Turbine Blade Dual Tip Flag Cooling for Lower Tip Heat Pickup
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Solution Overview
Problem
Existing turbine blades in gas turbine engines face challenges in effectively cooling the tip region due to high temperatures, leading to potential thermal degradation and reduced durability.
Innovation Solution
A dual tip flag passage system is implemented in the turbine blades, comprising a first outer tip flag passage oriented axially and a second radially located tip flag passage, with radial and serpentine core passages connected to these flag passages, enhancing cooling air distribution and reducing heat absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If cooling air is directed to the turbine blade tip region, then cooling effectiveness is improved, but heat pickup in the passages increases and reduces cooling air effectiveness
Solution Approach 1:
The cooling passages are segmented into multiple distinct passages (first tip flag passage, second tip flag passage, third tip flag passage, and core passages) with different flow paths and orientations. This segmentation allows each passage to serve specific cooling zones independently, optimizing cooling effectiveness while managing heat pickup in each passage separately.
Solution Approach 2:
Different passages are designed with different characteristics tailored to local cooling needs. The first tip flag passage extends axially near the tip to cool the tip region directly, while core passages extend radially to cool internal regions. Each passage's geometry and orientation are optimized for its specific location and thermal requirements.
2Temperature
If multiple cooling passages are added to improve cooling coverage, then cooling performance is improved, but device complexity increases
Solution Approach 1:
Multiple cooling passages are merged into a integrated cooling system where passages share common structures and flow paths. The tip flag passages and core passages work together as a unified cooling network, with some passages potentially sharing walls or connection points, reducing overall complexity while maintaining comprehensive cooling coverage.
Solution Approach 2:
The cooling passages serve multiple functions simultaneously. The tip flag passages not only cool the blade tip region but also help manage thermal gradients across the blade thickness. The serpentine core passages provide both cooling and structural support, serving dual purposes that reduce the need for additional dedicated components.
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 dual tip flag passage system improves cooling efficiency by minimizing heat pickup and increasing mass flow rate, resulting in lower operating metal temperatures and enhanced durability of the turbine blade tips.
Implementation Method 1
enhancing cooling air flow capacity and mass flow rate to improve internal convective cooling performance
Implementation Method 2
minimizes cooling air heat pickup, increases thermal cooling potential at the blade tip
Data Source
AI summary
A turbine blade includes a platform, a root section, and an airfoil section extending from the platform to a tip. The airfoil section includes a leading edge and a trailing edge extending from the platform to the tip. A tip wall is at the tip and extends from the leading edge to the trailing edge. A first core passage extends from the root section to the tip wall between the leading edge and the trailing edge. A first tip flag passage extends adjacent to the tip wall from the first core passage to a first flag outlet on the trailing edge. A second tip flag passage extends toward the leading edge from a second flag outlet on the trailing edge and is between the first tip flag passage and the root section. A second core passage extends from the root section to the second tip flag passage.