Centrifugal Compressor Scroll Flow Path Curvature Design
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Solution Overview
Problem
The radially-inner end of the scroll flow path in centrifugal compressors is positioned too close to the diffuser flow path, leading to a large curvature on the inner side, causing significant air separation along the scroll flow path wall.
Innovation Solution
The centrifugal compressor design includes a scroll flow path with a radially-inner end positioned at the radially-innermost position, spaced apart from the diffuser flow path's middle point of maximum flow path width, featuring first and second curvature surfaces with equal or varying radii to reduce air separation, and a varying separation distance along the rotational axis direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the radially-inner end of the scroll flow path is located closer to the diffuser flow path, then the scroll flow path can be more compact, but the curvature of the cross-sectional shape increases causing air separation
Solution Approach 1:
The patent applies local quality by differentiating the curvature radius of the radially-inner surface into two zones: a first curvature surface with a larger radius of curvature near the diffuser flow path to reduce air separation, and a second curvature surface with a smaller radius of curvature further from the diffuser to maintain compactness. This localized variation in geometric properties resolves the contradiction between compactness and air separation prevention.
2Length of moving object
If the radially-inner end is positioned closer to the diffuser flow path, then the overall compressor size can be reduced, but flow direction changes significantly causing performance degradation
Solution Approach 1:
The patent utilizes curvature principles by carefully designing the radially-inner surface with varying radius of curvature. The first curvature surface has a larger radius to reduce flow direction changes and prevent air separation, while the second curvature surface has a smaller radius to achieve the desired compact length. This controlled curvature variation maintains both compact dimensions and flow stability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design effectively curbs flow separation along the scroll flow path wall, enhancing the compressor's performance by maintaining smooth air flow and reducing the expansion of the separation area.
Implementation Method 1
air is likely to separate from an inner surface of the scroll flow path on the inner side closer to the diffuser flow path
Data Source
AI summary
A centrifugal compressor includes: a housing accommodating an impeller; a diffuser flow path formed radially outside the impeller in the housing; and a scroll flow path formed in the housing and connected to the diffuser flow path from a radially-outer side, the scroll flow path extending in a rotational axis direction and a rotational direction of the impeller with respect to the diffuser flow path, the scroll flow path including a radially-inner end located at the radially-innermost position, and the radially-inner end being spaced apart from the diffuser flow path with respect to a middle point of the maximum flow path width of the scroll flow path in the rotational axis direction.