Thermal Analysis and Simulation of Auxiliary Bearings and Its Application in the High Temperature Reactor-10

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Yulan Zhao ◽  
Guojun Yang ◽  
Zhengang Shi ◽  
Lei Zhao
Keyword(s):  
High Temperature ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Hertzian Contact ◽  
Thermal Growth ◽  
Study Results ◽  
New Energy ◽  
Huge Impact ◽  
Auxiliary Bearing ◽  
Amb System

The auxiliary bearing is applied to provide mechanical uphold for the rotational dropping rotor when contact event happens due to the active magnetic bearing (AMB) failure emergencies. During the rotor drop process, the auxiliary bearing will endure huge impact force and friction heat generation. The thermal behavior will affect the mechanical interaction and dynamic behavior of the auxiliary bearing and even induce rapid failure especially when excessive temperature growth occurs. The Institute of Nuclear and New Energy Technology (INET) of Tsinghua University in China has proposed the 10 MW high-temperature gas-cooled reactor (HTR-10). It is designed to guarantee the inherent safety and economic competitiveness. The dry-lubricated ceramic auxiliary bearing is utilized to protect the AMB and aims to ensure the safety of the AMB system in the HTR-10 in the case of the special operational requirements in the reactor. This paper simulates the process of the rotor drop on the auxiliary bearings in the AMB system of the helium blower of the HTR-10, including the analysis of thermal growth based on the Hertzian contact model and a one-dimensional (1D) thermal heat transfer network model. The study results demonstrate the validation of the bearing models and elucidate different responses between mechanical and ceramic auxiliary bearings during contact events. The research in this paper offers important theoretical bases for the auxiliary bearing design to guarantee the safety of the whole system.

Dynamic Behavior of the AMB’s Vertical Arranged Rotor During Its Drop Process

2014 ◽  
Author(s):  
Xiao Kang ◽  
Guojun Yang ◽  
Suyuan Yu
Keyword(s):  
High Temperature ◽  
Dynamic Behavior ◽  
Rotational Frequency ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Axial Stiffness ◽  
Experimental Conditions ◽  
Auxiliary Bearing ◽  
Amb System ◽  
Stiffness And Damping

The active magnetic bearing (AMB) system is a crucial part in the helium circulator system of the 10MW high temperature gas-cooled reactor (HTR-10). Though the AMB has been widely used in industrial fields, it is still limited in the research of the dynamic behavior of AMB’s vertical arranged rotor with axial magnetic load during its drop process. This paper establishes the dynamic model of such drop process by Matlab. Meanwhile using the Hertz contact theory establishes the contact model of different configurations. Analyze the axial friction between the rotor and thrust interface of the inner ring of Auxiliary Bearing System (ABS). Besides, the numerical model is verified by the drop experiment with the axial magnetic force. Moreover, this paper analyzes the influence of the rotor’s drop rotational frequency and the axial bracing features including stiffness and damping on the dynamic behavior during vertical arranged rotor’s drop process. Moreover, the paper provides the optimal axial stiffness and damping for the ABS satisfying the experimental conditions so as to reduce the contact force. Such results provide important references to the design of the ABS with a vertical arranged rotor and its application in HTR-10 and High Temperature Reactor-Pebblebed Modules (HTR-PM).

Modelling, Analysis and Identification of the Parallel and Angular Misalignments in a Coupled Rotor-Bearing-AMB System

2020 ◽  
Author(s):  
Siva Srinivas R ◽  
Rajiv Tiwari ◽  
Ch. Kanna Babu
Keyword(s):  
Mathematical Model ◽  
Vibration Suppression ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Identification Algorithm ◽  
Rotor Systems ◽  
Force Moment ◽  
Coupling Force ◽  
Auxiliary Bearing ◽  
Amb System

Abstract The standard techniques used to detect the misalignment in rotor systems are loopy orbits, multiple harmonics with predominant 2X component, and high axial vibration. This paper develops a new approach for the identification of misalignment in coupled rotor systems modelled using 2-node Timoshenko beam finite elements. The coupling connecting the turbine and generator rotor systems is modelled by a stiffness matrix, which has both static and additive components. While the magnitude of static stiffness component is fixed during operation, the time varying additive stiffness component displays a multi-harmonic behaviour and exists only in the presence of misalignment. To numerically simulate the multi-harmonic nature coupling force/moment as observed in experiments, a pulse wave is used as the steering function in the mathematical model of the additive coupling stiffness (ACS). The representative TG system has two-rotor systems, each having two discs and supported on two flexible bearings - connected by coupling. An active magnetic bearing (AMB) is used as an auxiliary bearing on each rotor for the purposes of vibration suppression and fault identification. The formulation of mathematical model is followed by the development of an identification algorithm based on the model developed, which is an inverse problem. Least-squares linear regression technique is used to identify the unbalances, bearing dynamic parameters, AMB constants and importantly the coupling static and additive stiffness coefficients. The sensitivity of the identification algorithm to signal noise and bias errors in modelling parameters have been tested. The novelty of paper is the representation and identification of misalignment using the ACS matrix coefficients, which are direct indicators of both type and severity of the misalignment.

scholarly journals Dynamic Behavior Analysis of Touchdown Process in Active Magnetic Bearing System Based on a Machine Learning Method

2017 ◽  
Vol 2017 ◽  
pp. 1-11
Author(s):  
Zhe Sun ◽  
Xunshi Yan ◽  
Jingjing Zhao ◽  
Xiao Kang ◽  
Guojun Yang ◽  
...  
Keyword(s):  
Machine Learning ◽  
Dynamic Model ◽  
Dynamic Behavior ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Machine Learning Method ◽  
Learning Method ◽  
Auxiliary Bearing ◽  
Filtering Technique ◽  
Amb System

Magnetic bearings are widely applied in High Temperature Gas-cooled Reactor (HTGR) and auxiliary bearings are important backup and safety components in AMB systems. The performance of auxiliary bearings significantly affects the reliability, safety, and serviceability of the AMB system, the rotating equipment, and the whole reactor. Research on the dynamic behavior during the touchdown process is crucial for analyzing the severity of the touchdown. In this paper, a data-based dynamic analysis method of the touchdown process is proposed. The dynamic model of the touchdown process is firstly established. In this model, some specific mechanical parameters are regarded as functions of deformation of auxiliary bearing and velocity of rotor firstly; furthermore, a machine learning method is utilized to model these function relationships. Based on the dynamic model and the Kalman filtering technique, the proposed method can offer estimation of the rotor motion state from noisy observations. In addition, the estimation precision is significantly improved compared with the method without learning. The proposed method is validated by the experimental data from touchdown experiments.

Preliminary Research of Auxiliary Bearing in HTR-10GT Project

2008 ◽  
Author(s):  
Qingquan Qin ◽  
Guojun Yang ◽  
Zhengang Shi ◽  
Suyuan Yu
Keyword(s):  
Reference Value ◽  
Free Fall ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Main Function ◽  
Test Results ◽  
Test Rig ◽  
Advantages And Disadvantages ◽  
Auxiliary Bearing ◽  
Amb System

Active Magnetic Bearing (AMB) was used in the project of 10MW high temperature gas-cooled reactor (HTR-10GT) for the advantages over conventional mechanical bearings: without any mechanical friction and lubrication, etc. Auxiliary Bearings (ABs) is one of the most important parts in the AMB system, and its main function is to support the rotor at rest and provide protection for the rotor system during an overload or magnetic bearings failure situation. This paper introduced auxiliary bearings used in the HTR-10GT project and compared its advantages and disadvantages with other types of auxiliary bearings. The dynamic behaviors and temperature variation are the most important factors that may affect the performance of auxiliary bearings in a rotor drop event, this paper also analyzed the touching down course and dynamics in detail, divided the drop down process into four distinct stages of motion: free fall, impact, sliding-whirling and rolling. Finally, a test rig built up for the following rotor drop test is presented in the article. Test results at lower drop down speed were discussed. The result of the theory and experiment research has important reference value for the auxiliary bearings design of HTR-10GT.

Behavior of a Magnetically Suspended Rotor Dropped Into Auxiliary Bearings

2013 ◽  
Author(s):  
Zhen Xiao ◽  
Guojun Yang ◽  
Zhengang Shi ◽  
Suyuan Yu
Keyword(s):  
High Temperature ◽  
Element Model ◽  
Magnetic Bearing ◽  
Structure Design ◽  
Active Magnetic Bearing ◽  
Contact Theory ◽  
Beam Elements ◽  
Spring Element ◽  
Amb System ◽  
Simplified Finite Element Model

Auxiliary bearings (ABs), as the back-up support when the Active Magnetic Bearing (AMB) system doesn’t work, play an important role on the assurance of AMB system’s safety. According to the structure design of ABs-rotor system on back-up helium circulator of 10MW high temperature gas-cooled reactor (HTR-10) equipped with AMB, this paper presents a simplified finite element model (FEM) in Ansys, applied in the transient response of the dropped rotor. The ABs load characteristics were determined based on Hertz contact theory. Furthermore, a special spring element named Combin40, which is coupled to a gap, was introduced to communicate information of displacement and force between auxiliary bearings which were simplified into nonlinear spring elements and rotor which was simplified into beam elements. Based on the developed FEM, the behavior of vertical and horizontal magnetically suspended rotor dropped into the ABs was analyzed respectively and the safety of the rotor and ABs was evaluated. The results provide an important reference to the ABs design and application in HTR-10 and High Temperature Reactor-Pebblebed Modules (HTR-PM).

Dynamic Analysis for the Rotor Drop Process and Its Application to a Horizontal Rotor-Active Magnetic Bearing System in Helium Gas

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Zhao Yulan ◽  
Liu Xingnan ◽  
Yang Guojun ◽  
Shi Zhengang ◽  
Zhao Lei
Keyword(s):  
High Speed ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Actual Behavior ◽  
Energy Technology ◽  
Active Magnetic Bearings ◽  
Helium Gas ◽  
New Energy ◽  
Auxiliary Bearing ◽  
Left And Right

The high-temperature gas-cooled reactor pebble-bed modular (HTR-PM) has been proposed by the Institute of Nuclear and New Energy Technology of Tsinghua University, in which the active magnetic bearings (AMBs) are equipped to support the high-speed rotor in the helium circulator system. In the case of AMB failures, emergencies, or overload conditions, the auxiliary bearing is applied as the backup protector to provide temporary mechanical support and displacement constraint for the dropping rotor. A detailed dynamic model is established to reveal the behavior of the dropping rotor. This model is able to describe the rotor displacement and inclination around each axis. The left and right rotor orbits are revealed. Dropping experiments are also carried out to reveal the actual behavior of the dropping rotor in helium. The predicted and experimental results will benefit further study, design, and application of the auxiliary bearing in HTR-PM helium circulator.

Research on Auxiliary Bearing Structure With Buffer Shim Based on LS-DYNA for Helium Circulator of HTR-10

2018 ◽  
Author(s):  
Guojun Yang ◽  
Zhe Sun ◽  
Xingnan Liu ◽  
Zhengang Shi
Keyword(s):  
Stress Distribution ◽  
Impact Load ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Structure Characteristic ◽  
System A ◽  
Huge Impact ◽  
Auxiliary Bearing ◽  
The Impact ◽  
Bearing Structure

The active magnetic bearing (AMB) is introduced to the helium circulator of the 10 MW high temperature gas-cooled reactor (HTR-10). Auxiliary bearing bears huge instantaneous impact load when the AMB fails to work in the helium circulator. The huge load may cause serious damage to the auxiliary bearing. In order to reduce the impact load and protect the AMB and rotor system, a new type of auxiliary bearing with axial buffer shim is presented in this paper. There are two different structures of auxiliary bearing to be studied in the paper. One is the auxiliary bearing with the buffer shim and another one is without the buffer shim. The finite element method and LS-DYNA software are applied to analyze the structure characteristic of the auxiliary bearing. The rotor dropping trajectory and the stress distribution of the auxiliary bearing are analyzed by comparing two different auxiliary bearing structures during the rotor drop. The stress change of the auxiliary bearing in each impact course is mainly studied, and the law of stress variation in impact course is analyzed. Besides, the stress distribution and deformation of two auxiliary bearing is the focus research when impact force is maximum in the paper. Finally, the research shows the auxiliary bearing structure without the buffer shim can bear the huge impact of the rotor drop, and the addition of buffer shim can also reduce the damage of the rotor drop to the auxiliary bearing structure. These researches’ result provides an important reference for the experiment of rotor drop, and has laid a theoretical foundation for the practical application of this structure.

Some Nonlinear Effects of Magnetic Bearings

1999 ◽  
Author(s):  
Norbert Steinschaden ◽  
Helmut Springer
Keyword(s):  
Equations Of Motion ◽  
Period Doubling ◽  
Path Following ◽  
Nonlinear Effects ◽  
Magnetic Bearing ◽  
Operating Conditions ◽  
Active Magnetic Bearing ◽  
Nonlinear Phenomena ◽  
Amb System ◽  
Large Rotor

Abstract In order to get a better understanding of the dynamics of active magnetic bearing (AMB) systems under extreme operating conditions a simple, nonlinear model for a radial AMB system is investigated. Instead of the common way of linearizing the magnetic forces at the center position of the rotor with respect to rotor displacement and coil current, the fully nonlinear force to displacement and the force to current characteristics are used. The AMB system is excited by unbalance forces of the rotor. Especially for the case of large rotor eccentricities, causing large rotor displacements, the behaviour of the system is discussed. A path-following analysis of the equations of motion shows that for some combinations of parameters well-known nonlinear phenomena may occur, as, for example, symmetry breaking, period doubling and even regions of global instability can be observed.

Optimization of Active Magnetic Bearings’ Power Supply System for Main Helium Fan in High Temperature Gas-Cooled Reactor

2021 ◽  
Author(s):  
Huan Luo ◽  
Zhengang Shi ◽  
Yan Zhou ◽  
Ni Mo
Keyword(s):  
High Temperature ◽  
Power Supply ◽  
Power Supply System ◽  
Magnetic Bearing ◽  
Supply System ◽  
Buck Converter ◽  
Normal Operation ◽  
Rotating Equipment ◽  
Amb System ◽  
High Temperature Gas

Abstract High temperature gas-cooled reactor (HTR) is a kind of reactor with inherent safety developed by Institute of Nuclear Energy and New Energy Technology of Tsinghua University. In the first circuit, pure helium is used as coolant and the main helium fan is used to promote the coolant circulation. In order to meet the requirements of service environment and performance, the main helium fan adopts the non-lubricant active magnetic bearing (AMB) system as its support system. For the high-speed rotating equipment supported by AMBs, losing power would lead to bearing failure and cause serious damage to the equipment. In this paper, the power supply system of AMBs is optimized. The power supply of AMB system is connected with the DC-link of the motor converter through DC/DC converter. During normal operation, the AMB system is supplied by external power supply, and the DC/DC converter is used as the backup redundant power supply. In the event of a power failure accident, the DC/DC converter is put into operation, converting the remanet kinetic energy of the motor into stable power to maintain the normal operation of the AMB system. The DC/DC converter adopts two-stage topology structure of the former BUCK converter and the later LLC converter, and completes the voltage stabilization control of the latter LLC converter through the digital signal processor (DSP). Experimental results show that this scheme can realize the power loss protection function of the rotating equipment supported by AMBs.

On the Use of Actively Controlled Auxiliary Bearings in Magnetic Bearing Systems

2008 ◽  
Author(s):  
Iain S. Cade ◽  
M. Necip Sahinkaya ◽  
Clifford R. Burrows ◽  
Patrick S. Keogh
Keyword(s):  
Controller Design ◽  
Control Strategies ◽  
Frictional Heating ◽  
Magnetic Bearing ◽  
Contact Forces ◽  
Active Magnetic Bearing ◽  
Physical Limit ◽  
Drop Tests ◽  
Auxiliary Bearing ◽  
And Control

Auxiliary bearings are used to prevent rotor/stator contact in active magnetic bearing systems. They are sacrificial components providing a physical limit on the rotor displacement. During rotor/auxiliary bearing contact significant forces normal to the contact zone may occur. Furthermore, rotor slip and rub can lead to localized frictional heating. Linear control strategies may also become ineffective or induce instability due to changes in rotordynamic characteristics during contact periods. This work considers the concept of using actively controlled auxiliary bearings in magnetic bearing systems. Auxiliary bearing controller design is focused on attenuating bearing vibration resulting from contact and reducing the contact forces. Controller optimization is based on the H∞ norm with appropriate weighting functions applied to the error and control signals. The controller is assessed using a simulated rotor/magnetic bearing system. Comparison of the performance of an actively controlled auxiliary bearing is made with that of a resiliently mounted auxiliary bearing. Rotor drop tests, repeated contact tests, and sudden rotor unbalance resulting in trapped contact modes, are considered.

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