BULLNOSE SEAL TURBINE STAGE

摘要

A bullnose type seal turbine stage is provided to raise the turbine efficiency by using a rotary sealing section interposed between a stator nozzle and a rotor blade. A bullnose type seal turbine stage comprises an annular stator nozzle(40) and blades(52). The annular stator nozzle includes vanes(42) mounted between an internal band(44) and an external band(46). The internal band has a mounting flange(48) extending radially inward from the internal band. The blades are mounted around a rotor disk(54), and are spaced apart from the mounting flange to form a front cavity(56) for guiding purge air. Each blade includes an internal platform(58) adjacent to the internal band in a rotary sealing section(60) disposed at the upper end of the front cavity in order to discharge the purge air. The internal band includes a stator bullnose at the rear edge thereof to reduce aerodynamic loss in cooperation with the rotary sealing section.