Gas Turbine Picture Frame Cooling via Segmented Insert Design
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Solution Overview
Problem
The existing gas turbine designs for power plants face high manufacturing costs and reduced combustion efficiency due to the need for long cooling holes in the 'picture frame' component, which also results in unused compressed air not participating in combustion, thereby affecting emissions.
Innovation Solution
A new picture frame design with a recessed seat and insert configuration that creates separate air collectors and a transfer duct for cooling air, allowing for efficient cooling without expensive manufacturing steps and enabling the air to either discharge into the hot gas flow or form a closed loop, reducing air consumption and potential hot gas ingestion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If long cooling holes are realized inside the picture frame, then cooling reliability is improved, but manufacturing costs increase
Solution Approach 1:
The picture frame is divided into a seat and an insert, with cooling holes only in the insert. This segmentation allows simple drilling of short holes in the insert while the seat provides structural support, resolving the contradiction between cooling reliability and manufacturing simplicity
Solution Approach 2:
The insert is nested within the seat, creating a hierarchical structure where the insert containing cooling holes is housed inside the larger seat structure. This nesting allows the cooling function to be implemented in a separate, easily manufactured component while maintaining the overall structural integrity
2Temperature
If compressed air is used for cooling the picture frame, then cooling effect is improved, but combustion efficiency deteriorates due to air not participating in combustion
Solution Approach 1:
The cooling function is extracted from the main combustion air flow by using a separate insert with dedicated cooling holes. This allows cooling air to be taken from the plenum separately, and the main combustion air can proceed to the combustor without being diverted for cooling, thus resolving the contradiction between cooling effect and combustion efficiency
Solution Approach 2:
The insert acts as an intermediary component that receives cooling air from the plenum through the seat and directs it to cool the picture frame. This intermediary structure enables the separation of cooling air supply from the main combustion air path, allowing both cooling and combustion to function optimally
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 reduces manufacturing costs, enhances cooling reliability, and improves combustion efficiency by utilizing compressed air more effectively, thereby increasing the lifetime of the component and minimizing emissions.
Implementation Method 1
the cooling air flows through long cooling holes passing the picture frame before being discharged in the hot gas flow
Implementation Method 2
The cooling medium used for cooling the picture frame is a portion of the compressed air present inside the plenum
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A gas turbine for power plants, the gas turbine (1) having an axis (9) and comprising a compressor (2) for compressing ambient air, a plenum (16) for receiving compressed air leaving the compressor (2), a plurality of can combustors (4) for mixing and combusting the compressed air leaving the plenum (16) with at least a fuel, a turbine (3) for expanding the combusted hot gas leaving the can combustors (4) and performing work on a rotor (8); wherein each can combustor (4) comprises a picture frame (21) for connecting the can combustor (4) to a turbine (3); each picture frame (21) comprising: a seat (22) in form a recess facing the turbine (3); an insert (23) housed in the seat (22) and configured to be coupled with the turbine (3) ; a first (29) and a second collector (30) for collecting cooling air between the seat (22) and the insert (23); an inlet hole (32) connecting the first collector (29) to the plenum (16) for feeding the first collector (29) with cooling air; at least a duct (31) connecting the first (29) to the second collector (30) for transferring the cooling air from the first (29) to the second collector (30); the transfer duct(31) being realized either inside the insert (23) or by being defined by matching portions of the seat (22) and the insert (23). (figure 3)