Transition Scroll Effusion Cooling for Turbine Engines
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Solution Overview
Problem
Conventional cooling methods for transition scrolls in turbine engines, such as louvers and impingement cooling, are ineffective in managing temperature variations and extending component life due to the helical, asymmetrical nature and non-uniform temperatures of exhaust gases.
Innovation Solution
The implementation of effusion cooling holes with varying densities on the inner and outer portions of the transition scroll, which supply a layer of cooling air to the hot surfaces, reducing temperature gradients and minimizing additional component requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional cooling methods (louver and impingement cooling) are used on the transition scroll, then some cooling effect is achieved, but the cooling effectiveness is insufficient due to the helical asymmetrical nature and non-uniform temperatures of exhaust gases
Solution Approach 1:
The effusion cooling holes are distributed across the transition scroll surface with varying densities - higher density on the outer portion and lower density on the inner portion. This local variation in cooling hole density provides non-uniform cooling that matches the non-uniform temperature distribution of the exhaust gases, with more cooling where temperatures are highest, thereby improving overall cooling effectiveness
Solution Approach 2:
The invention uses effusion cooling where cooling air is introduced through numerous small holes in the transition scroll wall, creating a film of cooling air between the hot exhaust gases and the transition scroll surface. This pneumatic approach allows the cooling air to conform to the complex helical geometry and provide effective thermal protection
2Reliability
If effusion cooling holes with varying densities are implemented, then cooling effectiveness is improved, but manufacturing complexity increases
Solution Approach 1:
The invention varies the density parameter of the effusion cooling holes across different regions of the transition scroll. By changing the hole density from high on the outer portion to low on the inner portion, the system optimizes cooling effectiveness while maintaining a relatively simple effusion cooling structure that can be manufactured using standard aerospace fabrication techniques
3Duration of action of stationary object
If the transition scroll is cooled more effectively, then component life is extended, but additional cooling components and systems are required
Solution Approach 1:
The effusion cooling holes are integrated directly into the transition scroll structure itself, merging the cooling function with the structural component. This eliminates the need for separate cooling components such as external cooling channels, heat sinks, or active cooling systems, thereby extending component life while avoiding additional system complexity
Solution Approach 2:
The transition scroll provides its own cooling through the effusion cooling holes that are part of its structure. The cooling air is supplied through the scroll wall itself, allowing the component to self-regulate its temperature without requiring external cooling systems or additional maintenance, thus extending component life autonomously
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
Effusion cooling effectively buffers hot surfaces from exhaust gases, convectively cools the transition scroll, and extends its durability while potentially reducing manufacturing costs and maintaining optimized primary flow patterns.
Implementation Method 1
The transition scroll has a hot surface, a cold surface, and effusion cooling holes for providing a layer of cooling air to the hot side
Implementation Method 2
convectively cools the transition scroll
Data Source
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AI summary
An engine assembly (10) includes a combustor (12) having a combustion chamber (13) in which an air and fuel mixture is combusted to produce combustion gases. The engine assembly further includes a transition scroll (14) coupled to the combustor (12) for receiving the combustion gases. The transition scroll (14) includes an interior surface, an exterior surface, and effusion cooling holes (150) for providing cooling air to the interior surface. The engine assembly further includes a turbine (22) coupled to the transition scroll (14) for receiving and extracting energy from the combustion gases.