Rotating diffuser for pressure recovery in a steam cooling circuit of a gas turbine

摘要

The buckets (12a,14a,16a,18a) of a gas turbine are steam-cooled via a bore tube assembly (48,50) having concentric supply (52) and spent cooling steam return (54) passages rotating with the rotor (10). A diffuser (70) is provided in the return passage to reduce the pressure drop. In a combined cycle system, the spent return cooling steam with reduced pressure drop is combined with reheat steam from a heat recovery steam generator for flow to the intermediate pressure turbine. The exhaust steam from the high pressure turbine of the combined cycle unit supplies cooling steam to the supply conduit of the gas turbine. <IMAGE>