Fluid Dynamic Characteristics of a Malti-Blade Radial Fan : 1st Report : Effects of the inner diameter, the number of blades and the volute angle of scroll casing on the characteristics of fluid dynamics

The impeller of this fan is consisted of many thin plate radial blades. This fan could make the separation of blade surface flow controlled at low flow and the wake behind the blade diffused in short distance. Therefore it is expected that the fan noise become lower at whole flow rate than ordinary centrifugal fans. Experimental investigations of the fluid dynamic characteristics of malti-blade radial fans were conducted to the effects of three parameters : (1) the inner diameter (D_i) of impeller, (2) the number of blades (B), (3) the volute angle (α) of scroll casing. It was experimentally shown that the condition of D_i=58mm, B=120, α=4.5 gave the highest fan efficiency and pressure coefficient over the most flow rate region in those experiments