Cooling for capacitance probe center conductor
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Solution Overview
Problem
Current capacitance probes are limited to operating at temperatures below 2270°F due to thermal insulation around the center conductor, which prevents effective heat transfer and increases the risk of debris deposition, leading to electrical performance degradation.
Innovation Solution
A cooling system is implemented within the capacitance probe center conductor and housing, featuring channels that allow cooling air to directly contact the center conductor, bypassing thermal insulation, thereby maintaining the conductor at a lower temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal insulation is provided around the center conductor, then electrical performance is maintained, but temperature control deteriorates and debris deposition increases
Solution Approach 1:
The probe is divided into thermally isolated segments: the center conductor is separated from the cooled housing by an electrical insulator, allowing independent thermal management. This segmentation enables the housing to be cooled while the center conductor maintains higher operating temperatures necessary for electrical performance.
Solution Approach 2:
An electrical insulator serves as an intermediary element between the center conductor and the probe housing. This intermediary provides electrical isolation while allowing the center conductor to operate at higher temperatures without direct thermal coupling to the cooled housing, thus maintaining electrical performance while enabling temperature control of the overall probe.
2Temperature
If cooling channels are added through the electrical insulator, then center conductor cooling is improved, but device complexity increases
Solution Approach 1:
The electrical insulator performs multiple functions: it provides electrical isolation between the center conductor and housing, serves as a structural support element, and acts as a conduit for cooling channels. By making the insulator multi-functional, the design avoids adding separate cooling components that would increase device complexity.
Solution Approach 2:
The cooling channel function is merged with the electrical insulator structure. Instead of adding separate cooling components, the insulator itself is designed to contain and guide cooling air flow, combining thermal management and electrical isolation functions into a single integrated component.
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
The system enables capacitance probes to operate at higher temperatures with reduced debris contamination and maintains electrical performance by effectively cooling the center conductor.
Implementation Method 1
a cooling system is implemented within the capacitance probe center conductor and housing, featuring channels that allow cooling air to directly contact the center conductor
Implementation Method 2
maintains the conductor at a lower temperature
Data Source
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AI summary
A capacitance probe for measuring clearances within a gas turbine engine includes a center conductor (102; 402; 702) having a face (112; 412; 712) that is exposed to a high temperature source of the gas turbine engine, a connection line (126...726) connected to the center conductor (102...702). A probe housing (104; 404; 704) surrounds the center conductor (102...702), the connection line (126; 426; 726) and the connection circuitry (124; 424; 724). The probe housing (104; 404; 704) defines an opening for exposing the face (112; 412; 712) of the center conductor (102; 402; 702) to the high temperature source of the gas turbine engine. The probe housing (104; 404; 704) and the center conductor (102; 402; 702) define at least one cooling channel (106; 406; 706; 114; 414; 714) that passes through the center conductor (102; 402; 702) to provide cooling air from a cool air source to the high temperature source to provide cooling to the face (112; 412; 712) of the center conductor (102; 402; 702).