Reduction of equally spaced turbine nozzle vane excitation

Patent metadata

Field	Value
Publication number	US-9963974-B2
Application number	US-201213658184-A
Country	US
Kind code	B2
Filing date	Oct 23, 2012
Priority date	Oct 23, 2012
Publication date	May 8, 2018
Grant date	May 8, 2018

Abstract

A reduction in excitation amplitudes affecting turbine blade durability in a turbine nozzle assembly having a plurality of vanes and turbine blades, includes: identifying a turbine blade design of the turbine nozzle assembly; performing a modal model analysis of at least one of the turbine blades in the turbine blade design; reducing aerodynamic impact by ensuring that each of the turbine blades is free of aero-excitation from an upstream flow at the vanes in an operating speed range; identifying blade natural frequencies with respect to the nozzle vanes; and modifying a trailing edge of at least one of the vanes to reduce the excitation amplitudes.

First claim

What is claimed is:

1. Method for reducing excitation amplitudes affecting turbine blade durability in a turbine nozzle assembly having a plurality of vanes and turbine blades, comprising the steps of:
identifying a turbine blade design of said turbine nozzle assembly;
performing a modal model analysis of at least one of said plurality of turbine blades in said turbine blade design using a computer;
reducing aerodynamic impact by ensuring that each of said plurality of turbine blades is free of aero-excitation from an upstream flow at said vanes in an operating speed range;
identifying blade natural frequencies with respect to said plurality of vanes using said computer;
determining at least one modification to a trailing edge of at least one of said plurality of vanes to reduce said excitation amplitudes;
modifying at least one of said plurality of vanes at said trailing edge;
modifying a local pressure field by use of an air bleed air flow proximate said trailing edge;
modifying a vane exit angle in a direction of shifting blade pressure loading toward a leading edge of said at least one of said plurality of turbine blades away from a blade anti-node; and
limiting a number of air bleeds distributed in a few locations on said at least one of said plurality of vanes.

2. The method of claim 1 , wherein said modifying at least one of said plurality of vanes at said trailing edge comprises altering an angle at which a flow of gas enters said plurality of turbine blades and interrupts energy build up.

3. The method of claim 1 , wherein said determining comprises performing a CFD analysis to determine a vane exit angle resulting in maximum pressure perturbance and minimizing P(ω).

4. The method of claim 3 , further comprising performing a CFD analysis to determine an air bleed angle resulting in maximum pressure perturbance and in minimizing said P(ω).

5. The method of claim 1 , further comprising introducing said air bleed air flow to said trailing edge through at least one of a turbine shroud and an internal vane cooling system.

6. The method of claim 1 , further comprising performing a CFD analysis to determine an air bleed angle resulting in maximum perturbance and in minimizing P(ω).

7. The method of claim 1 , wherein said trailing edge modifying step comprises modifying said trailing edge in a spanwise direction.

8. The method of claim 1 , wherein said trailing edge modifying step comprises modifying an airfoil with said trailing edge to have a reduced chord.

9. The method of claim 1 , wherein said trailing edge modifying step comprises including cut back portions in said trailing edge.

10. The method of claim 1 , wherein said trailing edge modifying step comprises including an arcuate portion in said trailing edge.

Assignees

• United Technologies Corp

Inventors

• Duong Loc Quang
• Hu Xiaolan
• Yang Gao
• Falconer Steven R
• Gordon Ralph E
• Garcia Jesus A
• Sapiro Dan G
• Kaul Ulrike
• Johnson Gregory G
• Fishler Benjamin E

Classifications

• G01M13/00

  Testing of machine parts · CPC title

• Y10T29/49318

  Repairing or disassembling · CPC title

• F05D2260/81

  Modelling or simulation · CPC title

• F05D2240/122

  related to the trailing edge of a stator vane · CPC title

• F01D9/04

  forming ring or sector · CPC title