遷音速タービン翼列の振動特性 : 第2報数値解析

概要

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The unsteady flow field around an oscillating blade of a transonic turbine cascade was numerically analyzed with a developed Euler code. The aim was to clarify the mechanism of vibration instability of the turbine blades found in the previous experiment. The numerical results were verified to well re-produce the unsteady flow fields obtained in the experiment in a qualitative sense. The vibration insta-bllity was found to come from the strong unsteady aerodynamic force in the midchord area of a blade, which was generated by the change of flow channel area due to the blade oscillation. When the shock wave from the adjacent blade impinged around the midchord position in an off- design flow condition, the phase angle of the unsteady force significantly changed between the upstream and the down-stream region of the shock. The vibration instability was thereby suppressed. When the oscillation fre-quency increased, the vibration was observed to become stable.
社団法人日本ガスタービン学会の論文
1999-01-20