Large Eddy Simulations for Indirect Combustion Noise Assessment in a Nozzle Guide Vane Passage

Ceci, Alessandro; Gojon, Romain; Mihăescu, Mihai

doi:10.1007/s10494-018-9964-9

Cited by 5 publications

(5 citation statements)

References 23 publications

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“…The reflected acoustic wave shows a slight reduction, which it is suggested is due to the choked operating condition [16]. This is in agreement with investigations of entropy noise in turbine blades with a shock, showing that pressure waves created downstream of the sonic line cannot travel upstream [17]. While previous studies have only considered planar entropy waves, Becerril et al…”

Section: Introductionsupporting

confidence: 83%

“…where is the forcing frequency [16,17]. When imposing a temperature fluctuation at the inlet, a pressure wave is created -often referred to as direct noise.…”

Section: B Boundary Conditionsmentioning

confidence: 99%

“…Previous research of entropy noise in turbine blades [11,12,16,17,19] has not yet considered the effect film cooling on entropy wave convection. Typically, turbine entry temperatures are very high (exceeding 1850 K for take-off conditions), requiring sophisticated cooling designs [20].…”

Section: Introductionmentioning

confidence: 99%

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Effect of Film Cooling on Entropy Noise Generation in a Stator Blade Row

et al. 2021

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Section: Introductionsupporting

confidence: 83%

“…where is the forcing frequency [16,17]. When imposing a temperature fluctuation at the inlet, a pressure wave is created -often referred to as direct noise.…”

Section: B Boundary Conditionsmentioning

confidence: 99%

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Effect of Film Cooling on Entropy Noise Generation in a Stator Blade Row

et al. 2021

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“…The contradictory reported results, where entropy waves lead to an overall acoustic noise attenuation [16] or additional noise source [7,15,18], are inconclusive having considered only partially the nature of incoming entropy waves and the broadband noise at low frequencies. All investigations employed idealised entropy wave shapes, i.e.…”

Section: Introductionmentioning

confidence: 95%

Entropy and Vorticity Wave Generation in Realistic Gas Turbine Combustors

Semlitsch¹,

Hynes²,

Langella

et al. 2019

Journal of Propulsion and Power

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Understanding the nature of the unsteady flow at the combustor exit is required to accurately simulate time dependent phenomena in the turbine entry, such as indirect noise generation. Using Large Eddy Simulations of the combustion process in a realistic geometry, we analyse the flow at its exit. Two realistic, near-ground certification operating conditions are considered. Different mechanisms for large-scale flow and thermal structure generation are described, which are ejected into the turbine. Modal decomposition methods are used to extract the spatial and temporal scales at the turbine entry. We find that, depending on the operating condition, the entropy waves convect as elongated streaks in the core of the combustor annulus or the proximity of the walls. The dominant unsteady character of the fluctuations exhibits different spectral properties, i.e. low-frequency in the core and high-frequency towards walls. At the combustor exit, the vortical field is dominated by the swirl in the air inlet, which is found to have little influence on the entropy perturbations. Further, the importance of considering the interaction of multiple fuel injectors and combustion zones in an annular combustor is investigated. It is shown that pulsating circumferential vorticity modes can occur in multi-sector annular combustors but these, however, do not affect the entropy wave distribution.

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“…More recently, Wang [11] and Papadogiannis [12] evaluated the propagation mechanisms of the indirect combustion noise generated by entropy plane waves in the Oxford MT1 high pressure (HP) stage, and revealed the variation of the upstream and downstream entropy noise in the turbine guide vanes and blades. Besides, Ceci [13] used the large eddy simulation (LES) to analyze the blade acoustic response to forced temperature perturbations at the inlet, and found the dynamics of shocks emitted from the trailing edge was completely characterized by the inlet forcing frequency of the entropy waves. The present work investigated the variation of downstream acoustic characteristics of a turbine guide vane under the influence of the inlet entropy wave.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of Influence of Entropy Wave on the Acoustic and Wall Heat Transfer Characteristics of a High-Pressure Turbine Guide Vane

Fang

Zheng

et al. 2020

Acoustics

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As an indirect noise source generated in the combustion chamber, entropy waves are widely prevalent in modern gas turbines and aero-engines. In the present work, the influence of entropy waves on the downstream flow field of a turbine guide vane is investigated. The work is mainly based on a well-known experimental configuration called LS89. Two different turbulence models are used in the simulations which are the standard k-ω model and the scale-adaptive simulation (SAS) model. In order to handle the potential transition issue, Menter’s ð-Reθ transition model is coupled with both models. The baseline cases are first simulated with the two different turbulence models without any incoming perturbation. Then one forced case with an entropy wave train set at the turbine inlet at a given frequency and amplitude is simulated. Results show that the downstream maximum Mach number is rising from 0.98 to 1.16, because the entropy waves increase the local temperature of the flow field; also, the torque of the vane varies as the entropy waves go through, the magnitude of the oscillation is 7% of the unforced case. For the wall (both suction and pressure side of the vane) heat transfer, the entropy waves make the maximum heat transfer coefficient nearly twice as the large at the leading edge, while the minimum heat transfer coefficient stays at a low level. As for the averaged normalized heat transfer coefficient, a maximum difference of 30% appears between the baseline case and the forced case. Besides, during the transmission process of entropy waves, the local pressure fluctuates with the wake vortex shedding. The oscillation magnitude of the pressure wave at the throat is found to be enhanced due to the inlet entropy wave by applying the dynamic mode decomposition (DMD) method. Moreover, the transmission coefficient of the entropy waves, and the reflection and transmission coefficients of acoustic waves are calculated.

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Large Eddy Simulations for Indirect Combustion Noise Assessment in a Nozzle Guide Vane Passage

Cited by 5 publications

References 23 publications

Effect of Film Cooling on Entropy Noise Generation in a Stator Blade Row

Effect of Film Cooling on Entropy Noise Generation in a Stator Blade Row

Entropy and Vorticity Wave Generation in Realistic Gas Turbine Combustors

Numerical Investigation of Influence of Entropy Wave on the Acoustic and Wall Heat Transfer Characteristics of a High-Pressure Turbine Guide Vane

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