Turbulent velocity and pressure fluctuations in gas turbine combustor exit flows

Lubbock, R.; Oldfield, M. L. G.

doi:10.1177/0957650917732885

Cited by 6 publications

(3 citation statements)

References 30 publications

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“…Despite the combustor simulator tested in the present work is not able to reproduce unsteady phenomena linked to reactive processes, it is known that the gross of the turbulence intensity, for lean combustor, should follow the swirl profiles (Hall et al 2013;Lubbock and Oldfield 2017) and the aerodynamic field. For this reason the following experimental results in terms of turbulence quantities could represent valuable data to help in the NGV design in engines that adopt lean burn combustors.…”

Section: Turbulence Intensitymentioning

confidence: 97%

Turbulence intensity measurements across a NGV cooled cascade with representative Lean Burn combustor outflow

Bacci

Picchi

Lenzi

et al. 2019

European Conference on Turbomachinery Fluid Dynamics and Hermodynamics

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Significant turbulence levels can be achieved at the exit of modern lean-burn aeroengine combustors, due to the limited interaction between swirling mainflow and liner flows. In this study, hot wire anemometry was exploited to assess the turbulence intensity across a film-cooled NGV cascade, installed downstream of a non-reactive lean burn combustor simulator. The interpretation of the turbulence measurements was improved thanks to the average flow field and pressure results, gathered by five hole probe investigation. The results showed that the swirling mainflow was responsible for very high turbulence intensities on the combustor exit plane. Important turbulence intensities were also found at the NGV exit, due to the conservation of the residual swirling structure and to its interaction with the endwall flows. The effect of nozzle film-cooling injection was also assessed: a limited effect was found, with film-cooling injection generally leading to slightly reduced turbulence intensities.

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Section: Turbulence Intensitymentioning

confidence: 97%

Turbulence intensity measurements across a NGV cooled cascade with representative Lean Burn combustor outflow

Bacci

Picchi

Lenzi

et al. 2019

European Conference on Turbomachinery Fluid Dynamics and Hermodynamics

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“…The lean premixed combustors are equipped on modern gas turbines to meet the strict requirements of environment protection by reducing the NOx emission effectively and meanwhile, saving the engine axial space compared with the rich burn-quick quench-lean burn (RQL) combustor. 1 In order to mix air and fuel adequately and stabilize the flame, the recirculation zone should be created by the swirler inside the lean premixed combustor. However, the extremely complex main flow with non-uniform temperature and velocity distribution from the combustor outlet extends downstream causing a severe influence on the aerothermal characteristic of the turbine nozzle guide vane (NGV).…”

Section: Introductionmentioning

confidence: 99%

Turbine vane endwall aerothermal and film cooling performance considering realistic swirling inflow conditions

Zhang

et al. 2023

Proceedings of the Institution of Mechanical Engineers, Part A:

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The turbine vane inlet downstream of the lean premixed combustor presents nonuniform distributions of velocity and temperature. For obtaining swirling inflow profiles close to reality, the simulated non-reacting combustor is designed firstly. Applying these profiles as inflow boundary conditions, the effects of realistic swirling inflow on the turbine vane endwall aerothermal characteristics and film cooling performance are numerically investigated through solving the three-dimensional Reynolds-Averaged Navier-Stokes equations coupled with the shear stress transfer ([Formula: see text]) turbulence model. Two swirling orientations (anticlockwise and clockwise) and five swirling core pitch-wise positions (aligned with vane 1 to vane 2) are considered in the current work. The results indicate that the residual vortices in the vane passage are strengthened and move with the swirling core along the pitch-wise direction. The migration of the horseshoe vortex is controlled by this movement. The shrinkage or expansion of the separation line of the horseshoe vortex can be observed under the anticlockwise and clockwise swirling inflow conditions respectively. The anticlockwise swirling inflow results in a larger aerodynamic loss by a 10%–35% increase of the laterally [Formula: see text]. The high Nu region near the pressure side surface enlarges and the area-averaged Nu at [Formula: see text] increases from 2337.9 to 2878.3. For the cases with clockwise swirling inflow, the area of the hot ring is enlarged and the Nu downstream of the row 3 film holes is decreased. As for the film cooling performance, the endwall coverage area shrinks and the phantom cooling area enlarges when the anticlockwise swirling core is aligned with vane 2. The endwall loses the protection from the row 3 film holes and the cooling failure ([Formula: see text]) occurs at [Formula: see text] when the swirling core is aligned with the vane passage. This is an extremely bad phenomenon that should be avoided. Among all cases, the highest endwall area-averaged [Formula: see text] (0.122) is obtained when the clockwise swirling core is aligned with vane 1. The largest endwall coverage area is achieved when the clockwise swirling core is aligned with vane 2.

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“…As a result, high thermal load is caused on hot components and it can significantly influence hot component life. To avoid undesirable NO x production 1,2 under extreme temperature in the combustor stage, lean combustion technique with high swirl motion is used to make turbine inlet temperature profile more flat, and it can further increase the heat load of turbine endwall. To deal with these issues, advanced cooling technologies should be utilized in gas turbine for the purpose of operation safety.…”

Section: Introductionmentioning

confidence: 99%

Influence of slashface leakage coupled with quasi-labyrinth seal technique on gas turbine endwall aerothermal performance and blade suction side surface phantom cooling

Zhang

2020

Proceedings of the Institution of Mechanical Engineers, Part A:

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Quasi-labyrinth seal technique was innovatively adopted to control the slashface flow, and the effect of slashface leakage on endwall aerothermal performance and blade suction side surface phantom cooling was numerically investigated. Simulations of five different labyrinth seal lengths ( Ls) and three coolant momentum flux ratios ( I) were conducted by computationally solving the Reynolds-averaged Navier–Stokes equations coupled with the shear stress transport k-ω turbulence model. The results show that the slashface coolant can be accelerated and conveyed downstream inside the slashface carried by the ingested mainstream and passage vortex. By setting up the quasi-labyrinth seal composed of a series of aperture cavities along the slashface, the coolant downstream transportation can be largely weakened, and the labyrinth seal with various lengths all have the potential to move the endwall coolant coverage toward upstream. When I = 0.48, the coolant downstream migration is severest and it has the best coverage on the endwall with seal. The laterally averaged cooling effectiveness is elevated for the fore part endwall but decreased for the back part endwall after sealing, and the highest cooling effectiveness is increased by 5% for 0.6 Ls seal. The 0.6–1.0 Ls seal has the approximate effect and is better than 0.4 Ls seal, and 0.6 Ls seal has the best outcome considering the countering effects of structural strength and endwall cooling performance. For 0.6 Ls sealed case, the high heat transfer level caused by coolant attachment is enhanced by 3.5% when I = 0.48 but decreased by 3.3% and 4.4% when I = 0.96 and 1.42 compared with baseline case. The low heat transfer caused by horseshoe vortex separation is enhanced when I = 1.42 for the sealed case. The quasi-labyrinth seal mainly weakens the back part suction side phantom cooling performance, and the well phantom cooling region moves upstream with the increase of I. The averaged phantom cooling effectiveness is decreased by 0.56%, 0.3%, and 1.44% when I = 0.48, 0.96, and 1.42 for the sealed cases. The results provide the gas turbine designers a better insight into improved slashface leakage control as well as its detailed surface cooling effects.

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Turbulent velocity and pressure fluctuations in gas turbine combustor exit flows

Cited by 6 publications

References 30 publications

Turbulence intensity measurements across a NGV cooled cascade with representative Lean Burn combustor outflow

Turbulence intensity measurements across a NGV cooled cascade with representative Lean Burn combustor outflow

Turbine vane endwall aerothermal and film cooling performance considering realistic swirling inflow conditions

Influence of slashface leakage coupled with quasi-labyrinth seal technique on gas turbine endwall aerothermal performance and blade suction side surface phantom cooling

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