Gas Turbine Blade Tip Cooling Notch Segmentation
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Solution Overview
Problem
The high temperature at the tip of gas turbine engine airfoils poses a challenge for effective cooling, as existing cooling configurations may lead to leakage and inefficiencies due to the design of cooling passages and film cooling holes.
Innovation Solution
The airfoil design incorporates a notch around the perimeter of the tip, with cooling holes spaced from a plateau, and shelves on the pressure and suction sides that are strategically positioned to prevent leakage and enhance cooling, including a camber line that bisects the pressure and suction sides, and a blade outer air seal adjacent to the tip.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a notch circumscribed about the entire perimeter of the airfoil at the tip is used for cooling, then cooling coverage is improved, but leakage of working fluid increases and cooling efficiency deteriorates
Solution Approach 1:
The tip notch is segmented into distinct regions: a first notch region on the pressure side and a second notch region on the suction side, separated by a plateau. This segmentation allows differential cooling strategies for each side, preventing working fluid leakage while maintaining cooling coverage. The plateau acts as a barrier to contain the cooling fluid within the intended regions.
Solution Approach 2:
Different cooling configurations are applied to different sides of the tip notch. The pressure side has a first notch region with specific cooling holes, while the suction side has a second notch region with different cooling hole arrangements. This local differentiation optimizes cooling effectiveness for each side's specific thermal conditions while minimizing working fluid loss.
2Temperature
If cooling holes are positioned close to the tip perimeter for maximum cooling effect, then cooling effectiveness is improved, but wall thickness decreases and structural integrity deteriorates
Solution Approach 1:
The cooling holes are arranged in a two-dimensional pattern within the tip notch regions rather than simply along the perimeter. Cooling holes are positioned at multiple locations including near the leading edge, near the trailing edge, and at intermediate positions, creating a distributed cooling network that provides effective cooling while maintaining adequate wall thickness for structural integrity.
3Loss of energy
If shelves are added to the pressure and suction sides to prevent leakage, then working fluid containment is improved, but device complexity increases
Solution Approach 1:
The shelves on the pressure and suction sides are merged with the plateau to form an integrated tip structure. The plateau connects the two shelves and creates a unified containment system that prevents working fluid leakage without requiring separate, complex leakage prevention mechanisms. This merging reduces overall structural complexity while achieving the containment objective.
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 effectively reduces heat transfer and prevents burn-through and cracking by creating a boundary cooling layer, maintaining sufficient wall thickness and enhancing the cooling efficiency at the tip region.
Implementation Method 1
Film cooling holes communicate cooling fluid from the cooling passages to areas on the exterior surface of the turbine blade that may experience undesirably high temperatures
Implementation Method 2
shelves on the pressure and suction sides that are strategically positioned to prevent leakage and enhance cooling
Data Source
Figure 1
Figure 2A~2B
Figure 3~4
AI summary
An airfoil for a gas turbine engine includes pressure and suction walls spaced apart from one another and joined at leading and trailing edges to provide an airfoil having an exterior surface that extends in a radial direction to a tip. A camber line at the tip extends from the leading edge to the trailing edge. Pressure and suction side shelves are arranged in the exterior surface on opposing sides of the camber line respectively in the pressure and suction side walls. A plateau is proud of and separates the pressure and suction side shelves. The plateau is arranged along the camber line and extends to the leading edge.