Optimization of stator blade profile design for last stages of steam turbines based on the features of coarse droplets movement in inter-blade channels

Results of the investigation of coarse droplets movement in steam turbine blade passages are presented in the paper. The structure of generated streams of secondary droplets was considered. The analysis of the effect of these streams on the liquid film formation on the blade surfaces was performed. On the basis of obtained data, several recommendations for blade design operating in wet steam conditions were formulated. They were used to optimize the baseline profile geometry in order to control the coarse droplets streams and provide the increasing of liquid film suction effectiveness. The numerical and experimental comparison of the baseline and optimized geometries was performed.