EFFECT OF ROTOR-TO-STATOR SPACING ON ACOUSTIC PERFORMANCE OF A FULL-SCALE FAN (QF-5) FOR TURBOFAN ENGINES

摘要

A study was made of the effect of increasing the fan rotor-to-stator spacing on the noise level of a full-scale, single-stage, 1.6-pressure-ratio fan. Noise data were obtained with axial spacings of 1.14, 1.65, and 2.27 rotor chord lengths. Over this spacing range, data indicate a reduction of 1.5 PNdB. Apparently, rotor-alone noise at the frequency at which the rotor-stator interaction noise was cut off limited the noise reduction for the QF-5 fan. It seems, however, that the reduction in sound power level with increases in spacing is potentially about 6 dB over the range of spacings tested.