Measurement and Analysis of Three-Dimensional Flow in a Centrifugal Fan Volute at Low Flow Rate
Cao Shuzhen£¬Qi Datong£¬Zhang Yiyun£¬Wen Suping£¬Lu Yubei£¬Zou Lin
(School of Energy and Power Engineering,Xi'an¡¡Jiaotong¡¡University,Xi'an  710049,China)

Abstract£ºThe 3D flow in a centrifugal fan volute, which has big volute width and rectangular cross section, has been measured in detail by means of fiveª²hole probe at 1600 r/min and low flowrate. The time-average velocity, static and total pressure distibutions in 38 cross sections along the throughflow direction of the volute are presented. These results show some peculiar flow phenomena. Under the condition of low flowrate, the swirling flow has been formed in the cross section at the volute tongue, and along the throughflow direction, the number of swirls in a cross section is increased progressively from one to two, even to three. In the cross sections of volute, the velocity distributions along radial direction are different from the law of conservation of mumentum. Near the area of volute tongue, the velocity and pressure distributions are different obviously form the original understanding. The types of main hydraulic losses in this kind of fan volute at low flowrate may be preliminarily suggested as swirling flow loss, inner leakage loss, shock loss and friction loss. Under the condition of low flowrate, the losses due to swirling flow and inner leakage are usually higher than the others.
Keywords£ºcentrifugal fan£»volute£»low flowrate£»measurement and analysis of flow