Development of Adaptive Acoustic Impedance Control Technologies of Acoustic Duct Liner
Figure 15
Effect of tunable perforated plate hole diameter on overall fan noise reduction by adaptive duct liner II of AAC technology II model. Fan rotational speed 4000 rpm; acoustic measuring point 60 deg.; fixed perforated plate hole dia. = 1.0; pitch = 2.0; acoustic absorbent material stuck on plate; poal + acousticel.