Water Droplets Dispersion and Optimization of Water Removal Suction Slot Locations on Stationary Blades in Last-Stage of a 600 MW Steam Turbine

Water droplets dispersion through a stationary cascade channel and their deposition on the blade surface in the last-stage of a 600MW steam turbine have been simulated with CFD software FLUENT. So the deposition on stationary blades along the axial and radial direction was determined. In the experiment, the performance of water removal by suction slots on stationary blades surface was investigated. The results showed that: 12.2% of water at the inlet still existed as droplets, depositing on the concave side of the airfoils in contrast with only 1.6% on the convex side. The volume of the water removed by the suction slots on the concave side was bigger than that on the convex side. The closer the slot position was to the trailing edge, the bigger the volume was. The volume became smaller and then larger with the increase in slot width; the minimum value occurred when slots were about 3.0 mm in width. The bigger suction pressure difference would initiate a bigger volume of water removed by suction slots, but the increase in main flow rate would quickly initiate a smaller volume.Copyright © 2009 by ASME