Abstract: Methods and apparatus for cooling gas turbine rotor blades is provided. The blade includes an airfoil having an internal three pass serpentine cooling circuit having radially extending first, second, and third serpentine cooling cavities partially separated by, in axially aft succession, a first radially extending internal rib and a second radially extending internal rib. The serpentine cooling circuit includes a first inlet in flow communication with the first cavity and a second inlet in flow communication with at least one of the second and third cavities wherein the first and second inlets are formed during casting of the airfoil.

Abstract: Methods and apparatus for cooling gas turbine rotor blades is provided. The rotor blades include an airfoil having a pressure sidewall and a second suction sidewall connected together at a leading edge and a trailing edge, such that an internal three pass serpentine cooling circuit is formed therebetween. The cooling circuit includes radially extending first, second, and third serpentine cooling cavities partially separated by, in axially aft succession, a first radially extending internal rib and a second internal rib. The second rib includes a radially inner first portion and a radially outer portion wherein the radially outer portion is angled obliquely with respect to the first portion.

Abstract: A method for assembling a gas turbine engine includes coupling a rotor assembly including a plurality of rotor blades about a rotatable main shaft of the gas turbine engine. The main shaft is aligned in an axial direction of the gas turbine engine. A shroud assembly is coupled to the gas turbine engine. The shroud assembly includes a plurality of shroud segments circumferentially coupled about the rotor assembly such that a shroud spacing gap is formed in the axial direction between adjacent shroud segments. A cooling fluid source is coupled to each shroud segment such that cooling fluid is channeled through each shroud segment into a corresponding shroud spacing gap to facilitate positive purge flow through the shroud spacing gap.