Turbine bucket with platform leading edge scallop for performance and secondary flow, corresponding turbine wheel and method of controlling secondary purge air flow

摘要

A turbine bucket (64) includes a platform (80) and an airfoil (68). A leading edge of the platform (100) is circumferentially defined by a continuous curve forming at least one axially extending projection (102) and an adjacent recess (104), the axially-extending projection (102) located adjacent a leading edge (72) of the airfoil (68). A corresponding method of controlling secondary purge air flow is also provided.