Effect of clocking on the unsteady rotor blade loading in a 1.5-stage low-speed axial compressor

This paper presents the effect of clocking on the unsteady loading of the rotor blades in the first stage with an inlet guide vane row (IGV) of the Dresden Low-Speed Research Compressor (LSRC). The unsteady flow field of the Dresden LSRC at 10 IGV clocking positions for the design point was investigated using a 3D time-accurate viscous solver. The time-averaged pressure distributions on the pressure side (PS) and the suction side (SS) of the rotor blades at midspan (MS) are presented for different clocking positions. The effect of the clocking on the time-averaged Root Mean Square-value (RMS) of the unsteady pressure fluctuations of the rotor blades at MS is investigated. The unsteady pressure fluctuations on the PS and the SS of the rotor blades at MS for different clocking positions are presented and discussed. The unsteady blade pressure forces on the rotor blades, which are calculated from the profile pressure distributions, are presented and analysed for different clocking positions. The maximal fluctuation amplitude of the unsteady pressure forces on the rotor blades, which fluctuate around the nearly identical mean values for different clocking positions, can be reduced about 60 percent with the IGV clocking for the design point in the investigated configuration. The effect of the clocking on the time-resolved inlet- and outlet flow fields of the rotor blades is investigated and discussed.