Abstract
Centrifugal Turbo-Blower is able to produce high pressure, but operation sound of it is bigger than that of other blowers. The mechanism of the noise generation has to be elucidated in order to decrease that noise. In this study, we focus on lap area (gap between inlet pipe and impeller) which affects blower noise, and investigate the noise at lap area by measurement of sound level and numerical analysis. As a result, we found that there is a re-entrant flow from casing to impeller at lap area, and the interaction between the re-entrant flow and a suction flow causes the noise.
