Rotor Interaction Noise in Counter-Rotating Propfan Propulsion Systems
Due to their inherent noise challenge and potential for significant reductions in fuel burn, counter-rotating propfans (CRPs) are currently being investigated as potential alternatives to high-bypass turbofan engines. This paper introduces an integrated noise and performance assessment methodology f...
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| Other Authors: | |
| Format: | Article |
| Language: | English |
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ASME International
2019
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| Online Access: | https://hdl.handle.net/1721.1/122675 |
| _version_ | 1826188021185118208 |
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| author | Peters, Andreas Spakovszky, Zoltan S |
| author2 | Massachusetts Institute of Technology. Department of Aeronautics and Astronautics |
| author_facet | Massachusetts Institute of Technology. Department of Aeronautics and Astronautics Peters, Andreas Spakovszky, Zoltan S |
| author_sort | Peters, Andreas |
| collection | MIT |
| description | Due to their inherent noise challenge and potential for significant reductions in fuel burn, counter-rotating propfans (CRPs) are currently being investigated as potential alternatives to high-bypass turbofan engines. This paper introduces an integrated noise and performance assessment methodology for advanced propfan powered aircraft configurations. The approach is based on first principles and combines a coupled aircraft and propulsion system mission and performance analysis tool with 3D unsteady, full-wheel CRP computational fluid dynamics computations and aeroacoustic simulations. Special emphasis is put on computing CRP noise due to interaction tones. The method is capable of dealing with parametric studies and exploring noise reduction technologies. An aircraft performance, weight and balance, and mission analysis was first conducted on a candidate CRP powered aircraft configuration. Guided by data available in the literature, a detailed aerodynamic design of a pusher CRP was carried out. Full-wheel unsteady 3D Reynolds-averaged Navier-Stokes (RANS) simulations were then used to determine the time varying blade surface pressures and unsteady flow features necessary to define the acoustic source terms. A frequency domain approach based on Goldstein’s formulation of the acoustic analogy for moving media and Hanson’s single rotor noise method was extended to counter-rotating configurations. The far field noise predictions were compared to measured data of a similar CRP configuration and demonstrated good agreement between the computed and measured interaction tones. The underlying noise mechanisms have previously been described in literature but, to the authors’ knowledge, this is the first time that the individual contributions of front-rotor wake interaction, aft-rotor upstream influence, hub-endwall secondary flows, and front-rotor tip-vortices to interaction tone noise are dissected and quantified. Based on this investigation, the CRP was redesigned for reduced noise incorporating a clipped rear-rotor and increased rotor-rotor spacing to reduce upstream influence, tip-vortex, and wake interaction effects. Maintaining the thrust and propulsive efficiency at takeoff conditions, the noise was calculated for both designs. At the interaction tone frequencies, the redesigned CRP demonstrated an average reduction of 7.25 dB in mean sound pressure level computed over the forward and aft polar angle arcs. On the engine/aircraft system level, the redesigned CRP demonstrated a reduction of 9.2 dB in effective perceived noise (EPNdB) and 8.6 EPNdB at the Federal Aviation Regulations (FAR) 36 flyover and sideline observer locations, respectively. The results suggest that advanced open rotor designs can possibly meet Stage 4 noise requirements. Keywords: aerospace propulsion; aircraft; computational fluid dynamics; fans; flow instability; flow simulation; jet engines; rotors; wakes |
| first_indexed | 2024-09-23T07:53:23Z |
| format | Article |
| id | mit-1721.1/122675 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T07:53:23Z |
| publishDate | 2019 |
| publisher | ASME International |
| record_format | dspace |
| spelling | mit-1721.1/1226752022-09-23T09:27:18Z Rotor Interaction Noise in Counter-Rotating Propfan Propulsion Systems Peters, Andreas Spakovszky, Zoltan S Massachusetts Institute of Technology. Department of Aeronautics and Astronautics Due to their inherent noise challenge and potential for significant reductions in fuel burn, counter-rotating propfans (CRPs) are currently being investigated as potential alternatives to high-bypass turbofan engines. This paper introduces an integrated noise and performance assessment methodology for advanced propfan powered aircraft configurations. The approach is based on first principles and combines a coupled aircraft and propulsion system mission and performance analysis tool with 3D unsteady, full-wheel CRP computational fluid dynamics computations and aeroacoustic simulations. Special emphasis is put on computing CRP noise due to interaction tones. The method is capable of dealing with parametric studies and exploring noise reduction technologies. An aircraft performance, weight and balance, and mission analysis was first conducted on a candidate CRP powered aircraft configuration. Guided by data available in the literature, a detailed aerodynamic design of a pusher CRP was carried out. Full-wheel unsteady 3D Reynolds-averaged Navier-Stokes (RANS) simulations were then used to determine the time varying blade surface pressures and unsteady flow features necessary to define the acoustic source terms. A frequency domain approach based on Goldstein’s formulation of the acoustic analogy for moving media and Hanson’s single rotor noise method was extended to counter-rotating configurations. The far field noise predictions were compared to measured data of a similar CRP configuration and demonstrated good agreement between the computed and measured interaction tones. The underlying noise mechanisms have previously been described in literature but, to the authors’ knowledge, this is the first time that the individual contributions of front-rotor wake interaction, aft-rotor upstream influence, hub-endwall secondary flows, and front-rotor tip-vortices to interaction tone noise are dissected and quantified. Based on this investigation, the CRP was redesigned for reduced noise incorporating a clipped rear-rotor and increased rotor-rotor spacing to reduce upstream influence, tip-vortex, and wake interaction effects. Maintaining the thrust and propulsive efficiency at takeoff conditions, the noise was calculated for both designs. At the interaction tone frequencies, the redesigned CRP demonstrated an average reduction of 7.25 dB in mean sound pressure level computed over the forward and aft polar angle arcs. On the engine/aircraft system level, the redesigned CRP demonstrated a reduction of 9.2 dB in effective perceived noise (EPNdB) and 8.6 EPNdB at the Federal Aviation Regulations (FAR) 36 flyover and sideline observer locations, respectively. The results suggest that advanced open rotor designs can possibly meet Stage 4 noise requirements. Keywords: aerospace propulsion; aircraft; computational fluid dynamics; fans; flow instability; flow simulation; jet engines; rotors; wakes 2019-11-01T17:40:22Z 2019-11-01T17:40:22Z 2011-05 2010-09 2019-11-01T16:05:01Z Article http://purl.org/eprint/type/JournalArticle 0889-504X 1528-8900 https://hdl.handle.net/1721.1/122675 Peters, Andreas and Zoltan S. Spakovszky. "Rotor Interaction Noise in Counter-Rotating Propfan Propulsion Systems." Journal of Turbomachinery 134, 1 (January 2012): 011002 © 2012 American Society of Mechanical Engineers en http://dx.doi.org/10.1115/1.4003223 Journal of Turbomachinery Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf ASME International ASME |
| spellingShingle | Peters, Andreas Spakovszky, Zoltan S Rotor Interaction Noise in Counter-Rotating Propfan Propulsion Systems |
| title | Rotor Interaction Noise in Counter-Rotating Propfan Propulsion Systems |
| title_full | Rotor Interaction Noise in Counter-Rotating Propfan Propulsion Systems |
| title_fullStr | Rotor Interaction Noise in Counter-Rotating Propfan Propulsion Systems |
| title_full_unstemmed | Rotor Interaction Noise in Counter-Rotating Propfan Propulsion Systems |
| title_short | Rotor Interaction Noise in Counter-Rotating Propfan Propulsion Systems |
| title_sort | rotor interaction noise in counter rotating propfan propulsion systems |
| url | https://hdl.handle.net/1721.1/122675 |
| work_keys_str_mv | AT petersandreas rotorinteractionnoiseincounterrotatingpropfanpropulsionsystems AT spakovszkyzoltans rotorinteractionnoiseincounterrotatingpropfanpropulsionsystems |