Aerodynamic and Noise Characteristics of a Multi-Blade Centrifugal Fan
抄録
The effects of a volute angle of scroll casing and a groove on the suction surface of blades were investigated relating to the characteristics of aerodynamics and noise of a multi-blade centrifugal fan with forward swept blades. It was shown that in the aerodynamic characteristics, the optimal volute angle existed between 4.8 and 7.2 degrees, and in the characteristics of noise, that existed in the near 7.2 degrees. The wake width of grooved blade fan became narrower than that of the ordinary blade fan. Therefore, the grooved blade fan was superior in noise characteristics to the ordinary blade fan. Using the method of predicting width of wake and the formulae to estimate the turbulent noise level which we proposed in this paper, the sound pressure level can be predicted with the accuracy of about ±3dB within these experiments.