Gas Turbine Compressor Blade Tip Groove Segmentation
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Solution Overview
Problem
Existing gas turbine compressors face challenges in maintaining optimal operating behavior under both design and off-design conditions, with unwanted flow phenomena occurring due to the design of blade tips and circumferential grooves, as seen in EP 2927503 A1.
Innovation Solution
A gas turbine compressor design featuring blades with radially outer tips opposite a flow channel wall, incorporating a circumferential groove with axial undercuts and webs that have radial cutbacks, optimizing the axial and radial distances between blade tips and groove edges to reduce unwanted flow phenomena and improve aerodynamics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blade tips are designed without cover strips and circumferential grooves are added to the flow channel wall, then the housing structuring improves off-design operation behavior, but unwanted flow phenomena occur under nominal operating conditions
Solution Approach 1:
The circumferential groove is segmented by arranging multiple webs (at least two, preferably three or more) spaced around the circumference. This divides the single groove into multiple smaller grooves, each interacting with individual blade tips. This segmentation allows the groove structure to maintain effectiveness in off-design operations while reducing the intensity and extent of unwanted flow phenomena during nominal operation, as the flow disturbances are distributed and reduced rather than concentrated in a single large groove.
Solution Approach 2:
The groove geometry is optimized with specific dimensional relationships: the axial distance between the upstream groove edge and blade tip leading edge is controlled to be between 5-40% of the blade tip chord length, and the radial distance is controlled to be between 10-200% of the gap height. These localized geometric optimizations ensure that the groove structure provides beneficial housing structuring effects during off-design operations while minimizing adverse flow phenomena during nominal operation.
2Reliability
If the axial distance between upstream groove edge and blade tip leading edge is increased, then off-design operation is improved, but the groove may extend too far upstream causing flow interference
Solution Approach 1:
The axial distance L_Ol between the upstream groove edge and blade tip leading edge is precisely controlled as a key geometric parameter, set to be between 5-40% of the blade tip chord length S_AX. This parameter optimization ensures that the groove is positioned far enough upstream to provide effective housing structuring for off-design operations, yet not so far upstream as to cause excessive flow interference or extend into regions that would disrupt the incoming flow field.
3Reliability
If the radial distance between blade tip and groove edge is increased, then the groove structure becomes more effective, but the groove may extend too far radially causing excessive disruption to the flow channel
Solution Approach 1:
The radial distance L_KOz between the blade tip and groove edge is precisely controlled as a key geometric parameter, set to be between 10-200% of the gap height H_GAP. This parameter optimization ensures that the groove extends far enough radially to provide effective housing structuring and flow control, yet remains within acceptable limits to avoid excessive disruption to the flow channel and maintain proper flow guidance.
Data Source
Figure 1
AI summary
The present invention relates to a gas turbine compressor, comprising at least one blade tip (10) having an upstream leading edge (11) and a downstream trailing edge (12), and a flow channel wall (20) radially opposite this blade tip, in which a circumferential groove (31-33) having an upstream groove edge (21) and a downstream groove edge (22) is arranged, wherein at least one web (40) is arranged in the circumferential groove having a radial recess (44), wherein in at least one meridional section through a blade tip-side end face of the web an axial distance (LKOZ) between an upstream beginning (41) of the recess and the upstream leading edge (11) of the blade tip is at least 1% and/or at most 40% of a chord length (SAX) between the upstream leading edge (11) and the downstream trailing edge (12) of the blade tip and/or an axial distance (LOL) betweenthe upstream leading edge (11) of the blade tip and the downstream groove edge (22) is at least 5% and/or at most 40% of the chord length (SAX) between the upstream leading edge (11) and the downstream trailing edge (12) of the blade tip and/or an axial distance (Δ45) between the upstream leading edge (11) of the blade tip and a kink of a blade tip-side upper edge (43) of the web in the back section is at most 10% of the chord length (SAX) between the upstream leading edge (11) and the downstream trailing edge (12) of the blade tip and/or a radial distance (HKOZ) between the blade tip (10) and a blade tip-side upper edge (43) of the web in the back section is at least 50% and/or at most 1500% of a radial distance (HGAP) between the blade tip (10) and the radially opposite downstream groove edge (22).