High Efficiency Steam Turbines with Ultra Long Buckets

摘要

The ''High Efficiency Steam Turbines with Ultra Long Buckets'' program developed and analytically validated the conceptual designs for full-speed 54 inch steel-hybrid and 62 inch titanium-hybrid last stage buckets (LSBs). It identified, tested (both environmentally and operationally), and selected candidate lightweight filler materials suitable for steel and titanium LSBs, with extensibility to upstream bucket stages. To mitigate risk and accelerate the introduction of this technology, the project designed and built a full-scale demonstrator 33.5 inch steel-hybrid LSB, with an advanced 3-dimensional aerodynamic shape that may serve as the basis for the first introduction into service. The project included subscale testing of a stage of 33.5 inch buckets in the GE Energy Low Pressure Development Turbine (LPDT) facility. Preliminary investigation into high temperature materials was studied to broaden applicability of this technology. Finally, the program assessed the benefits of hybrid bucket technology including bucket/system dynamic tuning, damping and mid-span damping devices.