Thin Film Temperature Sensor for Aero-Propulsion Components

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Solution Overview

Problem

Components in gas turbine engines, made from temperature-sensitive materials, face premature failure due to exposure to high temperatures, which existing active and non-contact temperature monitoring methods struggle to detect reliably, especially in rotating or occluded environments.

Innovation Solution

Thin films, such as alumina, hafnia, or platinum, are applied to component surfaces using atomic layer deposition, configured to undergo detectible changes in properties like crystalline structure, electrical, optical, or surface roughness when exposed to threshold temperatures, allowing for non-invasive temperature monitoring during maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If active temperature sensors (thermocouples) are used to monitor temperature, then temperature detection capability is improved, but device complexity and wiring requirements increase

Engineering Contradiction:

Improvetemperature detection capabilityVSAvoidwiring complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the temperature sensing function from complex active sensor systems and implements it through a passive thin film coating applied directly to the component surface. The thin film undergoes detectable property changes (optical, electrical, or mechanical) when exposed to threshold temperatures, eliminating the need for thermocouples and their associated wiring while maintaining temperature detection capability

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical/electrical thermocouple system with a passive material-based sensing system. The thin film's inherent material properties (such as phase transition, color change, or electrical property changes) are used to indicate temperature exposure, substituting complex electrical measurement systems with simpler optical or material property detection methods

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If non-contact temperature monitoring methods are used, then device complexity is reduced, but reliability decreases due to inability to monitor rotating or occluded components

Engineering Contradiction:

Improvemonitoring system complexityVSAvoidtemperature monitoring reliability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent applies the thin film coating to the component surface during manufacturing or maintenance, before the component enters service. This preliminary action ensures the sensor is permanently attached and will reliably indicate temperature exposure regardless of the component's operational state (rotating, occluded, or stationary), eliminating the need for line-of-sight monitoring during operation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The thin film acts as a self-contained temperature indicator that automatically responds to temperature exposure through inherent material property changes. The component with the thin film essentially monitors itself, eliminating the need for external active sensing systems that would require line of sight or additional complexity to monitor rotating or occluded parts

Inventive Principle:

Principle #25Self-service

3Reliability

If thin films are applied to detect temperature exposure, then reliability of temperature detection is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvetemperature detection reliabilityVSAvoidthin film application complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent utilizes phase transition or property change parameters of thin film materials at specific threshold temperatures. By selecting materials with well-defined transition temperatures matching the component's maximum operating temperature, the system achieves reliable temperature detection through inherent material behavior rather than complex sensing electronics, maintaining ease of manufacture through standard coating processes

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

Enables effective detection of excessive temperature exposure, preventing premature failure and unnecessary part replacement by passively sensing temperature-induced changes, thus ensuring component safety and extending service life.

Implementation Method 1

the thin film is configured to undergo a detectible change in properties when exposed to a temperature exceeding a threshold temperature

Methodology Applied

Scientific EffectPhase change: Phase Change

Implementation Method 2

the thin film is configured to undergo at least one of a change in crystalline structure, a change in electrical properties, a change in optical properties and a change in surface roughness when exposed to the temperature exceeding the threshold temperature

Methodology Applied

Scientific EffectElectrical property change: Electrical Resistance

Implementation Method 3

Methodology Applied

Scientific EffectOptical property change: Reflection

Implementation Method 4

Methodology Applied

Scientific EffectSurface roughness change:

Data Source

PatentUS20240418101A1Thin film temperature sensor and method

Publication Date: 2024.12.19 RTX CORP

AI summary

A component of an aero-propulsion apparatus, wherein the component includes a material and has a surface, and a thin film on the surface, wherein the thin film is configured to undergo a detectible change in properties when exposed to a temperature exceeding a threshold temperature. Methods are also disclosed.