Centrifugal Compressor Hub With Through Hole Reducing Thrust Load
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Solution Overview
Problem
The existing centrifugal compressors with through holes in the impeller suffer from reduced pressure ratio due to air current collisions with the inner circumferential surface downstream of the hole, leading to increased moment of inertia and thrust load.
Innovation Solution
A centrifugal compressor design featuring a hub with an external radial surface that gradually increases in diameter and a back surface, along with a through hole that has an inner and outer radial surface, where the outer surface is closer to the back surface than an imaginary curved surface, reducing moment of inertia and thrust load while minimizing air current collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a through hole is formed in the hub to reduce moment of inertia and thrust load, then the moment of inertia and thrust load are reduced, but air current collides with the inner circumferential surface downstream of the hole causing reduced pressure ratio
Solution Approach 1:
The patent applies local quality by creating a specific stepped structure at the downstream end of the through hole. The outer external radial surface is positioned closer to the back surface than an imaginary curved surface, creating a localized geometric feature that modifies airflow behavior precisely where the collision problem occurs, without changing the overall hub structure or adding significant weight.
Solution Approach 2:
The patent introduces an intermediary geometric structure (the stepped outer external radial surface) between the through hole and the back surface. This intermediary structure serves as a flow guide that redirects air currents away from the problematic collision zone, mediating between the through hole's weight reduction function and the pressure ratio maintenance requirement.
2Weight of moving object
If a through hole is formed in the hub to reduce moment of inertia and thrust load, then the moment of inertia and thrust load are reduced, but the thrust load increases due to air current collision
Solution Approach 1:
The patent applies local quality by creating a specific stepped structure at the downstream end of the through hole. The outer external radial surface is positioned closer to the back surface than an imaginary curved surface, creating a localized geometric feature that modifies airflow behavior precisely where the collision problem occurs, without changing the overall hub structure or adding significant weight.
Solution Approach 2:
The patent converts the harmful effect of air current collision into a beneficial flow pattern. By designing the outer external radial surface to be closer to the back surface, the structure intentionally creates a flow path that directs air currents away from collision points, transforming what would be a harmful impact into a controlled flow direction that reduces thrust load.
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 reduces the moment of inertia and thrust load on the impeller while maintaining pressure ratio performance by directing air currents away from collision points and optimizing the shape of the through hole and blades.
Implementation Method 1
The through hole thus formed reduces a moment of inertia of the impeller
Implementation Method 2
a portion of an air current flowing toward a discharging side along the external radial surface of the hub
Data Source
AI summary
A centrifugal compressor comprises an impeller including a hub and a plurality of blades. The hub is provided with a through hole. The hub has an external radial surface having an inner external radial surface and an outer external radial surface. The outer external radial surface is formed closer to a back surface than an imaginary curved surface having as a radius a radius of curvature of the inner external radial surface at a radially outer edge thereof.