Compressor Coupling Hub Layout for High-Speed Rotor Dynamics
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Solution Overview
Problem
The mechanical coupling in existing centrifugal compressor systems, which couples the rotary shafts, overhangs outward in the axial direction, adversely affects rotor dynamics and limits the increase in rotation speed due to the presence of heavy components outside the bearing.
Innovation Solution
A compressor system design that includes a coupling shaft detachably connected to a compressor connecting hub, which alleviates misalignment and supports the rotary shaft with a gas bearing, allowing for improved rotor dynamics and increased rotation speed by positioning the compressor and motor connecting hubs on the inner side of the radial direction, reducing the impact of heavy components on the bearing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a mechanical coupling is disposed at a position that overhangs outward in the axial direction from a bearing, then the coupling can connect the rotary shafts, but the rotor dynamics of the rotary shaft will be adversely affected and the rotation speed cannot be increased
Solution Approach 1:
The coupling is repositioned from an axial overhang configuration to a radial inner side configuration. The coupling shaft is disposed on the inner side in the radial direction with respect to the bearing, changing the spatial dimension of the coupling arrangement. This dimensional change allows the coupling to connect the rotary shafts without adversely affecting rotor dynamics, enabling increased rotation speed.
Solution Approach 2:
A coupling shaft is introduced as an intermediary component to connect the motor rotor to the rotary shaft. The coupling shaft is detachably connected to a compressor connecting hub that is fixed to the rotary shaft. This intermediary structure allows for misalignment alleviation and proper force transmission while maintaining favorable rotor dynamics.
2Ease of manufacture
If a heavy object such as the mechanical coupling is provided outside the bearing, then the coupling can be installed, but it hinders an increase in the rotation speed of the rotary shaft
Solution Approach 1:
The coupling and coupling shaft are repositioned from an axial outer side location to a radial inner side location relative to the bearing. This dimensional repositioning places the heavy coupling components inside the bearing's radial footprint rather than outside it, reducing the moment of inertia and adverse effects on rotor dynamics, thereby enabling higher rotation speeds while maintaining ease of installation.
3Stability of the object's composition
If the coupling shaft is rigidly connected to the compressor connecting hub, then the connection is stable, but misalignment cannot be alleviated
Solution Approach 1:
The connection between the coupling shaft and the compressor connecting hub is made detachable rather than rigid. This dynamic connection allows the coupling shaft to be connected and disconnected as needed, and more importantly, allows for misalignment alleviation when connected. The detachable nature provides adaptability to handle misalignment while maintaining connection stability during operation.
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 enhances rotor dynamics and increases the rotation speed of the rotary shaft by alleviating misalignment and reducing frictional resistance, while also eliminating the need for lubricating oil, thus improving the overall efficiency and reliability of the compressor system.
Implementation Method 1
supports the rotary shaft with a gas bearing
Implementation Method 2
the coupling shaft is allowed to alleviate misalignment with the compressor connecting hub
Data Source
AI summary
A compressor system includes a compressor including a rotary shaft, an impeller, and a casing, a motor including a motor rotor disposed coaxially with the rotary shaft, and a coupling shaft coupling the motor rotor to the rotary shaft. The compressor includes a compressor bearing that rotatably supports the rotary shaft, and a compressor connecting hub that is fixed to the rotary shaft at a position where the compressor connecting hub overlaps the compressor bearing in the axial direction and at a position on an inner side in the radial direction. The coupling shaft is allowed to alleviate misalignment with the compressor connecting hub. The compressor bearing rotatably supports an outer peripheral surface of the compressor connecting hub.