Centrifugal Compressor Impeller Fillet Design
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Solution Overview
Problem
Increasing the peripheral speed of a centrifugal compressor impeller to achieve a high compression ratio while maintaining durability, as simply projecting the trailing edge radially outward leads to increased stress and decreased natural frequency due to centrifugal forces.
Innovation Solution
The impeller design includes a hub with airfoil portions having a trailing edge configuration where the distance from the trailing edge to the axis increases with distance from the hub back surface, and a first fillet connecting the trailing edge to the outer peripheral surface of the hub, enhancing rigidity and stress distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the trailing edge of the airfoil is projected radially outward to increase peripheral speed, then the compression ratio is improved, but the stress on the airfoil portion increases and natural frequency decreases
Solution Approach 1:
A fillet portion is formed at the connection between the airfoil portion and the hub, replacing a sharp corner with a curved surface. This curvature distributes stress more evenly and prevents stress concentration, allowing the trailing edge to be projected radially outward for increased peripheral speed while maintaining structural strength and natural frequency.
2Speed
If the trailing edge of the airfoil is projected radially outward to increase peripheral speed, then the compression ratio is improved, but the manufacturing complexity increases
Solution Approach 1:
The fillet portion is defined by specific dimensional parameters (radius, position, curvature) that can be directly controlled during manufacturing processes such as CNC machining or mold making. By specifying these parameters, the complex curved surface becomes a routine manufacturing operation rather than a complex design challenge.
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 increases the compression ratio while ensuring the durability of the centrifugal compressor by mitigating stress and maintaining natural frequency, facilitating easier processing during manufacturing.
Implementation Method 1
an increase in stress due to a centrifugal force acting on the airfoil portion
Data Source
AI summary
An impeller of a centrifugal compressor is an impeller 5 of a centrifugal compressor, that is, a compressor impeller 5 and includes a hub, at least one airfoil portion erected on a hub surface of the hub, and a first fillet. The at least one airfoil portion has a trailing edge configured such that a distance between the trailing edge and an axis of the centrifugal compressor increases with increasing distance from a back surface of the hub. The first fillet is formed on a radially outer side of an outer peripheral surface of a back plate portion forming a back surface portion of the hub. The first fillet connects the outer peripheral surface of the back plate portion and the trailing edge of the at least one airfoil portion.