0410 インレットベーン付多段遠心ブロワで発生する非定常圧力変動に関する実験的研究(OS4-2 流体機械の研究開発とそれに関連した複雑流動現象,OS4 流体機械の研究開発とそれに関連した複雑流動現象)

Abstract

This study experimentally examines unstable flow phenomena occur in a five-stage centrifugal blower equipped with inlet guide vanes (IGV) before the first stage. Six high response pressure transducers were mounted on several parts of the blower to detect a surge and a rotating stall. We confirmed three types of pressure fluctuation in low flowrate region; deep surge, spike-like rotating stall, and mild surge. At 4.5 percent IGV opening condition, mild surge was observed in the steep negative slope region of the total system head curve, where the whole compression system was supposed to be stable. We considered that mild surge was caused by a balance between a stabilization effect of the first stage with prewhirl and a destabilization effect of the other stages that had no prewhirl and stalled.