Torque Monitoring in Turbine Rotor Assemblies

Solution Overview

Problem

Existing systems for monitoring torque in rotor assemblies, such as those in turbine engines, face increasing errors as the axial length of the shaft decreases and stiffness increases, particularly when using strain gauges or two shaft sensors.

Innovation Solution

A monitoring system that includes a processing system connected to both a blade sensor and a shaft sensor, utilizing non-contact sensors to measure the time of arrival of rotor blades and shaft data, which calculates torque by comparing estimated and actual times of arrival, and further determines efficiency and power by processing this data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If strain gauges or two shaft sensors are used to measure torque, then torque measurement is achieved, but measurement precision deteriorates as axial length of the shaft decreases and stiffness increases

Engineering Contradiction:

Improvetorque measurement precisionVSAvoidaxial length of shaft

Core Design Contradiction:

Measurement precisionVSLength of moving object

Solution Approach 1:

The patent replaces mechanical strain gauge measurements with an optical/timing-based measurement system. It uses a once-per-revolution sensor to detect shaft position and compares the actual arrival time of a blade with the expected arrival time, substituting direct mechanical strain measurement with a temporal comparison method that is insensitive to shaft stiffness and length

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary measurement approach by using blade passage timing as an indirect indicator of shaft torque. Instead of measuring strain directly on the shaft, the system measures the time delay caused by shaft windup, which then infers torque through comparison with expected timing, providing accurate measurement without direct mechanical coupling

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If strain gauges or two shaft sensors are used to measure torque, then torque measurement is achieved, but measurement precision deteriorates as stiffness of the shaft increases

Engineering Contradiction:

Improvetorque measurement precisionVSAvoidstiffness of shaft

Core Design Contradiction:

Measurement precisionVSStrength

Solution Approach 1:

The patent replaces mechanical strain gauge measurements with an optical/timing-based measurement system. It uses a once-per-revolution sensor to detect shaft position and compares the actual arrival time of a blade with the expected arrival time, substituting direct mechanical strain measurement with a temporal comparison method that is insensitive to shaft stiffness and length

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary measurement approach by using blade passage timing as an indirect indicator of shaft torque. Instead of measuring strain directly on the shaft, the system measures the time delay caused by shaft windup, which then infers torque through comparison with expected timing, providing accurate measurement without direct mechanical coupling

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentEP3071940B1Monitoring a dynamic parameter such as torque in a rotational system

Publication Date: 2019.01.30 UNITED TECH CORP

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AI summary

A system is provided for a turbine engine. The system includes a rotor assembly and a monitoring system. The rotor assembly includes a plurality of rotor blades connected to a shaft. The monitoring system includes a processing system. This processing system is adapted to receive blade data indicative of a rotational position of at least a first of the rotor blades. The processing system is also adapted to process shaft data with the blade data to provide torque data indicative of a torque to which at least a portion of the rotor assembly is being subjected, where the shaft data is indicative of a rotational position of the shaft.