tailieunhanh - UNSTEADY AERODYNAMICS, AEROACOUSTICS AND AEROELASTICITY OF TURBOMACHINES Episode 13

Tham khảo tài liệu 'unsteady aerodynamics, aeroacoustics and aeroelasticity of turbomachines episode 13', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Two-Stage Turbine Experimental Unsteady Stator-to-Stator Interaction 623 speeds. The differences are visible for all speeds and the shape of the curves is similar showing the visible drop in the near the walls regions especially nearby the hub. From earlier studies it is known that the turbulence level is very high in these regions Krysinski et al. 2001 . Fig. 12 b and c show the efficiency changes due to the clocking effect at different ft w channel heights. The variations in the region near the hub are about 1 . Along the height of the ft w channel the variations of the turbine efficiency are phase shifted. This shift makes the overall efficiency variation to be small and not clearly visible. If the shift does not exist that means across the ft w channel height the efficiency obtains maximum value at the same clocking position for the nominal rotating speed we will obtain the efficiency benefit about . Figure 12. Measured thermodynamic turbine efficiency along the height of the fl w channel for different rotational speeds left and for different clocking positions middle and right Figure 13. a Stator and rotor leading edge LE and trailing edge TE compared to the radial direction RL b Results of the numerical calculation downstream the first stator and the first rotor 5. Conclusions Two-stage low-pressure turbine at the Institute of Turbomachinery Technical University of Lodz Poland was prepared for experimental investigations of the stator-to-stator clocking effect. Special attention was directed into machine work conditions and strictly constant inlet conditions especially in-let outlet pressure ratio. The changes due to the ft w blocking effect were re- 624 duced with the help of special inlet condition control system. Continuation of earlier experimental investigations of the stator-to-stator interaction has been performed in the axial gaps on the vane profile and outer casing. The results of precise measurements of the power and torque output differed .