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METHOD FOR REDUCING VARIABILITY IN TURBINE NOZZLE THROAT AREA

IP.com Disclosure Number: IPCOM000249726D
Publication Date: 2017-Mar-28
Document File: 7 page(s) / 186K

Publishing Venue

The IP.com Prior Art Database

Abstract

A turbine engine nozzle is fabricated with extra material and then adaptively machined to define a throat area thereof.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 41% of the total text.

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METHOD FOR REDUCING VARIABILITY IN TURBINE NOZZLE THROAT AREA

ABSTRACT

[0001] A turbine engine nozzle is fabricated with extra material and then adaptively

machined to define a throat area thereof.

BACKGROUND

[0002] This disclosure relates generally to turbine engine components and more

particularly to methods of manufacturing turbine engine components to reduce

dimensional variability.

[0003] A gas turbine engine includes one or more turbines each of which includes a

series of stages, each stage including at least one row of stationary nozzle vanes and at

least one row of rotating turbine blades. Each pair of adjacent nozzle vanes define flow

channels therebetween. Within each flow channel is a "throat" representing the minimum

cross-sectional flow area for that channel. The throat area is a critical aerodynamic

parameter affecting engine performance, compressor operability, and bearing loads.

[0004] It is desirable to have the as-manufactured throat area match the intended throat

area as closely as possible.

[0005] Described herein is a method for manufacturing a turbine nozzle or other similar

component in which throat area variation is minimized.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The concept may be best understood by reference to the following description

taken in conjunction with the accompanying drawing figures, in which:

[0007] FIG. 1 is a schematic perspective view of a turbine nozzle segment;

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[0008] FIG. 2 is a schematic cross-sectional view taken along lines 2-2 of FIG. 1;

[0009] FIG. 3 is a schematic cross-sectional view taken along lines 3-3 of FIG. 1; and

[0010] FIG. 4 is a block diagram illustrating a nozzle machining process.

DETAILED DESCRIPTION OF THE CONCEPT

[0011] Referring to the drawings wherein identical reference numerals denote the same

elements throughout the various views, FIG. 1 illustrates a turbine nozzle segment 10

comprising a plurality of stationary airfoils referred to as turbine vanes 12 extending

between an arcuate inner band 14 and an arcuate outer band 16. The inner band 14

defines an inner flowpath surface 18 and the outer band 16 defines an outer flowpath

surface 20. The inner and outer flowpath surfaces 18, 20 are exposed to the primary gas

flowpath during engine operation.

[0012] In the illustrated example, the turbine nozzle segment 10 is a "doublet" including

two turbine vanes 12. A plurality of such segments 10 are assembled in an annular array

to form a complete 360° nozzle ring in a gas turbine engine.

[0013] The nozzle segment 10 may be manufactured using techniques such as casting,

forging, and/or machining, or combinations of such techniques. The nozzle segment 10

may be a single unitary or integral component, or may be built up as an assembly of

individual components. For example, it is known in the state-of-the-art to make the

illustrated nozzle doublet in one-piece, two-piece, three-piece, or four-piece

configurations.

[0014] Referring to FIG. 2, each turbine vane 12 is an...