Effect of Prediffuser Angle on the Static Pressure Recovery in Flow Through Casing-Liner Annulus of a Gas Turbine Combustor at Various Swirl Levels

Ghose, Prakash; Datta, Amitava; Mukhopadhyay, Achintya

doi:10.1115/1.4030734

Cited by 6 publications

(6 citation statements)

References 11 publications

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“…Unfortunately, as the ame temperature of a fuel and air admixture is decreased to approximately 1500°C, typically combustion becomes unstable and high carbon monoxide emissions are generated [11,12]. Therefore, legal compliance requirements placed on both nitrogen oxides and carbon monoxide make the operating window for a lean, premixed combustor quite limited [13,14], even operating at rich enough conditions where nitrogen oxides levels are as high as 15 or 20 milligrams per cubic meter.…”

Section: Introductionmentioning

confidence: 99%

WITHDRAWN: Combustion stability and flame characteristics of hydrocarbon-air mixtures in millimeter-scale cavity-stabilized burners with proper thermal management

Chen

2022

Preprint

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Flame stabilization is a common problem in these combustion systems, and a flame will propagate through a fuel-air mixture only when certain conditions prevail. However, the precise mechanism underlying the stabilizing effect of the cavity method remains unclear. This study relates to the thermal management of micro-structured cavity-stabilized burners. The design factors affecting combustion stability and flame characteristics of hydrocarbon-air mixtures in millimeter-scale cavity-stabilized burners are determined. The results indicate that the flow velocity, wall thermal conductivity, channel height, and heat loss are critical factors in assuring combustion stability within the cavity-stabilized burner. The axial heat transfer from the post-flame to the pre-flame via wall conduction widens stability limits and can enable the construction of smaller burners. Axial heat transfer also enhances the benefits of operating under high admixture inlet velocity and wall heat transfer coefficient conditions. Heat exchange through the structure can lead to a broadening of the reaction region, but heat loss to the environment decreases the broadening effect and eventually results in flame quenching. The maximum power density tends to increase with increasing the channel height. Fast flows can cause blowout and slow flows can cause extinction. The anisotropic wall thermal conductivity influences the maximum achievable power density. The channel height has an important effect on the stability and performance of the cavity-stabilized burner and should be included when estimating burner performance.

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Section: Introductionmentioning

confidence: 99%

WITHDRAWN: Combustion stability and flame characteristics of hydrocarbon-air mixtures in millimeter-scale cavity-stabilized burners with proper thermal management

Chen

2022

Preprint

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“…Too higher values of it lead to flow separation on its wall, as per the results of Ghose et al (2016). At lower magnitudes of PDA such as 12°, 18°, from Klein (1995), it is clear that losses at 18° are higher than those at 12°.…”

Section: Computational Domainmentioning

confidence: 76%

“…They have mentioned the important requirements of the liner wall and casing wall pressure distributions. Ghose et al (2016) have studied numerically, the effect of pre-diffuser angle (PDA) on the liner wall and casing wall pressure variation, with and without inlet swirl. They have considered 4 pre-diffuser angles which are 0°, 12°, 27°, and 50°.…”

Section: Fig 1 Diffuser Types Faired Diffuser (B) Dumpmentioning

confidence: 99%

“…The conclusions of the above works have motivated the authors to study the liner and casing wall pressure distributions along with flow field study in the present work. Along with this, the work of Ghose et al (2016) has given an idea of the range in which PDA for the present work is to be considered. Another geometrical parameter which has a significant effect on the performance of dump diffuser is the dome head shape.…”

Section: Fig 1 Diffuser Types Faired Diffuser (B) Dumpmentioning

confidence: 99%

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Effect of Side Wall Expansion Angle on the Performance of a Dump Diffuser Model for a Combustor

Chetan

Chakrabarti

2019

JAFM

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In the present article, numerical analysis has been performed on a dump diffuser model, to study the effect of sidewall expansion angle (SWA), on its performance aspects. SWA has been varied from 90° to 1° and performance has been evaluated in terms of major influencing aspects. It is observed that, at SWA of magnitudes greater than 11°, there is no significant change in the performance. But at SWA below 11°, significant changes, which enhance the performance are observed. It is noticed that at SWA in range, from 3.57° to 8°, higher static pressure recovery (almost from 25 to 33% of inlet dynamic pressure) happens in the dump and annular regions. SWA of magnitudes less than 11° have resulted in smaller, low dense and higher intense recirculation zones. At the SWA of 3.57°, static pressure recovered is maximum and total pressure lost is minimum. But that SWA causes too much delay in pressure stabilization on the liner wall. However, SWA of magnitudes less than 3.57° have resulted in comparatively poor performance. Eventually, sidewall angle in the range from 5° to 7° is found to be optimum as it yields higher static pressure recovery and low total pressure loss. This range also results in early stabilization of pressure both on the liner and casing walls.

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“…It is concluded that in addition to the dump gap ratio, the aerodynamic shape of the flame tube case and the other geometric variables are also needed to be optimized judiciously after considering the fluid dynamic constraints for controlling the pressure recovery and the losses. Ghose et al [21] have studied the effects of different prediffuser angles, inlet swirl levels, and different dump gaps on the streamline distribution and the static pressure recovery coefficients. They observed that the dump gap has significant influence on the static pressure recovery only at small prediffuser angle.…”

Section: Introductionmentioning

confidence: 99%

Optimization Study of the Dump Diffuser in Gas Turbine to Reduce Pressure Loss

Xing

Chan

et al. 2018

International Journal of Aerospace Engineering

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As a key component-connecting compressor and the entrance of combustion chamber, the diffuser is able to increase the pressure and slow down the airflow in order to promote efficient combustion as well as avoid a large amount of pressure loss. In this paper, experimental investigation and numerical studies have been carried out to understand the effects of air bleeding from dump region and dump gap ratio on the total pressure loss and static pressure recovery of the dump diffusers. The ultimate objective is optimizing the dump diffuser design to get the maximum static pressure recovery and minimum total pressure loss. A simplified test model is used to study the effect of the air bleeding from the outer dump region and the dump gap ratio on the total pressure loss and static pressure recovery in the dump diffuser. The impact of the dump gap ratio in the performance of the dump diffusers has also been discussed. Nearly all the pressure raise occurs in the prediffuser, and most of the total pressure loss occurs in the dump region. For the recirculating area in the dump region, the controllable vortex can be introduced. Bleeding air from the outer dump region can improve the velocity distribution near the flame tube. The results show that when 0.4% of the air is bled from outer dump region, the performance of the dump diffuser is optimal. Hence, the controllable vortex method is effective for improving the performance of the dump diffuser.

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Effect of Prediffuser Angle on the Static Pressure Recovery in Flow Through Casing-Liner Annulus of a Gas Turbine Combustor at Various Swirl Levels

Cited by 6 publications

References 11 publications

WITHDRAWN: Combustion stability and flame characteristics of hydrocarbon-air mixtures in millimeter-scale cavity-stabilized burners with proper thermal management

WITHDRAWN: Combustion stability and flame characteristics of hydrocarbon-air mixtures in millimeter-scale cavity-stabilized burners with proper thermal management

Effect of Side Wall Expansion Angle on the Performance of a Dump Diffuser Model for a Combustor

Optimization Study of the Dump Diffuser in Gas Turbine to Reduce Pressure Loss

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