Gas Turbine Aft Frame Cooling via Segmented Channels
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Solution Overview
Problem
The machining of cooling holes in small spaces within aft frame assemblies for gas turbine transition pieces is limited, and existing cooling systems require additional compressor discharge air due to the limited distribution of straight-passage cooling holes, which affects the efficiency of heat transfer and component cooling.
Innovation Solution
The aft frame assembly incorporates a supplemental component with cooling channels that fluidly connect exterior cooling holes to interior cooling outlets, enhancing the distribution of compressor discharge air and improving cooling efficiency without the need for extensive machining in small spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If straight-passage cooling holes are used in aft frame assemblies, then the structure is simple and easy to manufacture, but the distribution of cooling air is limited and additional compressor discharge air is required
Solution Approach 1:
The cooling system is segmented into multiple functional components: exterior cooling holes for air intake, interior cooling outlets for air discharge, and cooling channels for air distribution. This segmentation allows the cooling air to be distributed through multiple pathways, improving coverage without requiring additional compressor discharge air.
Solution Approach 2:
The cooling channels are positioned between the aft frame assembly and the transition piece, nesting the cooling functionality within the existing structural components. This nested arrangement allows efficient use of space while improving cooling air distribution.
2Temperature
If cooling holes are machined in small spaces of aft frame assemblies, then direct cooling is achieved, but machining is limited and cooling distribution is insufficient
Solution Approach 1:
Cooling channels serve as intermediary pathways between the exterior cooling holes and interior cooling outlets. These channels facilitate the distribution of cooling air throughout the transition piece, achieving effective cooling without the need for extensive machining in difficult-to-reach areas.
Solution Approach 2:
The cooling system transitions from simple linear passages to three-dimensional cooling channels that can navigate complex geometries. This dimensional approach allows cooling air to reach interior surfaces that would be inaccessible to traditional straight-passage holes.
3Temperature
If more compressor discharge air is used for cooling, then component cooling is improved, but operating efficiency decreases
Solution Approach 1:
The cooling channels ensure continuous and uniform distribution of cooling air throughout the transition piece, maximizing the effectiveness of each unit of compressor discharge air. This continuous action improves cooling efficiency without requiring additional air flow.
Solution Approach 2:
The system changes the distribution parameters of cooling air from concentrated straight passages to distributed cooling channels, improving thermal coverage and heat transfer efficiency throughout the component while maintaining the same compressor discharge air flow rate.
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 design promotes better operating efficiency by allowing for more effective heat transfer and reduced compressor discharge air usage, effectively cooling the transition piece components while maintaining mechanical and environmental properties.
Implementation Method 1
compressor discharge air may be forced through internal cooling holes within aft frame assemblies for transition pieces then discharged internally therein to transfer heat from the component
Implementation Method 2
cooling air serves to film cool the surrounding surface of the component
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Aft frame assemblies (50) for a gas turbine transition pieces include a body (51) comprising an exterior surface (52) and a plurality of interior surfaces (53), one or more exterior cooling holes (60) disposed on the exterior surface (52) of the body (51) for capturing compressor discharge air (30) outside of the transition piece, and a supplemental component bonded (70) to at least one of the plurality of interior surfaces (53) of the body (51). At least one cooling channel (60) is at least partially defined by the supplemental component (70) and the interior surface (53) that the supplemental component (70) is bonded to, wherein the at least one cooling channel (60) fluidly connects at least one of the one or more exterior cooling holes (57) to one or more interior cooling outlets (58) that discharge the compressor discharge air (30) captured from the at least one of the one or more exterior cooling holes (57).