Gas Turbine Airfoil Tip Cooling via Segmented Plenum
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Solution Overview
Problem
Gas turbine engine tips experience inefficient cooling due to pressure imbalances caused by tip baffles, leading to cooling fluid washing out without effectively cooling the airfoil tip, which affects turbine efficiency and durability.
Innovation Solution
The design incorporates a rib and tip baffle system that creates a tip plenum with multiple pockets and slots to laterally constrain and direct cooling air, minimizing fluid disruption and enhancing cooling efficiency by routing airflow through baffle and tip slots to the trailing edge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a tip baffle is used to improve airfoil efficiency associated with tip clearances, then airfoil efficiency is improved, but cooling fluid washes out without properly cooling the airfoil tip
Solution Approach 1:
The tip plenum is segmented into multiple pockets by the tip baffle, creating distinct cooling zones. The baffle divides the plenum into a first pocket and a second pocket, allowing separate control of cooling fluid distribution to different regions of the airfoil tip, thereby maintaining both efficiency and cooling effectiveness
Solution Approach 2:
Different regions of the tip plenum are given different functions through the baffle configuration. The first pocket provides cooling to one region while the second pocket cools another region, allowing localized optimization of cooling effectiveness while maintaining overall airfoil efficiency
2Temperature
If cooling air is ducted to turbine components to cool them, then cooling is achieved, but pressure imbalances cause cooling fluid to wash out
Solution Approach 1:
The tip baffle acts as an intermediary structure that mediates between the cooling fluid supply and the tip clearance region. It controls the pressure distribution and flow paths, preventing direct washing out of cooling fluid while still delivering effective cooling to the airfoil tip
Solution Approach 2:
The cooling air is pre-distributed into separate pockets within the tip plenum before reaching the tip clearance region. This preliminary segmentation and pressure equalization prevents pressure imbalances that would otherwise cause cooling fluid to wash out
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 configuration improves airfoil tip cooling, reduces leakage, and maintains turbine efficiency while extending durability and operational time by effectively routing and exhausting cooling air without washing out over the rib, thus addressing the inefficiencies in existing cooling methods.
Implementation Method 1
The rib and tip baffle system that creates a tip plenum with multiple pockets and slots to laterally constrain and direct cooling air, minimizing fluid disruption and enhancing cooling efficiency by routing airflow through baffle and tip slots to the trailing edge
Implementation Method 2
cooling is accomplished by ducting cooler air from the high and/or low pressure compressors to the engine components that require cooling
Implementation Method 3
Temperatures in the high pressure turbine can be around 1000° C. to 2000° C. and the cooling air from the compressor is around 500° C. to 700° C.
Data Source
AI summary
An apparatus and method of cooling a tip of an airfoil for a gas turbine engine, includes a rib circumscribing the tip to define a tip plenum. A tip baffle partially divides the tip plenum, being spaced from the rib by a baffle slot. The rib includes a tip slot in fluid communication with the baffle slot to provide a flow of cooling fluid along the tip of the airfoil for exhausting out the tip slot.