The Rotordynamic Forces on an Open-Type Centrifugal Compressor Impeller in Whirling Motion

摘要: In recent years, increasing interest has been given to the rotordynamic forces on impellers, from view point of shaft vibration analysis. Previous experimental and analytical results have shown that fluid-induced closed-type (with shroud) centrifugal impellers in whirling motion contribute substantially potential destabilization subsynchronous vibrations. However, date nothing is known open-type (without impellers. This paper examines fluid an compressor impeller motion. For impeller, variation tip clearance due main forces. Experiments were performed investigate by direct measurement using a force balance device, indirectly unsteady pressure casing wall over range whirl speed ratio (Ω/ω) for several flow rates. this paper, following obtained: (1) Destabilizing occur at small positive (0 < Ω/ω 0.3) throughout normal operation; (2) At smaller rate with inlet backflow, magnitude changes dramatically close Ω/ω=0.8, resulting destabilizing From pressure, it was drastic are related coupling rotating instability, similar stall; (3) The estimated distribution those difference across blades compared measurements. correlate better wall.