Airfoil attachment for turbine rotor
A turbine for a gas turbine engine includes, among other things, a shaft rotatable about a longitudinal axis, a turbine rotor including one or more rows of turbine blades and a disk assembly coupled to the shaft. The disk assembly includes one or more disks each having an attachment region extending radially between an inner boundary and an outer boundary, the outer boundary is established by an outer periphery of the respective disk, the attachment region defines an array of slots distributed about the outer periphery, each of the slots extends radially inwardly from the outer boundary to the inner boundary, and each of the slots is dimensioned to receive a root section of a respective one of the turbine blades to mount the turbine blades to the disk assembly.
1. A turbine for a gas turbine engine, comprising:
a shaft rotatable about a longitudinal axis;
a turbine rotor including one or more rows of turbine blades and a disk assembly coupled to the shaft, wherein each of the turbine blades includes an airfoil section extending radially outwardly from a root section relative to the longitudinal axis, and each of the turbine blades comprises a ceramic matrix composite (CMC) material;
wherein the disk assembly includes one or more metallic disks each having an attachment region extending radially between an inner boundary and an outer boundary, the outer boundary is established by an outer periphery of the respective disk, the attachment region defines an array of slots distributed about the outer periphery, each of the slots extends radially inwardly from the outer boundary to the inner boundary, and each of the slots is dimensioned to receive the root section of a respective one of the turbine blades to mount the turbine blades to the disk assembly;
wherein the inner boundary establishes a live rim radius relative to the longitudinal axis, the outer boundary establishes a dead rim radius relative to the longitudinal axis, each of the one or more disks establishes a disk ratio of the live rim radius to the dead rim radius, and the disk ratio is greater than or equal to 0.8:1 for at least one disk of the one or more disks; and
wherein the attachment region includes an array of attachment members that define the array of slots, a minimum width of each of the attachment members establishes a first width, a minimum width of each of the slots establishes a second width, and a ratio of the first width of each one of the respective attachment members to the second width of an adjacent one of the slots is less than or equal to 0.5:1.
2. The turbine as recited in claim 1 , wherein the one or more rows of turbine blades includes a plurality of rows of turbine blades distributed axially with respect to the longitudinal axis, the one or more disks includes a plurality of disks that mount respective rows of the plurality of rows of turbine blades, and the at least one disk establishing the disk ratio includes an aftmost one of the plurality of disks relative to the longitudinal axis.
3. The turbine as recited in claim 2 , wherein the disk ratio is greater than or equal to 0.8:1 for each one of the plurality of disks in the turbine.
4. The turbine as recited in claim 3 , wherein each of the rows of turbine blades establishes a radial distance between the longitudinal axis and a radially outermost portion of the turbine blades and establishes a blade ratio of the dead rim radius to the radial distance, and the blade ratio is less than or equal to 0.5:1 for at least an aftmost row of the plurality of rows of turbine blades.
5. The turbine as recited in claim 4 , wherein the disk ratio is greater than or equal to 0.85:1 and is less than or equal to 0.95:1 for each one of the plurality of disks in the turbine.
6. The turbine as recited in claim 5 , wherein a cross-sectional area is defined at a downstream end of the turbine rotor, the turbine rotor is rotatable at a first speed measured at an engine redline condition, a performance quantity is defined by the cross-sectional area multiplied by the first speed squared, and the performance quantity is equal to or greater than 5.0×10 2 in 2 rpm 2 .
7. The turbine as recited in claim 1 , wherein each of the one or more rows of turbine blades includes at a quantity of least 40 but no more than 70 turbine blades.
8. The turbine as recited in claim 1 , wherein:
a total number of the rows of turbine blades includes at least three rows, but no more than six rows; and
the shaft interconnects the disk assembly and a geared architecture that drives a propulsor for propulsion.
9. The turbine as recited in claim 1 , wherein:
each of the attachments members includes a main body extending radially from a neck and includes a pair of protrusions extend circumferentially from opposite sides of the main body relative to the longitudinal axis;
the minimum width of each of the attachment members is established across the respective neck; and
the protrusions on opposite sides of the respective slot are dimensioned to establish the minimum width of the respective slot such that the protrusions cooperate to capture the root section in the slot.
10. A gas turbine engine comprising:
a propulsor section including a propulsor rotatable about an engine longitudinal axis;
a compressor section including a first compressor and a second compressor;
a turbine section including a first turbine and a second turbine, wherein the first turbine includes a first turbine rotor, and the second turbine includes a second turbine rotor; and
wherein at least one of the first turbine rotor and the second turbine rotor comprises:
one or more rows of turbine blades and a disk assembly, wherein each of the turbine blades includes an airfoil section extending from a root section, and each of the turbine blades comprises a ceramic matrix composite (CMC) material;
wherein the disk assembly includes one or more metallic disks each having an attachment region extending radially between an inner boundary and an outer boundary relative to the engine longitudinal axis, the outer boundary is established by an outer periphery of the respective disk, the attachment region defines an array of slots distributed about the outer periphery, each of the slots extending radially inwardly from the outer boundary to the inner boundary, and each of the slots is dimensioned to receive the root section of a respective one of the turbine blades to mount the turbine blades to the disk assembly;
wherein the inner boundary establishes a live rim radius relative to the longitudinal axis, the outer boundary establishes a dead rim radius relative to the longitudinal axis, each of the one or more disks establishes a disk ratio of the live rim radius to the dead rim radius, and the disk ratio is greater than or equal to 0.8:1 for the one or more disks; and
wherein the attachment region includes an array of attachment members that define the array of slots, a minimum width of each of the attachment members establishes a first width, a minimum width of each of the slots establishes a second width, and a ratio of the first width of each one of the respective attachment members to the second width of an adjacent one of the slots is less than or equal to 0.5:1.
11. The gas turbine engine as recited in claim 10 , wherein the second turbine rotor is axially aft of the first turbine rotor relative to the engine longitudinal axis, and further comprising:
a first turbine shaft interconnecting the first compressor and the first turbine rotor;
a geared architecture; and
a second turbine shaft interconnecting the geared architecture and the second turbine rotor such that the second turbine rotor drives the propulsor through the geared architecture.
12. The gas turbine engine as recited in claim 11 , wherein:
the second turbine comprises the at least one disk; and
a total number of the rows of turbine blades in the second turbine includes at least three rows, but no more than six rows.
13. The gas turbine engine as recited in claim 12 , wherein:
at least one of the rows of turbine blades is a row of shrouded turbine blades.
14. The gas turbine engine as recited in claim 10 , wherein:
each of the one or more rows of turbine blades includes a quantity of at least 25 but no more than 100 turbine blades.
15. The gas turbine engine as recited in claim 14 , wherein the disk ratio is less than or equal to 0.95:1 for each disk of the one or more disks in the second turbine.
16. The gas turbine engine as recited in claim 14 , wherein the one or more rows of turbine blades includes a plurality of rows of turbine blades, each of the rows of turbine blades establishes a radial distance between the engine longitudinal axis and a radially outermost portion of the turbine blades and establishes a blade ratio of the dead rim radius to the radial distance, and the blade ratio is less than or equal to 0.5:1 for at least an aftmost row of the plurality of rows of turbine blades.
17. The gas turbine engine as recited in claim 16 , wherein the second turbine rotor is axially aft of the first turbine rotor relative to the engine longitudinal axis, and further comprising:
a first turbine shaft interconnecting the first compressor and the first turbine rotor;
an epicyclic geared architecture; and
a second turbine shaft interconnecting the geared architecture and the second turbine rotor such that the second turbine rotor drives the propulsor through the geared architecture.
18. The gas turbine engine as recited in claim 10 , wherein the propulsor is a fan, and a fan case surrounds the fan to define a bypass duct.
19. The gas turbine engine as recited in claim 18 , wherein:
the second turbine comprises the at least one disk; and
a total number of the rows of turbine blades in the second turbine includes at least three rows, but no more than six rows.
20. The gas turbine engine as recited in claim 10 , wherein:
each of the attachments members includes a main body extending radially from a neck and includes a pair of protrusions extend circumferentially from opposite sides of the main body relative to the longitudinal axis;
the minimum width of each of the attachment members is established across the respective neck; and
the protrusions on opposite sides of the respective slot are dimensioned to establish the minimum width of the respective slot such that the protrusions cooperate to capture the root section in the slot.