Variable Vane Control System for Gas Turbine Engines

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Solution Overview

Problem

Variable vanes in gas turbine engines experience wear during operation, limiting their performance and requiring replacement, as they can only be scheduled at fixed positions determined by on-ground testing, which does not account for in-flight operational modes.

Innovation Solution

A method and system for controlling variable vane assemblies in gas turbine engines that involves sensing angular deflections of vane arrays, adjusting these deflections using sensors and actuators, and a full authority digital engine controller to optimize vane positions in real-time, allowing for infinite incremental adjustments and extending vane lifetime.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If variable vanes are scheduled at fixed first and second positions determined by on-ground testing, then the engine can operate in different modes during flight, but the vanes experience wear on primary air-contacting faces and may need replacement

Engineering Contradiction:
Improveengine operational modesVSAvoidvane wear and performance
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies the dynamics principle by enabling continuous adjustment of vane positions during flight operations. The control system allows the vanes to be positioned at any angle within a range, transitioning from fixed discrete positions to dynamic continuous positioning. This resolves the wear problem by allowing the system to optimize vane angles in real-time based on actual flight conditions, distributing wear more evenly and maintaining performance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by modifying the vane position from discrete fixed values to continuous variable angles. The control system adjusts the vane deflection angle as a variable parameter based on flight conditions, allowing optimization of aerodynamic performance and wear distribution. This enables the system to adapt to different operational modes while extending vane life through optimized positioning.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If variable vanes are limited to fixed positions determined by on-ground testing, then the control system is simpler, but the vanes cannot accommodate in-flight operational modes and wear interferes with engine performance

Engineering Contradiction:
Improvecontrol systemVSAvoidin-flight operational modes
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent applies feedback by implementing a control system that continuously monitors flight conditions and adjusts vane positions accordingly. Sensors detect parameters such as flight mode, altitude, and speed, and the controller uses this information to optimize vane angles in real-time. This feedback mechanism enables adaptability to in-flight operational modes while maintaining manageable system complexity through automated control.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent implements self-service by enabling the control system to automatically adjust vane positions based on detected flight conditions without requiring manual intervention. The system autonomously optimizes vane angles for different operational modes, extending vane life and maintaining performance through self-adjustment. This reduces the burden on operators and enables real-time adaptation to changing flight conditions.

Inventive Principle:
Principle #25Self-service

3Reliability

If variable vanes are replaced when wear interferes with performance, then engine reliability is maintained, but component lifetime is limited and replacement is required

Engineering Contradiction:
Improveengine performanceVSAvoidvane component lifetime
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent applies dynamics by enabling continuous adjustment of vane positions during operation, which optimizes aerodynamic loads and distributes wear more evenly across the vane surfaces. By allowing the vanes to adapt to different flight conditions, the system reduces peak wear rates and extends component lifetime while maintaining performance, delaying the need for replacement.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by continuously varying the vane deflection angle based on flight conditions. This dynamic parameter adjustment optimizes the aerodynamic performance at different operating points and distributes mechanical and thermal loads more evenly, reducing wear accumulation and extending the service life of the vane components while maintaining engine reliability.

Inventive Principle:
Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The system enables real-time adjustment of variable vanes during flight, improving engine efficiency and extending the life of vane components by accommodating wear and changing operational conditions, thereby enhancing the overall performance and reliability of the gas turbine engine.

Implementation Method 1

sensing a first angular deflection of a first array of variable vanes about a first vane axis, and a second angular deflection of a second array of variable vanes about a second vane axis

Methodology Applied
Scientific EffectAngular deflection sensing:

Implementation Method 2

the method includes measuring using rotary variable differential transformers

Methodology Applied
Scientific EffectRotary variable differential transformation:

Data Source

PatentEP2971598B1Variable vane control system
Publication Date: 2019.08.21 UNITED TECH CORP
  • EP2971598B1 patent drawingFigure 1
  • EP2971598B1 patent drawingFigure 2
  • EP2971598B1 patent drawingFigure 3

AI summary

A method of controlling a variable vane assembly includes the steps of sensing a first angular deflection of a first array of variable vanes about a first vane axis, and a second angular deflection of a second array of variable vanes about a second vane axis, the first array of variable vanes axially spaced from the second array of variable vanes, and adjusting the angular deflection of one of the first and second arrays of variable vanes, based on the sensed angular deflections from the other of the first and second arrays of variable vanes. A compressor including the variable vane assembly and a method of operating the variable vane assembly for a compressor are also disclosed.