Radial Compressor Guide Vane Asymmetry for Vibration Reduction
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Solution Overview
Problem
Radial compressor stages, particularly open impellers, experience high vibration excitation due to asynchronous mechanical excitations, leading to potential damage from unsteady and three-dimensional flow phenomena, with existing methods failing to effectively counteract these excitations.
Innovation Solution
The design of the radial compressor stage involves stator-side guide vanes with flow entry edges on a first circular contour and flow exit edges on a second circular contour, with varying distances and stagger angles at specific positions, and diffuser flow channel sections with non-uniform cross-sections to reduce unsteady flow phenomena and asynchronous excitations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the flow entry edges of all stator-side guide vanes are evenly distributed on a circular contour, then the manufacturing precision is improved, but asynchronous excitations and vibrations occur due to unsteady flow phenomena
Solution Approach 1:
The patent applies asymmetry by intentionally creating non-uniform spacing between guide vanes in the diffuser. Specifically, at least one diffuser flow channel section has a different flow cross-section compared to others, achieved by positioning guide vanes with varying circumferential distances. This asymmetric configuration disrupts the periodicity of flow interactions, thereby reducing asynchronous excitations and vibrations that would otherwise occur with evenly distributed vanes.
Solution Approach 2:
The patent implements local quality by introducing specific geometric variations at particular locations within the diffuser. Instead of uniform design throughout, the guide vanes are configured with different stagger angles and spacing at specific circumferential positions. This localized modification allows the system to maintain overall functional performance while targeting the reduction of vibrational excitations in critical areas.
2Object-affected harmful factors
If the diffuser flow channel sections have non-uniform cross-sections, then asynchronous excitations are reduced, but the device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the diffuser into multiple flow channel sections, each with potentially different geometric characteristics. The guide vanes are treated as discrete elements that can be individually positioned and angled, allowing the system to achieve the desired non-uniform cross-section configuration through modular arrangement rather than complex continuous variation.
Data Source
Figure 1~2
Figure 3~4
AI summary
A radial compressor stage comprising an impeller (10) rotating relative to a stator (12) with several rotor-side impeller blades (11) and a diffuser (19) positioned downstream of the impeller (10) in the flow direction, with several stator-side guide vanes (20), wherein an impeller side space (28) is formed between the impeller (10) and the stator (12). Flow inlet edges (22) of the stator-side guide vanes (20) lie on a first circular contour, such that the flow inlet edges (22) of all stator-side guide vanes (20) are spaced identically apart from the flow inlet edges (22) of the adjacent guide vanes (20).The flow outlet edges (23) of the stator-side guide vanes (20) lie on a second circular contour, such that at at least one first circumferential position the flow outlet edge (23) of the respective stator-side guide vane (20) has a different distance to the flow outlet edge (23) of at least one adjacent guide vane (20) than at second circumferential positions. (Fig. 1).