A unified analytical approach for the acoustic conceptual design of fans of modern aero-engines

Moreau, Antoine

doi:10.14279/depositonce-5935

Cited by 8 publications

(26 citation statements)

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“…A global and simplified modelling approach, described in details by Moreau [14], is adopted to fulfill the objectives of the present study. It is also this approach that was followed in the previous study by the author dedicated to the VAN in 2021.…”

Section: Fan Pre-design and Aerodynamic/acoustic Evaluationmentioning

confidence: 99%

“…Jet noise is estimated with the single-stream model developed by Stone [21]. The tonal and broadband components of the rotor-stator interaction are the sources calculated for fan noise estimation, according to Goldstein's version of the linear Acoustic Analogy as implemented by Moreau [14]. For high-speed fans, the tonal rotor self-noise (also known as buzz-saw noise) is calculated with a nonlinear approach [15].…”

Section: Fan Pre-design and Aerodynamic/acoustic Evaluationmentioning

confidence: 99%

“…Some details are given now about the physical modelling underlying the estimation of fan noise. The analytical model by Moreau [14] for rotor-stator noise interaction provides a sound power that basically scales with flow quantities inside the fan stage. Equation (1) shows that sound power scales with some power (around 5) of the flow Mach number M between rotor and stator, and with the square of the velocity perturbation related to the rotor wakes, represented by a wake area A wake Another approach, based on empirical correlations by NASA [8], relies only on global performance parameters such as the mass flow Q and the total-temperature rise across the rotor ∆T t , as described in Eq.…”

Section: Fan Pre-design and Aerodynamic/acoustic Evaluationmentioning

confidence: 99%

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Acoustic preliminary design of a low-noise fan stage considering a variable-area nozzle and variable-pitch rotor blades

Moreau¹,

Schnell²,

Mennicken³

2023

CEAS Aeronaut J

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A low-noise low-pressure ultra-high-bypass-ratio fan stage to be implemented in the next generation of aircraft engines is described and evaluated acoustically with semi-empirical and analytical methods suited for preliminary design. As expected, good reduction potentials are observed for the jet noise and fan tonal noise components when the UHBR design is compared to current fans in service. However, concerns are identified for fan broadband noise, which are attributed to the off-design operation of the UHBR fan too close from its stability limit. By unloading the fan and thus reducing the size of the rotor wakes, the variable-area nozzle provides a substantial fan broadband noise reduction with a nozzle opened by around 15% from its design value. Alternatively, with the variable-pitch fan, closing the rotor blades by roughly 5° turns out to be an even more effective method to reduce fan noise, as the unloading mechanism is combined with a stronger tilting of the rotor wakes and a lower intra-stage flow Mach number. Opening the nozzle or closing the blades beyond the setting that provides the best fan efficiency is not recommended as the acoustic benefit progressively vanishes, whereas technical feasibility becomes more challenging. Finally, the presence of one of these systems may allow for the design of a low-solidity rotor, with a smaller contribution from the rotor wakes and thus a weaker fan noise emission.

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Section: Fan Pre-design and Aerodynamic/acoustic Evaluationmentioning

confidence: 99%

Section: Fan Pre-design and Aerodynamic/acoustic Evaluationmentioning

confidence: 99%

Section: Fan Pre-design and Aerodynamic/acoustic Evaluationmentioning

confidence: 99%

See 1 more Smart Citation

Acoustic preliminary design of a low-noise fan stage considering a variable-area nozzle and variable-pitch rotor blades

Moreau¹,

Schnell²,

Mennicken³

2023

CEAS Aeronaut J

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“…The model is restricted to Zero Gradient Pressure (ZPG) flows. • A modified WRA model was proposed by Moreau [40]. He introduced the drag coefficient as an additional parameter.…”

Section: Empirical Modelsmentioning

confidence: 99%

On the Modeling of Wall Surface Pressure Spectra for Trailing Edge Noise Prediction

Kissner

Guérin

Thisse

et al. 2022

28th AIAA/CEAS Aeroacoustics 2022 Conference

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Broadband noise is a significant source for open rotors and Ultra High Bypass Ratio fans. The analytical description of the leading edge noise component is typically linked to the upwash velocity autospectrum of the impinging turbulence, and the modeling of the trailing edge component due to the interaction of the boundary layer turbulence with the trailing edge relies on the surface pressure autospectrum near the trailing edge. But while there is some consensus on describing transverse velocity frequency spectra for leading edge noise, there are a plethora of different models of varying complexity to describe wall surface pressure autospectra. Choosing an appropriate model to apply in the framework of fast and robust acoustic prediction tools is therefore no easy task. This paper aims to apply different models for predicting the surface pressure spectrum near the trailing edge of an airfoil. Experimental data for two airfoils at realistic flight Mach and Reynolds numbers were studied and different RANSinformed empirical models as well as the Stalnov TNO model were investigated regarding their ability to capture experimental trends.

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“…In the next step, an equivalent flow is determined and matched with the streamline, which intersects the equivalent radial position at the position of the If this unsteady loading noise is assumed to be the dominant source, this term can be related to the squares of mean flow velocity and mean density and to the auto-correlation spectrum of the transverse velocity component. The hereafter used proportionality is formulated according to Moreau [45]:…”

Section: D-equivalent Approach For 2d Simulationsmentioning

confidence: 99%

Comparison of predicted fan broadband noise using a two- versus a three-dimensional synthetic turbulence method

Kissner

Guérin

2021

Journal of Sound and Vibration

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A unified analytical approach for the acoustic conceptual design of fans of modern aero-engines

Cited by 8 publications

References 0 publications

Acoustic preliminary design of a low-noise fan stage considering a variable-area nozzle and variable-pitch rotor blades

Acoustic preliminary design of a low-noise fan stage considering a variable-area nozzle and variable-pitch rotor blades

On the Modeling of Wall Surface Pressure Spectra for Trailing Edge Noise Prediction

Comparison of predicted fan broadband noise using a two- versus a three-dimensional synthetic turbulence method

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