Compressor Rotor Blade Sealing with Partial Upstream Shroud
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Solution Overview
Problem
In multi-stage axial flow compressors, leakage flows through gaps between rotor and stator blade rows lead to performance deterioration, and existing solutions like shroud integrated rotor blades and shroud segments do not fully address the issue of low energy fluid accumulation and separation, affecting efficiency and surge margin.
Innovation Solution
A compressor rotor blade arrangement with a seal mechanism that hermetically seals the radial inner end on the upstream side and includes a hub or tip clearance on the downstream side, using a hollow cylindrical shroud and seal member to reduce leakage and low energy fluid accumulation, verified through CFD analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a shroud is provided from the front edge to the rear edge of the rotor blade tip (full shroud), then leakage flow is reduced, but device complexity and weight increase
Solution Approach 1:
The shroud is divided into two segments: a first shroud from the front edge to an intermediate position, and a second shroud from the intermediate position to the rear edge. This segmentation allows the system to achieve leakage flow reduction benefits while reducing overall complexity by using a simplified second shroud structure in the rear portion where leakage impact is less critical.
Solution Approach 2:
Different shroud structures are applied to different regions of the blade tip based on local requirements. The first shroud provides complete sealing where leakage impact is highest, while the second shroud uses a simplified structure (such as a seal fin without a full shroud) in regions where complete sealing is less critical, optimizing the balance between performance and complexity.
2Loss of energy
If a full shroud is provided along the entire blade tip, then leakage flow is reduced, but weight of the rotor blade increases
Solution Approach 1:
The shroud is divided into two segments: a first shroud from the front edge to an intermediate position, and a second shroud from the intermediate position to the rear edge. This segmentation allows the system to achieve leakage flow reduction benefits while reducing overall complexity by using a simplified second shroud structure in the rear portion where leakage impact is less critical.
Solution Approach 2:
Different shroud structures are applied to different regions of the blade tip based on local requirements. The first shroud provides complete sealing where leakage impact is highest, while the second shroud uses a simplified structure (such as a seal fin without a full shroud) in regions where complete sealing is less critical, optimizing the balance between performance and complexity.
3Ease of manufacture
If clearance is maintained between rotor and stator blade rows, then ease of manufacture is improved, but leakage flow increases causing performance deterioration
Solution Approach 1:
A shroud structure is introduced as an intermediary element between the rotor blade tip and the stator blade row. This shroud acts as a mediator that reduces the effective clearance gap without requiring changes to the rotor or stator blade manufacturing, thereby maintaining ease of manufacture while significantly reducing leakage flow and improving compressor performance.
Data Source
Figure 1
Figure 2
Figure 3A~3E
AI summary
The present invention relates to a compressor rotor blade (20) comprising a seal mechanism (22) configured to hermetically seal a part between a radial outer end on the upstream side and an inner surface of a stationary body (9), wherein a remainder part on the downstream side of the seal mechanism (22) includes a tip clearance (24) between the inner surface of the stationary body (9) and the radial outer end of the compressor rotor blade (20).