Turbine airfoil with single aft flowing three pass serpentine cooling circuit

A gas turbine engine airfoil comprising:

• an airfoil outer wall having width wise spaced apart pressure and suction side walls joined together at chordally spaced apart leading and trailing edges of said airfoil and extending radially from a radially inner base to a radially outer airfoil tip,
• a plurality of radially extending internal ribs extending width wise between said pressure and suction side walls;
• an internal single three pass serpentine cooling circuit having radially extending first, second, and third serpentine channels between, in axially aft succession, first, second, third, and fourth ribs of said radially extending internal ribs;
• said first, second, and third serpentine channels bounded by said first, second, third, and fourth ribs of said plurality of radially extending internal ribs and said pressure and suction side walls;
• said serpentine cooling circuit including an entrance and a terminal end wherein said terminal end is positioned aft of said entrance so as to have a chordal flow direction aftwards from said leading edge to said trailing edge within said serpentine circuit;
• a straight through single pass leading edge cooling channel located between said first rib, said leading edge, and said outer wall;
• said first serpentine channel and said leading edge cooling channel extending radially through said the base;
• a trailing edge cooling plenum located between an aftwardmost one of said plurality of internal transverse ribs and said trailing edge, and said pressure and suction side walls;
• a straight through single pass trailing edge feed channel located between said aftwardmost one of said internal transverse ribs and said fourth rib and extending radially through said base;
• and
• cooling air discharge apertures disposed in said aftwardmost one of said plurality of internal transverse ribs, said discharge apertures disposed between said trailing edge feed channel and said trailing edge cooling plenum.

A gas turbine engine blade comprising:

• a hollow airfoil extending radially outwardly from a root;
• said airfoil comprising;
• an airfoil outer wall having width wise spaced apart pressure and suction side walls joined together at chordally spaced apart leading and trailing edges of said airfoil and extending radially from a radially inner base to a radially outer airfoil tip,
• a plurality of radially extending internal ribs extending width wise between said pressure and suction side walls;
• an internal single three pass serpentine cooling circuit having radially extending first, second, and third serpentine channels between, in axially aft succession, first, second, third, and fourth ribs of said radially extending internal ribs;
• said first, second, and third serpentine channels bounded by said first, second, third, and fourth ribs of said plurality of radially extending internal ribs and said pressure and suction side walls;
• said serpentine cooling circuit including an entrance and a terminal end at an outer tip wall of the airfoil wherein said terminal end is positioned aft of said entrance and includes at least one tip cooling holes extending through said outer tip wall from said terminal end so as to have a chordal flow direction aftwards from said leading edge to said trailing edge within said serpentine circuit;
• a straight through single pass leading edge cooling channel located between said first rib, said leading edge, and said outer wall;
• and
• said first serpentine channel and said leading edge cooling channel extending radially through said base and root.

A gas turbine engine blade comprising:

• a hollow airfoil extending radially outwardly from a root;
• said airfoil comprising;
• an airfoil outer wall having width wise spaced apart pressure and suction side walls joined together at chordally spaced apart leading and trailing edges of said airfoil and extending radially from a radially inner base to a radially outer airfoil tip,
• a plurality of radially extending internal ribs extending width wise between said pressure and suction side walls;
• an internal single three pass serpentine cooling circuit having radially extending first, second, and third serpentine channels between, in axially aft succession, first, second, third, and fourth ribs of said radially extending internal ribs;
• said first, second, and third serpentine channels bounded by said first, second, third, and fourth ribs of said plurality of radially extending internal ribs and said pressure and suction side walls;
• said serpentine cooling circuit including an entrance and a terminal end wherein said terminal end is positioned aft of said entrance so as to have a chordal flow direction aftwards from said leading edge to said trailing edge within said serpentine circuit;
• a straight through single pass leading edge cooling channel located between said first rib, said leading edge, and said outer wall;
• said first serpentine channel and said leading edge cooling channel extending radially through said base and root;
• a trailing edge cooling plenum located between an aftwardmost one of said plurality of internal transverse ribs and said trailing edge, and said pressure and suction side walls;
• a straight through single pass trailing edge feed channel located between said aftwardmost one of said internal transverse ribs and said fourth rib and extending radially through said base and said root;
• and
• cooling air discharge apertures disposed in said aftwardmost one of said plurality of internal transverse ribs, said discharge apertures disposed between said trailing edge feed channel and said trailing edge cooling plenum.