Turbine wheel with clamped blade attachment

Abstract

A turbine wheel for use in a gas turbine engine having a plurality of blades attached to a rotor disk. Each blade is formed from a composite comprising ceramic matrix material. The blades each include a root that fits within dovetail slots of the rotor disk and cooperates with a blade retention assembly to couple the blades to the rotor disk.

What is claimed is: 
     
         1 . A turbine wheel for a gas turbine engine, the turbine wheel comprising
 a disk formed to include a dovetail slot that extends through the disk in an axial direction from a forward side to an aft side of the disk and inwardly in a radial direction from an outer diameter of the disk toward a central axis,   a blade comprising ceramic-containing materials, the blade formed to include an airfoil that extends outwardly in the radial direction from the outer diameter of the disk and a root that extends into the dovetail slot, the root including a stem that extends from the airfoil into the dovetail slot and at least one engagement surface extending from the stem, and   a blade retention assembly including at least two clamp blocks positioned to receive portions of the root of the blade and to be received in the dovetail slot of the disk so that centrifugal forces applied to the blade when the turbine wheel is rotated about the central axis are transferred from the at least one engagement surface through the blade retention assembly to the disk.   
     
     
         2 . The turbine wheel of  claim 1 , wherein the clamp blocks are formed to include recesses, each of the recesses positioned to receive at least a portion of the root of the blade. 
     
     
         3 . The turbine wheel of  claim 2 , wherein the at least one engagement surface includes a first engagement surface and a second engagement surface positioned opposite of the first engagement surface. 
     
     
         4 . The turbine wheel of  claim 3 , wherein each of the recesses is formed to match a profile created by the first and second engagement surfaces and positioned to engage the first and second engagement surfaces. 
     
     
         5 . The turbine wheel of  claim 3 , wherein one of the recesses of one of the clamp blocks is formed to match a profile created by the first engagement surface and positioned to engage the first engagement surface, and wherein the other recess of the other clamp block is formed to match a profile created by the second engagement surface and positioned to engage the second engagement surface. 
     
     
         6 . The turbine wheel of  claim 1 , further including a pin positioned to extend through the clamp blocks and the root. 
     
     
         7 . The turbine wheel of  claim 1 , wherein the blade further includes a platform positioned between the airfoil and the root. 
     
     
         8 . The turbine wheel of  claim 1 , wherein each clamp block further includes a platform portion positioned to extend circumferentially away from the blade. 
     
     
         9 . The turbine wheel of  claim 8 , wherein the recesses of the clamp blocks are formed at an angle relative to the dovetail slot. 
     
     
         10 . The turbine wheel of  claim 9 , wherein the dovetail slot is formed at a broach angle relative to the central axis, and wherein clamp blocks are arranged to position the airfoil of the blade at a greater relative angle to the central axis than the broach angle. 
     
     
         11 . A turbine wheel for a gas turbine engine, the turbine wheel comprising
 a disk formed to include a dovetail slot that extends through the disk in an axial direction from a forward side to an aft side of the disk and inwardly in a radial direction from an outer diameter of the disk toward a central axis,   a blade comprising ceramic-containing materials, the blade formed to include an airfoil that extends outwardly in the radial direction from the outer diameter of the disk and a root that extends into the dovetail slot, the root including a stem that extends from the airfoil into the dovetail slot and a retention head arranged in the dovetail slot that extends from the stem, and   a blade retention assembly including at least two clamp blocks that engage the retention head of the root and are received in the dovetail slot of the disk so that centrifugal forces applied to the blade when the turbine wheel is rotated about the central axis are transferred from the retention head through the blade retention assembly to the disk.   
     
     
         12 . The turbine wheel of  claim 11 , wherein the retention head extends axially out from the stem. 
     
     
         13 . The turbine wheel of  claim 12 , wherein the retention head extends circumferentially out from the stem. 
     
     
         14 . The turbine wheel of  claim 11 , wherein the dovetail slots include a pair of converging angled surfaces and a rounded inner surface connecting the angled surfaces, the angled surfaces extending radially outward from the rounded inner surface and toward one another. 
     
     
         15 . The turbine wheel of  claim 14 , wherein each of the clamp blocks includes a cam surface positioned to engage with one of the angled surfaces during rotation of the rotor disk about the central axis. 
     
     
         16 . The turbine wheel of  claim 15 , wherein the clamp blocks are formed to include recesses, each of the recesses positioned to receive at least a portion of the retention head and to form a gap between the clamp blocks when the blade retention assembly and root are received in the dovetail slot. 
     
     
         17 . The turbine wheel of  claim 11 , wherein the blade further includes a platform positioned between the airfoil and the root. 
     
     
         18 . The turbine wheel of  claim 11 , wherein each clamp block further includes a platform portion positioned to extend circumferentially away from the blade. 
     
     
         19 . A method of making a turbine wheel, the method comprising
 positioning a first clamp block to surround and engage at least a portion of a root of a composite blade,   positioning a second clamp block to surround and engage at least a different portion of the root than the first clamp block such that a gap is positioned between the first and second clamp blocks, the first and second clamp blocks forming a blade retention assembly, and   positioning the blade retention assembly in a dovetail slot of a rotor disk such that the blade retention assembly is positioned to engage the dovetail slot formed by the rotor disk to force the first clamp block toward the second clamp block to retain the blade in place relative to the rotor disk during rotation of the rotor disk.   
     
     
         20 . The method of  claim 19 , further comprising positioning a pin through the root of the blade and the first and second clamp blocks.