Identification of fluid force dynamic characteristics in rigid rotor supported by magnetic bearings

2004 ◽  
Vol 2004.57 (0) ◽  
pp. 429-430
Author(s):  
Teajin PARK ◽  
Yoichi KANEMITSU ◽  
Shinya KIJIMOTO
Keyword(s):  
Dynamic Characteristics ◽  
Magnetic Bearings ◽  
Rigid Rotor ◽  
Fluid Force

Nonlinear Analysis of a Rigid Rotor on Magnetic Bearings

1995 ◽  
Author(s):  
C. Nataraj
Keyword(s):  
Nonlinear Analysis ◽  
Equations Of Motion ◽  
Forced Response ◽  
Magnetic Bearings ◽  
Rigid Rotor ◽  
Stability Criteria ◽  
Safe Operation ◽  
Qualitative And Quantitative ◽  
Quantitative Results ◽  
Nonlinear Equations Of Motion

A simple model of a rigid rotor supported on magnetic bearings is considered. A proportional control architecture is assumed, the nonlinear equations of motion are derived and some essential nondimensional parameters are identified. The free and forced response of the system is analyzed using techniques of nonlinear analysis. Both qualitative and quantitative results are obtained and stability criteria are derived for safe operation of the system.

scholarly journals Dynamic characteristics of triaxial active control magnetic bearing with asymmetric structure

Open Physics ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 9-13 ◽  
Author(s):  
Atsushi Nakajima ◽  
Katsuhiro Hirata ◽  
Noboru Niguchi ◽  
Masayuki Kato
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Active Control ◽  
Dynamic Characteristics ◽  
Negative Pressure ◽  
Axial Direction ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Asymmetric Structure ◽  
Element Analysis

Abstract Supporting forces of magnetic bearings are lower than those of mechanical bearings. In order to solve these problems, this paper proposes a new three-axis active control magnetic bearing (3-axis AMB) with an asymmetric structure where its rotor is attracted only in one axial direction due to a negative pressure of fluid. Our proposed 3-axis AMB can generate a large suspension force in one axial direction due to the asymmetric structure. The performances of our proposed 3-axis AMB are computed through 3-D finite element analysis.

A Numerical Study on the Effect of Unbalance and Misalignment Fault Parameters in a Rigid Rotor Levitated by Active Magnetic Bearings

2019 ◽  
Author(s):  
Prabhat Kumar ◽  
Rajiv Tiwari
Keyword(s):  
Numerical Study ◽  
Equations Of Motion ◽  
Rotor System ◽  
Magnetic Bearings ◽  
Inertia Force ◽  
Dimensional System ◽  
Rigid Rotor ◽  
Active Magnetic Bearings ◽  
Fault Parameters ◽  
Misalignment Fault

Abstract This paper focusses on analysing the vibration behaviour of a rigid rotor levitated by active magnetic bearings (AMB) under the influence of unbalance and misalignment parameters. Unbalance in rotor and misalignment between rotor and both supported AMBs are key fault parameters in the rotor system. To demonstrate this dynamic analysis, an unbalanced rigid rotor with a disc at the middle levitated by two misaligned active magnetic bearings has been mathematically modelled. One of the novel concepts is also described as how the force due to active magnetic bearings on the rigid rotor is modified when the rotor is parallel misaligned with AMBs. With inclusion of inertia force, unbalance force and force due to misaligned AMBs, the equations of motion of the rigid rotor system are derived and converted into dimensionless form in terms of various non-dimensional system and fault parameters. Numerical simulations have been performed to yield the dimensionless rotor displacement and controlling current responses at AMBs. The prime intention of the present paper is to study the effect on the displacement response of the rigid rotor system and the current consumption of AMBs for different ranges of disc eccentricities and rotor-AMB misalignments.

A Comparative Study of Structural Analyses for Flat and Curved Mechanical Heart Valve Prostheses to Enhance Durability

2003 ◽  
Author(s):  
Young Joo Kwon
Keyword(s):  
Comparative Study ◽  
Heart Valve ◽  
Dynamic Characteristics ◽  
Mechanical Heart Valve ◽  
Rigid Body Dynamics ◽  
Valve Prosthesis ◽  
Fluid Force ◽  
Heart Valve Prostheses ◽  
Valve Prostheses ◽  
Dynamics Analyses

This paper addresses a comparative study of structural analyses for flat and curved mechanical heart valve prostheses. The same fluid force computed by the fluid mechanics analysis for the blood flow passing through the leaflets of a bileaflet mechanical heart valve prosthesis is used to both flat and curved mechanical heart valve prostheses for comparison. This fluid force is applied to both mechanical heart valve prostheses for the rigid body dynamics analyses to confirm the kinematic and dynamic characteristics of leaflet motions, the structural mechanics analyses for deformed leaflets of both flat and curved mechanical heart valve prostheses are executed to give quite different stress and deflection results even though they have the almost same kinematic and dynamic characteristics.

scholarly journals Dynamic Characteristics of Flow Induced Vibration in a Rotor-Seal System

2011 ◽  
Vol 18 (1-2) ◽  
pp. 139-146 ◽  
Author(s):  
Nan Zhang ◽  
Ying Liu ◽  
Fulei Chu
Keyword(s):  
Fluid Flow ◽  
Dynamic Characteristics ◽  
Nonlinear Models ◽  
Point Of View ◽  
Nonlinear Phenomena ◽  
Flow Induced Vibration ◽  
Nonlinear Characteristics ◽  
Fluid Force ◽  
Synchronization Phenomenon ◽  
Unbalanced Rotor

Flow induced vibration is an important factor affecting the performance of the rotor-seal system. From the point of view of flow induced vibration, the nonlinear models of the rotor-seal system are presented for the analysis of the fluid force, which is induced by the interaction between the unstable fluid flow in the seal and the vibrating rotor. The nonlinear characteristics of flow induced vibration in the rotor-seal system are analyzed, and the nonlinear phenomena in the unbalanced rotor-seal system are investigated using the nonlinear models. Various nonlinear phenomena of flow induced vibration in the rotor-seal system, such as synchronization phenomenon and amplitude mutation, are reproduced.

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