Gas Turbine Sensor Assembly Thermal Barrier Design
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Solution Overview
Problem
Sensor assemblies in gas turbine engines face reliability issues due to high temperatures, which exceed the rating of standard electrical connectors, leading to potential embrittlement and fracture of electrical leads and ceramic structures.
Innovation Solution
The sensor assembly design includes a housing spaced apart from the mounting flange by an intermediate flange, with radially offset point and arcuate standoffs creating inboard and outboard gaps to limit thermal communication, allowing for the use of standard electrical connectors and reducing heat transfer, thereby maintaining the housing at a lower temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensors are positioned in proximity to hot engine structures to monitor parameters, then measurement capability is improved, but the electrical connector and leads are exposed to temperatures above their rating, causing embrittlement and fracture
Solution Approach 1:
The sensor assembly is divided into distinct thermal zones: a hot zone containing the mounting flange exposed to engine temperatures, and a cool zone containing the housing with the electrical connector. The intermediate flange acts as a thermal barrier, segmenting the heat path and allowing each component to operate within its temperature rating.
Solution Approach 2:
The intermediate flange serves as a thermal intermediary or mediator between the hot mounting flange and the cooler housing. It conducts necessary structural support while limiting thermal communication, protecting the electrical connector from direct heat exposure.
2Ease of manufacture
If standard electrical connectors are used in high temperature applications, then manufacturing cost is reduced, but the connectors are exposed to temperatures exceeding their rating, leading to embrittlement and fracture
Solution Approach 1:
The intermediate flange and thermal barrier structures act as intermediaries that protect the standard electrical connector from direct heat exposure. This allows the use of cost-effective standard connectors while maintaining their reliability by keeping them in a cooler zone.
Solution Approach 2:
The electrical connector is extracted from the hot environment and placed in a separate, thermally protected zone within the housing. This spatial separation allows standard connectors to be used without exposing them to damaging temperatures.
3Volume of moving object
If the housing is positioned close to the mounting flange for compact design, then device size is reduced, but thermal communication increases, causing the housing temperature to rise above connector ratings
Solution Approach 1:
The intermediate flange serves as a thermal mediator that allows compact positioning of the housing near the mounting flange while still limiting heat transfer. It enables spatial proximity without thermal coupling.
Solution Approach 2:
The thermal path is segmented by the intermediate flange, allowing the housing to be positioned close to the mounting flange for compactness while maintaining thermal separation between the hot and cool zones.
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 design enables the use of standard electrical connectors, such as circular connectors conforming to MIL-STD specifications, in high-temperature applications, enhancing the reliability and cost-effectiveness of sensor assemblies by preventing embrittlement and fracture, while maintaining the housing at a lower temperature than the mounting flange.
Implementation Method 1
the one or more intermediate flange is spaced apart from the housing to limit thermal communication between the mounting flange and the housing
Implementation Method 2
the two or more point standoffs are radially offset from the sensor axis... creating inboard and outboard gaps to limit thermal communication
Data Source
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AI summary
A sensor assembly (100) includes a housing (102) defining a potting chamber (108) and arranged along a sensor axis (110), a mounting flange (104) extending about the sensor axis the axially offset along the sensor axis from the housing, and one or more intermediate flange (106). The one or more intermediate flange is arranged between the housing and the mounting flange along the sensor axis, the one or more intermediate flange coupling the mounting flange to the housing. The one or more intermediate flange is spaced apart from mounting flange to limit thermal communication between the mounting flange and the housing. Gas turbine engines (10) and methods (200) of cooling sensor assemblies are also described.