Improving the Efficiency of a Steam Turbine with the Use of a Grooved Surface to Increase the Deposition on the Separators in the Last Stage of Steam Turbines

This paper presents the development and improvement methodologies of wet-steam turbines in modern power plants. This may be accomplished by reducing the erosion of the nozzle and rotor blades and increasing the deposition after the droplet impacts with the surface of a separator. Reducing the erosion of the rotor blades in the last stage of the steam turbine depends on the increase of moisture separation in front of the rotor blades. The deposition of a drop onto a surface after the impact depends on various factors, including the drop's properties, the droplet's normal velocity upon the impact, and the surface type. The deposition after impact on different surfaces and four droplet regimes after impact are discussed. The results of the change in the deposition amount after the impact of drops of different diameters on a grooved and flat surface are discussed and compared with the impact results on the flat surface. Finally, recommendations are made as to the ideal angle in which the grooved surface should be placed in front of the impact of a drop to cause the most deposition and minimize surface erosion.