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

نویسندگان

چکیده

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

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ژورنال

عنوان ژورنال: CEAS Aeronautical Journal

سال: 2023

ISSN: ['1869-5582', '1869-5590']

DOI: https://doi.org/10.1007/s13272-023-00658-x