Scroll Flow Path Wall 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 leads to a decrease in flow path cross-sectional area, compromising compression efficiency, while reducing the wall thickness of the flow path wall impairs structural integrity.
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 that transitions smoothly from the thickened portion to the inner wall, maintains structural integrity and flow path cross-sectional area, while allowing for a smaller size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the outer diameter of the scroll flow path is reduced to decrease compressor size, then the device dimensions are improved, but the flow path cross-sectional area decreases resulting in reduced compression efficiency
Solution Approach 1:
The flow path wall is designed with non-uniform thickness distribution, featuring a thickened outer peripheral wall portion and a thinner inner peripheral wall portion. This local quality variation allows the outer diameter to be reduced for compactness while the thickened outer portion maintains sufficient flow path cross-sectional area for compression efficiency.
2Area of stationary object
If the wall thickness of the flow path wall is reduced to maintain flow path cross-sectional area, then the device dimensions are improved, but the structural integrity of the containment is impaired
Solution Approach 1:
Different portions of the flow path wall are assigned different thicknesses based on their functional requirements. The outer peripheral wall portion is thickened to provide structural integrity and contain operational anomalies, while the inner peripheral wall portion is thinner to maintain adequate flow path cross-sectional area.
Solution Approach 2:
The flow path wall exhibits asymmetric thickness distribution, with the outer peripheral wall portion having greater thickness than the inner peripheral wall portion. This asymmetric design optimizes both structural strength and flow path area within the same component.
3Length of stationary object
If the outer diameter of the scroll flow path is reduced to decrease compressor size, then the device dimensions are improved, but the containment property of the compressor impeller is compromised
Solution Approach 1:
The outer peripheral wall portion is specifically thickened to enhance containment capability against operational anomalies of the compressor impeller. This localized reinforcement maintains reliability even when the overall outer diameter is reduced for compactness.
Data Source
AI summary
An example centrifugal compressor includes 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 includes an outer peripheral wall located on an outer side of the scroll flow path in a radial direction of the rotary shaft; and an inner peripheral wall located on an inner side of the scroll flow path closer to the rotary shaft than the outer peripheral wall in the radial direction. The outer peripheral wall includes a thickened portion having a wall thickness greater than a wall thickness of a portion of the inner peripheral wall that is opposite the thickened portion in the radial direction.