Multi-Physics Coupling Dynamics Simulation of Thermally Induced Vibration of Magnetically Suspended Rotor in Small and Micro Nuclear Reactors

The power conversion system of a small micro-reactor has strict requirements on the compactness of the rotating mechanical support. Although the active magnetic bearing is an ideal choice, the thermally induced vibration caused by it may destroy the stability of the system. As such, this study propo...

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Main Authors: Yihao Xu, Zeguang Li, Dianchuan Xing
Format: Article
Language:English
Published: MDPI AG 2025-05-01
Series:Energies
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Online Access:https://www.mdpi.com/1996-1073/18/10/2433
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author Yihao Xu
Zeguang Li
Dianchuan Xing
author_facet Yihao Xu
Zeguang Li
Dianchuan Xing
author_sort Yihao Xu
collection DOAJ
description The power conversion system of a small micro-reactor has strict requirements on the compactness of the rotating mechanical support. Although the active magnetic bearing is an ideal choice, the thermally induced vibration caused by it may destroy the stability of the system. As such, this study proposes a multi-physics coupling simulation framework, which integrates electromagnetic, thermal, and mechanical multi-physics coupling mechanisms and quantifies the stability of the system under thermal-induced vibration in the frequency domain. Firstly, the equivalent magnetic circuit and electromagnetic finite element modeling and calculation of the compressor rotor are carried out. In the case of the maximum AC current of 10 A, the equivalent stiffness of the magnetic pole is 4.21 × 10<sup>8</sup> N/m and 2.1 × 10<sup>8</sup> N/m, and the eddy current loss of the rotor is 4.17496 W. Based on the eddy current loss, a magneto-thermal coupling model is established to reveal the temperature gradient distribution and the thermal sensitivity coefficient of the journal is 0.006. Subsequently, the thermal stress and equivalent stiffness are coupled to the rotor dynamics equation, and the maximum amplitude of the rotor is obtained at a value of 0.001 mm. Finally, the critical stability threshold of the system is determined by a Nyquist diagram, and the results show that the system is stable as a whole. In this paper, the quantitative analysis of the cross-scale coupling mechanism of electromagnetic, thermal, and mechanical multi-physical fields is realized, which provides a systematic analysis method for the thermally induced vibration of magnetically suspended rotors and has important engineering significance for high power density rotating mechanical systems in small micro-reactors.
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series Energies
spelling doaj-art-57334bd7aaf84f40ae6f797e3a0137a82025-08-20T03:47:52ZengMDPI AGEnergies1996-10732025-05-011810243310.3390/en18102433Multi-Physics Coupling Dynamics Simulation of Thermally Induced Vibration of Magnetically Suspended Rotor in Small and Micro Nuclear ReactorsYihao Xu0Zeguang Li1Dianchuan Xing2Department of Engineering Physics, Tsinghua University, Beijing 100084, ChinaDepartment of Engineering Physics, Tsinghua University, Beijing 100084, ChinaNuclear Power Institute of China, CNNC, Chengdu 610213, ChinaThe power conversion system of a small micro-reactor has strict requirements on the compactness of the rotating mechanical support. Although the active magnetic bearing is an ideal choice, the thermally induced vibration caused by it may destroy the stability of the system. As such, this study proposes a multi-physics coupling simulation framework, which integrates electromagnetic, thermal, and mechanical multi-physics coupling mechanisms and quantifies the stability of the system under thermal-induced vibration in the frequency domain. Firstly, the equivalent magnetic circuit and electromagnetic finite element modeling and calculation of the compressor rotor are carried out. In the case of the maximum AC current of 10 A, the equivalent stiffness of the magnetic pole is 4.21 × 10<sup>8</sup> N/m and 2.1 × 10<sup>8</sup> N/m, and the eddy current loss of the rotor is 4.17496 W. Based on the eddy current loss, a magneto-thermal coupling model is established to reveal the temperature gradient distribution and the thermal sensitivity coefficient of the journal is 0.006. Subsequently, the thermal stress and equivalent stiffness are coupled to the rotor dynamics equation, and the maximum amplitude of the rotor is obtained at a value of 0.001 mm. Finally, the critical stability threshold of the system is determined by a Nyquist diagram, and the results show that the system is stable as a whole. In this paper, the quantitative analysis of the cross-scale coupling mechanism of electromagnetic, thermal, and mechanical multi-physical fields is realized, which provides a systematic analysis method for the thermally induced vibration of magnetically suspended rotors and has important engineering significance for high power density rotating mechanical systems in small micro-reactors.https://www.mdpi.com/1996-1073/18/10/2433small micro-reactoractive magnetic bearingthermally induced vibrationmulti-physics coupling simulationstability analysis
spellingShingle Yihao Xu
Zeguang Li
Dianchuan Xing
Multi-Physics Coupling Dynamics Simulation of Thermally Induced Vibration of Magnetically Suspended Rotor in Small and Micro Nuclear Reactors
Energies
small micro-reactor
active magnetic bearing
thermally induced vibration
multi-physics coupling simulation
stability analysis
title Multi-Physics Coupling Dynamics Simulation of Thermally Induced Vibration of Magnetically Suspended Rotor in Small and Micro Nuclear Reactors
title_full Multi-Physics Coupling Dynamics Simulation of Thermally Induced Vibration of Magnetically Suspended Rotor in Small and Micro Nuclear Reactors
title_fullStr Multi-Physics Coupling Dynamics Simulation of Thermally Induced Vibration of Magnetically Suspended Rotor in Small and Micro Nuclear Reactors
title_full_unstemmed Multi-Physics Coupling Dynamics Simulation of Thermally Induced Vibration of Magnetically Suspended Rotor in Small and Micro Nuclear Reactors
title_short Multi-Physics Coupling Dynamics Simulation of Thermally Induced Vibration of Magnetically Suspended Rotor in Small and Micro Nuclear Reactors
title_sort multi physics coupling dynamics simulation of thermally induced vibration of magnetically suspended rotor in small and micro nuclear reactors
topic small micro-reactor
active magnetic bearing
thermally induced vibration
multi-physics coupling simulation
stability analysis
url https://www.mdpi.com/1996-1073/18/10/2433
work_keys_str_mv AT yihaoxu multiphysicscouplingdynamicssimulationofthermallyinducedvibrationofmagneticallysuspendedrotorinsmallandmicronuclearreactors
AT zeguangli multiphysicscouplingdynamicssimulationofthermallyinducedvibrationofmagneticallysuspendedrotorinsmallandmicronuclearreactors
AT dianchuanxing multiphysicscouplingdynamicssimulationofthermallyinducedvibrationofmagneticallysuspendedrotorinsmallandmicronuclearreactors