Abstract
The present study intended mechanism clarification of blade passing frequency (BPF) noise generation in wing profile centrifugal blower. First, visualized flow in the vicinity of cut-off that source of BPF noise brought out relation between blade passing and flow. Next, fluctuating pressure on cut-off surface was measured by probe microphone. Distribution of fluctuating pressure pinpointed major source of BPF noise. Measurement of fluctuating pressure on cut-off by probe microphone and detection of blade position by laser brought out relation between blade passing and fluctuating pressure. Measuring transfer function in casing cleared that the noise was amplified by resonance.
