HIGH-SPEED AERODYNAMIC INVESTIGATION OF THE MIDSECTION OF A 48" ROTOR BLADE FOR THE LAST STAGE OF STEAM TURBINE

A blade cascade representing midspan section of long rotor blading (48 '') was investigated experimentally in a high-speed aerodynamic wind tunnel and numerically by means of commercial code. In the experimental part, both optical and pneumatic measurements were performed. Measured data were evaluated and different aerodynamic characteristics were obtained. Velocity characteristics determined inlet parameters namely for subsonic regimes and for aerodynamic choking. Exit angle characteristics provided important information about flow parameters downstream of the blade cascade for comparison of design and off-design conditions. Quality of energy transfer was evaluated from kinetic energy loss coefficient characteristics. Selected results of experiments were compared to 2D numerical simulations. Discussion based on synthesis of relevant results is mainly concerned with influence of high-speed flow field structures and their development on the performance of the blade cascade and study of flow at shock wave/boundary layer interaction on the suction side of the profile.