Effect of a drooped intake on performance of compressor

The steady flow distortion induced by the drooped intakes intensifies with the design trend of shortening the nacelle length. To investigate whether drooped intakes impact compressor performance and noise, this study designed a drooped intake and conducted compressor experiments under static intake conditions. Experimental results demonstrate that for the subject investigated, at a distance of 2.3 times the duct diameters upstream of the fan, the drooped intake exerts negligible influence on fan pressure rise and efficiency characteristics and does not alter its stall inception pattern. The spectral characteristics and mode composition of the exhaust sound field from the drooped intake align with those of standard intakes, while steady flow distortion perturbs rotor-stator interaction noise. Mode analysis reveals that theoretical modes are not fully applicable to the TA29 experiment rig examined herein. Additionally, the asymmetry of the drooped intake enhances or suppresses upstream-propagating noise modes across multiple non-dominant mode orders.