Gas Turbine Compressor Casing Groove with Axial Undercuts
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Solution Overview
Problem
Existing gas turbine compressors face challenges in maintaining optimal performance and reducing undesired flow phenomena during both design and off-design operations, particularly due to limitations in casing treatment and aerodynamic efficiency.
Innovation Solution
A gas turbine compressor design featuring a circumferential groove with axial undercuts and radially cutback webs on the flow channel wall, where the webs extend continuously over 360°, maintaining constant curvature with the flow channel contour to minimize asymmetries and enhance manufacturing and aerodynamic efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If casing treatment with circumferential grooves and webs is implemented, then off-design performance is improved, but undesired flow phenomena occur under nominal conditions
Solution Approach 1:
The groove geometry is optimized with specific parameters (groove width s between 0.005D and 0.02D, groove depth d between 0.002D and 0.005D, web thickness e between 0.003D and 0.006D) to create different flow control effects in different operating conditions. The axial undercut dimension a (between 0.001D and 0.003D) specifically addresses flow separation at the groove edge, providing local flow control quality that improves off-design performance while minimizing adverse effects at nominal conditions.
Solution Approach 2:
The invention changes the geometric parameters of the circumferential groove and web structure, specifically introducing the axial undercut dimension and optimizing the ratio of groove dimensions to rotor outlet diameter D. These parameter changes enable the casing treatment to adapt its flow control characteristics, improving performance across different operating points while reducing harmful flow phenomena.
2Ease of manufacture
If complex casing treatment structures are added to improve aerodynamic efficiency, then manufacturing complexity increases
Solution Approach 1:
The casing treatment is segmented into discrete circumferential grooves separated by radial webs, allowing the structure to be manufactured using standard machining operations. The grooves can be milled or turned individually around the compressor casing, and the webs provide natural separation between grooves. This segmentation enables complex aerodynamic functionality to be achieved through relatively simple, repeatable manufacturing steps.
Solution Approach 2:
The circumferential groove structure with radial webs serves multiple functions simultaneously: it acts as a casing treatment to control boundary layer flow, provides structural reinforcement to the compressor casing, and creates flow separation control features. This multi-functionality reduces the need for additional separate components, thereby simplifying manufacturing while maintaining aerodynamic efficiency.
Data Source
Figure 1
AI summary
The present invention relates to a gas turbine compressor, comprising at least one blade tip (10) and a flow channel wall (20) radially opposite the blade tip, in which a circumferential groove (31-33) is arranged, in which at least one web (40) is arranged, having a radial recess (44), wherein an upstream beginning (41) of the recess is arranged axially downstream of an upstream groove edge (21) between this groove edge and an upstream leading edge (11) of the blade tip, and a downstream end (42) of the recess is arranged in a blade tip-adjacent half (34) of a radial height (35) of the circumferential groove.