Nonuniform Centrifugal Compressor Tip Clearance Noise Reduction
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Solution Overview
Problem
The existing uniform tip clearance structure in centrifugal compressors leads to increased aerodynamic noise due to tip clearance leakage vortices, which complicate the flow situation and enhance rotating and vortex noise.
Innovation Solution
A noise-reducing and nonuniform tip clearance structure is introduced, where the impeller tip clearance gradually decreases from the leading edge to the trailing edge, with a decreasing change rate, effectively reducing radial backflow and cross-blade circumferential flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a uniform tip clearance structure is used, then the manufacturing is simple, but the aerodynamic noise increases due to tip clearance leakage vortices
Solution Approach 1:
The tip clearance structure transitions from a uniform design to a nonuniform design where the clearance height varies along the circumferential direction. Specifically, the tip clearance is divided into different sections with different clearance heights, creating local quality variations that suppress the formation of tip clearance leakage vortices and reduce aerodynamic noise while maintaining manufacturing feasibility.
2Object-generated harmful factors
If the tip clearance is reduced to minimize leakage flow, then the aerodynamic noise decreases, but the flow loss inside the impeller increases due to radial backflow
Solution Approach 1:
The tip clearance is designed with different clearance heights at different circumferential positions. The leading edge region has a smaller clearance to suppress leakage vortices and reduce noise, while the trailing edge region has a larger clearance to prevent radial backflow and minimize flow loss. This local quality differentiation resolves the contradiction between noise reduction and energy loss prevention.
Solution Approach 2:
The tip clearance structure is segmented into multiple sections along the circumferential direction, with each section having an optimized clearance height. This segmentation allows independent optimization of different regions: the leading edge section focuses on noise reduction while the trailing edge section focuses on minimizing flow loss, thereby resolving the contradiction between these two objectives.
3Object-generated harmful factors
If a nonuniform tip clearance structure is implemented, then the aerodynamic noise is reduced, but the device complexity increases
Solution Approach 1:
The tip clearance structure is optimized by changing the clearance height parameter along the circumferential direction. By varying this single geometric parameter (clearance height) in different sections, the patent achieves noise reduction without introducing complex additional structures or components, thus limiting the increase in device complexity while effectively addressing the aerodynamic noise problem.
Data Source
AI summary
A noise-reducing and nonuniform tip clearance structure of centrifugal compressor is provided, which includes a compressor impeller body and a compressor impeller shroud. The compressor impeller shroud is circumferentially wrapped outside the compressor impeller body, and multiple impeller blade bodies are uniformly arranged in a circumferential direction of the compressor impeller body. A clearance between an impeller tip meridian line of the impeller blade body and an impeller shroud meridian line on the compressor impeller shroud is an impeller tip clearance. The impeller tip clearance gradually decreases in a direction from a leading edge to a trailing edge of the impeller blade body, and a change rate of the impeller tip clearance in the direction from the leading edge to the trailing edge of the impeller blade body also gradually decreases.