Turbine Bucket Plenum Cooling Circuit Segmentation
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Solution Overview
Problem
Existing bucket assemblies in turbine systems face inadequate cooling, particularly in the aft portion of the platform and the area adjacent to the suction side face, leading to higher-than-desired temperatures despite the use of conventional cooling passages and circuits.
Innovation Solution
The bucket assembly incorporates a plenum defined in the platform, which is in fluid communication with the main cooling circuit and extends towards the suction side face, tapering towards the root, allowing for improved distribution and mixing of the cooling medium to effectively cool previously hard-to-reach areas, including the aft portion and suction side face.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional cooling passages and circuits are used in the platform, then cooling is provided to general areas, but the aft portion and suction side face adjacent areas reach higher than desired temperatures
Solution Approach 1:
The cooling system is segmented into multiple independent circuits: a first cooling circuit with a first plenum for cooling the forward portion, and a second cooling circuit with a second plenum for cooling the aft portion. This segmentation allows each circuit to be optimized for its specific region, enabling effective cooling of previously hard-to-reach areas like the suction side face adjacent region without requiring a single complex circuit to serve all areas.
Solution Approach 2:
Plenums are introduced as intermediary components between the cooling medium source and the platform surfaces. The first plenum and second plenum act as intermediate chambers that distribute cooling medium to multiple outlet passages, allowing for more uniform and effective cooling distribution across the platform, particularly to the aft portion and suction side face adjacent areas that were previously under-cooled.
2Temperature
If cooling medium flow is increased to cool the aft portion and suction side face, then temperature control improves, but cooling medium consumption increases
Solution Approach 1:
Different regions of the platform are provided with dedicated cooling circuits tailored to their specific cooling requirements. The second cooling circuit with the second plenum is specifically configured for the aft portion and suction side face adjacent region, allowing cooling medium to be directed precisely where needed. This local quality approach ensures that cooling medium is not wasted in areas that already have adequate cooling from the first circuit, while providing enhanced cooling to areas that require it.
3Reliability
If the platform is cooled more effectively, then component reliability improves, but the device complexity increases due to additional cooling circuits
Solution Approach 1:
The cooling system is divided into two separate but coordinated circuits, each with its own plenum and outlet passages. This segmentation allows for independent optimization and maintenance of each cooling zone, improving overall reliability by isolating potential failure modes to specific circuits rather than affecting the entire cooling system. The first and second cooling circuits can be designed with appropriate redundancy and monitoring for their respective regions.
Solution Approach 2:
The cooling circuits are nested within the platform structure, with plenums and passageways integrated into the platform's internal geometry. The first and second plenums are positioned to utilize the existing platform thickness and internal volume, allowing multiple cooling functions to be nested within the same structural envelope. This nesting approach provides enhanced cooling capability without proportionally increasing the external dimensions or overall complexity of the bucket assembly.
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 enhances cooling efficiency by directing the cooling medium to previously under-cooled areas, preventing temperature increases and potentially reducing the weight of the bucket assembly while allowing for more uniform loading and improved performance.
Implementation Method 1
The plenum is in fluid communication with the main cooling circuit and extends from the main cooling circuit towards the suction side slash face
Implementation Method 2
cooling medium may be flowed through the various cooling passages and cooling circuits to cool the bucket
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A bucket assembly for a turbine system includes a main body (32) having an exterior surface and defining a main cooling circuit (82,84). The bucket assembly further includes a platform (34) surrounding the main body (32) and at least partially defining a platform cooling circuit (90). The platform includes a forward portion and an aft portion each extending between a pressure side slash face and a suction side slash face and further includes a forward face, an aft face, and a top face. The bucket assembly further includes a plenum (100) at least partially defined in the platform. The plenum is in fluid communication with the main cooling circuit (82,84) and extends from the main cooling circuit towards the suction side slash face.