Rotatable Nozzle Liner Cooling via Curved Seal Diffusion Holes
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Solution Overview
Problem
Gas turbine engine exhaust ducts face damage from high-temperature core gases, as titanium-based exhaust ducts have limited temperature tolerance, and traditional nickel-based liners require expensive and environmentally unfriendly coatings, making them difficult to manufacture and limiting material options.
Innovation Solution
A cooling system for rotatable nozzles using a curved seal with strategically located diffusion and infusion holes to direct cooling air, allowing for efficient heat management and reducing the need for high-strength, scarce columbium alloys by using more available materials like nickel alloy steel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If nickel-based alloys are used for exhaust duct liners, then temperature resistance is improved (up to 700°F), but manufacturing complexity increases due to required expensive and environmentally unfriendly coatings
Solution Approach 1:
The patent extracts the cooling function from the liner material itself and implements it through a separate cooling system with channels and holes that direct cooling air to the exhaust duct, allowing the use of simpler nickel-based alloys without complex coatings
Solution Approach 2:
The patent introduces cooling air as an intermediary substance that transfers heat away from the exhaust duct through the liner, enabling the use of less expensive materials that would otherwise be inadequate for high-temperature exposure
2Temperature
If cooling air is passed between exhaust duct and liner, then heat management is improved, but device complexity increases
Solution Approach 1:
The patent integrates the cooling system into the existing liner structure, where the liner serves both as a structural component and as the housing for cooling channels, allowing cooling air to be directed precisely where needed without adding separate complex cooling apparatus
Solution Approach 2:
The cooling channels and holes are nested within the liner structure itself, with cooling air pathways embedded in the liner material, creating a compact integrated system that provides effective cooling without significant additional complexity
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 cooling system effectively manages thermal gradients across different engine positions, reducing the requirement for expensive coatings and enabling the use of less expensive materials while maintaining performance, thus protecting the exhaust ducts from excessive heat.
Implementation Method 1
Cooling air is directed through a first diffusion hole in the curved seal to cool the nozzle
Implementation Method 2
cooling air is passed between the exhaust duct and liner
Data Source
AI summary
A method for cooling a rotatable nozzle includes rotating a curved seal about a seal land while maintaining contact therewith. Cooling air is directed through a first diffusion hole in the curved seal to cool the nozzle if the rotatable curved seal is in a first position where higher heat is encountered. Cool air is directed through a second diffusion hole in the curved seal to cool the nozzle if the rotatable curved seal is in a first position where higher heat is encountered and if in a second position where relatively lower heat is encountered.