Tip shrouds of turbine rotor blades and methods of manufacture related thereto

Abstract

A rotor blade for use in a turbine of a turbine engine is described. The rotor blade may include an airfoil that extends from a connection with a root. The airfoil may include a pressure sidewall and a suction sidewall that define an outer periphery and an outboard tip. The rotor blade may further include a tip shroud assembly disposed at the outboard tip of the airfoil. The tip shroud assembly includes a non-integral tip shroud.

1 . A rotor blade for use in a turbine of a turbine engine, the rotor blade comprising an airfoil that extends from a connection with a root, the airfoil including a pressure sidewall and a suction sidewall that define an outer periphery and an outboard tip, the rotor blade further comprising:
 a tip shroud assembly disposed at the outboard tip of the airfoil;   wherein the tip shroud assembly includes a non-integral tip shroud.   
     
     
         2 . The rotor blade according to  claim 1 , wherein the tip shroud assembly includes one of a weld and a braze connection between the non-integral tip shroud and the outboard tip of the airfoil. 
     
     
         3 . The rotor blade according to  claim 1 , wherein the non-integral tip shroud comprises a detachable tip shroud. 
     
     
         4 . The rotor blade according to  claim 3 , wherein the tip shroud assembly includes a mechanical interference joint formed between the detachable tip shroud and the outboard tip of the airfoil. 
     
     
         5 . The rotor blade according to  claim 4 , wherein the mechanical interference joint comprises a dovetail joint in which a flared tenon engages a mortise. 
     
     
         6 . The rotor blade according to  claim 5 , wherein the dovetail joint is configured such that the flared tenon engages the mortise so to oppose radial separation between the detachable tip shroud and the outboard tip of the airfoil;
 wherein the flared tenon includes a tang.   
     
     
         7 . The rotor blade according to  claim 6 , wherein an engaged flared tenon and mortise comprise a tenon-mortise pairing; and
 wherein the dovetail joint comprises a plurality of tenon-mortise pairings.   
     
     
         8 . The rotor blade according to  claim 6 , wherein the flared tenon comprises an elongated rail and the mortise comprises an elongated groove; and
 wherein the flared tenon engages the mortise via sliding in a direction of a longitudinal axis of the elongated rail.   
     
     
         9 . The rotor blade according to  claim 6 , wherein the tenon and the mortise are configured such that the tenon slidably engages the mortise with one of: axial movement; circumferential movement; and movement that has both axial and circumferential components. 
     
     
         10 . The rotor blade according to  claim 9 , further comprising an assembly opening that resides adjacent to the mortise;
 wherein the assembly opening comprises an opening configured to accept the flared tenon so that, during installation, the flared tenon may be brought inboard to a radial height of the mortise and slidably engaged therein.   
     
     
         11 . The rotor blade according to  claim 9 , wherein the tenon and the mortise are configured such that the mortise slidably engages the tenon with circumferential movement that is opposite a direction of rotation for the rotor blade in operation. 
     
     
         12 . The rotor blade according to  claim 6 , wherein the mortise is disposed on the outboard tip of the airfoil and the flared tenon projects from an inboard surface of the tip shroud; and
 wherein the flared tenons engage the mortises via rotation movement of the tips shroud relative to the airfoil.   
     
     
         13 . The rotor blade according to  claim 6 , wherein the flared tenon projects from the outboard tip of the airfoil and the mortise is disposed on the inboard surface of the tip shroud. 
     
     
         14 . The rotor blade according to  claim 4 , wherein the mechanical interference joint comprises a pin configuration. 
     
     
         15 . The rotor blade according to  claim 14 , wherein the pin configuration comprises a radial pin that extends through the tip shroud from a position on an outboard surface of the tip shroud, the radial pin engaging an opening formed in the outboard tip of the tip shroud. 
     
     
         16 . The rotor blade according to  claim 14 , wherein the pin configuration includes the tip shroud and the outboard tip of the airfoil having structure that overlaps radially, and a pin extends in the circumferential and/or axial direction through the structure that overlaps radially;
 wherein the pin configuration comprises a tab projecting from an inboard surface of the tip shroud that is configured to engage a slot formed in the outboard tip of the airfoil;   wherein the tab includes an aperture formed therethrough and the slot includes an aperture formed in a sidewall, the aperture of the tab and the aperture of the sidewall aligning upon fitting the tab in the slot so to form a pin channel;   wherein the pin extends through the pin channel; and   wherein the pin channel includes an opening formed through at least one of the pressure sidewall and the suction sidewall of the airfoil, the opening being configured as an insertion point for the pin during assembly and disassembly of the mechanical interference joint.   
     
     
         17 . The rotor blade according to  claim 14 , wherein the pin configuration includes the tip shroud and the outboard tip of the airfoil having structure that overlaps radially, and a pin extends in the circumferential and/or axial direction through the structure that overlaps radially;
 wherein the pin configuration comprises a tab projecting from the outboard tip of the airfoil that is configured to engage a slot formed in an inboard surface of the tip shroud;   wherein the tab includes an aperture formed therethrough and the slot includes an aperture formed in a sidewall of the slot, the aperture of the tab and the apertures of the sidewall aligning upon engagement of the tab in the slot so to form a pin channel; and   wherein the pin extends through the pin channel.   
     
     
         18 . The rotor blade according to  claim 4 , wherein the mechanical interference joint includes an integral stem extending from the outboard tip of the airfoil, wherein the integral stem comprising structure formed integrally to the airfoil that is used to connect the detachable tip shroud to the airfoil; and
 wherein the integral stem comprises a tab that includes an aperture formed therethrough, wherein the mechanical interference joint comprises a pin configuration.   
     
     
         19 . The rotor blade according to  claim 4 , wherein the mechanical interference joint includes an integral stem extending from the outboard tip of the airfoil, wherein the integral stem comprising structure formed integrally to the airfoil that is used to connect the detachable tip shroud to the airfoil;
 wherein the integral stem comprises a looped rail, the looped rail including two radially extending posts that are connected by a crossbar, the radially extending posts having a predetermined radial height such that the crossbar is offset a predetermined distance from the outboard tip of the airfoil; and   wherein the detachable tip shroud is configured having an opening formed therein through which the looped rail passes, which is configured to allow the detachable tip shroud to slide inboard to a seated position atop the outboard tip of the airfoil   
     
     
         20 . The rotor blade according to  claim 19 , wherein the slot and the posts are configured to oppose relative circumferential and axial movement between the detachable tip shroud and the airfoil once the detachable tip shroud comprises the seated position;
 further comprising a locking bar configured to pass between a rail slot of the rail, the locking bar configured to engage an outboard surface of the tip shroud and the crossbar so to oppose radial separation between the detachable tip shroud and the outboard tip of the airfoil.   
     
     
         21 . The rotor blade according to  claim 20 , wherein the looped rail is aligned with a circumferential direction of the turbine engine; and
 wherein the looped rail is configured to comprise a seal rail.   
     
     
         22 . The rotor blade according to  claim 20 , further comprising an additional looped rail;
 wherein a first looped rail engages a first end of the locking bar and a second looped rail engages a second end of the locking bar.   
     
     
         23 . The rotor blade according to  claim 3 , wherein an interior cooling passage extends through the airfoil from a connection to an air source made through the root of the rotor blade to an outlet formed at the outboard tip of the airfoil; and
 wherein the detachable tip shroud includes an interior cooling passage that extends from an inlet formed at an inboard surface of the tip shroud;   wherein the outlet formed at the outboard tip of the airfoil and the inlet formed at the inboard surface of the detachable tip shroud are configured to align once the detachable tip shroud is fitted to the airfoil.   
     
     
         24 . A method of manufacturing a rotor blade for use in a turbine of a combustion turbine engine, the rotor blade comprising an airfoil that extends from a connection with a root, the airfoil including a pressure sidewall and a suction sidewall that define an outer periphery and an outboard tip, the method comprising the steps of:
 manufacturing the rotor blade with connecting means at the outboard tip of the airfoil;   manufacturing the tip shroud to have corresponding connecting means at an inboard surface of the tip shroud; and   connecting the tip shroud to the airfoil via the connecting means of the airfoil and the corresponding connecting means of the tip shroud;   wherein the connecting means of the airfoil and the connecting means of the tip shroud together comprise a mechanical interference joint.   
     
     
         25 . The method according to  claim 24 , further comprising the steps of:
 during the step of manufacturing the rotor blade, casting interior cooling channels within the rotor blade; and   during the step of manufacturing the tip shroud, casting interior cooling channels within the tip shroud.