Non-axisymmetric Impeller Hub Flowpath for Secondary Flow Reduction
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Solution Overview
Problem
Centrifugal impellers experience significant secondary flows due to high streamwise curvature, leading to efficiency losses and non-uniform gas flow exiting the impeller, which existing designs fail to adequately address.
Innovation Solution
A centrifugal impeller with a non-axisymmetric flowpath surface, where the runout of pressure-side and suction-side fillets are asymmetric, reducing vane-to-vane secondary flows by aligning with Mach number contours, thereby improving flow uniformity and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a conventional axisymmetric flowpath surface is used, then the impeller structure is simple and easy to manufacture, but significant secondary flows occur due to high streamwise curvature leading to efficiency losses and non-uniform gas flow
Solution Approach 1:
The patent applies asymmetry by designing a non-axisymmetric flowpath surface where the runout of the pressure-side fillet is asymmetric to the runout of the suction-side fillet. This asymmetric geometry aligns the flowpath with Mach number contours, reducing secondary flows and improving efficiency while maintaining manufacturability through systematic design approaches
2Manufacturing precision
If a conventional axisymmetric flowpath surface is used, then the manufacturing process is straightforward, but the gas flow exiting the impeller is non-uniform due to vane-to-vane secondary flows
Solution Approach 1:
The non-axisymmetric flowpath surface with asymmetric fillet runouts is designed to align with Mach number contours, which reduces vane-to-vane secondary flows and improves flow uniformity at discharge. The systematic approach to implementing this asymmetry maintains reasonable manufacturability
Solution Approach 2:
The patent applies local quality by specifically modifying the fillet runout regions of the flowpath surface where secondary flows are generated. The asymmetric runout geometry is implemented locally at critical locations rather than throughout the entire impeller, allowing targeted improvement of flow uniformity while limiting overall manufacturing complexity
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 non-axisymmetric flowpath surface design reduces secondary flows and enhances the uniformity and efficiency of gas discharge, improving the overall performance of the centrifugal impeller.
Implementation Method 1
a rotating rotor or impeller delivers air at relatively high velocity by the effect of centrifugal force on the gas within the impeller
Data Source
AI summary
A centrifugal impeller is disclosed having a non-axisymmetric flowpath surface. The centrifugal compressor may comprise a hub and a plurality of circumferentially spaced vanes. The hub has a flowpath surface and an axis of rotation. The plurality of circumferentially spaced vanes extend from the flowpath surface, with each of the vanes having a pressure-side fillet and a suction-side fillet extending from a leading edge to a trailing edge of the vane. The pressure-side fillet and suction-side fillet intersect the flowpath surface at a runout. The runout of the pressure-side fillet of a first vane is asymmetric to the runout of the suction-side fillet of the first vane.