Deflector Key Washer for Gas Turbine Thermal Gradient Reduction
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Solution Overview
Problem
Gas turbine engines face thermal gradients that lead to undesirable stresses and efficiency issues due to varying temperatures across components, which conventional cooling systems fail to adequately address.
Innovation Solution
A key washer with an annular body and deflector is used in a gas turbine engine to redirect flows between turbine assemblies, creating a mixed flow that reduces thermal gradients by directing hot air from the first flow path towards a cooler second flow path, thereby mitigating thermal stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional cooling systems are used to compensate for combustion temperatures, then component temperature control is improved, but thermal gradients still occur causing stresses and efficiency losses
Solution Approach 1:
A deflector washer is introduced as an intermediary component between the first and second turbine assemblies. This deflector redirects the first flow (hot combustion gases) to mix with the second flow (cooler air) in the gap between turbine assemblies, creating a mixed flow that reduces thermal gradients. The deflector acts as a mediator that combines hot and cool flows to achieve more uniform temperature distribution, thereby reducing thermal stresses while maintaining temperature control.
2Temperature
If cooling air is circulated through turbine hub or disc, then turbine rotor cooling is improved, but thermal gradients vary over engine life affecting efficiency
Solution Approach 1:
The invention changes the flow parameters by redirecting and mixing flows dynamically. The deflector washer modifies the temperature, velocity, and distribution parameters of the cooling air by combining it with hot combustion gases in controlled proportions. This creates a mixed flow with optimized parameters that maintains effective cooling while reducing harmful thermal gradients, thereby preserving engine efficiency throughout the engine's operational life.
3Temperature
If hot flow is directed through first flow path and cooler flow through second flow path, then cooling coverage is improved, but thermal mixing is insufficient leading to persistent thermal gradients
Solution Approach 1:
The cooling system is segmented into two distinct flow paths: a first flow path carrying hot combustion gases and a second flow path carrying cooler air. The deflector washer segments the hot flow, redirecting portions of it to mix with the cooler second flow in the gap between turbine assemblies. This segmentation approach ensures comprehensive cooling coverage while promoting thermal mixing to stabilize temperature distribution and reduce thermal gradients.
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 thermal gradients and corresponding stresses in turbine components, potentially increasing their lifespan by mixing hot and cold air flows, thus enhancing engine efficiency and component durability.
Implementation Method 1
the deflector obstructing the first flow path and extending toward the second flow path
Implementation Method 2
creating a mixed flow that reduces thermal gradients by directing hot air from the first flow path towards a cooler second flow path
Data Source
AI summary
A gas turbine engine comprising: a shaft about an axis; a first turbine assembly mounted to the shaft, a first flow path and a second flow path extending through first turbine assembly along the axis. The second flow path is located radially inward of the first flow path relative to the axis. A second turbine assembly is about the axis downstream of the first turbine assembly, with a gap defined between the first turbine assembly and the second turbine assembly, the gap in fluid communication with the first flow path and the second flow path. A washer is downstream of the first turbine assembly. The washer has an annular body including a deflector between the first turbine assembly and the second turbine assembly, the deflector obstructing the first flow path and extending toward the second flow path.