Gas Turbine Outer Case Cooling via Ambient Air Flow
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Solution Overview
Problem
Gas turbine engines face increased outer case deformation and stress due to high operating temperatures, leading to potential cracks and failures in bearing support struts, as conventional cooling methods rely on compressor bleed air and may not adequately manage thermal loads.
Innovation Solution
A thermal barrier/cooling system comprising an internal insulating layer and a convective cooling channel that directs ambient air flow to reduce radiated heat on the outer case, minimizing the need for compressor bleed air and reducing thermal stresses by providing a thermal resistance and convective cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional forced convection cooling using compressor bleed air is used, then the outer case temperature can be controlled, but the system complexity increases and relies on additional cooling air supply mechanisms
Solution Approach 1:
The patent extracts the cooling function from the internal engine system and relocates it to the external environment. The cooling channel allows ambient air to cool the outer case from the outside, eliminating the need to use compressor bleed air for cooling purposes. This separates the cooling function from the engine's internal air supply system.
Solution Approach 2:
The outer case cooling system utilizes ambient air flow that naturally occurs during engine operation to provide cooling. The design allows the engine's own operation to create the air flow conditions necessary for cooling, without requiring additional active cooling mechanisms or external power sources.
2Temperature
If compressor bleed air is used for cooling the outer case, then cooling effectiveness is improved, but the loss of compressor air increases reducing overall efficiency
Solution Approach 1:
The cooling function is extracted from the internal compressor bleed air system and relocated to the external environment. The cooling channel enables ambient air to perform the cooling function, completely eliminating the extraction of air from the compressor for cooling purposes.
Solution Approach 2:
The system utilizes the engine's operational environment and naturally occurring air flow to provide cooling, rather than consuming valuable compressor air. The engine operation itself creates the conditions for effective cooling without sacrificing performance-critical resources.
3Power
If high operating temperatures are maintained for efficiency, then power output is improved, but outer case deformation and stress increase leading to potential failures
Solution Approach 1:
The patent segments the thermal management function into a dedicated external cooling channel system, separate from the internal combustion and power generation processes. This allows independent optimization of power output temperatures while providing separate thermal protection for the outer case through ambient air cooling.
Solution Approach 2:
The cooling channel acts as an intermediary thermal management system between the high-temperature internal combustion processes and the external environment. It provides a controlled pathway for heat dissipation that protects the outer case from excessive thermal loads while allowing the internal engine to operate at optimal temperatures for power generation.
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 system effectively controls the temperature of the outer case, reducing the risk of deformation and strut failures by minimizing thermal gradients and eliminating the reliance on compressor bleed air, thus enhancing the operational efficiency and reliability of the gas turbine engine.
Implementation Method 1
providing a thermal resistance to radiated energy from an exhaust diffuser located radially inwardly from the outer case
Implementation Method 2
an internal insulating layer supported on an inner case surface opposite the outer case surface
Implementation Method 3
a convective cooling channel... forms a flow path for directing an ambient non-forced air flow in an upward direction to cool the outer case surface
Data Source
AI summary
An attachment system for attaching at least one exhaust diffuser downstream from a turbine assembly in a gas turbine engine is disclosed. The attachment system may include at least one attachment flange extending from a downstream edge and attached to a spring plate diffuser support structure and at least one attachment flange extending from side edges of the exhaust diffuser to couple sections of the exhaust diffuser together. The diffuser may also include a thermal barrier/cooling system for controlling a temperature of an outer case of the gas turbine engine. The thermal barrier/cooling system may form a flow path for an ambient air flow cooling.