Andreas Peters
Advisor: Prof. Spakovszky
Aircraft engines design trends tend towards higher bypass ratio, lower fan speed and fan pressure ratio (FPR) configurations for improved fuel burn, reduced emissions and noise. Low-pressure ratio fans offer increased propulsive efficiency and, besides enabling thermodynamic cycle changes for improved fuel efficiency, significant noise reductions can be achieved. As fan pressure ratios are reduced, innovative nacelle design concepts are required to limit the impact of larger diameter fans on nacelle weight and drag. Due to the shorter inlet ducts and the lower pressure ratios, fan design becomes more sensitive to inlet flow distortion at angle-of-attack or crosswind operating conditions and installation stagnation pressure losses. A second major consequence of short inlet and exhaust ducts is increased fan noise. Attenuation and shielding of blade-row interaction noise, fan broadband and BPF tone noise is limited in short nacelles. Since low FPR propulsors and their nacelles are more closely coupled than in current turbofan engines, inlet-fan and fan-exhaust nozzle interactions must be included in the aerodynamic and aero-acoustic assessment of the propulsion system. The goal of this effort is to define an advanced fan/nacelle design with benefits in performance, noise, and operability. Working towards this aim, the objectives are to (1) investigate inlet distortion transfer and determine the potential of endwall treatment and asymmetric geometries in short-nacelle designs using a coupled fan-inlet body force based approach, (2) interrogate flow features near the blade tip region and determine forces to improve performance, stability, and inlet distortion sensitivity, and (3) explore options to reduce fan source noise and radiated noise in short nacelles.
Pratt & Whitney low FPR, high-bypass ratio geared turbofan (source: AviationWeek.com, Jan. 2010)
Advisor: Prof. Spakovszky
Aircraft engines design trends tend towards higher bypass ratio, lower fan speed and fan pressure ratio (FPR) configurations for improved fuel burn, reduced emissions and noise. Low-pressure ratio fans offer increased propulsive efficiency and, besides enabling thermodynamic cycle changes for improved fuel efficiency, significant noise reductions can be achieved. As fan pressure ratios are reduced, innovative nacelle design concepts are required to limit the impact of larger diameter fans on nacelle weight and drag. Due to the shorter inlet ducts and the lower pressure ratios, fan design becomes more sensitive to inlet flow distortion at angle-of-attack or crosswind operating conditions and installation stagnation pressure losses. A second major consequence of short inlet and exhaust ducts is increased fan noise. Attenuation and shielding of blade-row interaction noise, fan broadband and BPF tone noise is limited in short nacelles. Since low FPR propulsors and their nacelles are more closely coupled than in current turbofan engines, inlet-fan and fan-exhaust nozzle interactions must be included in the aerodynamic and aero-acoustic assessment of the propulsion system. The goal of this effort is to define an advanced fan/nacelle design with benefits in performance, noise, and operability. Working towards this aim, the objectives are to (1) investigate inlet distortion transfer and determine the potential of endwall treatment and asymmetric geometries in short-nacelle designs using a coupled fan-inlet body force based approach, (2) interrogate flow features near the blade tip region and determine forces to improve performance, stability, and inlet distortion sensitivity, and (3) explore options to reduce fan source noise and radiated noise in short nacelles.
Pratt & Whitney low FPR, high-bypass ratio geared turbofan (source: AviationWeek.com, Jan. 2010)
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