Characteristics of the aerodynamics and the noise of dual-cascade centrifugal fan have been experimentally investigated with respect to the effects of the bare ratio and the outlet angle of scroll casing. It was shown that the performance of the fans became best when the bare ratio was around between 9% to 25%, then the characterisitics of the dualcascade centrifugal fan were superior to that of the single-cascade centrifugal fan. The former was little influenced by the different bare ratio and the fans were able to be widely designed in comparison with the latter, the both characterisitics were improved when the outlet angle was 20 degrees.
Medical Subject Headings: human activities
free text keywords: Dual-cascade Centrifugal Fan, Noise, Internal Flow, Specific Noise, Scroll Casing