3825 遠心送風機の低流量域不安定流動の抑制 : ガイドベーン付き入口環状溝の効果(J15-3 流体関連の騒音と振動(3)-ファン・はく離流れ-,J15 流体関連の騒音と振動,2005年度年次大会)

抄録

The inlet ring groove arrangement is one kind of casing treatment technique for suppression of unstable flow at small flow rates in a centrifugal blower. The suppression of unstable flow is achieved by the formation of inlet recirculation flow from the inducer tip throat to the blower inlet through the annular bypass. The tip leakage flow and the reverse flow in the inducer is sucked from the ring groove located near the inducer tip throat, in addition, the flow incidence is effectively reduced. In the present study, the effect of the pre-whirl induced by the recirculation flow on the flow incidence and the impeller characteristics are analyzed numerically. In order to change the swirl intensity of the recirculation flow, guide vane is installed in the flow passage of the ring groove arrangement. It is clearly shown that the flow incidence distribution between hub and shroud and the recirculation flow rate vary remarkably by changing the setting angle of the guide vane.