NOISE REDUCTION OF A CROSS-FLOW FAN

Authors:
Publisher website
Google Scholar
Abstract
This study attempts to reduce the aerodynamic sound noise from a cross-flow fan by varying the geometrical parameters of the cross- flow fan as the similar amount of air flow rate is delivered by the cross- flow fan. Two different rotors (fixed-pitch and staggered-pitch) and tongues (wedge- shape and saw-tooth shape), and four different tongue clearances (ε=3mm, 5mm, 7mm, and 10mm) are also tested. At Ω≥ 1200 r/min, a screech tone produced from the peak sound pressure levels at the harmonics of blade passage frequency always occurs for the cross- flow fan with the fixed-pitch rotor, the wedge shape, and ε=3 mm. At Ω≥1200 r/min, the sound pressure level at the first harmonic of blade passage frequency is significantly reduced by either replacing the fixed- pitch rotor with the staggered-pitch one as well as replacing the wedge shape with the saw-tooth tongue or enlarging the tongue clearance. However, the overall sound pressure level from the cross-flow fan to deliver the same air flow rate is slightly changed with geometrical parameters varied in this study.