出口円管付環状翼列下流に生じる流体振動特性

抄録

A small centrifugal compressor with a high rotation speed is necessary for the 100-kW class gas turbine, and variable inlet guide vanes (IGVs) should be installed at the inlet of such a compressor. Under lower flow rates, the vane angle (β₂) is set smaller in order to align the flow with the compressor blade motion, and flow instabilities having specific frequency characteristics appear and the performance of the compressor degrades. On the other hand, it is known that the periodic oscillation occurs in a suction pipe with swirling flow. This phenomenon is induced by spiral vortices. In this study, an attempt is made to clarify the relation between the flow instabilities downstream of annular inlet guide vanes and the swirling flow in a strait suction pipe. The influence of the suction pipe length on the oscillating characteristics of the flow downstream of IGVs is discussed based on the measured pressure fluctuation.