Engineering Aspects of Complex Gas Turbine Combustion Mixers Part I: High Delta-T

Mongia, H. C.

doi:10.2514/6.2011-107

Cited by 29 publications

(8 citation statements)

References 9 publications

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“…It is now worth considering how confinement due to the com bustion chamber sidewalls affects the flame topology. A criterion based on the confinement ratio C r ¼ W 2 =ðpr 2 2 Þ, where W ¼ 150 mm is the width of the square combustion chamber and r 2 ¼ 10 mm the outer radius of the annular stream, is used to dis criminate whether aerodynamics effects caused by the confine ment need to be considered [38,39]. It has been shown in a former study conducted with premixed flames that the Oxytec combus tion chamber operates in a free jet regime [33].…”

Section: Effect Of Confinement and Thermal Environmentmentioning

confidence: 99%

Effects of Swirl on the Stabilization of Non-Premixed Oxygen-Enriched Flames Above Coaxial Injectors

Degenève

Mirat

Caudal

et al. 2019

Journal of Engineering for Gas Turbines and Power

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An experimental study is carried out to analyze the effects of swirl on the structure and stabilization of methane non-premixed oxygen-enriched flames above a coaxial injector in which the two streams are eventually swirled. The mean position of the flame and the liftoff height above the injector lips are investigated with OH* chemiluminescence images. The oxygen enrichment, the momentum flux ratio between the two coflows, the swirl level inside the central jet, and the swirl level in the annular jet are varied over a large range of operating conditions. It is found that, in the absence of swirl in the central stream, the flame is always attached to the lips of the internal injection tube. As the inner swirl level increases, the flame front located at the lips of the internal injection tube disappears. When the annular swirl level is high enough to create a central recirculating bubble, the flame detaches from the nozzle rim and remains lifted at a finite distance above the injector. Increasing the oxygen concentration shifts this transition to smaller momentum flux ratios and smaller annular swirl levels. The liftoff distance can be finely tuned and depends on the inner and outer swirl levels, and on the momentum flux ratio between the two coaxial streams. It is shown that this feature depends neither on the confinement of the injector nor on the thermal stress exerted by the hot burnt gases on the injector back plane. About 1000 configurations were investigated that could be classified into only four distinct stabilization modes, in which the flame structure was shown to follow a similar pathway when the momentum flux ratio between the two streams, the swirl level in the central and external streams, and the quarl angle of the annular stream are varied. It is finally shown how these limits are altered when the oxygen concentration in the annular oxidizer stream is varied from air to oxygen-enriched operation.

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Section: Effect Of Confinement and Thermal Environmentmentioning

confidence: 99%

Effects of Swirl on the Stabilization of Non-Premixed Oxygen-Enriched Flames Above Coaxial Injectors

Degenève

Mirat

Caudal

et al. 2019

Journal of Engineering for Gas Turbines and Power

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“…E-mail address: hxm@nuaa.edu.cn combustor is a promising solution for high temperature rise combustors [3] . Triple swirler is a typical representation of multiple swirler and the topic of the present investigation.…”

Section: Introductionmentioning

confidence: 99%

Effect of dilution holes on the performance of a triple swirler combustor

Ding

Zhao

et al. 2014

Chinese Journal of Aeronautics

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A triple swirler combustor is considered to be a promising solution for future high temperature rise combustors.The present paper aims to study dilution holes including primary dilution holes and secondary dilution holes on the performance of a triple swirler combustor. Experimental investigations are conducted at different inlet airflow velocities (40-70 m/s) and combustor overall fuel-air ratio with fixed inlet airflow temperature (473 K) and atmospheric pressure. The experimental results show that the ignition is very difficult with specific performance of high ignition fuel-air ratio when the primary dilution holes are located 0.6H (where H is the liner dome height)downstream the dome, while the other four cases have almost the same ignition performance. The position of primary dilution holes has an effect on lean blowout stability and has a large influence on combustion efficiency.The combustion efficiency is the highest when the primary dilution holes are placed 0.9H downstream the dome among the five different locations. For the secondary dilution holes, the pattern factor of Design A is better than that of Design B.

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“…The result indicates that the heat transfer coefficient is affected by jet radial length, nozzle-to-plate spacing, and Reynolds number. An overview is given on the use of several complex multi-swirler devices in gas turbine combustion by Mongia et al [20] They investigated the impingement-film cooling scheme in an annular combustor liner, which is shown in Figure 5 (numbers in the picture represent the percentage of coolant). The research indicates that a higher fraction of the cooling air and a higher convection velocity creates an additional shear-layer to complete combustion without creating hot-streak on the liner walls.…”

Section: Introductionmentioning

confidence: 99%

Study on the Hybrid Cooling of the Flame Tube in a Small Triple-Swirler Combustor

Zhang

Sun

et al. 2020

Energies

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An experimental and numerical investigation is conducted to study the influence of different cooling schemes on the wall temperature of the flame tube in a small triple-swirler combustor in this paper. Two different cooling structures are adopted: the impingement-film and inclined multi-hole cooling structure (Scheme B, C), and the inclined multi-hole control group (Scheme A). The impact of parameters including inlet temperature (373–423 K), inlet Mach number (Ma) (0.12–0.18), and fuel–air ratio (FAR) (0.02–0.03) are discussed. The results show that the wall temperature of the flame tube rises with the increase in inlet temperature; as the inlet Mach number increases, the wall temperature (Scheme B, C) of the primary zone goes up and is distributed more uniformly; as FAR rises, the wall temperature in Scheme C is nearly unchanged, while it is increased in Scheme A and B. For the range of parameters considered in this study, the lowest wall temperature and the best cooling effect are observed in Scheme C. The experiment conducted on the impingement-film and inclined multi-hole structure shows a better cooling effect than that conducted on the traditional inclined multi-hole structure. Compared with the row number of multi-inclined holes, the diameter of jet hole has a more significant influence on the cooling effect.

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Engineering Aspects of Complex Gas Turbine Combustion Mixers Part I: High Delta-T

Cited by 29 publications

References 9 publications

Effects of Swirl on the Stabilization of Non-Premixed Oxygen-Enriched Flames Above Coaxial Injectors

Effects of Swirl on the Stabilization of Non-Premixed Oxygen-Enriched Flames Above Coaxial Injectors

Effect of dilution holes on the performance of a triple swirler combustor

Study on the Hybrid Cooling of the Flame Tube in a Small Triple-Swirler Combustor

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