High Temperature Uncooled Optical Probe Design
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Solution Overview
Problem
Current optical probes for non-intrusive stress measurement systems in gas turbine engines are limited by temperature constraints, requiring cooling passages and significant gaseous nitrogen usage, which increases costs and probe size, and can disrupt bleed flows.
Innovation Solution
The development of a high temperature uncooled optical probe using high temperature materials for optical lenses, fibers, and adhesives, along with flow holes for purging debris, eliminates the need for cooling and reduces nitrogen usage, allowing the probe to withstand higher temperatures and fit in tighter engine spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling passages are included in the probe, then the probe can withstand higher temperatures, but the probe size increases and nitrogen usage increases
Solution Approach 1:
The patent removes the cooling passages entirely from the probe design. By extracting this component, the probe size is reduced while maintaining temperature resistance through the use of high-temperature materials such as sapphire lenses, silicon carbide windows, and specialized adhesives that can operate at temperatures up to 1200°F without active cooling.
Solution Approach 2:
The patent changes the material parameters of the probe components to withstand high temperatures. Specifically, it uses sapphire for lenses (withstanding up to 2000°F), silicon carbide for windows (withstanding up to 1650°F), and high-temperature adhesives (withstanding up to 1200°F), thereby eliminating the need for cooling passages and reducing probe size.
2Temperature
If cooling passages are included in the probe, then the probe can withstand higher temperatures, but nitrogen usage increases
Solution Approach 1:
The patent removes the cooling passages that consume nitrogen, thereby eliminating the need for significant nitrogen flow to cool the probe. The high-temperature materials allow the probe to operate directly in hot environments without active cooling, reducing nitrogen usage.
Solution Approach 2:
The probe materials themselves provide the temperature resistance function that previously required active cooling with nitrogen. The sapphire, silicon carbide, and high-temperature adhesives inherently withstand high temperatures, making the system self-sufficient and eliminating the need for external nitrogen cooling.
3Temperature
If cooling flows are used, then the probe temperature is controlled, but bleed flows are disrupted
Solution Approach 1:
The patent removes the cooling flows that were disrupting bleed flows. By eliminating the active cooling system, the probe no longer introduces cooling flows into the engine cavity that could reverse or disrupt bleed flow directions.
Solution Approach 2:
The high-temperature materials inherently control the probe temperature through their thermal properties, eliminating the need for active cooling flows. The materials withstand the high temperatures directly, preventing disruption to engine bleed flows while maintaining probe functionality.
4Quantity of substance
If high temperature materials are used, then nitrogen usage is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent employs composite material construction, combining sapphire lenses, silicon carbide windows, and high-temperature adhesives in a layered assembly. While each material is specialized for high-temperature resistance, their integration creates a manufacturable composite structure that eliminates nitrogen cooling requirements.
Solution Approach 2:
The patent changes the material parameters to high-temperature resistant materials, which inherently reduce nitrogen usage. The manufacturing complexity is managed through careful selection of materials with compatible thermal expansion properties and established fabrication processes for sapphire and silicon carbide components.
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 high temperature uncooled optical probe significantly reduces cooling requirements and nitrogen usage, lowering costs and probe size, while maintaining or improving temperature resistance and preventing debris accumulation, thus enhancing its applicability in gas turbine engines.
Implementation Method 1
a high temperature adhesive for securing the optical fibers, the fiber holders, and the high temperature optical lenses
Implementation Method 2
The high temperature uncooled probe also includes flow holes for GN2 purge flow to keep debris off of the lenses
Implementation Method 3
optical fibers coated in a high temperature material extending from inside fiber holders towards the second end
Implementation Method 4
optical fibers coated in a high temperature material
Data Source
AI summary
An optical probe includes a first end, a second end, an outer housing, an inner housing concentric with the outer housing, flow holes within the inner housing at the first end, and an optics holder within the inner housing between the flow holes and the second end. The optical probe further includes high temperature optical lenses inside the optics holder between the flow holes and the second end, fiber holders inside the optics holder between the high temperature optical lenses and the second end, optical fibers coated in a high temperature material extending from inside fiber holders towards the second end, and a high temperature adhesive for securing the optical fibers, the fiber holders, and the high temperature optical lenses.