Effects of Airfoil Clocking on Aero-performance and Unsteady Blade Loading in a High-Speed Axial Compressor

概要

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This paper investigates numerically the effects of airfoil clocking on aero-performance and unsteady blade loading in low-speed and high-speed compressor rotor-stator-rotor stages using a quasi-3D unsteady multi-stage Navier-Stokes code. In each of the 1.5-stage cases, four computations are performed at different clocking positions between the upstream rotor and the downstream rotor, in 25% blade-pitch increment. Computation of the low-speed case shows that the maximum efficiency is achieved when the upstream rotor wake impinges on the leading edge of downstream rotor, a similar efficiency variation trend with that of the previous studies for low-speed cascades. The high-speed case, on the other hand, indicates different efficiency variation trend from the low-speed case. Underlying mechanism is related to the change in the downstream rotor blade suction-surface shock strength depending on the path of the upstream rotor blade wake through the downstream rotor blade-to-blade passage. Furthermore, due to the change in the rotor shock strength, unsteady loading on the stator vane in between the two rotors is found to vary significantly. The present computation's ability to predict unsteady vane-surface pressures is also validated using in-house rig test data.
公益社団法人日本ガスタービン学会の論文
2005-11-20