.001.
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N. R. Kartjanov, M. G. Zhumagulov i S. B. Sadykova. "AERODYNAMIC FLOWS INSIDE GAS TURBINE COMBUSTION CHAMBER MODULE". Bulletin of Toraighyrov University. Energetics series, nr 4.2021 (28.11.2021): 33–43. http://dx.doi.org/10.48081/qrfa5104.
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The article contains the results of experiments on the research of aerodynamic parameters in the cylindrical module of the combustion chamber in a gas turbine. The intensity of turbulence and flow velocity are considered in the article as the main factors affecting the efficiency of the formation of the fuel-air mixture and, as a consequence, the efficiency of its subsequent combustion. The air flow is studied under isothermal conditions inside two cylindrical channels of different diameters with swirl blades at the inlet. Turbulence intensity and flow velocity are obtained for various points inside the channel. The graphical format for the result presenting was chosen as the most convenient for understanding. The factors influencing the value of intensity and speed are given on the basis of the analysis of experimental data. The study of the structure of the air flow in the channels gives us the opportunity to determine the fuel injection zones. The article may be of interest to researchers and specialists in the field of power and aerodynamics.
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Touchton, G. L. "Influence of Gas Turbine Combustor Design and Operating Parameters on Effectiveness of NOx Suppression by Injected Steam or Water". Journal of Engineering for Gas Turbines and Power 107, nr 3 (1.07.1985): 706–13. http://dx.doi.org/10.1115/1.3239792.
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Steam or water injection has become the state-of-the-art abatement technique for NOx, with steam strongly preferred for combined-cycle application. In combined-cycle plants, the degradation of the plant efficiency due to steam injection into the gas turbine combustor provides a powerful incentive for minimizing this flow over the entire plant operating map. This paper presents the results of extensive tests carried out on a variety of gas turbine combustor designs. Both test stand and field test data are presented. The usual fuel in the tests is methane; however, some data are presented for combustion of No. 2 distillate oil and intermediate Btu gas fuel. Similarly, the usual inert injected is steam, but some water injection data are included for comparison. The results support the conclusions: 1. Steam and water injection suppress NOx exclusively through thermal mechanisms, i.e., by lowering the peak flame temperature. 2. Design changes have little effect on NOx suppression effectiveness of steam or water in jet-stirred or swirl-mixed combustors. 3. Primary zone injection of steam in methane-fueled, jet-stirred combustors is equally effective whether the steam enters with an air stream or with the fuel stream. 4. Water-to-fuel ratio corrected to equivalent energy content correlates NOx suppression effectiveness for turbulent diffusion flame combustors.
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Heath, Christopher M. "Characterization of Swirl-Venturi Lean Direct Injection Designs for Aviation Gas Turbine Combustion". Journal of Propulsion and Power 30, nr 5 (wrzesień 2014): 1334–56. http://dx.doi.org/10.2514/1.b35077.
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Davis, D. W., P. L. Therkelsen, D. Littlejohn i R. K. Cheng. "Effects of hydrogen on the thermo-acoustics coupling mechanisms of low-swirl injector flames in a model gas turbine combustor". Proceedings of the Combustion Institute 34, nr 2 (styczeń 2013): 3135–43. http://dx.doi.org/10.1016/j.proci.2012.05.050.
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Feitelberg, A. S., V. E. Tangirala, R. A. Elliott, R. E. Pavri i R. B. Schiefer. "Reduced NOx Diffusion Flame Combustors for Industrial Gas Turbines". Journal of Engineering for Gas Turbines and Power 123, nr 4 (1.10.2000): 757–65. http://dx.doi.org/10.1115/1.1376722.
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This paper describes reduced NOx diffusion flame combustors that have been developed for both simple cycle and regenerative cycle MS3002 and MS5002 gas turbines. Laboratory tests have shown that when firing with natural gas, without water or steam injection, NOx emissions from the new combustors are about 40 percent lower than NOx emissions from the standard combustors. CO emissions are virtually unchanged at base load, but increase at part load conditions. Commercial demonstration tests have confirmed the laboratory results. The standard combustors on both the MS3002 and MS5002 gas turbine are cylindrical cans, approximately 10.5 inches (27 cm) in diameter. A single fuel nozzle is centered at the inlet to each can and produces a swirl stabilized diffusion flame. The walls of the cans are louvered for cooling, and contain an array of mixing and dilution holes that provide the air needed to complete combustion and dilute the burned gas to the desired turbine inlet temperature. The MS3002 turbine is equipped with six combustor cans, while the MS5002 turbine is equipped with twelve combustors. The new, reduced NOx emissions combustors (referred to as a “lean head end,” or LHE, combustors) retain all of the key features of the conventional combustors; the only major difference is the arrangement of the mixing and dilution holes in the cylindrical combustor cans. By optimizing the number, diameter, and location of these holes, NOx emissions can be reduced considerably. Minor changes are also sometimes made to the combustor cap. The materials of construction, pressure drop, and fuel nozzle are all unchanged. The differences in NOx emissions between the standard and LHE combustors, as well as the variations in NOx emissions with firing temperature, are well correlated using turbulent flame length arguments. Details of this correlation are presented.
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Garland, R. V., i P. W. Pillsbury. "Status of Topping Combustor Development for Second-Generation Fluidized Bed Combined Cycles". Journal of Engineering for Gas Turbines and Power 114, nr 1 (1.01.1992): 126–31. http://dx.doi.org/10.1115/1.2906294.
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Addition of a fluidized bed combustor to a high-efficiency combined cycle plant enables direct firing of inexpensive run-of-the-mine coal in an environmentally acceptable manner. To attain high thermal efficiencies, coal pyrolysis is included. The low heating value fuel gas from the pyrolyzer is burned in a topping combustion system that boosts gas turbine inlet temperature to state of the art while the pyrolyzer-produced char is burned in the bed. The candidate topping combustor, the multi-annular swirl burner, based on a design by J. M. Bee´r, is presented and discussed. Design requirements differ from conventional gas turbine combustors. The use of hot, vitiated air for cooling and combustion, and the use of low heating value fuel containing ammonia, are two factors that make the design requirements unique. The multi-annular swirl burner contains rich-burn, quick-quench, and lean-burn zones formed aerodynamically rather than the physically separate volumes found in other rich-lean combustors. Although fuel is injected through a centrally located nozzle, the combustion air enters axially through a series of swirlers. Wall temperatures are controlled by relatively thick layers of air entering through the various swirler sections, which allows the combustor to be of all-metal construction rather than the ceramic often used in rich-lean concepts. This 12-in.-dia design utilizes some of the features of the previous 5-in. and 10-in. versions of the multi-annular swirl burner; test results from the previous projects were utilized in the formulation of the test for the present program. In the upcoming tests, vitiated air will be provided to simulate a pressurized fluidized bed effluent. Hot syngas seeded with ammonia will be used to simulate the low-Btu gas produced in the pyrolyzer.
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Paschereit, Christian Oliver, Peter Flohr i Ephraim J. Gutmark. "Combustion Control by Vortex Breakdown Stabilization". Journal of Turbomachinery 128, nr 4 (1.02.2002): 679–88. http://dx.doi.org/10.1115/1.2218521.
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Flame anchoring in a swirl-stabilized combustor occurs in an aerodynamically generated recirculation region which is a result of vortex breakdown (VBD). The characteristics of the recirculating flow are dependent on the swirl number and on axial pressure gradients. Coupling with downstream pressure pulsations in the combustor affects the VBD process. The present paper describes combustion instability that is associated with vortex breakdown. The mechanism of the onset of this instability is discussed. Passive control of the instability was achieved by stabilizing the location of vortex breakdown using an extended lance. The reduction of pressure pulsations for different operating conditions and the effect on emissions in a laboratory scale model atmospheric combustor, in a high pressure combustor facility, and in a full scale land-based gas-turbine are described. The flashback safety, one of the most important features of a reliable gas turbine burner, was assessed by CFD, water tests, and combustion tests. In addition to the passive stabilization by the extended lance it enabled injection of secondary fuel directly into the recirculation zone where the flame is stabilized. Tests were conducted with and without secondary fuel injection. Measurements and computations optimized the location of the extended lance in the mixing chamber. The effect of variation of the amount of secondary fuel injection at different equivalence ratios and output powers was determined. Flow visualizations showed that stabilization of the recirculation zone was achieved. Following the present research, the VBD stabilization method has been successfully implemented in engines with sufficient stability margins and good operational flexibility. This paper shows the development process from lab scale tests to full scale engine tests until the implementation into field engines.
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Akinyemi, Oladapo S., i Lulin Jiang. "Development and combustion characterization of a novel twin-fluid fuel injector in a swirl-stabilized gas turbine burner operating on straight vegetable oil". Experimental Thermal and Fluid Science 102 (kwiecień 2019): 279–90. http://dx.doi.org/10.1016/j.expthermflusci.2018.11.014.
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Vermes, G., L. E. Barta i J. M. Bee´r. "Low NOx Emission From an Ambient Pressure Diffusion Flame Fired Gas Turbine Cycle (APGC)". Journal of Engineering for Gas Turbines and Power 125, nr 1 (27.12.2002): 46–50. http://dx.doi.org/10.1115/1.1520160.
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The prospects of reduced NOx emission, improved efficiency, stable, and oscillation-free combustion, and reduced construction costs achieved by an “Inverted Brayton Cycle” applied to midsize (0.5 to 5.0 MWe) power plants are discussed. In this cycle, the combustion products of an atmospheric pressure combustor are expanded in the gas turbine to subatmospheric pressure and following heat extraction are compressed back to slightly above the atmospheric, sufficient to enable a controlled fraction of the exhaust gas to be recirculated to the combustor. Due to the larger volume flow rate of the gas, the polytropic efficiency of both the turbine and compressor of this small machine is increased. Because of the low operating pressure and flue gas recirculation, both of which are instrumental to low NOx formation, the combustor can be operated in the diffusion flame mode; this, on the other hand, assures good flame stability and oscillation-free combustion over wide ranges of the operating variables. For the task of obtaining very low NOx formation, the well-tested multi annular swirl burner (MASB) is chosen. Recent computational and experimental development of the MASB by Siemens-Westinghouse as a topping combustor is discussed. It is shown that the MASB operated in rich-quench-lean mode is capable of single-digit NOx emission. The emissions are further lowered in the APGC by ambient pressure combustion, and by the injection of the recirculated gas in the quench zone of the combustor. Results of a computational optimization study of the ambient pressure gas turbine cycle (APGC) are presented.
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Crocker, D. S., i C. E. Smith. "Numerical Investigation of Enhanced Dilution Zone Mixing in a Reverse Flow Gas Turbine Combustor". Journal of Engineering for Gas Turbines and Power 117, nr 2 (1.04.1995): 272–81. http://dx.doi.org/10.1115/1.2814091.
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An advanced method for dilution zone mixing in a reverse flow gas turbine combustor was numerically investigated. For long mixing lengths associated with reverse flow combustors (X/H > 2.0), pattern factor was found to be mainly driven by nozzle-to-nozzle fuel flow and/or circumferential airflow variations; conventional radially injected dilution jets could not effectively mix out circumferential nonuniformities. To enhance circumferential mixing, dilution jets were angled to produce a high circumferential (swirl) velocity component. The jets on the outer liner were angled in one direction while the jets on the inner liner were angled in the opposite direction, thus enhancing turbulent shear at the expense of jet penetration. Three-dimensional CFD calculations were performed on a three-nozzle (90 deg) sector, with different fuel flow from each nozzle (90, 100, and 110 percent of design fuel flow). The computations showed that the optimum configuration of angled jets reduced the pattern factor by 60 percent compared to an existing conventional dilution hole configuration. The radial average temperature profile was adequately controlled by the inner-to-outer liner dilution flow split.
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Feitelberg, Alan S., Michael D. Starkey, Richard B. Schiefer, Roointon E. Pavri, Matt Bender, John L. Booth i Gordon R. Schmidt. "Performance of a Reduced NOx Diffusion Flame Combustor for the MS5002 Gas Turbine". Journal of Engineering for Gas Turbines and Power 122, nr 2 (3.01.2000): 301–6. http://dx.doi.org/10.1115/1.483217.
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This paper describes a reduced NOx diffusion flame combustor that has been developed for the MS5002 gas turbine. Laboratory tests have shown that when firing with natural gas, without water or steam injection, NOx emissions from the new combustor are about 40 percent lower than NOx emissions from the standard MS5002 combustor. CO emissions are virtually unchanged at base load, but increase at part load conditions. The laboratory results were confirmed in 1997 by a commercial demonstration test at a British Petroleum site in Prudhoe Bay, Alaska. The standard MS5002 gas turbine is equipped with a conventional, swirl stabilized diffusion flame combustion system. The twelve standard combustors in an MS5002 turbine are cylindrical cans, approximately 27 cm (10.5 in.) in diameter and 112 cm (44 in.) long. A small, annular, vortex generator surrounds the single fuel nozzle that is centered at the inlet to each can. The walls of the cans are louvered for cooling, and contain an array of mixing and dilution holes that provide the air needed to complete combustion and dilute the burned gas to the desired turbine inlet temperature. The new, reduced NOx emissions combustor (referred to as a “lean head end,” or LHE, combustor) retains all of the key features of the conventional combustor; the only significant difference is the arrangement of the mixing and dilution holes in the cylindrical combustor can. By optimizing the number, diameter, and location of these holes, NOx emissions were substantially reduced. The materials of construction, fuel nozzle, and total combustor air flow were unchanged. The differences in NOx emissions between the standard and LHE combustors, as well as the variations in NOx emissions with firing temperature, were well correlated using turbulent flame length arguments. Details of this correlation are also presented. [S0742-4795(00)01602-1]
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Kuharonak, G. M., M. Klesso, A. Predko i D. Telyuk. "Organization of Six-Cylinder Tractor Diesel Working Process". Science & Technique 20, nr 5 (7.10.2021): 427–33. http://dx.doi.org/10.21122/2227-1031-2021-20-5-427-433.
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The purpose of the work is to consider the organization of the working process of six-cylinder diesel engines with a power of 116 and 156 kW and exhaust gas recirculation. The following systems and components were used in the experimental configurations of the engine: Common Rail BOSСH accumulator fuel injection system with an injection pressure of 140 MPa, equipped with electro-hydraulic injectors with seven-hole nozzle and a 500 mm3 hydraulic flow; direct fuel injection system with MOTORPAL fuel pump with a maximum injection pressure of 100 MPa, equipped with MOTORPAL and AZPI five-hole nozzle injectors; two combustion chambers with volumes of 55 and 56 cm3 and bowl diameters of 55.0 and 67.5 mm, respectively; cylinder heads providing a 3.0–4.0 swirl ratio for Common Rail system, 3.5–4.5 for mechanical injection system. The recirculation rate was set by gas throttling before the turbine using a rotary valve of an original design. The tests have been conducted at characteristic points of the NRSC cycle: minimum idle speed 800 rpm, maximum torque speed 1600 rpm, rated power speed 2100 rpm. It has been established that it is possible to achieve the standards of emissions of harmful substances: on the 116 kW diesel engine using of direct-action fuel equipment and a semi-open combustion chamber; on the 156 kW diesel using Common Rail fuel supply system of the Low Cost type and an open combustion chamber.
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Correa, S. M., A. J. Dean i I. Z. Hu. "Combustion Technology for Low-Emissions Gas-Turbines:Selected Phenomena Beyond NOx". Journal of Energy Resources Technology 118, nr 3 (1.09.1996): 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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Zhang, Tao, Bo Dong, Xun Zhou, Linan Guan, Weizhong Li i Shengqi Zhou. "Experimental Study of Spray Characteristics of Kerosene-Ethanol Blends from a Pressure-Swirl Nozzle". International Journal of Aerospace Engineering 2018 (7.11.2018): 1–14. http://dx.doi.org/10.1155/2018/2894908.
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Partial replacement of kerosene by ethanol in a gas turbine is regarded as a good way to improve the spray quality and reduce the fossil energy consumption. The present work is aimed at studying the spray characteristics of kerosene-ethanol blends discharging from a pressure-swirl nozzle. The spray cone angle, discharge coefficient, breakup length, and velocity distribution are obtained by particle image velocimetry, while droplet size is acquired by particle/droplet imaging analysis. Kerosene, E10 (10% ethanol, 90% kerosene), E20 (20% ethanol, 80% kerosene), and E30 (30% ethanol, 70% kerosene) have been considered under the injection pressure of 0.1–1 MPa. The results show that as injection pressure is increased, the discharge coefficient and breakup length decrease, while the spray cone angle, drop size, and spray velocity increase. Meanwhile, the drop size decreases and the spray velocity increases with ethanol concentration when the injection pressure is lower than 0.8 MPa. However, the spray characteristics are not affected obviously by the ethanol concentration when the injection pressure exceeds 0.8 MPa. A relation to breakup length for kerosene-ethanol blends is obtained. The findings demonstrate that the adding of ethanol into kerosene can promote atomization performance.
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Kim, Sangwook, Hyungyu Lee, Jungsoo Lee, Donghwa Kim i Jinsoo Cho. "Comparative Study on a Tangential and Radial On-Board Injection Pre-swirl System of Gas Turbine Secondary Air System". KSFM Journal of Fluid Machinery 21, nr 1 (28.02.2018): 19–26. http://dx.doi.org/10.5293/kfma.2018.21.1.019.
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Payri, R., R. Novella, M. Carreres i M. Belmar-Gil. "Modeling gaseous non-reactive flow in a lean direct injection gas turbine combustor through an advanced mesh control strategy". Proceedings of the Institution of Mechanical Engineers, Part G: Journal of Aerospace Engineering 234, nr 11 (20.04.2020): 1788–810. http://dx.doi.org/10.1177/0954410020919619.
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Fuel efficiency improvement and harmful emissions reduction are the main motivations for the development of gas turbine combustors. Numerical computational fluid dynamics (CFD) simulations of these devices are usually computationally expensive since they imply a multi-scale problem. In this work, gaseous non-reactive unsteady Reynolds-Averaged Navier–Stokes and large eddy simulations of a gaseous-fueled radial-swirled lean direct injection combustor have been carried out through CONVERGE™ CFD code by solving the complete inlet flow path through the swirl vanes and the combustor. The geometry considered is the gaseous configuration of the CORIA lean direct injection combustor, for which detailed measurements are available. The emphasis of the work is placed on the demonstration of the CONVERGE™ applicability to the multi-scale gas turbine engines field and the determination of an optimal mesh strategy through several grid control tools (i.e., local refinement, adaptive mesh refinement) allowing the exploitation of its automatic mesh generation against traditional fixed mesh approaches. For this purpose, the normalized mean square error has been adopted to quantify the accuracy of turbulent numerical statistics regarding the agreement with the experimental database. Furthermore, the focus of the work is to study the behavior when coupling several large eddy simulation sub-grid scale models (i.e., Smagorinsky, Dynamic Smagorinsky, and Dynamic Structure) with the adaptive mesh refinement algorithm through the evaluation of its specific performances and predictive capabilities in resolving the spatial-temporal scales and the intrinsically unsteady flow structures generated within the combustor. This investigation on the main non-reacting swirling flow characteristics inside the combustor provides a suitable background for further studies on combustion instability mechanisms.
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Wang, H. Y., V. G. McDonell i S. Samuelsen. "Influence of Hardware Design on the Flow Field Structures and the Patterns of Droplet Dispersion: Part I—Mean Quantities". Journal of Engineering for Gas Turbines and Power 117, nr 2 (1.04.1995): 282–89. http://dx.doi.org/10.1115/1.2814092.
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In a gas turbine engine combustor, performance is likely tied to the spatial distribution of the fuel injected into the dome. The GE/SNECMA CFM56 combustor swirl cup is one example of a design established to provide a uniform presentation of droplets to the dome. The present study is part of a series to detail the dispersion of droplets in practical hardware, and to assess the effect of isolated parameters on the continuous- and dispersed-phase distributions. In this study, the influence of the swirling air outlet geometry is evaluated relative to the effect on the flow field structures and the patterns of droplet dispersion. This is accomplished by comparing the continuous-phase (air in the presence of a spray) and dispersed-phase (droplets) behavior downstream of the swirl cup assembly outfitted with two different conical expansions (“flares”). One features a narrow expansion angle, the other possesses a wide expansion angle. Two-component phase-Doppler interferometry was employed to provide the information of droplet size and velocity components as well as continuous-phase velocity components. Photographs of light scattered by droplets from a laser sheet were used for the study of flow field structures. This study reveals that (1) the air stream issued from the narrow flare remains close to the centerline and expands gradually downstream while the air stream issued from the wide flare expands immediately downstream of the swirl cup, and (2) the narrow flare provides weaker droplet dispersion, slower decay of droplet velocities, and finer droplet sizes compared to the wide flare. The results demonstrate that a relatively modest change in flare geometry can create a significant change in the structure of both the continuous and dispersed phases.
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BARATA, Jorge. "On the modeling of droplet transport, dispersion and evaporation in turbulent flows". Combustion Engines 122, nr 3 (1.07.2005): 42–55. http://dx.doi.org/10.19206/ce-117399.
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The present paper presents a numerical study on evaporating droplets injected through a turbulent cross-stream. Several models have been used with more or less success to describe similar phenomena, but much of the reported work deals only with sprays in stagnant surroundings. The ultimate goal of this study is to develop an Eulerian/Lagragian approach to account for turbulent transport, dispersion, evaporation and coupling between both processes in practical spray injection systems, which usually include air flows in the combustion chamber like swirl, tumble and squish in I.C. engines or crossflow in gas turbines. In this work a method developed to study isothermal turbulent dispersion is extended to the case of an array of evaporating droplets through a crossflow, and the performance of two different evaporation models widely used is investigated. The convection terms were evaluated using the hybrid or the higher order QUICK scheme. The dispersed phase was treated using a Lagrangian reference frame. The differences between the two evaporation models and its applicability to the present flow are analysed in detail. During the preheating period of the Chen and Pereira [1] model the droplets are transported far away from the injector by the crossflow, while with the Sommerfeld [2] formulation for evaporation the droplet has a continuous variation of the diameter. This result has profound implications on the results because the subsequent heat transfer and turbulent dispersion is extremely affected by the size of the particles (or droplets). As a consequence, droplet diameter, temperature and mass fraction distributions were found to be strongly dependent on the evaporation model used. So, a new formulation that takes into account also the transport of the evaporating droplets needs to be developed if practical injection systems are to be simulated. Also, in order to better evaluate and to improve the vaporization models more detailed measurements of three-dimensional configurations are required.
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Dulin, Vladimir, Leonid Chikishev, Dmitriy Sharaborin, Aleksei Lobasov, Roman Tolstoguzov, Zundi Liu, Xiaoxiang Shi, Yuyang Li i Dmitriy Markovich. "On the Flow Structure and Dynamics of Methane and Syngas Lean Flames in a Model Gas-Turbine Combustor". Energies 14, nr 24 (8.12.2021): 8267. http://dx.doi.org/10.3390/en14248267.
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The present paper compares the flow structure and flame dynamics during combustion of methane and syngas in a model gas-turbine swirl burner. The burner is based on a design by Turbomeca. The fuel is supplied through injection holes between the swirler blades to provide well-premixed combustion, or fed as a central jet from the swirler’s centerbody to increase flame stability via a pilot flame. The measurements of flow structure and flame front are performed by using the stereo particle image velocimetry and OH planar laser-induced fluorescence methods. The measurements are performed for the atmospheric pressure without preheating and for 2 atm with the air preheated up to 500 K. The flow Reynolds numbers for the non-reacting flows at these two conditions are 1.5 × 103 and 1.0 × 103, respectively. The flame dynamics are analyzed based on a high-speed OH* chemiluminescence imaging. It is found that the flame dynamics at elevated conditions are related with frequent events of flame lift-off and global extinction, followed by re-ignition. The analysis of flow structure via the proper orthogonal decomposition reveals the presence of two different types of coherent flow fluctuations, namely, longitudinal and transverse instability modes. The same procedure is applied to the chemiluminescence images for visualization of bulk movement of the flame front and similar spatial structures are observed. Thus, the longitudinal and transverse instability modes are found in all cases, but for the syngas at the elevated pressure and temperature the longitudinal mode is related to strong thermoacoustic fluctuations. Therefore, the present study demonstrates that a lean syngas flame can become unstable at elevated pressure and temperature conditions due to a greater flame propagation speed, which results in periodic events of flame flash-back, extinction and re-ignition. The reported data is also useful for the validation of numerical simulation codes for syngas flames.
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Fossi, Alain, Alain DeChamplain i Benjamin Akih-Kumgeh. "Unsteady RANS and scale adaptive simulations of a turbulent spray flame in a swirled-stabilized gas turbine model combustor using tabulated chemistry". International Journal of Numerical Methods for Heat & Fluid Flow 25, nr 5 (1.06.2015): 1064–88. http://dx.doi.org/10.1108/hff-09-2014-0272.
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Purpose – The purpose of this paper is to numerically investigate the three-dimensional (3D) reacting turbulent two-phase flow field of a scaled swirl-stabilized gas turbine combustor using the commercial computational fluid dynamic (CFD) software ANSYS FLUENT. The first scope of the study aims to explicitly compare the predictive capabilities of two turbulence models namely Unsteady Reynolds Averaged Navier-Stokes and Scale Adaptive Simulation for a reasonable trade-off between accuracy of results and global computational cost when applied to simulate swirl-stabilized spray combustion. The second scope of the study is to couple chemical reactions to the turbulent flow using a realistic chemistry model and also to model the local chemical non-equilibrium(NEQ) effects caused by turbulent strain such as flame stretching. Design/methodology/approach – Standard Eulerian and Lagrangian formulations are used to describe both gaseous and liquid phases, respectively. The computing method includes a two-way coupling in which phase properties and spray source terms are interchanging between the two phases within each coupling time step. The fuel used is liquid jet-A1 which is injected in the form of a polydisperse spray and the droplet evaporation rate is calculated using the infinite conductivity model. One-component (n-decane) and two-component fuels (n-decane+toluene) are used as jet-A1 surrogates. The combustion model is based on the mean mixture fraction and its variance, and a presumed-probability density function is used to model turbulent-chemistry interactions. The instantaneous thermochemical state necessary for the chemistry tabulation is determined by using initially the equilibrium (EQ) assumption and thereafter, detailed NEQ calculations through the steady flamelets concept. The combustion chemistry of these surrogates is represented through a reduced chemical kinetic mechanism (CKM) comprising 1,045 reactions among 139 species, derived from the detailed jet-A1 surrogate model, JetSurf 2.0 using a sensitivity based method, Alternate Species Elimination. Findings – Numerical results of the gas velocity, the gas temperature and the species molar fractions are compared with their experimental counterparts obtained from a steady state flame available in the literature. It is observed that, SAS coupled to the tabulated flamelet-based chemistry, predicts reasonably the main flame trends, while URANS even provided with the same combustion model and computing resources, leads to a poor prediction of the global flame trends, emphasizing the asset of a proper resolution when simulating spray flames. Research limitations/implications – The steady flamelet model even coupled with a robust turbulence model does not reproduce accurately the trend of species with slow oxidation kinetics such as CO and H2, because of the restrictiveness of the solutions space of flamelet equations and the assumption of unity Lewis for all species. Practical implications – This work is adding a contribution for spray flame modeling and can be seen as an extension to the significant efforts for the modeling of gaseous flames using robust turbulence models coupled with the tabulated flamelet-based chemistry approach to considerably reduce computing cost. The exclusive use of a commercial CFD code widely used in the industry allows a direct application of this simulation approach to industrial configurations while keeping computing cost reasonable. Originality/value – This study is useful to engineers interested in designing combustors of gas turbines and others combustion systems fed with liquid fuels.
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Somarathne, Kapuruge Don Kunkuma Amila, Sotaro Hatakeyama, Akihiro Hayakawa i Hideaki Kobayashi. "Numerical study of a low emission gas turbine like combustor for turbulent ammonia/air premixed swirl flames with a secondary air injection at high pressure". International Journal of Hydrogen Energy 42, nr 44 (listopad 2017): 27388–99. http://dx.doi.org/10.1016/j.ijhydene.2017.09.089.
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Arai, Masataka, Kenji Amagai i Toshio Mogi. "Catalytic Combustion of Pre-Vaporized Liquid Fuel". Journal of Energy Resources Technology 123, nr 1 (30.10.2000): 44–49. http://dx.doi.org/10.1115/1.1345893.
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Fundamental characteristics of the catalytic combustion of vaporized kerosene spray were experimentally investigated. This study is a part of the development of a ceramic gas turbine engine for automobiles. Kerosene was used as a test fuel and its spray was injected from a swirl atomizer into a hot air stream. The inlet air temperature was elevated up to 900 K to vaporize the kerosene spray. Premixed gas of air and kerosene vapor was introduced into the catalyst. The total equivalence ratio was controlled from ϕ=0.18–0.32. The palladium catalyst was supported on a cordierite honeycomb monolith. Catalytic combustion phenomena were categorized in three typical states: (a) state of partial reaction in the catalytic monolith, (b) state of homogeneous reaction in the monolith, (c) state of homogeneous reaction with a blue flame supposed on the monolith. A parabolic shape blue flame in the state of (c) appeared downstream of the monolith. This flame was very stable and its temperature was relatively low compared with conventional premixed flames of hydrocarbon fuel because the equivalence ratio was much lower than those of premixed flames. The distance from the monolith to the ignition point of this flame became short with a rise of the inlet air temperature, even if the volumetric airflow rate increased with the air temperature. Spontaneous emission spectra of radiation from the blue flame were measured. Strong spectral peaks of OH, CH, and CO+ radicals were observed in the spectra. This spectral structure was quite different from that of a blue flame of premixed propane.
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Anand, Rahul, PR Ajayalal, Vikash Kumar, A. Salih i K. Nandakumar. "Spray and atomization characteristics of gas-centered swirl coaxial injectors". International Journal of Spray and Combustion Dynamics 9, nr 2 (5.08.2016): 127–40. http://dx.doi.org/10.1177/1756827716660225.
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To achieve uniform and efficient combustion in a rocket engine, a fine uniform spray is needed. The same is achieved by designing an injector with good atomization characteristics. Gas-centered swirl coaxial (GCSC) injector elements have been preferred recently in liquid rocket engines because of an inherent capability to dampen the pressure oscillations in the thrust chamber. The gas-centered swirl coaxial injector chosen for this study is proposed to be used in a semi-cryogenic rocket engine operating with oxidizer rich hot exhaust gases from the pre-burner and liquid kerosene as fuel. In this paper, nine different configurations of gas-centered swirl coaxial injector, sorted out by studying the spray angle and coefficient of discharge with swirl number varying from 9 to 20 and recess ratio of 0.5, 1, and 1.5 are investigated for their atomization characteristics. Spray uniformity, spray cone angle, and droplet size in terms of Sauter mean diameter and mass median diameter are studied at various momentum flux ratios for all configurations. Sauter mean diameter is almost independent of recess ratio, whereas cone angle was inversely proportional to the recess ratio. A finer atomization was observed for injectors of high swirl number but the pressure drop also increased to achieve the same flow rate. An injector of medium swirl number and recess ratio of 1.5 is deemed most fit for above-mentioned application.
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Siddharth, K. S., Mahesh V. Panchagnula i T. John Tharakan. "EFFECT OF GAS SWIRL ON THE PERFORMANCE OF A GAS-CENTERED SWIRL CO-AXIAL INJECTOR". Atomization and Sprays 27, nr 8 (2017): 741–57. http://dx.doi.org/10.1615/atomizspr.2017019923.
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Yang, Li-jun, Ming-he Ge, Meng-zheng Zhang, Qing-fei Fu i Guo-biao Cai. "Spray Characteristics of Recessed Gas-Liquid Coaxial Swirl Injector". Journal of Propulsion and Power 24, nr 6 (listopad 2008): 1332–39. http://dx.doi.org/10.2514/1.23977.
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Khalil, Ahmed E. E., i Ashwani K. Gupta. "Distributed swirl combustion for gas turbine application". Applied Energy 88, nr 12 (grudzień 2011): 4898–907. http://dx.doi.org/10.1016/j.apenergy.2011.06.051.
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Jia, Lei, Shi Liu, Yao Song Huang, Neng Wang, Fu Zhen Wang i Zhi Hong Li. "Numerical Simulation of Burner for Micro Gas Turbine". Advanced Materials Research 569 (wrzesień 2012): 51–55. http://dx.doi.org/10.4028/www.scientific.net/amr.569.51.
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In order to study affects of oxy fuel combustion on micro gas turbine ,three axial swirl burners with different installation angles for micro gas turbine were designed, flue gas recycle/oxy fuel was used to burn natural gas. Numerical simulation was used to study flow field and combustion conditions. The result shows that application of axial swirl burner promotes mixing process of natural gas and oxygen and recirculation brought about to promote the stability of fire, uniformity of outlet temperature was reduced. With the increase of swirl installation angle, backflow becomes more intense, and uniformity of outlet temperature becomes smaller, however, total pressure loss coefficient increased. These results will have a great significance in the design of better burners.
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Chong, Cheng Tung, i Simone Hochgreb. "Flow Field of a Model Gas Turbine Swirl Burner". Advanced Materials Research 622-623 (grudzień 2012): 1119–24. http://dx.doi.org/10.4028/www.scientific.net/amr.622-623.1119.
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The flow field of a lab-scale model gas turbine swirl burner was characterised using particle imaging velocimetry (PIV) at atmospheric condition. The swirl burner consists of an axial swirler, a twin-fluid atomizer and a quartz tube as combustor wall. The main non-reacting swirling air flow without spray was compared to swirl flow with spray under unconfined and enclosed conditions. The introduction of liquid fuel spray changes the flow field of the main swirling air flow at the burner outlet where the radial velocity components are enhanced. Under reacting conditions, the enclosure generates a corner recirculation zone that intensifies the strength of the radial velocity. Comparison of the flow fields with a spray flame using diesel and palm biodiesel shows very similar flow fields. The flow field data can be used as validation target for swirl flame modelling.
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Johnson, M. R., D. Littlejohn, W. A. Nazeer, K. O. Smith i R. K. Cheng. "A comparison of the flowfields and emissions of high-swirl injectors and low-swirl injectors for lean premixed gas turbines". Proceedings of the Combustion Institute 30, nr 2 (styczeń 2005): 2867–74. http://dx.doi.org/10.1016/j.proci.2004.07.040.
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Ghaffar, Zulkifli Abdul, Ahmad Hussein Abdul Hamid i Mohd Syazwan Firdaus Mat Rashid. "Spray Characteristics of Swirl Effervescent Injector in Rocket Application: A Review". Applied Mechanics and Materials 225 (listopad 2012): 423–28. http://dx.doi.org/10.4028/www.scientific.net/amm.225.423.
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Injector is one of the vital devices in liquid rocket engine (LRE) as small changes in its configurations and design can result in significantly different LRE performance. Characteristics of spray such as spray cone angle, breakup length and Sauter mean diameter (SMD) are examples of crucial parameters that play the important role in the performance of liquid propellant rocket engine. Wider spray cone angle is beneficial for widespread of fuel in the combustion chamber for fast quiet ignition and a shorter breakup length provides shorter combustion chamber to be utilized and small SMD will result in fast and clean combustion. There are several mechanisms of liquid atomization such as swirling, e.g. jet swirl atomization or introducing bubbles into the liquid and effervescent atomization. Introducing a swirl component in the flow can enhance the propellant atomization and mixing whereas introducing bubbling gas directly into the liquid stream inside the injector leads to finer sprays even at lower injection pressures. This paper reviews the influence of both operating conditions and injector internal geometries towards the spray characteristics of swirl effervescent injectors. Operating conditions reviewed are injection pressure and gas-to-liquid ratio (GLR), while the injector internal geometries reviewed are limited to swirler geometry, mixing chamber diameter (dc), mixing chamber length (lc), aeration hole diameter (da), discharge orifice diameter (do) and discharge orifice length (lo).
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Woo, Seongphil, Jungho Lee, Ingyu Lee, Seunghan Kim, Yeoungmin Han i Youngbin Yoon. "Analyzing Combustion Efficiency According to Spray Characteristics of Gas-Centered Swirl-Coaxial Injector". Aerospace 10, nr 3 (10.03.2023): 274. http://dx.doi.org/10.3390/aerospace10030274.
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The momentum flux ratio (MFR) significantly affects the mixing characteristics and combustion efficiency of propellants in rocket engine injectors. The spray characteristics of three gas-centered swirl-coaxial injectors used in a full-scale combustion test were investigated according to the change in the momentum flux ratio. The difference in combustion efficiency was analyzed through the comparison with combustion test results using spray visualization and quantification. The spray cross-sectional shape and droplet distribution were measured using a structured laser illumination planar imaging technique. As the swirl effect was more apparent at a low MFR, the flow rate of the liquid that was sprayed outside was high. The flow rate of the liquid sprayed around the gas injection increased with the MFR. The Sauter mean diameter (SMD) of each injector liquid spray was obtained using the laser shadow imaging method. The SMD decreased as the MFR of all injector types increased, and the injector with a high liquid flow rate and small SMD injected towards the gas center exhibited higher combustion efficiency than the injector with a dominant liquid spray and the large SMD at a large injection angle. The outcomes of the study could help contribute to the increase in the combustion efficiency of the full-scale staged combustion cycle engine combustor.