University of California, Irvine
Aeroacoustics Lab

ROTOR ACOUSTICS

Sponsorhip:  The Boeing Co.

We are investigating the aeroacoustics of ducted fans through a subscale experimental simulation, focusing on the conditions typical of a geared turbofan (GTF).  The goal is to measure the directivity of the tones arising from rotor-stator interaction and their shielding by a barrier having the shape of the hybrid-wing-body airplane.    The rotor, stator, and nacelle are fabricated using high-definition stereolithograpy, a process that enables unprecedented flexibiiy in designing/ re-designing these components at low cost.   The rotor is powered by a brushless DC motor typically used on extreme-performance RC airplanes.  The subscale simulation is to match the fan pressure ratio and rotor tip speed of a realistic GTF.     This means running at very high power levels (50V x 150A), using lithium-polymer batteries, and fairly insane rotational speeds of ~60,000 RPM.   

A predecessor of this effort, funded internally, examined the aeroacoustics of counter-rotating open rotors in isolation and in the presence of a shield. 

Publications:

Truong, A. and Papamoschou, D., "Aeroacoustic Testing of Open Rotors at Very Small Scale,"   AIAA-2013-0217, 51st AIAA Aerospace Sciences Meeting, Grapevine, TX, Jan. 7-10, 2013.  (PDF)

Truong, A. and Papamoschou, D., "Experimental Simulation of Ducted Fan Acoustics at Very Small Scale,"   AIAA-2014-0718, 52st AIAA Aerospace Sciences Meeting, National Harbor, MD, Jan. 13-17, 2014.  (PDF)

gtf01.jpg (448138 bytes)

GTF model on test stand outside anechoic chamber.

Movie of inital RPM test (AVI, 16 Mb).    Sensor indicated 58,000 RPM.

rotor01.jpg (212384 bytes)

GTF rotor (70-mm dia.)

 

openrotor.jpg (284006 bytes)

Counter-rotating open rotor experiment.

openrotor_props.jpg (626396 bytes)

Rapid-prototyped propellers used in open-rotor tests.

 

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