Centrifugal Compressor Diffuser Vane with Differential Turning Angles
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Solution Overview
Problem
As centrifugal compressors are miniaturized to reduce costs, the increased flow speed in the return flow path leads to separation issues at the diffuser vane, particularly at low flow rates, limiting the operational range.
Innovation Solution
The diffuser vane features distinct turning angles and chord lengths for hub-side and shroud-side blade shapes, with a continuous transition, allowing for gentle speed reduction and minimizing separation by matching blade shapes to fluid speed distributions, thereby maintaining a broader operational range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the diffuser vane is provided to reduce flow speed and suppress separation at the return flow path, then loss at the return flow path is reduced, but separation is likely to occur at the diffuser vane especially when flow rate is low
Solution Approach 1:
The patent applies local quality by differentiating the blade shapes at the hub side and shroud side of the diffuser vane. Specifically, the turning angle of the hub-side blade shape is set to be smaller than that of the shroud-side blade shape, creating locally optimized flow control characteristics that prevent separation at low flow rates while maintaining efficient deceleration across the entire diffuser vane span.
Solution Approach 2:
The diffuser vane is segmented into distinct hub-side and shroud-side blade shapes with different turning angles. This segmentation allows independent optimization of flow control at different radial positions, enabling the vane to handle varying flow conditions across its span and prevent separation at low flow rates.
2Ease of manufacture
If the centrifugal compressor is reduced in diameter for cost reduction, then manufacturing cost is reduced, but flow speed at the return flow path is increased leading to separation issues
Solution Approach 1:
The patent addresses the increased flow speed in miniaturized compressors by implementing local quality through differentiated blade shapes. The hub-side blade shape with smaller turning angle specifically targets the high-speed flow region near the hub, providing gentle deceleration that prevents separation even in compact designs with elevated flow velocities.
Solution Approach 2:
The patent changes the geometric parameters of the diffuser vane blades, specifically varying the turning angles between hub-side and shroud-side blades. This parameter optimization enables effective flow control in miniaturized compressors, allowing cost reduction through smaller diameter while maintaining acceptable flow speeds and preventing separation.
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 effectively suppresses separation at both the hub and shroud sides, even at low flow rates, thereby maintaining a larger operational range for the centrifugal compressor.
Implementation Method 1
a diffuser vane 60 which is provided in a diffuser channel 23 through which a fluid G that is sucked in by an impeller 4 rotating around an axis O from one side in an axial direction and is pressurized along to a radial outer side flows
Data Source
AI summary
This diffuser vane (60), of which a blade height direction is aligned with an axial direction, has an airfoil shape in cross section orthogonal to the blade height direction, and comprises a body which, starting from a leading edge at the end on the radially inner side toward the radially outer side, extends toward the front side in an impeller rotating direction (R) and reaches a trailing edge at the end on the radially outer side. In the body of the diffuser vane, the turning angle of a shroud-side blade shape (S) that is the airfoil of an end face on one side in the axial direction is different from the turning angle of a hub-side blade shape (H) that is the airfoil of an end face on the other side in the axial direction. The airfoils form a transition continuously between the shroud-side blade shape and the hub-side blade shape. The turning angle of the hub-side blade shape is smaller than the turning angle of the shroud-side blade shape.