Optical Vane Position Sensor for Gas Turbine Thermal Expansion

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Solution Overview

Problem

Existing gas turbine engines face challenges in accurately determining the angular position of movable vanes due to errors in mechanical linkages and the harsh, high-temperature environment, which leads to inefficiencies and premature engine repairs.

Innovation Solution

A movable vane control system utilizing a distance sensor that measures the varying distance between the sensor and a movable target attached to the vane, compensating for thermal expansion and providing accurate angular position feedback, allowing for precise vane adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional angle measurement sensors (RVDTs or resolvers) are used to measure vane position, then the measurement can be performed, but the high temperature environment causes thermal expansion that introduces errors greater than 20% in gap measurements

Engineering Contradiction:

Improvevane position measurement accuracyVSAvoidthermal expansion errors

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces conventional mechanical angle measurement sensors (RVDTs, resolvers) with an optical measurement system consisting of an optical sensor, a reflective target on the vane, and a signal processor. This optical system measures vane position by detecting the position of the reflective target, eliminating the mechanical contact and measurement gaps that are susceptible to thermal expansion errors in the high-temperature turbine environment.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a reflective target as an intermediary element mounted on the vane. This reflective target serves as a mediator between the optical sensor and the vane, allowing the optical sensor to measure vane position indirectly through the reflection of light off the target. This intermediary approach enables accurate measurement without direct mechanical contact between the sensor and the hot vane, thereby eliminating thermal expansion errors.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If additional margin is built into engine designs to compensate for vane position uncertainties, then reliability is improved, but fuel burn efficiency decreases and performance is reduced

Engineering Contradiction:

Improveengine operation reliabilityVSAvoidfuel burn efficiency

Core Design Contradiction:

ReliabilityVSLoss of energy

Solution Approach 1:

The patent implements a feedback mechanism where the optical sensor continuously measures the actual vane position and provides this information to a control system. The control system uses this feedback to adjust the vane position precisely, eliminating the need for excessive design margins while maintaining reliable operation. This closed-loop feedback enables optimized fuel burn efficiency by ensuring the vanes are positioned accurately without unnecessary compensation.

Inventive Principle:

Principle #23Feedback

3Ease of operation

If the actuator position is used as a proxy for vane position, then the control system can operate, but errors in mechanical linkages cause the actuator position to be unrepresentative of the actual vane position

Engineering Contradiction:

Improvecontrol system operationVSAvoidvane position accuracy

Core Design Contradiction:

Ease of operationVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical linkage-based position proxy approach with an optical measurement system. Instead of relying on the actuator position to indirectly indicate vane position (which is affected by mechanical linkage errors), the optical sensor directly measures the vane position through the reflective target, eliminating the source of mechanical errors while maintaining ease of control system operation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

This solution enables precise angular positioning of vanes, reducing errors and thermal expansion impacts, leading to optimized fuel burn efficiencies and extended engine performance.

Implementation Method 1

A first vane position sensor comprising a first distance sensor is configured to sense the distance between the first distance sensor and a surface portion of a first of said plurality of vanes

Methodology Applied

Scientific EffectTime of Flight: Time of Flight

Data Source

PatentUS9970315B2Movable vane control system

Publication Date: 2018.05.15 HAMILTON SUNDSTRAND CORP

AI summary

A movable vane control system is disclosed for use with a gas turbine engine having a turbine axis of rotation. The system includes a plurality of rotatable turbine vanes in a gas flow path within a turbine case of the gas turbine engine. A first vane position sensor having a first distance sensor is configured to sense the distance between the first distance sensor and a surface portion of a first of said plurality of vanes or a first movable target connected to the first vane. Additionally, the first distance sensor, the first vane surface portion, the first movable target, or a combination thereof is configured to provide a variable distance between the first distance sensor and the first vane surface portion or first movable target that varies as a function of a position of the first vane.