Combustion and environmental challenges for gas turbines in the 1990s

Gupta, Ashwani K.; Lilley, David G.

doi:10.2514/3.23722

Cited by 21 publications

(4 citation statements)

References 27 publications

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“…If the whole swirling body of fluid is divided into two parts, i.e., before the most swollen part of the swirling body and after the most swollen part of the swirling body, the effect of shredding and nibbling is more dominant on the latter downstream part of the swirling body of fluid, whereas in the upstream fluid domain, the shear due to the concurrently flowing fluid acts to stabilize the jet [4]. The topic of vortex interaction with shearing flow has been investigated with a great deal of attention from the scientific community [7][8][9]; however, within the topics related to the combustion, myriad facets of these studies still need attention and focus towards the swirl section's generation and its breakdown, axisymmetric flows and their break down, and instabilities [10][11][12][13]. There are few phenomena that contradict the laws of conservation, e.g., the whirlpool inside the sink does not obey the laws of conservation of angular momentum; however, it occurs and is investigated based on the symmetry breaking [14].…”

Section: Introductionmentioning

confidence: 99%

Hydrodynamics of Swirling Steam–Water Two-Phase Flows under External Shear

Ghazwani

Sanaullah

Khan

2023

Fluids

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The hydrodynamics of steam–water two-phase flows under the effects of shearing, swirling, and large-scale discrete boundary conditions were investigated on an experimental basis. The steam was injected in a swirling configuration into concurrently flowing water. Both the steam and water were injected at gauge pressures of 1.0 and 2.0 bars, whereas the swirling was caused by a propeller moving at rotational speeds of 60 and 300 rpm. The ensembled normalized amplitudes of the velocity fluctuations across a layer defined by spatial positions along the radial and axial directions inhibited the swirling steam–water two-phase flows. This ensembled nature and the normalized amplitudes of the velocity fluctuations were investigated under the action of the above-stated operating conditions, and it was found that the swirling steam–water two-phase body of the flow showed proportionally varying percentages of ensembled-normalized amplitudes of the velocity fluctuations.

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Section: Introductionmentioning

confidence: 99%

Hydrodynamics of Swirling Steam–Water Two-Phase Flows under External Shear

Ghazwani

Sanaullah

Khan

2023

Fluids

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“…The topic of vortex interaction with shear flow has been investigated with due attention from the scientific community [5][6][7], but in the studies related to combustion, myriad facets still need attention, e.g., swirl generation and breakdown, axisymmetric flows and their breakdown, and instabilities involved in these types of flows [8][9][10]. Kelvin-Helmholtz (KH) instabilities are generally observed in packed bed reac-tors, in which parallel flow of fluids having different viscosity, velocity, and density occurs through porous media.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on the Effects of Shear on Co‐Currently Swirling Steam‐Water Flow Instabilities

et al. 2022

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The shear effect of co‐currently flowing water on the flow instabilities induced by swirling steam was investigated. With shear, a 22–27 % decrease in velocity fluctuation amplitude was observed. The decrease was 29–41 % on an exponential and 12–17 % on a proportional basis. Shear reduced the layer thickness on increasing the inlet water pressure from 1 to 2 bar by 1.9–2.9 and 6.35–12.89 % at steam inlet pressures of 1 and 2 bar, respectively. The ratio of the swirl intensity along the dimensionless axial length scale and the initial swirl intensity was changed from < 1 to > 1 across critical point due to the nearly equal values of buoyancy and rotational frequencies. A critical limit of the initial swirl intensity within the control plane was investigated wherein the swirl‐induced instabilities can be attenuated uniformly and the rotational effects dominate over the gravity waves and buoyancy.

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“…Dense environmental barrier coatings (EBCs) are an essential prerequisite for the exploitation of the advantages offered by SiC-based fiber reinforced ceramic matrix composites (CMCs) to increase efficiency in modern gas turbines. Thanks to their good mechanical high-temperature properties and low specific weight, the non-oxide SiC/SiC CMCs represent a promising alternative to temperature-limited metallic materials for modern gas turbines [1][2][3] . However, a particular problem with these CMCs is their high susceptibility to corrosion in atmospheres containing water vapor at temperatures above 1200 °C.…”

Section: Introductionmentioning

confidence: 99%

Crystalline ytterbium disilicate environmental barrier coatings made by high velocity oxygen fuel spraying

Wolf

Mack

Mauer

et al. 2021

Int J Applied Ceramic Tech

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Dense environmental barrier coatings (EBCs) are an essential prerequisite to exploit the advantages offered by SiC-based fiber reinforced ceramic matrix composites (CMCs) to increase efficiency in gas turbines. Today's state-of-the art materials for application as EBCs are rare-earth (RE) silicates which, however, form amorphous phases upon rapid quenching from the melt. This makes their processing by thermal spray a challenge. Recently, high velocity oxygen fuel (HVOF) spraying was proposed as potential solution Accepted ArticleThis article is protected by copyright. All rights reserved since the melting degree of the feedstock can be controlled effectively. This work studies the deposition of ytterbium disilicate (YbDS) at short stand-off distances and variant total feed rates and oxy-fuel ratios of the working gas. It was found that the overall degree of crystallinity could be kept at high level above 90%. The kinetic energy transferred by impinging particles was found to be an effective parameter to control the densification of the coatings. Porosities well below 10% were achieved while fully dense coatings were impeded due to the progressive accumulation of stresses in the coatings.

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Combustion and environmental challenges for gas turbines in the 1990s

Cited by 21 publications

References 27 publications

Hydrodynamics of Swirling Steam–Water Two-Phase Flows under External Shear

Hydrodynamics of Swirling Steam–Water Two-Phase Flows under External Shear

Experimental Study on the Effects of Shear on Co‐Currently Swirling Steam‐Water Flow Instabilities

Crystalline ytterbium disilicate environmental barrier coatings made by high velocity oxygen fuel spraying

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