Cooling circuit for a large highly twisted and tapered rotor blade

摘要

A large turbine blade having a large amount of taper and twist, the blade having a internal cooling circuit that includes an axial flow serpentine flow passage in the lower span and a plurality of radial flow channels in the upper span such that the cooling air flow is always passing toward the blade tip. During blade rotation, the cooling air is forced upward and the pressure increases from the centrifugal force to allow for a lower cooling air supply pressure. The axial flow serpentine flow passage includes a series of forward and aft flowing axial channels that extend from the leading edge to the trailing edge such that the cooling air flow in a back and forth direction. The cooling air from the axial flow channels passes into the plurality of radial flow channels formed by radial extending ribs, and then out through blade tip cooling holes. The axial flow channels are formed by axial extending ribs that provide chordwise sectional strength to prevent the blade from un-twisting.