Scroll Flow Path Wall Thickness Layout for Compact Centrifugal Compressors
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Solution Overview
Problem
Reducing the outer diameter of a scroll flow path in a centrifugal compressor to minimize size results in a decrease in flow path cross-sectional area, compromising compression efficiency, while reducing the wall thickness of the flow path wall to maintain area risks impairing containment properties if the impeller is damaged.
Innovation Solution
A centrifugal compressor design with a thickened outer peripheral wall portion and a thinner inner peripheral wall portion, along with a connecting wall portion featuring a continuous thickness change, maintains containment properties and secures the required flow path cross-sectional area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the outer diameter of the scroll flow path is reduced to minimize size, then the size of the centrifugal compressor is reduced, but the flow path cross-sectional area decreases resulting in decreased compression efficiency
Solution Approach 1:
The flow path wall is designed with non-uniform thickness, featuring a thickened portion in the outer peripheral wall where containment is most critical. This local quality variation allows the wall to provide enhanced containment protection in the outer region while maintaining thinner sections elsewhere, thereby preserving flow path cross-sectional area and compression efficiency without compromising overall containment capability
2Volume of moving object
If the wall thickness of the flow path wall is reduced to maintain flow path cross-sectional area, then the size is reduced, but the containment property is impaired if the impeller is damaged
Solution Approach 1:
The flow path wall incorporates a thickened portion specifically in the outer peripheral wall where containment demand is highest. This localized thickness enhancement ensures that even with overall reduced wall thickness, the critical outer region maintains sufficient containment property to safely contain a damaged impeller, while thinner sections in less critical areas preserve size reduction goals
3Reliability
If the wall thickness is increased to maintain containment property, then the containment property is improved, but the flow path cross-sectional area is reduced resulting in decreased compression efficiency
Solution Approach 1:
Rather than uniformly increasing wall thickness throughout, the invention applies thickness enhancement only to the thickened portion in the outer peripheral wall where containment is most critical. This selective approach maintains containment property in critical areas while preserving flow path cross-sectional area in other regions, thereby avoiding the trade-off between containment and compression efficiency
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
The design maintains containment properties and secures the necessary flow path cross-sectional area, allowing for a reduction in size without compromising efficiency.
Implementation Method 1
the outer peripheral wall portion disposed outward from the rotary shaft in the radial direction is most likely to be affected
Data Source
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AI summary
This centrifugal compressor is provided with a rotary shaft, a compressor impeller fixed to the rotary shaft, and a flow path wall forming a scroll flow path around the compressor impeller. The flow path wall is provided with an outer peripheral wall portion disposed on an outer side in a radial direction of the rotary shaft, and an inner peripheral wall portion disposed on an inner side closer to the rotary shaft than the outer peripheral wall portion in the radial direction. The outer peripheral wall portion is provided with a thickened portion having a wall thickness greater than that of the inner peripheral wall portion facing in the radial direction.