Damped EGT Probe Vibration Reduction
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Solution Overview
Problem
Existing temperature sensing probes in gas turbine engines are prone to failure due to vibration, leading to inaccurate exhaust gas temperature readings, which can cause performance issues, emissions problems, and potential engine shutdowns.
Innovation Solution
A temperature probe design featuring a twisted configuration with guide plates and backbone rods that provides mechanical damping when inserted into a housing, reducing vibration-induced fatigue and breakage of thermocouple wires by forming points of contact that preload the probe against the housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature probe is installed in a gas turbine engine to measure exhaust gas temperature, then temperature measurement capability is improved, but the probe is subjected to high vibration and thermal stress causing failure
Solution Approach 1:
The probe is divided into multiple sections with guide plates positioned at different locations along the probe length. These guide plates create segmented contact points with the housing, distributing the vibration and stress along the probe rather than concentrating it at a single location, thereby reducing fatigue and breakage.
Solution Approach 2:
The guide plates act as intermediary elements between the probe and the housing. They provide controlled contact points that allow the probe to be preloaded against the housing, creating a dampening effect that reduces vibration transmission to the thermocouple wires while maintaining measurement capability.
2Stability of the object's composition
If the probe is rigidly mounted to maintain positional stability, then measurement stability is improved, but vibration-induced fatigue and breakage increases
Solution Approach 1:
The probe incorporates a flexible backbone rod structure that allows controlled movement and damping. This flexible structure enables the probe to maintain contact with the housing through elastic deformation rather than rigid constraint, reducing stress concentration on the thermocouple wires while maintaining positional stability for accurate measurement.
Solution Approach 2:
The guide plates are positioned to create preloaded contact points between the probe and housing. This preloading creates a cushioning effect that absorbs vibration energy before it can propagate to the thermocouple wires, protecting them from fatigue and breakage while maintaining measurement stability.
3Reliability
If damping elements are added to reduce vibration, then probe reliability is improved, but device complexity increases
Solution Approach 1:
The guide plates serve multiple functions simultaneously: they provide structural support for the probe, create damping contact points to reduce vibration, establish preload forces to stabilize the probe position, and guide the probe during installation. This multi-functionality reduces the need for separate damping elements, maintaining simplicity while improving reliability.
Solution Approach 2:
The damping function is merged into the existing probe structure through the guide plates, which are integral to the probe's mechanical support system. Rather than adding separate damping elements, the design combines vibration reduction functionality with the structural components already required for probe support and positioning.
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 solution effectively reduces high cycle fatigue and breakage of thermocouple tips, ensuring more reliable temperature measurements and preventing undesirable distortions in average temperature calculations, thereby enhancing engine performance and stability.
Implementation Method 1
A temperature probe design featuring a twisted configuration with guide plates and backbone rods that provides mechanical damping when inserted into a housing, reducing vibration-induced fatigue and breakage of thermocouple wires by forming points of contact that preload the probe against the housing
Data Source
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AI summary
A temperature probe includes a flange, a support structure, thermocouple wires, and guide plates. The flange has a midline. The support structure is attached to the midline and extends away from the flange. The thermocouple wires extend along the support structure, and terminate in a set of outer sensing tips and a set of inner sensing tips. The guide plates secure the thermocouple wires to the support structure. The guide plates are offset laterally from the midline of the flange.