Turbine component having cooling passages with varying diameter

Abstract

Systems and devices configured to cool turbine components in a turbine by passing a cooling flow through the turbine component via a cooling passage with a variable diameter are disclosed. In one embodiment, a turbine component includes: at least one elongated cooling passage extending from a root of the bucket to a tip of the bucket, wherein the elongated cooling passage has a variable diameter along a length of the bucket.

What is claimed is: 
     
         1 . A turbine component comprising:
 a base portion; and   at least one elongated cooling passage extending from a root of the base portion to a tip of the base portion, wherein the elongated cooling passage has a variable diameter along a length of the turbine component.   
     
     
         2 . The turbine component of  claim 1 , wherein the at least one elongated cooling passage includes a Shaped Tube Electrochemical Machining (STEM) drilled passage. 
     
     
         3 . The turbine component of  claim 1 , wherein a diameter of the at least one elongated cooling passage varies incrementally between the root of the turbine component and the tip of the turbine component. 
     
     
         4 . The turbine component of  claim 1 , wherein the at least one elongated cooling passage has a frusto-conical shape. 
     
     
         5 . The turbine component of  claim 1 , wherein the at least one elongated cooling passage includes:
 a first section proximate the root, the first section having a first diameter, and a second section fluidly connected to the first section, the second section located proximate the tip and having a second diameter.   
     
     
         6 . The turbine component of  claim 5 , wherein the first diameter is larger than the second diameter. 
     
     
         7 . The turbine component of  claim 1 , wherein the at least one elongated cooling passage includes at least one turbulator disposed on a surface of the elongated cooling passage. 
     
     
         8 . The turbine component of  claim 7 , wherein the at least one turbulator includes at least one of: a segmented turbulator and a swirl shaped turbulator. 
     
     
         9 . The turbine component of  claim 1 , wherein the at least one elongated cooling passage includes a metering feature disposed substantially proximate the tip of the turbine component. 
     
     
         10 . A turbine bucket comprising:
 a root configured to connect to a turbine;   a base disposed on the root and configured to extend into a turbine flowpath, the base having an airfoil shape and including a tip; and   at least one elongated cooling passage formed in the root and the base, the at least one elongated cooling pass including:
 a first section disposed proximate the root and including an aperture at a terminus of the at least one elongated cooling passage, the first section extending into the base, and 
 a second section fluidly connected to the first section and disposed proximate the tip, wherein a second diameter of the second section is smaller than a first diameter of the first section. 
   
     
     
         11 . The turbine bucket of  claim 10 , wherein the at least one elongated cooling passage includes a Shaped Tube Electrochemical Machining (STEM) drilled passage. 
     
     
         12 . The turbine bucket of  claim 10 , wherein a diameter of the at least one elongated cooling passage varies incrementally throughout the first section and the second section. 
     
     
         13 . The turbine bucket of  claim 10 , wherein the at least one elongated cooling passage has a frusto-conical shaped passage and includes a metering feature. 
     
     
         14 . The turbine bucket of  claim 10 , wherein the first diameter is larger than the second diameter. 
     
     
         15 . The turbine bucket of  claim 10 , wherein the at least one elongated cooling passage includes at least one turbulator disposed on a surface of the elongated cooling passage. 
     
     
         16 . The turbine bucket of  claim 10 , wherein the at least one turbulator includes at least one of: a segmented turbulator and a swirl shaped turbulator. 
     
     
         17 . A turbine comprising:
 a stator;   a working fluid passage substantially surrounded by the stator;   a rotor disposed radially inboard of the stator and in the working fluid passage; and   a turbine bucket connected to the rotor, the turbine bucket including:
 at least one elongated cooling passage extending from a root of the turbine bucket to a tip of the turbine bucket, wherein the elongated cooling passage has a variable diameter along a length of the turbine bucket. 
   
     
     
         18 . The turbine of  claim 17 , wherein the at least one elongated cooling passage is a frusto-conical shaped passage and includes a metering feature disposed substantially proximate a tip of the turbine bucket. 
     
     
         19 . The turbine of  claim 17 , wherein the at least one elongated cooling passage includes:
 a first section proximate the root, the first section having a first diameter, and   a second section fluidly connected to the first section, the second section having a second diameter and proximate the tip, wherein the first diameter is larger than the second diameter.   
     
     
         20 . The turbine of  claim 17 , wherein the at least one elongated cooling passage includes at least one turbulator disposed on a surface of the elongated cooling passage, the at least one turbulator includes at least one of: a segmented turbulator and a swirl shaped turbulator.