Turbine Blade Tip Cavity Segmentation for Leakage Control
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Solution Overview
Problem
Over tip leakage in turbine blades leads to aerodynamic losses and reduced efficiency, as high-speed rotation and pressure differences cause gas flow through the gap between the blade tip and the turbine casing, forming a tip leakage vortex.
Innovation Solution
The solution involves a turbine blade design with a squealer tip wall and a separator wall that divides the tip cavity into two sub-cavities, with exit openings at the trailing edge to discharge leaked fluid back into the main flow, reducing pressure differences and leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a squealer tip wall is used to reduce over tip leakage, then aerodynamic losses are reduced, but the device complexity increases due to the need for additional separator walls and exit openings
Solution Approach 1:
The tip cavity is segmented into a first tip cavity on the pressure side and a second tip cavity on the suction side using a separator wall. This segmentation allows independent management of leakage flows from each side, enabling optimized exit openings that discharge leaked fluid back into the main flow at the trailing edge, thereby reducing aerodynamic losses while maintaining manageable structural complexity through systematic division of the cavity space
2Loss of energy
If the separator wall extends along the entire axial direction, then leakage flow is effectively separated and redirected, but the manufacturing precision requirements increase
Solution Approach 1:
The separator wall is positioned to extend from the leading edge to the trailing edge of the airfoil, providing localized separation of leakage flows. The exit openings are strategically positioned at the trailing edge where the separator wall meets the squealer tip wall, creating a controlled discharge path. This local quality approach ensures effective leakage separation while concentrating manufacturing precision requirements at critical interfaces rather than throughout the entire component
3Loss of energy
If exit openings are positioned at the trailing edge, then leaked fluid is discharged back into the main flow to reduce pressure differences, but the device complexity increases due to additional manufacturing steps
Solution Approach 1:
The exit openings are formed by merging the separator wall and squealer tip wall structures at the trailing edge. This integration allows the exit openings to be created as part of the overall tip cavity formation process, combining multiple manufacturing operations into a unified approach. The merged structure enables leaked fluid to be discharged back into the main flow, reducing pressure differences, while minimizing additional manufacturing complexity through structural integration
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 effectively reduces over tip leakage by redirecting leaked fluid back into the main flow at the trailing edge, minimizing aerodynamic losses and enhancing turbine efficiency.
Implementation Method 1
A separator wall (4) is provided which divides the tip cavity (3) into a first tip cavity (31) and a second tip cavity (32)
Implementation Method 2
with a first exit opening (5) formed in the squealer tip wall (2) in the area of the trailing edge and a second exit opening (6) formed in the squealer tip wall (2) in the area of the trailing edge
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
A blade (100) for a turbine (330) includes an airfoil (1) extending between a platform end (11) and a tip (12) and between a leading edge (13) and a trailing edge (14). A squealer tip wall (2) protrudes from a tip surface (12a) of the tip and defines a tip cavity (3). At least one separator wall (4) protrudes from the tip surface and divides the tip cavity into at least a first tip cavity (31) lying on a first side of the separator wall facing the pressure side (PS), and a second tip cavity (32) lying on a second side of the separator wall facing the suction side (SS). A first exit opening (5) is formed in the squealer tip wall in the area of the trailing edge, wherein the first exit opening defines a fluid passage between the first tip cavity and the pressure side. A second exit opening (6) is formed in the squealer tip wall in the area of the trailing edge, wherein the second exit opening defines a fluid passage between the second tip cavity and the suction side. A rotor assembly (200) and a turbine (300) are also provided.