Numerical Research of Movement Characteristic and Deposition Ratio on Cylinder Wall of Secondary Water Droplet between Penultimate Stage and Last Stage

Secondary water droplet between the penultimate and last stage of a 300 MW steam turbine was researched by CFD on the basis of a two-phase flow mathematical model for steam and water droplet, and the Lagrangian methed was adopted to solve the discrete transport equation of water droplet. It indicated that secondary water droplet shows tendency to slop up to and get deposited on cylinder wall. The water deposition ratio on cylinder wall will be greater as the water droplets size increases or the blade height where the water droplets begin to move rises. Local deposition ratio increases as the blade height heightens according to the water deposition on cylinder wall behind penultimate stage and distribution of the secondary water droplet and steam moisture. (paper)