Effect of Turbine Inlet Pressure Fluctuation on Blade Vibration for a Marine Turbocharger

Abstract

One of the important goals in the design of a turbocharger is to reduce the resonance stress of the turbine blade. The resonance stress is influenced greatly by fluctuations of total pressure at the inlet of the blade. In this study, we have compared two kinds of mixed-flow type casings, Type-α and Type-β, that differ only in tongue geometry. Because of this difference, each casing creates a different pressure distribution at the blade inlet. Total pressure was measured at various circumferential locations in the two turbine casings. Then Fourier analysis was used to calculate the excitation force component caused by the total pressure fluctuations. Also, resonance stress was measured for the turbine blade for each casing. The experiments showed that the Type-β casing experienced higher total pressure fluctuations and produced higher blade resonance stress than the Type-α casing.