Turbine Bucket Tunable Plenums for Platform Cooling
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Solution Overview
Problem
Turbine buckets in gas turbines are prone to overheating due to high temperatures, leading to deterioration and increased operational costs from frequent replacements, as existing cooling passages may not adequately address cooling needs, especially on the bucket platforms.
Innovation Solution
The introduction of tunable plenums machined into cast turbine buckets, which include plenum chambers and passages connected to a cooling flow source, allowing for redirected cooling flow to enhance cooling efficiency and adapt to changing operational needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional cast cooling passages are used in turbine buckets, then the manufacturing process is simple, but the cooling effectiveness is insufficient especially on bucket platforms
Solution Approach 1:
The cooling system is divided into multiple independent plenums (first plenum, second plenum, third plenum) that can be separately controlled. Each plenum receives cooling flow through dedicated passages and distributes it to specific regions of the turbine bucket, allowing independent optimization of cooling effectiveness in different areas without redesigning the entire cooling system.
Solution Approach 2:
Different plenums are positioned to provide targeted cooling to specific high-temperature regions of the turbine bucket. The first plenum cools the bucket root, the second plenum cools the bucket platform, and the third plenum cools the airfoil leading edge, ensuring that cooling resources are concentrated where most needed rather than distributed uniformly.
2Reliability
If cooling passages are added to improve cooling, then cooling effectiveness increases, but manufacturing complexity increases
Solution Approach 1:
The plenums and cooling passages are pre-formed as integral parts of the turbine bucket during the casting process. The mold includes features that create the plenum chambers and passage structures before the bucket is manufactured, eliminating the need for complex post-casting machining or assembly operations to create the cooling system.
Solution Approach 2:
The plenums serve multiple functions: they act as cooling chambers, flow distribution manifolds, and structural components of the turbine bucket. The same plenum structure that provides cooling also serves as part of the bucket's mechanical framework, reducing the need for separate components and simplifying manufacturing.
3Reliability
If cooling flow is redirected to plenums, then cooling distribution is improved, but flow control complexity increases
Solution Approach 1:
The plenum system automatically distributes cooling flow based on the inherent pressure gradients and passage geometry. Cooling air entering the plenums is distributed to various regions according to the designed passage configurations without requiring external control mechanisms, valves, or active flow management systems.
Solution Approach 2:
The plenums act as intermediary chambers between the cooling air source and the various cooling locations on the turbine bucket. They receive cooling flow and passively distribute it through connected passages to the root, platform, and airfoil regions, simplifying the overall flow control by using the plenum chamber geometry as the control mechanism rather than active valves or pumps.
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 solution provides improved durability and reduced operational costs by ensuring effective cooling of turbine buckets, extending their lifespan and maintaining gas turbine efficiency through targeted cooling distribution.
Implementation Method 1
cooling gases flowing through internal passages in the buckets
Implementation Method 2
cooling effect that counteracts with the high temperature environment
Data Source
AI summary
A casted turbine bucket having at least one machined plenum including a plenum chamber and at least one plenum passage connected to a plenum inlet at a root portion of turbine bucket, and a method to feed cooling flow to the turbine bucket using the machined plenum that receives cooling flow from the root portion of the turbine bucket.