Turbine Blade Tip Cooling Circuits for Pressure Differential Management
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Solution Overview
Problem
Turbine engine blade cooling systems face inefficiencies due to pressure differentials along the blade surfaces, affecting the rate and effectiveness of cooling, particularly at the tip regions where cooling holes are located.
Innovation Solution
The design incorporates a first and second cooling circuit with tip portions extending along the leading and trailing edges of the turbine blade, respectively, with cooling holes at the tip in fluid communication, allowing for separate cooling fluid flows and optimized pressure ratios to enhance cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single cooling circuit is used with cooling holes at the tip, then the blade structure is simpler, but the cooling effectiveness is reduced due to varying pressure differentials along the blade surfaces
Solution Approach 1:
The cooling circuit is divided into multiple separate circuits (first cooling circuit and second cooling circuit), each serving different regions of the blade. The first cooling circuit serves the leading edge region with first tip portions and first cooling holes, while the second cooling circuit serves the trailing edge region with second tip portions and second cooling holes. This segmentation allows each circuit to be optimized for its specific region's pressure differential conditions, thereby improving overall cooling effectiveness without requiring excessive complexity.
Solution Approach 2:
Different cooling circuits are provided for different regions of the blade based on local cooling requirements. The first cooling circuit with its tip portions and cooling holes is specifically configured for the leading edge region, while the second cooling circuit is configured for the trailing edge region. This local quality approach ensures that each region receives cooling optimized for its specific thermal and pressure conditions.
2Temperature
If cooling holes are located at the tip regions, then cooling can be provided to critical areas, but the varying pressure differentials along the blade surfaces reduce the rate and effectiveness of cooling
Solution Approach 1:
The tip cooling function is segmented into first tip portions and second tip portions, each connected to separate cooling circuits. The first tip portions with first cooling holes address the cooling needs of the leading edge tip region, while the second tip portions with second cooling holes address the trailing edge tip region. This segmentation allows each tip region to be cooled independently according to its local pressure differential conditions.
Solution Approach 2:
Different tip regions are provided with different cooling configurations. The first tip portions and first cooling holes are optimized for the leading edge tip region's pressure conditions, while the second tip portions and second cooling holes are optimized for the trailing edge tip region's pressure conditions. This local quality approach maximizes cooling effectiveness at each critical tip location.
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 improves cooling efficiency by optimizing pressure ratios and reducing the cooling flow required, leading to a flow savings of 0.05-0.1% of total gas throughflow and an additional temperature benefit of 15° F. to 25° F. at the trailing edge, enhancing durability and reducing dust accumulation.
Implementation Method 1
passing a first cooling fluid through a first cooling circuit within the airfoil and having a first tip portion extending along the tip, passing a second cooling fluid through a second cooling circuit within the airfoil and having a second tip portion extending along the tip
Implementation Method 2
cooling the platform and blade used to cool the platform and blade
Implementation Method 3
pressure differential between an interior of the serpentine circuits and an exterior of the blade which varies along the surface of the blade
Data Source
AI summary
An apparatus and method an airfoil for a turbine engine, the airfoil comprising an outer wall defining an interior bound by a pressure side and a suction side extending axially between a leading edge and a trailing edge defining a chord-wise direction and extending radially between a root and a tip defining a span-wise direction. The airfoil further includes a first cooling circuit having a first portion and a first tip portion and a second cooling circuit having a second portion and a second tip portion.