Radial turbine assembly with ceramic matrix composite airfoils having circumferential dovetail retention
A radial turbine rotor incorporating ceramic matrix composite turbine blades is disclosed. The radial turbine rotor can include a dovetail shape retention features for coupling the ceramic matrix composite turbine blades to a central hub.
1 . A radial turbine rotor, the radial turbine rotor comprising:
a hub comprising metallic materials and the hub formed to include;
an annular shaft portion arranged around an axis,
a forward flange extending radially outward from the annular shaft portion and the forward flange having a first diameter, and
an aft flange spaced along the axis from the forward flange, the aft flange extending radially outward from the annular shaft portion, and the aft flange having a second diameter smaller than the first diameter;
wherein the annular shaft portion, the forward flange, and the aft flange of the hub are shaped to define a dovetail shape channel that extends annularly around the axis,
a plurality of turbine blades comprising ceramic matrix composite materials, each of the plurality of turbine blades shaped to include a dovetail root arranged in the dovetail shape channel of the hub and an airfoil that extends radially-outward for interaction with hot gases that flow over the radial turbine rotor during use, and
a retainer that contacts an aft face of the aft flange to block undesired withdrawal of the plurality of turbine blades from the dovetail shape channel, the retainer including a retention ring that forms a hoop around the axis.
2 . The radial turbine rotor of claim 1 , wherein the aft flange is shaped to include an assembly gap that extends along the axis and adjoins the dovetail shape channel, the assembly gap sized to accommodate insertion of a single one of the dovetail roots of the plurality of turbine blades into the dovetail shape channel during assembly of the radial turbine rotor.
3 . The radial turbine rotor of claim 1 , wherein the retention ring includes an annular washer portion that forms the hoop around the axis and a filler tab that extends parallel to the axis from the annular washer portion into the assembly gap of the aft flange.
4 . The radial turbine rotor of claim 1 , wherein the retainer further includes a shaft coaxial with the axis engaged with radially-inwardmost facing surfaces of both the hub and the retention ring to couple the hub, the plurality of turbine blades, and the retainer together for rotation about the axis.
5 . The radial turbine rotor of claim 1 , wherein each of the plurality of turbine blades is further formed to include a platform that extends circumferentially between the airfoils of adjacent turbine blades of the plurality of turbine blades to shield the hub radially inward of the platform.
6 . The radial turbine rotor of claim 5 , wherein each platform of the plurality of turbine blades is shaped to extend aft and radially outward of the aft flange to shield the aft flange of the hub radially inward of the platform.
7 . A radial turbine rotor, the radial turbine rotor comprising:
a hub that extends around a central axis, the hub shaped to define a dovetail shape channel that extends annularly around the central axis,
a plurality of turbine blades comprising ceramic matrix composite materials, each of the plurality of turbine blades shaped to include a dovetail root, each dovetail root of the plurality of turbine blades arranged in the dovetail shape channel of the hub, and each of the plurality of turbine blades further shaped to include an airfoil that extends radially-outward from the dovetail root, and
a retainer mounted axially adjacent to the hub to block withdrawal of the plurality of turbine blades from the dovetail shape channel, the retainer including a retention ring that forms a hoop around the central axis,
wherein the hub is shaped to include an assembly gap that extends along the central axis and adjoins the dovetail shape channel, the assembly gap sized to accommodate insertion of a single one of the dovetail roots of the plurality of turbine blades into the dovetail shape channel.
8 . The radial turbine rotor of claim 7 , wherein the retention ring includes an annular washer portion and a filler tab that extends from the annular washer portion into the assembly gap.
9 . The radial turbine rotor of claim 7 , wherein the retainer further includes a shaft engaged with radially-inwardmost facing surfaces of both the hub and the retention ring.
10 . The radial turbine rotor of claim 7 , wherein each of the plurality of turbine blades is further formed to include a platform that extends circumferentially between the airfoils of adjacent turbine blades of the plurality of turbine blades to shield the hub radially inward of the platform.
11 . The radial turbine rotor of claim 10 , wherein each platform of the plurality of turbine blades is shaped to extend aft and radially outward away from the central axis.
12 . The radial turbine rotor of claim 8 , wherein the washer portion forms the hoop around the central axis and the filler tab extends parallel to the central axis from the annular washer portion.
13 . The radial turbine rotor of claim 7 , wherein the retainer further includes a shaft engaged with a radially-inwardmost facing surface of the hub.
14 . The radial turbine rotor of claim 13 , wherein the shaft is further engaged with the retention ring to couple the hub and the retention ring.
15 . The radial turbine rotor of claim 14 , wherein the retention ring includes an annular washer portion and a filler tab that extends from the annular washer portion into the assembly gap of the aft flange.
16 . A radial turbine rotor comprising:
a hub that extends around a central axis, the hub shaped to define a dovetail shape channel that extends annularly around the central axis,
a plurality of turbine blades comprising ceramic matrix composite materials, each of the plurality of turbine blades shaped to include a dovetail root, each dovetail root of the plurality of turbine blades arranged in the dovetail shape channel of the hub, and each of the plurality of turbine blades further shaped to include an airfoil that extends radially-outward from the dovetail root,
a retainer including:
a filler tab that extends into an assembly gap formed in the hub, the assembly gap extending axially along the central axis and adjoining the dovetail shape channel, the assembly gap sized to accommodate insertion of a single one of the dovetail roots of the plurality of turbine blades into the dovetail shape channel,
a shaft that extends along the central axis, wherein the shaft is engaged with a radially-inwardmost facing surface of the hub and is configured to block movement of the of the filler tab relative to the hub so as to keep the filler tab from moving out of the assembly gap, and
a washer portion forming a hoop around the central axis and the shaft further engaged with the washer portion.
17 . The radial turbine rotor of claim 16 , wherein the filler tab and the washer portion cooperate to form a one-piece retainer ring in which the filler tab extends from the washer portion along the central axis.