Impact of the Inflow
Conditions on the Heavy-Duty Gas Turbine Exhaust Diffuser
Performance

Vassiliev, V. V.; Irmisch, Stefan; Abdel-Wahab, Samer; Granovskiy, Andrey

doi:10.1115/1.4003714

Cited by 16 publications

(5 citation statements)

References 12 publications

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“…Vassiliev et al ascertained that diffuser performance is influenced by inlet Mach number, total pressure distribution, flow angle, and turbulence characteristics of the inflow [10].…”

Section: Diffuser Researchmentioning

confidence: 99%

See 1 more Smart Citation

Total Pressure Loss Reduction in Annular Diffusers

Mimic

Jätz

Sauer

et al. 2019

JGPP

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“…Vassiliev et al ascertained that diffuser performance is influenced by inlet Mach number, total pressure distribution, flow angle, and turbulence characteristics of the inflow [10].…”

Section: Diffuser Researchmentioning

confidence: 99%

“…or, using the pressure coefficient , rr , , rr ≈ . Σ + r ,i al (10) with r being the diffuser effectiveness at reference operating point. The underlying Σ model was subsequently tested and expanded to correlations for various diffuser opening angles in [13].…”

Section: Stabilisation Numbermentioning

confidence: 99%

Total Pressure Loss Reduction in Annular Diffusers

Mimic

Jätz

Sauer

et al. 2019

JGPP

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“…However, these charts rely on simplified inflow conditions and require additional, semi-empirical corrections to account for non-uniform inflow conditions. For example, Vassiliev et al (2011) showed that the diffuser performance depends on the inlet Mach number, total pressure distribution, flow angle, and turbulence characteristics.…”

Section: Stabilisation Numbermentioning

confidence: 99%

Correlation between total pressure losses of highly loaded annular diffusers and integral stage design parameters

Mimic

Jätz

Herbst

2018

J. Glob. Power Propuls. Soc.

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Diffusers convert kinetic flow energy into a rise in static pressure. This pressure recovery is the primary aerodynamic design objective for exhaust gas diffusers in power-generating steam and gas turbines. The total pressure loss is an equally important diffuser design parameter. It is strongly linked to the pressure recovery and the residual kinetic energy of the diffuser outlet flow. A reduction benefits the overall thermodynamic cycle, which requires the adjacent components of a diffuser to be included in the design process. This paper focuses on the total pressure losses in the boundary layer of a highly loaded annular diffuser. Due to its large opening angle the diffuser is susceptible to flow separation under uniform inlet conditions, which is a major source for total pressure losses. However, the unsteady tip leakage vortices of the upstream rotor, which are a source of losses, stabilise the boundary layer and prevent separation. Experiments and unsteady numerical simulation conducted show that the total pressure loss reduction caused by the delayed boundary layer separation exceed the vortex-induced losses by far. This flow interaction between the rotor and diffuser consequently decreases the overall total pressure losses. The intensity of the tip leakage vortex is linked to three rotor design parameters, namely work coefficient, flow coefficient and reduced blade-passing frequency. Based on these parameters, we propose a semi-empiric correlation to predict and evaluate the change in total pressure losses with regards to design operating conditions.

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“…15 The obtained results show that the vortices of the wakes at the rotor tip lead to the higher static pressure recovery performance in the annular diffuser compared with the flow condition without consideration of the upstream vortices. Vassiliev et al 16 conducted the effects of the inlet Mach number, total pressure distribution, flow angle, and turbulence on the flow field of the exhaust diffuser using numerical simulation and experimental method. They demonstrated that non-uniform pressure distribution and moderate swirl can improve the performance of the exhaust diffuser.…”

Section: Introductionmentioning

confidence: 99%

Effects of struts profiles and skewed angles on the aerodynamic performance of gas turbine exhaust diffuser

Dong

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part A:

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The strut structure directly affects the flow field characteristics and aerodynamic performance of the gas turbine exhaust diffuser. The effects of the strut profiles and strut skewed angles on the aerodynamic performance of the exhaust diffuser at different inlet pre-swirls were numerically investigated using three-dimensional Reynolds-Averaged Navier-Stokes(RANS) and Realizable k-ε turbulence model. The numerical static pressure recovery coefficient of the exhaust diffuser is in agreement with the experimental data well. The reliability of the numerical method for the exhaust diffuser performance analysis was demonstrated. Exhaust diffusers with four kinds of vertical strut profiles obtain the highest static pressure recovery coefficient at the inlet pre-swirl of 0.35. The similar static pressure recovery coefficient of exhaust diffusers with four kinds of vertical strut airfoils are observed when the inlet pre-swirl is less than 0.48. The static pressure recovery coefficient of exhaust diffusers with vertical b1 and b2 struts are higher than that with the a1 and a2 struts when the inlet pre-swirl is greater than 0.48. At the inlet pre-swirl of 0.35, The static pressure recovery coefficient of the exhaust diffuser with the a1 strut decreases with the increasing of the strut skewed angles. The static pressure recovery coefficient of the exhaust diffuser with the b1 strut increases with the increasing of the strut skewed angles, and the static pressure recovery coefficient increases by 3.6% compared with the vertical design when the skewed angle of b1 strut is 40[Formula: see text]. At the inlet pre-swirl of 0.64. The static pressure recovery coefficient of the exhaust diffuser with the a1 strut increases by 8.7% compared with the vertical design when the skewed angle of a1 strut is greater than 20°. In addition, the static pressure recovery coefficient of the exhaust diffuser with the b1 strut decreases by 3.8% compared with the vertical design when the skewed angle of b1 strut is 40°. The method to improve the aerodynamic performance of the exhaust diffuser by appropriate increase the strut maximum thickness and design the strut skewed angle is proposed in this work.

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Impact of the Inflow Conditions on the Heavy-Duty Gas Turbine Exhaust Diffuser Performance

Cited by 16 publications

References 12 publications

Total Pressure Loss Reduction in Annular Diffusers

Total Pressure Loss Reduction in Annular Diffusers

Correlation between total pressure losses of highly loaded annular diffusers and integral stage design parameters

Effects of struts profiles and skewed angles on the aerodynamic performance of gas turbine exhaust diffuser

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