Thick-Walled Impeller Compressor for Low Mass Flow
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Solution Overview
Problem
Existing centrifugal compressor designs face challenges in operating at low mass-flow-rates and high pressure ratios without requiring extremely small impeller blade-heights, which complicates manufacturing and can lead to aerodynamic and efficiency issues.
Innovation Solution
The compressor wheel features a hub with a plurality of impellers forming flow channels, where at least some impellers are thick-walled at restriction points, limiting the sum of tangential dimensions at these points to a limited percentage of the circumference, such as 50%, to restrict fluid flow and allow taller impellers without compromising efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If impeller blade-heights are reduced to enable operation at low mass-flow-rates and high pressure ratios, then the compressor can operate at the desired performance levels, but manufacturing becomes complicated and aerodynamic efficiency deteriorates
Solution Approach 1:
The impellers are designed with non-uniform thickness distribution along their span, featuring thicker sections at specific locations (such as near the hub or at intermediate radii) and thinner sections elsewhere. This local variation in impeller geometry allows the compressor to achieve low mass-flow-rate operation and high pressure ratios without requiring uniformly small blade-heights throughout, thereby avoiding manufacturing complications and maintaining aerodynamic efficiency.
2Productivity
If impeller blade-heights are reduced to enable operation at low mass-flow-rates and high pressure ratios, then the compressor can operate at the desired performance levels, but aerodynamic efficiency deteriorates
Solution Approach 1:
The impellers are designed with non-uniform thickness distribution along their span, featuring thicker sections at specific locations (such as near the hub or at intermediate radii) and thinner sections elsewhere. This local variation in impeller geometry allows the compressor to achieve low mass-flow-rate operation and high pressure ratios without requiring uniformly small blade-heights throughout, thereby avoiding manufacturing complications and maintaining aerodynamic 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
This design enables operation at low mass-flow-rates and high pressure ratios without the need for small impeller blade-heights, reducing manufacturing complexities and maintaining aerodynamic efficiency.
Implementation Method 1
at least some of the impellers are thick-walled impellers at the flow-channel restriction points. A sum of the flow-channel restriction-point tangential dimensions for all of the plurality of flow channels is not greater than a limited percentage of the circumference at the flow-channel restriction points
Implementation Method 2
Centrifugal compressors transfer mechanical energy to a flowing stream of fluid to achieve an increased total energy level of the fluid
Data Source
AI summary
A compressor wheel having a hub and a plurality of impellers that define flow channels. At a restriction point downstream from an inducer-end and upstream from a point at which the flow channel turns from an axial flow to a radial flow, the impellers are thick-walled, and at that point a sum of the flow-channel restriction-point tangential dimensions is not greater than 50% of the circumference at the restriction point. The thick-walled impellers are formed with hollow cavities between pressure-side and suction-side walls. From the restriction point to an exducer, the sum of the flow-channels' tangential dimensions increases at least proportionately to the square of the radius from the axis-of-rotation.