Turbine Blade Tip Rail Cooling Insert Design
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Solution Overview
Problem
Conventional turbine blade tip cooling systems face challenges in effectively reducing leakage and providing efficient cooling to the tip rail, which is subjected to high heat loads and difficult to cool due to backflow pressure margin requirements and dust clogging issues, especially in regions with different temperature zones and during tip wear.
Innovation Solution
A turbine blade tip cooling system incorporating a tip rail cooling insert with a coolant collection plenum and insert cooling channels, designed to attach to the tip rail pocket, which directs coolant from internal cooling cavities to the insert cooling channels, addressing dust clogging and temperature variations through additive manufacturing techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If conventional tip rail cooling systems are used, then the structure is simple, but the cooling efficiency is insufficient due to high heat loads and backflow pressure margin requirements
Solution Approach 1:
The cooling system divides the tip rail into different temperature zones (first region with higher temperature, second region with lower temperature) and provides differentiated cooling to each zone. This local quality approach allows coolant to be directed precisely where most needed, improving overall cooling efficiency while reducing total coolant consumption.
Solution Approach 2:
The tip rail cooling system is segmented into multiple independent cooling channels (first cooling channel, second cooling channel) that can be controlled separately. This segmentation enables selective coolant flow to different regions of the tip rail, allowing optimization of cooling distribution and reduction of backflow pressure margins.
2Reliability
If coolant outlets are made larger to prevent dust clogging, then dust resistance improves, but cooling efficiency decreases due to increased backflow
Solution Approach 1:
Different outlet hole configurations are used in different regions of the tip rail. The first cooling channel has outlet holes with first dimensions in the first region, while the second cooling channel has outlet holes with second dimensions in the second region. This local differentiation allows each region to have optimized outlet characteristics for its specific thermal and flow conditions.
Solution Approach 2:
The outlet hole dimensions are varied as a parameter across different regions and channels. By changing the size and configuration of outlet holes based on local requirements, the system achieves both dust resistance and minimized backflow. The parameter variation allows optimization of the trade-off between clogging resistance and cooling efficiency.
3Temperature
If tip rail cooling is enhanced to handle high heat loads, then cooling effectiveness improves, but the system complexity increases due to multiple cooling channels and regions
Solution Approach 1:
The cooling system applies local quality by providing different cooling intensities and configurations to different regions of the tip rail based on their specific thermal requirements. The first region receives cooling through the first channel with specific outlet characteristics, while the second region receives cooling through the second channel with different characteristics, optimizing cooling effectiveness without uniform over-cooling.
Solution Approach 2:
The complex cooling requirement is managed through segmentation into distinct cooling channels and regions. Each segment can be designed and analyzed independently, making the overall complex system more manageable. The segmentation allows for modular design where each cooling channel serves a specific function and region.
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 system enhances cooling efficiency by selectively delivering coolant to high-temperature areas, reducing cooling flow requirements, and preventing clogging, while accommodating different temperature zones and tip wear, thereby improving the operational life of turbine blades.
Implementation Method 1
a coolant collection plenum for directing coolant from the at least one internal cooling cavity to the at least one insert cooling channel
Implementation Method 2
enhances cooling efficiency by selectively delivering coolant to high-temperature areas
Data Source
AI summary
A tip rail cooling insert for attaching into a tip rail pocket in a tip rail of a turbine blade is disclosed. The insert includes a first inner layer defining at least one first insert cooling channel therein, the first inner layer including a pair of spaced legs defining a first coolant collection plenum with at least the tip rail pocket for directing coolant from at least one internal cooling cavity in the turbine blade to the at least one first insert cooling channel. Each of the pair of spaced legs has an angled outer end configured to accommodate rounded inner corners of the tip rail pocket. A first outer layer is on a first side of the first inner layer, and a second outer layer is on a second side of the first inner layer.