A Study of Steam Turbine Droplet Formation, Shedding and Blade Impact

Blade erosion is a serious problem in steam turbines and reduces the life of turbine, requiring periodic maintenance. A fundamental experiment is being performed to evaluate effects of certain control parameters on the droplet formation process and distribution of the shed droplets sizes. Three blade coatings include Epoxy, Teflon®, Viton®, three trailing edge geometries and a new and innovative trailing edge effect are to be experimentally studied. Measurements are to be made in a simulated stationary cascade utilizing real turbine components. The condensed liquid film and the large droplets formed on the three coated blades and one original finish blade will be optically measured. A typical cascade is modeled using Volume of Fluid with different surface properties used to model the formation and breakup of a thin water layer into droplets. Droplet distributions for the various conditions will be compared and the best surface finish and configurations will be identified. Most importantly, the reason for a successful configuration will be given, based on the measurement results.