1999 Fiscal Year Final Research Report Summary

Effect of Flow in the Rotor on the Performance of a Sirocco Fan

Research Project

Project/Area Number	09650211
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Single-year Grants
Section	一般
Research Field	Fluid engineering
Research Institution	Osaka Sangyo University
Principal Investigator	ADACHI Tsutomu Osaka Sangyo University, Professor, 工学部, 教授 (50029394)
Co-Investigator(Kenkyū-buntansha)	SUGITA Naohiro Osaka Sangyo University, Assistant, 工学部, 助手 (90268251)
Project Period (FY)	1997 – 1999
Keywords	Sirocco fan / Flow angle and velocity / Flow in the blade passage / Measurement of flow velocity / Performance of fan
Research Abstract	Effects of blade shape on the performance of a Sirocco fan was measured using 9 runner blades with different blade shape in the same casing. These 9 different runner blades have inner diameter of 130 mm, outer diameter of 160 mm, and 46 mm in width. Considering from the velocity triangles at the blade inlet, the blade inlet angles are to be taken 10〜15°. For the runner blades with these values the efficiency was good, but large discharge couldn't be obtained. Inlet angle must be taken in the range of 75〜90°. The outlet angle is desired to be 150〜160°. For these runner blades flow flows along the blade surface, though it once separates at the leading edge and reattaches at the trailing edge. The flow velocity takes large value at the pressure surface and smaller values at the suction surface at the center of the blade width. Deviation angle, i.e., the difference of blade outlet angle and flow outlet angle, takes zero value, if proper design is conducted. The ratio of wake width to the blade pitch becomes larger, if the blade thickness is larger. If the blade outlet angle is larger than 160°, the outlet flow circulate. Inlet vortex arise because of the sudden flow turning at the blade inlet. The extent of inlet vortex is influenced by the inclination angle of blade. The inclination ratio,i.e., the ratio of blade inclination angle θand the inlet angle βィイD21ィエD2 is important. The maximum values of pressure and discharge can be obtained at (θ/βィイD21ィエD2) =0.35. Considering the above affairs, the values βィイD21ィエD2)=75〜90°, (θ/βィイD21ィエD2) =0.35 and βィイD22ィエD2=150〜160°are suitable for the blade design. The blade thickness must be thinner as possible.