Sensor Assembly in Turboengine Labyrinth Seal

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Solution Overview

Problem

Current sensor technologies in turbomachines, such as aircraft engines, are inadequate for efficiently and reliably monitoring fluid properties like temperature, mass flow, and composition within non-contact seals, particularly in labyrinth seals, which can lead to undetected issues like hot gas ingress or oil leaks.

Innovation Solution

A sensor arrangement with a sensor element positioned directly within the non-contact seal, capable of measuring fluid properties such as temperature, mass flow, and composition, and coupled with a control device to emit alerts or initiate shutdowns, ensuring real-time monitoring and prevention of malfunctions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a sensor element is positioned directly within the non-contact seal to measure fluid properties, then measurement precision and reliability are improved, but device complexity increases

Engineering Contradiction:
Improvefluid property measurementVSAvoidsensor arrangement structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The sensor element is integrated within the labyrinth seal structure itself, with the seal comprising multiple circumferential elements that create a tortuous flow path. The sensor element is positioned to measure fluid properties directly within this nested seal structure, allowing precise measurement while maintaining a compact integrated design rather than adding separate external monitoring systems.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The labyrinth seal structure acts as an intermediary between the hot gas path and the sensor element. The seal's tortuous flow path allows the sensor to measure fluid properties (temperature, composition, flow rate) of cooling air or oil without direct exposure to the extreme conditions of the main gas path, enabling accurate measurement while protecting the sensor.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the sensor element is placed close to the gas path to detect hot gas ingress, then detection capability is improved, but the sensor is exposed to higher temperatures and harsher conditions

Engineering Contradiction:
Improvehot gas ingress detectionVSAvoidsensor operating temperature
Core Design Contradiction:
ReliabilityVSTemperature

Solution Approach 1:

The labyrinth seal structure serves as a protective intermediary between the hot gas path and the sensor element. It allows the sensor to be positioned close enough to detect hot gas ingress through changes in fluid properties (temperature, composition), while the seal's tortuous flow path and cooling air/oil flow protect the sensor from direct exposure to extreme temperatures.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent uses optical sensors that measure fluid properties (temperature, composition, flow rate) through non-contact or minimal-contact methods. This replaces traditional mechanical sensors that would require direct physical contact with the fluid, allowing temperature detection without the sensor element being subjected to the full thermal load.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Loss of time

If cooling air temperature is monitored to detect problems, then early problem detection is improved, but additional monitoring systems and complexity are required

Engineering Contradiction:
Improveproblem detection timeVSAvoidmonitoring system complexity
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The sensor element performs multiple measurement functions simultaneously - it can measure temperature, composition, and flow rate of the cooling air or oil using optical detection methods. This multi-functional sensor replaces what would otherwise require multiple separate monitoring systems, enabling early problem detection while minimizing additional complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The sensor element provides real-time feedback on cooling air temperature and fluid properties directly within the seal. This continuous monitoring enables early detection of temperature rises or composition changes that indicate problems, allowing immediate corrective action before failures occur, thus reducing loss of time without requiring complex periodic inspection systems.

Inventive Principle:
Principle #23Feedback

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

Enables efficient and reliable monitoring of fluid properties within turbomachines, allowing for immediate detection of anomalies like hot gas ingress or oil leaks, thereby preventing engine damage and ensuring safety through automatic shutdowns.

Implementation Method 1

the sensor element can measure a temperature of the fluid flow

Methodology Applied
Scientific EffectTemperature measurement:

Implementation Method 2

a mass flow of the fluid flow

Methodology Applied
Scientific EffectMass flow measurement:

Implementation Method 3

optical sensors can be used, which can record the composition, the conductivity or the optical transparency of the fluid flow

Methodology Applied
Scientific EffectOptical detection:

Implementation Method 4

there is a pressure gradient across the flow path, so that a fluid is transported through the non-contact seal

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP3184754B1Sensor assembly and measuring method for a turboengine
Publication Date: 2020.07.08 ROLLS ROYCE DEUT LTD & CO KG
  • EP3184754B1 patent drawingFigure 1
  • EP3184754B1 patent drawingFigure 2
  • EP3184754B1 patent drawingFigure 3

AI summary

The invention relates to a sensor arrangement (50) with a sensor element (51) for measuring at least one physical and/or chemical fluid property in a turbomachine (10), characterized in that the sensor element (51) detects the at least one fluid property in a non-contact seal, in particular a labyrinth seal (40), between a rotor stage (29) and a stator stage (30), wherein the sensor element (51) has contact with the fluid flow (41) along the flow path (S) in the labyrinth seal (40) during operation, and wherein the sensor element (51) is arranged at the beginning, middle, or end of the flow path (S) through the non-contact seal. The invention also relates to a method.