Centrifugal Compressor Shroud Recesses Radial Vanes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional centrifugal compressors face challenges in reproducibly manufacturing a small, well-defined clearance between the shroud and impeller while maintaining no clearance between the shroud and diffuser vanes, due to manufacturing tolerances, which affects performance and requires high-precision manufacturing, limiting the use of certain materials.
Innovation Solution
The design incorporates a shroud and diffuser with recesses and radial vanes, allowing the shroud to cover the impeller and diffuser such that radial vanes project into recesses, enabling adjustable clearance without creating a radial gap between the vanes and shroud, and using plastics for cost-effective manufacturing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the clearance between the shroud and impeller is made as small as possible to maximise performance, then compressor efficiency is improved, but manufacturing precision requirements increase due to the difficulty of reproducibly manufacturing a small, well-defined clearance
Solution Approach 1:
The patent introduces radial vanes as an intermediary element between the shroud and impeller. These vanes extend into the clearance space and act to turn the working fluid, while their presence allows the shroud to be positioned at a larger, more manufacturable clearance distance without creating direct radial gaps that would allow fluid to bypass the vanes. The vanes mediate the interaction between the shroud and impeller, enabling both larger clearance and maintained efficiency.
Solution Approach 2:
The patent transitions from controlling clearance in the radial dimension to controlling it in the axial dimension. By positioning the shroud at a predetermined axial distance from the impeller (greater than the radial clearance), the design allows manufacturing tolerances in the axial direction while maintaining a well-defined, small radial clearance between the impeller and shroud. This dimensional shift enables more reproducible manufacturing.
2Productivity
If no clearance exists between the shroud and diffuser vanes to prevent fluid bypass, then compressor efficiency is improved, but manufacturing precision requirements increase due to the difficulty of ensuring no clearance while maintaining small shroud-impeller clearance
Solution Approach 1:
The radial vanes serve as an intermediary structure that eliminates the need for tight clearance control between the shroud and diffuser vanes. The vanes extend radially into the clearance space and are supported by the shroud structure, ensuring that no direct radial gap exists between the vanes and shroud. This intermediary arrangement prevents fluid bypass while allowing more tolerant manufacturing of the shroud-vane interface.
Solution Approach 2:
The patent applies different clearance requirements to different locations: a small, well-defined radial clearance between the impeller and shroud, and no radial clearance between the diffuser vanes and shroud (achieved by the vanes extending into recesses or being supported by the shroud). This localized quality approach allows efficient fluid turning at the vanes while maintaining manufacturable overall assembly tolerances.
3Productivity
If high-precision manufacturing is used to achieve small, well-defined clearance, then compressor performance is improved, but manufacturing cost increases
Solution Approach 1:
The radial vanes act as an intermediary that decouples the performance-critical clearance (between impeller and shroud) from the manufacturing-critical interfaces (between shroud and diffuser components). By introducing this intermediate structure, the patent allows standard manufacturing tolerances at the shroud-vane interfaces while maintaining the small, performance-critical clearance through the vane geometry and support structure, thereby reducing overall manufacturing cost.
Solution Approach 2:
The patent segments the clearance control function into two separate functions: (1) the radial vanes control the fluid turning and define the effective clearance space, and (2) the shroud positioning controls the overall assembly clearance. This segmentation allows each component to be manufactured with standard tolerances while achieving the combined effect of small, well-defined clearance, thereby reducing manufacturing complexity and cost.
4Ease of manufacture
If certain materials are used to reduce manufacturing cost, then ease of manufacture is improved, but manufacturing precision deteriorates due to the inability to achieve required tolerances
Solution Approach 1:
The radial vanes serve as an intermediary that compensates for manufacturing tolerances in cheaper materials. By positioning the vanes to extend into the clearance space and are supported by the shroud structure, the design ensures that small variations in material dimensions do not create direct radial gaps between the shroud and working surfaces. The vane geometry and support structure absorb tolerance variations, enabling the use of cost-effective materials while maintaining functional precision.
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 approach allows for a high-performance centrifugal compressor with a well-defined clearance, minimizing pressure losses and enabling the use of materials and processes that would otherwise be unsuitable, while maintaining efficient fluid turning and reducing manufacturing costs.
Implementation Method 1
A known design of centrifugal compressor comprises an impeller and vaned diffuser
Implementation Method 2
the shroud and diffuser define a chamber into which a working fluid ejected by the impeller is caused to expand
Implementation Method 3
The radial vanes are located within this chamber and act to turn the expanding fluid
Data Source
AI summary
A centrifugal compressor that includes an impeller, a diffuser and a shroud. One of the diffuser and shroud includes a plurality of recesses and the other of the diffuser and shroud includes a plurality of radial vanes. The shroud covers the impeller and diffuser such that each radial vane projects into a respective recess.