EFFECT OF INLET DISTORTION ON FORWARD SWEPT FAN ROTORS

摘要

This paper reports on the assessment of the payoff derived from forward sweep with respect to aerodynamic performance and stability in multistage fans. The experimental study compares, on a back-to-back test basis, two builds of an advanced good efficiency, high-pressure ratio, two-stage fan configuration tested alternately with a radial and a forward swept stage 1 blade. In the two-stage evaluations, the testing was extended to include the effect on inlet flow distortion. While the common second stage among the two builds prevented the overall fan from showing clean inlet performance and stability benefits with the forward swept rotor 1, this configuration did demonstrate superior front stage efficiency and tolerance to inlet distortion. The sensitivity to inlet distortion was halved with the forward swept rotor 1 configuration. In the case of the 180-degree one-per-rev distortion pattern, the two-stage fan was evaluated both with and without inlet guide vanes (IGVs). The presence of the inlet guide vanes had a profound impact in lowering the two-stage fan's sensitivity with inlet distortion.