Segmented Tip Shroud for High Aspect Ratio Compressor Blades
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Solution Overview
Problem
Modern gas turbine engine compressor blades with low aspect ratios face challenges in aeromechanical problems and compressor stability, while high aspect ratio designs are inefficient due to longer lengths and increased weight.
Innovation Solution
A tip shrouded compressor stage with a noncontiguous ring shroud and labyrinth seals, supporting blades with an aspect ratio of 1.6 to 2.8, which extends the full chord and provides an outer flow path surface, improving efficiency and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If compressor blades use low aspect ratio (1.2-1.4), then aeromechanical stability and compressor stability improve, but blade span must increase to maintain sufficient annulus area for desired airflow
Solution Approach 1:
The shroud is divided into discrete segments rather than forming a continuous ring. This segmentation allows the shroud to accommodate high aspect ratio blades while maintaining structural integrity and providing necessary sealing, thus enabling longer blade spans without compromising stability
Solution Approach 2:
The invention transitions from traditional low aspect ratio blades to high aspect ratio blades by changing the geometric dimensions. The aspect ratio increases from 1.2-1.4 to 2.0 or higher, fundamentally altering the blade geometry to achieve both longer span and maintained stability through the segmented shroud configuration
2Length of moving object
If compressor blades use high aspect ratio (2.0 or higher), then blade span increases providing sufficient annulus area for desired airflow, but aeromechanical problems and compressor stability issues increase
Solution Approach 1:
The shroud is divided into discrete segments rather than forming a continuous ring. This segmentation allows the shroud to accommodate high aspect ratio blades while maintaining structural integrity and providing necessary sealing, thus enabling longer blade spans without compromising stability
Solution Approach 2:
The invention changes the geometric parameters of the blade system by increasing the aspect ratio from traditional 1.2-1.4 to 2.0 or higher. This parameter change is made possible by the segmented shroud design, which accommodates the longer blades while maintaining the necessary structural and sealing properties
3Strength
If continuous unbroken shroud is used, then structural support is provided, but performance is degraded
Solution Approach 1:
The shroud is divided into discrete segments rather than forming a continuous ring. Each segment provides localized structural support while the gaps between segments improve performance by reducing weight, allowing relative movement, and enhancing sealing effectiveness through the labyrinth seal configuration
Solution Approach 2:
Different portions of the shroud system have different properties: the solid segments provide structural support and containment, while the gaps provide weight reduction and movement capability. The labyrinth seals at specific locations provide enhanced sealing where needed, creating a system with optimized local qualities throughout
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 solution allows for increased aspect ratios without the limitations of past designs, resulting in shorter length, lower weight, higher efficiency, and improved stability for compressor stages.
Implementation Method 1
The sealing structure has labyrinth seals
Data Source
Figure 1
Figure 2~2A
Figure 3
AI summary
A gas turbine engine compressor stage includes a rotor (70). Compressor blades (71) are supported by the rotor (70). The blades (71) include an inner flow path surface each supporting an airfoil that has a chord (80) that extends radially along a span (78) to a tip. A shroud (82) is supported at the tip and provides an outer flow path surface. The shroud (82) provides a noncontiguous ring about the compressor stage.