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 overhangs outward in the axial direction from the bearing, adversely affects rotor dynamics and limits the increase in rotation speed of the rotary shaft.
Innovation Solution
A compressor system with a coupling shaft that couples the motor rotor to the rotary shaft, allowing for misalignment alleviation through a detachable connection to the compressor and motor connecting hubs, and utilizing gas bearings and a thrust force adjusting unit to improve rotor dynamics and increase rotation speed.
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 the bearing, then the coupling can connect the motor rotor to the rotary shaft, but the rotor dynamics of the rotary shaft are 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, changing the spatial dimension of the coupling arrangement. This dimensional change allows the coupling to be located within the bearing support zone rather than outside it, eliminating the adverse effect on rotor dynamics while maintaining the coupling function.
Solution Approach 2:
A coupling hub is introduced as an intermediary component between the motor rotor and the rotary shaft. The coupling hub is rotatably supported by the bearing, acting as a mediator that transmits rotational force while allowing the bearing to support its weight, thus preventing adverse effects on rotor dynamics.
2Power
If a heavy mechanical coupling is provided outside the bearing, then the coupling can transmit rotation, but the rotor dynamics are adversely affected which hinders increase in rotation speed
Solution Approach 1:
The coupling hub serves as an intermediary that is rotatably supported by the bearing. This intermediary component transmits the rotational force from the motor rotor to the rotary shaft while allowing the bearing to support its weight, preventing adverse effects on rotor dynamics and enabling stable high-speed rotation.
Solution Approach 2:
The coupling arrangement is moved from an axial overhang position to a radial inner side position within the bearing support zone. This dimensional repositioning changes the weight support configuration, allowing the bearing to support the coupling hub's weight and maintain stable rotor dynamics during power transmission.
3Strength
If the coupling is rigidly connected to the rotary shaft, then the connection is strong, but misalignment cannot be alleviated
Solution Approach 1:
The coupling hub is designed to rotate relative to the rotary shaft through the bearing, introducing a dynamic element to the connection. This dynamic configuration allows the coupling to accommodate misalignment while maintaining a strong connection, as the bearing supports the coupling hub's weight and allows rotational movement.
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 solution 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 and simplifying maintenance.
Implementation Method 1
utilizing gas bearings and a thrust force adjusting unit to improve rotor dynamics and increase rotation speed
Implementation Method 2
The coupling shaft is allowed to alleviate misalignment with the compressor connecting hub, and the compressor bearing rotatably supports an outer peripheral surface of the compressor connecting hub
Data Source
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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.