System and method of transferring power in a gas turbine engine

Patent metadata

Field	Value
Publication number	US-2017191427-A1
Application number	US-201614987271-A
Country	US
Kind code	A1
Filing date	Jan 4, 2016
Priority date	Jan 4, 2016
Publication date	Jul 6, 2017
Grant date	—

Abstract

A method of extracting work from a convertible gas turbine engine having a core flowpath and a bypass flowpath. The method comprises operating the convertible gas turbine engine at a first volumetric flow rate through the core flowpath and a second volumetric flow rate through the bypass flowpath to produce a first work output of the convertible gas turbine engine; extracting the first work output via an unshrouded fan and a shaft at a first fan to shaft extraction ratio; altering the second volumetric flowrate through the bypass flowpath while maintaining the first work output; and extracting the first work output via an unshrouded fan and a shaft at a second fan to shaft extraction ratio.

First claim

What is claimed is:

1 . A method of extracting work from a convertible gas turbine engine having a core flowpath and a bypass flowpath, the method comprising:
operating said convertible gas turbine engine at a first volumetric flow rate through said core flowpath and a second volumetric flow rate through said bypass flowpath to produce a first work output of said convertible gas turbine engine; extracting said first work output via an unshrouded fan and a shaft at a first fan to shaft extraction ratio; altering said second volumetric flowrate through said bypass flowpath while maintaining said first work output; and extracting said first work output via an unshrouded fan and a shaft at a second fan to shaft extraction ratio.

2 . The method of claim 1 wherein said shaft is selectably coupled to a power transfer shaft via a clutch.

3 . The method of claim 1 wherein said shaft is coupled to a power transfer shaft via a beveled gear.

4 . The method of claim 1 wherein the step of altering said second volumetric flowrate is accomplished by adjusting the alignment of one or more of a plurality of fan inlet guide vanes.

5 . The method of claim 4 wherein said plurality of fan inlet guide vanes are radially split, having a fixed radially-inward portion axially aligned with said core flowpath and a variable radially-outward portion axially aligned with said bypass flowpath.

6 . The method of claim 4 wherein said plurality of fan inlet guide vanes are radially split, having a variable radially-inward portion axially aligned with said core flowpath and a variable radially-outward portion axially aligned with said bypass flowpath.

7 . The method of claim 7 wherein said convertible gas turbine engine is affixed to an aircraft and said turbofan operations provide propulsive force to said aircraft.

8 . A method of rapidly transitioning between turboshaft and turbofan operations in a convertible gas turbine engine comprising an unshrouded inlet fan and a shaft, a method comprising:
establishing airflow through a set of fixed inlet guide vanes to an engine core flowpath to achieve maximum operating efficiency of said convertible gas turbine engine; and transferring power between said unshrouded inlet fan and said shaft while maintaining a constant power output of said convertible gas turbine engine by altering the alignment of a plurality of variable inlet guide vanes forward of a bypass flowpath.

9 . The method of claim 8 wherein power is transferred from said unshrouded inlet fan to said shaft by altering the alignment of said plurality of variable inlet guide vanes to decrease airflow through the bypass flowpath.

10 . The method of claim 8 wherein power is transferred from said shaft to said unshrouded inlet fan by altering the alignment of said plurality of variable inlet guide vanes to increase airflow through the bypass flowpath.

11 . The method of claim 8 wherein said alignment of said plurality of variable inlet guide vanes is controlled by a controller via an actuator.

12 . The method of claim 11 wherein said alignment of said plurality of variable inlet guide vanes is adjusted based on a predetermined schedule of alignments.

13 . The method of claim 12 wherein said predetermined schedule of alignments includes a plurality of alignments for said plurality of variable inlet guide vanes to transfer loading of the convertible gas turbine engine between turboshaft and turbofan operations while maintaining steady overall loading of the convertible gas turbine engine.

14 . The method of claim 8 wherein said convertible gas turbine engine is affixed to an aircraft and said turbofan operations provide propulsive force to said aircraft.

15 . The method of claim 8 wherein said shaft is selectably coupled to a power transfer shaft via a clutch.

16 . The method of claim 8 wherein said shaft is coupled to a power transfer shaft via a beveled gear.

17 . A method of transferring power in a convertible gas turbine engine having a core flowpath through an air inlet, an unshrouded fan, a compressor, a combustor, and a turbine and a bypass flowpath through said air inlet and said unshrouded fan, the method comprising the steps of:
admitting a first volumetric flow rate of air into said core flowpath via a first portion of said air inlet comprising a plurality of fixed vanes, said first volumetric flow rate of air optimized for maximum power output of said convertible gas turbine engine; admitting a second volumetric flow rate of air into said bypass flowpath via a second portion of said air inlet comprising a plurality of variable vanes; and adjusting the incident angle of said plurality of variable vanes to alter said second volumetric flow rate of air admitted into said bypass flowpath while maintaining said first volumetric flow rate of air admitted into said core flowpath constant.

18 . The method of claim 17 wherein said convertible gas turbine engine is affixed to an aircraft and said turbofan operations provide propulsive force to said aircraft.

19 . The method of claim 17 wherein said maximum power output is at least partially extracted from said convertible gas turbine engine via a shaft, said shaft being selectably coupled to a power transfer shaft via a clutch.

20 . The method of claim 17 wherein said maximum power output is at least partially extracted from said convertible gas turbine engine via a shaft, said shaft being coupled to a power transfer shaft via a beveled gear.

Assignees

• Rolls Royce Nam Tech Inc

Inventors

• Mcneil Charles L
• Kusnierek John

Classifications

• F02C9/20 Primary

  by throttling; by adjusting vanes · CPC title

• F02K3/025

  the by-pass flow being at least partly used to create an independent thrust component · CPC title

• F05D2220/325

  to drive unshrouded, high solidity propeller · CPC title

• F02C3/04

  having a turbine driving a compressor (power transmission arrangements F02C7/36; control of working fluid flow F02C9/16) · CPC title

• F05D2260/4031

  as in toothed gearing · CPC title