Gas Turbine Air Bleed Manifold Splitter Design
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Solution Overview
Problem
Gas turbine engine inner case flanges experience reduced lifespan due to high temperature gradients caused by mixing of hot and cold air in the air bleed manifold, leading to increased steady-state temperatures despite the use of heat shields.
Innovation Solution
A splitter is introduced to segregate the air flow in the air bleed manifold, directing cold air into an inner cavity between the splitter and the inner case, where it flows over the flanges, and hot air into an outer cavity, with a circular deflector preventing hot air inflow and directing cold air into a radially outward flow path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If cold and hot air are mixed in the air bleed manifold cavity, then the air bleed manifold can supply air from two sources, but the hot air creates maximum temperature and lifting problems due to high temperature gradients, raising the steady state temperature of the inner case flanges and reducing engine part life
Solution Approach 1:
The air bleed manifold cavity is segmented into an inner cavity and an outer cavity using a splitter. The splitter divides the flow paths so that cold air from the HPC sixth stage bleed ducts flows through the inner cavity across the inner case flanges, while hot air from the diffuser strut flows through the outer cavity. This segmentation prevents mixing of hot and cold air, allowing the manifold to utilize both air sources while maintaining low temperatures at the flanges.
2Object-affected harmful factors
If a heat shield is used to protect inner case flanges, then some thermal protection is provided, but the hot air still raises the steady state temperature of the flanges and reduces engine part life
Solution Approach 1:
Instead of relying on heat shields that only provide partial protection, the manifold is segmented into inner and outer cavities. This prevents hot air from contacting the flanges in the first place, eliminating the temperature rise that would otherwise occur even with heat shield protection.
Solution Approach 2:
The splitter acts as an intermediary structure that separates the hot air flow from the cold air flow paths. By introducing this intermediate element, the harmful thermal interaction between hot air and flanges is eliminated, preserving engine part life more effectively than heat shields alone.
3Duration of action of stationary object
If the splitter directs cold air into the inner cavity and hot air into the outer cavity, then temperature gradients are minimized and engine part life is prolonged, but the device complexity increases
Solution Approach 1:
The manifold is segmented into two flow paths using a splitter, which extends axially within the cavity. This segmentation enables separate control of cold and hot air flows, minimizing temperature gradients and prolonging flange life. The segmented design achieves the desired thermal management with a relatively simple structural addition.
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
This solution reduces maximum temperatures and gradients on the inner case flanges, prolonging their life while maintaining air flow and supply air temperature, and protects against variations in hot air flow, resulting in a more robust engine system.
Implementation Method 1
a circular deflector configured to direct the cold air into a radially outward flow path
Implementation Method 2
a splitter configured to direct the cold air into an annular inner cavity between the splitter and the inner case and across the inner case flanges, and the hot air into an outer cavity between the splitter and the outer case
Data Source
Figure 1~2
AI summary
A splitter for protecting parts of a gas turbine engine is provided. The splitter segregates the flow of hot and cold gases into the air bleed manifold around the high compressor section to reduce maximum temperatures and minimize the temperature gradients of engine parts, especially inner case flanges The splitter divides the air bleed manifold into an annular inner cavity and an outer cavity. The splitter directs relatively cold air from the high compressor bleed ducts into the inner cavity and relatively hot air from the aft hub into the outer cavity, away from the inner case flanges.