Exhaust Gas Temperature Probe Housing Flow Path Design
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Solution Overview
Problem
Existing temperature sensing probe assemblies in gas turbine engines face challenges in accurately measuring exhaust gas temperatures due to thermal gradients caused by engine walls, leading to potential inaccuracies and slower response times, which can affect engine operation and component protection.
Innovation Solution
A temperature sensing probe assembly with a housing design that includes a lengthened inlet opening and a set of exhaust openings, configured to establish a flow path with equal cross-sectional areas, and strategically positioned thermocouple junctions to minimize the impact of thermal gradients and enhance airflow, ensuring accurate and rapid temperature sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the temperature sensing probe is exposed to exhaust gases through a conventional housing design, then the thermocouple junctions can measure temperature, but thermal gradients caused by engine walls lead to measurement inaccuracies and slower response times
Solution Approach 1:
The patent extends the inlet opening along the axial dimension of the housing, creating a lengthened flow path that allows exhaust gases to access both thermocouple junctions more directly. This dimensional extension enables the first junction (nearer the tip) and second junction (nearer the attachment point) to both receive heated air, compensating for thermal gradients along the probe length and improving measurement accuracy while maintaining rapid response.
Solution Approach 2:
The patent creates different flow conditions at different locations along the probe by positioning the lengthened inlet opening to extend from near the first thermocouple junction to near the second thermocouple junction. This local optimization ensures that each junction receives adequate heated air flow according to its specific thermal environment, with the exhaust openings strategically positioned to deliver cooling air to each junction's immediate vicinity.
2Productivity
If the housing has a lengthened inlet opening extending from the first thermocouple junction to the second thermocouple junction, then airflow is improved and response time is reduced, but the housing design becomes more complex
Solution Approach 1:
The patent merges the inlet opening function with the housing structure itself, integrating the flow path directly into the housing walls rather than using separate inlet ducts or channels. The lengthened inlet opening is formed as part of the housing's axial structure, eliminating the need for additional complex internal flow management components while achieving improved airflow to both thermocouple junctions.
Solution Approach 2:
The housing serves multiple functions: it protects the thermocouple junctions, provides structural support, and acts as the flow path conduit through its lengthened inlet opening and exhaust openings. This multi-functionality reduces the need for separate components, simplifying the overall design while maintaining improved response characteristics.
3Measurement precision
If the set of exhaust openings has a larger number of openings to improve cooling and airflow, then temperature measurement accuracy improves, but stress on the housing increases
Solution Approach 1:
The patent divides the exhaust opening function into multiple discrete openings distributed along the housing rather than using a single large opening. This segmentation allows the cooling and flow functions to be distributed across multiple locations, reducing the stress concentration that would occur at a single large opening while maintaining adequate airflow to improve temperature measurement accuracy.
Solution Approach 2:
The patent positions the set of exhaust openings offset from the inlet opening along the axial direction, creating an asymmetric arrangement. This asymmetric positioning optimizes the flow path and distributes thermal and mechanical loads more evenly across the housing structure, reducing peak stress while maintaining effective cooling and measurement capabilities.
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 enables faster and more accurate temperature sensing, allowing for quicker response to engine operating conditions, improved efficiency, and effective protection of downstream components by reducing thermal gradient effects and optimizing airflow through the probe assembly.
Implementation Method 1
A stream of heated air flows through the housing from the set of inlet openings to the set of exhaust openings to establish a flow path through the housing
Implementation Method 2
a temperature sensing probe having a tip and a first thermocouple junction located nearer the tip and a second thermocouple junction located nearer an attachment point
Data Source
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AI summary
A temperature sensing probe assembly (38) includes a temperature sensing probe (54) having a tip (66) and a first thermocouple junction (74) located nearer the tip (66) and a second thermocouple junction (76) located nearer an attachment point for the temperature sensing probe assembly (38), and a housing (52) positioned around at least a portion of the temperature sensing probe (54).