Effect of AMB winding configurations on static and dynamic performances and power consumptions of the AMB-rotor system

2020 ◽  
pp. 1-15
Author(s):  
Qing Liu ◽  
Li Wang ◽  
Shiping Zhang ◽  
Yuanyuan Li ◽  
Gang Lei
Keyword(s):  
Load Capacity ◽  
System Level ◽  
Gravity Load ◽  
Dynamic Performances ◽  
The Cross ◽  
Run Up ◽  
External Loads ◽  
Rotor Dynamic ◽  
Bearing Structure ◽  
Cross Type

Active magnetic bearings (AMBs) bring extraordinary benefits such as free of contact, elimination of lubrication, active control of rotor position, and a built-in monitoring system. In the design of AMBs, the bearing structure is of significance since it has an important impact on bearing performances. However, the effect of winding configurations of AMBs is still obscure. In this paper, the system-level implications of two radial AMB winding configurations termed the Ortho and the Cross types are investigated, including the bearing characteristics, power consumptions and rotor dynamic behaviors. The simulation results demonstrate that the Cross type contributes to larger load capacity in the direction of gravity. In condition of a heavier gravity load (−200 N), the Cross-type winding configuration saves power consumption with a percentage of 17.2% at steady state (20,000 rpm) and 12.7% considering unbalance mass during the run-up process. However, the rotor vibrations of the Cross type in case of external loads and unbalance mass are larger than the Ortho type. The proposed results of this paper provide some useful information for the AMB winding configuration design.

Analysis of static and dynamic characteristics of aerostatic bearing with reflux orifices

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Shixiong Chen ◽  
Qiyong Zhang ◽  
Bao Fu ◽  
Zhifan Liu ◽  
Shanshan Li
Keyword(s):  
Reynolds Equation ◽  
Load Capacity ◽  
Structure Design ◽  
Damping Factor ◽  
The Finite Element Method ◽  
Aerostatic Bearing ◽  
Content Type ◽  
Dynamic Performances ◽  
Newton Iteration Method ◽  
Bearing Structure

Purpose The purpose of this paper is to provide a solution for Reynolds equation with both throttling term and reverse throttling term and provides a reference for changing damping of hydrostatic bearing. Design/methodology/approach The reverse throttling term is introduced into the Reynolds equation, and the adaptive damping factor is used in the Newton iteration method to improve convergence of numerical calculations. The static and dynamic performances of this bearing are numerically investigated by the finite-element method. Findings The results indicate that the reflux orifices lead to a decrease in load capacity at a high eccentricity ratio. Additionally, the mass inflow rate is increased; however, the additional inflow increase can be controlled by enhanced backpressure of the reflux orifice. Nevertheless, the bearing with the reflux orifice shows superiority in resisting high-frequency disturbances and enhances direct damping by 20% under a high backpressure. Originality/value This work presents an adaptive Newton damping iterative method for solving Reynolds equation with both throttling term and reverse throttling term. This work also provides a new idea for bearing structure design in improving damping.

scholarly journals Influence of Temperature Effect on the Static and Dynamic Performance of Gas-Lubricated Microbearings

Micromachines ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 716
Author(s):  
Liangliang Li ◽  
Zhufeng Liu ◽  
Chongyu Wang ◽  
Yonghui Xie
Keyword(s):  
High Speed ◽  
Load Capacity ◽  
Dynamic Performance ◽  
Operating Environment ◽  
Low Friction ◽  
Operating Stability ◽  
Comprehensive Performance ◽  
Different Temperatures ◽  
Dynamic Performances ◽  
The Difference

Gas-lubricated microbearings are widely applied in multiple fields due to their advantages of high-speed, low friction level and other features. The operating environment of microbearings is complex, and the difference of temperature has an important influence on their comprehensive performance. In this investigation, FEM (finite element method) is employed to investigate the static, dynamic and limit characteristics of microbearings lubricated by different kinds of gas at different temperatures. The results show that the rise of temperature leads to the decline of equivalent viscosity of gas, which weakens the load capacity of microbearings, and furthermore, affects the operating stability of microbearings. The dynamic performances of microbearings at different temperatures are very different, and the two dynamic limit characteristics are more sensitive to temperature when it changes.

Dynamic behaviors of a high-speed turbocharger rotor on elliptical floating-ring bearings

2019 ◽  
Vol 233 (12) ◽  
pp. 1785-1799 ◽  
Author(s):  
Congcong Zhang ◽  
Yongliang Wang ◽  
Rixiu Men ◽  
Hong He ◽  
Wei Chen
Keyword(s):  
High Speed ◽  
Reynolds Equation ◽  
Low Cost ◽  
Dynamic Behaviors ◽  
Oil Whirl ◽  
Excited Vibration ◽  
Dynamic Performances ◽  
Simulation Results ◽  
Bearing Design ◽  
Run Up

Floating-ring bearings are commonly used in automotive turbocharger applications due to their low cost and their suitability under extreme rotation speeds. This type of bearings, however, can become a source of noise due to oil whirl-induced sub-synchronous vibrations. The scope of this paper is to examine whether the concept of a floating-ring bearing with an elliptical clearance might be a solution to suppress sub-synchronous vibrations. A very time-efficient approximate solution for the Reynolds equation to the geometry of elliptical bearings is presented. The nonlinear dynamic behaviors of a turbocharger rotor supported by two concepts of elliptical floating-ring bearings are systematically investigated using run-up simulations. For the first concept of elliptical floating-ring bearings i.e. the outer bearing of the floating-ring bearing changed in the form of elliptical pattern (see Figure 1(b) in the article), some studies have pointed out that its steady-state and dynamic performances are superior to plain cylindrical floating-ring bearings but, the nonlinear run-up simulation results shown that this type of elliptical floating-ring bearings is not conducive to reduce the self-excited vibration levels. However, for the second type of elliptical floating-ring bearings i.e. both the inner and outer films of the floating-ring bearing changed in the form of elliptical pattern (see Figure 1(c) in the article), it is shown that the sub-synchronous vibrations have been considerably suppressed. Hence, the second noncircular floating-ring bearing design is an attractive measure to suppress self-excited vibrations.[Figure: see text]

Secondary Stresses in Airship Hull Structures

1927 ◽  
Vol 31 (204) ◽  
pp. 1073-1109
Author(s):  
J. F. Baker
Keyword(s):  
Cross Section ◽  
External Load ◽  
Structural Engineering ◽  
Secondary Stress ◽  
Rigorous Definition ◽  
The Cross ◽  
Definition Of ◽  
Redundant Structure ◽  
Ball Joints ◽  
External Loads

In no branch of structural engineering is there a rigorous definition of the term “secondary stress.”If the primary stresses in a structure are determined, that is, the stresses in the members due to an external load system, assuming that all the members are joined together by perfect pin- or ball-joints, then the secondary stresses are in general taken to be the additional stresses due to the rigidity of the actual joints used in practice.In such a highly redundant structure as an airship hull the labour involved, in determining even the primary stresses, precludes the use of the normal methods of stressing. It is usual to make use of generalised methods which give approximate results. These generalised methods imply that the external loads are applied to the structure in a certain distribution. Though this is rarely achieved, yet the results obtained are in most cases sufficiently accurate if suitable bracing is supplied to redistribute the external loads over the cross-section; the effect of the initial wrong distribution being then merely local.

scholarly journals Mathematical Model and Analysis of the Water-Lubricated Hydrostatic Journal Bearings considering the Translational and Tilting Motions

2014 ◽  
Vol 2014 ◽  
pp. 1-15 ◽  
Author(s):  
Hui-Hui Feng ◽  
Chun-Dong Xu ◽  
Jie Wan
Keyword(s):  
High Speed ◽  
Reynolds Equation ◽  
Load Capacity ◽  
Journal Bearings ◽  
Linear Perturbation ◽  
Eccentricity Ratio ◽  
Dynamic Coefficients ◽  
Pressure Fields ◽  
Dynamic Performances ◽  
Rotary Speed

The water-lubricated bearings have been paid attention for their advantages to reduce the power loss and temperature rise and increase load capacity at high speed. To fully study the complete dynamic coefficients of two water-lubricated, hydrostatic journal bearings used to support a rigid rotor, a four-degree-of-freedom model considering the translational and tilting motion is presented. The effects of tilting ratio, rotary speed, and eccentricity ratio on the static and dynamic performances of the bearings are investigated. The bulk turbulent Reynolds equation is adopted. The finite difference method and a linear perturbation method are used to calculate the zeroth- and first-order pressure fields to obtain the static and dynamic coefficients. The results suggest that when the tilting ratio is smaller than 0.4 or the eccentricity ratio is smaller than 0.1, the static and dynamic characteristics are relatively insensitive to the tilting and eccentricity ratios; however, for larger tilting or eccentricity ratios, the tilting and eccentric effects should be fully considered. Meanwhile, the rotary speed significantly affects the performance of the hydrostatic, water-lubricated bearings.

scholarly journals Laser fusion driver using stimulated Brillouin scattering phase conjugate mirrors by a self-density modulation

2007 ◽  
Vol 25 (2) ◽  
pp. 225-238 ◽  
Author(s):  
H.J. Kong ◽  
J.W. Yoon ◽  
D.H. Beak ◽  
J.S. Shin ◽  
S.K. Lee ◽  
...  
Keyword(s):  
Brillouin Scattering ◽  
Stimulated Brillouin Scattering ◽  
Laser Fusion ◽  
Phase Conjugate ◽  
Beam Combination ◽  
Density Modulation ◽  
Scattering Phase ◽  
The Cross ◽  
Stimulated Brillouin ◽  
Cross Type

A new concept of laser fusion driver is proposed, which uses a beam combination technique with stimulated Brillouin scattering phase conjugate mirror (SBS-PCM). It is constructed systematically with a cross-type amplifier as a basic unit. In the first part of this paper, we introduce the cross-type laser amplifier using SBS-PCM, with several advantages by experimental results. These advantages are the ideal properties for practical laser fusion driver, such as the perfect isolation of leak beam, the compensation of thermally induced birefringence through the amplifiers, the easy maintenance and alignment insensitiveness, and the freely-scale-up energy. Next, some successful results for the phase control of SBS-PCM are presented, which is one of the main problems in the current beam combination laser using SBS-PCM. Particularly, a new technique for controlling the phase of SBS-PCM, “self-density modulation,” is introduced, which is the simplest ever among those reported. With the advantages of the cross-type amplifier using SBS-PCM and the novel method for controlling the phase of SBS-PCM, the proposed beam combination laser system is presented as the most promising one, which can contribute to the realization of high energy laser that can operate with high repetition rate over 10 Hz, even in the case of huge output energy over MJ.

scholarly journals Shaft Inserting into the Moving Object using Robot with the Cross Type PSD

2000 ◽  
Vol 120 (4) ◽  
pp. 516-521 ◽  
Author(s):  
Soichiro Hayakawa ◽  
Nuio Tsuchida ◽  
Hitoshi Tanaka
Keyword(s):  
Moving Object ◽  
The Cross ◽  
Cross Type

Non-Axisymmetric Flows and Rotordynamic Forces in an Eccentric Shrouded Centrifugal Compressor: Part 1 — Measurement

2019 ◽  
Author(s):  
Jieun Song ◽  
Suyong Kim ◽  
Tae Choon Park ◽  
Bong-Jun Cha ◽  
Dong Hun Lim ◽  
...  
Keyword(s):  
Centrifugal Compressor ◽  
System Level ◽  
Labyrinth Seals ◽  
Stiffness Coefficients ◽  
Pressure Distributions ◽  
Order Of Magnitude ◽  
Direct Stiffness ◽  
The Cross ◽  
Rotordynamic Forces ◽  
Pressure Perturbations

Abstract Centrifugal compressors can suffer from rotordynamic instability. While individual components (e.g., seals, shrouds) have been previously investigated, an integrated experimental or analytical study at the compressor system level is scarce. For the first time, non-axisymmetric pressure distributions in a statically eccentric shrouded centrifugal compressor with eye-labyrinth seals have been measured for various eccentricities. From the pressure measurements, direct and cross-coupled stiffness coefficients in the shrouded centrifugal compressor have been determined. Thus, the contributions of the pressure perturbations in the shroud cavity and labyrinth seals have been simultaneously investigated. The cross-coupled stiffness coefficients in the shroud and labyrinth seals are both positive and one order of magnitude larger than the direct stiffness coefficients. Furthermore, in the tested compressor, contrary to the common assumption, the cross-coupled stiffness in the shroud is 2.5 times larger than that in the labyrinth seals. Thus, the shroud contributes more to rotordynamic instability than the eye-labyrinth seals.

On the characteristics of gas foil conical bearings considering misalignment

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hongyang Hu ◽  
Ming Feng ◽  
Tianming Ren
Keyword(s):  
Film Thickness ◽  
Peer Review ◽  
Load Capacity ◽  
Dynamic Performance ◽  
Critical Role ◽  
Friction Torque ◽  
Misalignment Angle ◽  
Content Type ◽  
Stiffness Model ◽  
Dynamic Performances

Purpose The purpose of this paper is to study the characteristics of gas foil conical bearings (GFCBs) considering the misalignment, the static and dynamic performances with different misalignment cases were studied. Design/methodology/approach A test rig on the air compressor supported by GFCBs has been developed to measure the practicability. A nonlinear bump stiffness model and one-dimensional beam top foil stiffness model were used as a basis for the calculation of static and dynamic performance. The finite element method and finite difference method are adopted to solve the Reynolds equation and the film thickness equation coupled, in which different misalignment cases were considered by changing the film thickness. Findings The supporting performance of GFCB is excellent, and the film clearance plays a critical role. The misalignment effects depend on the assembled angle and the misalignment angle. The load capacity, friction torque, temperature of GFCB decrease when the misalignment assembled angle is between 120° and 240°, while the dynamic bearing stability is improved. The static and dynamic performances show the opposite law for the other assembled angles, and the misalignment effect is more dramatic when there is a larger misalignment angle. Moreover, the bearing and running parameters largely affect the bearing performance. Originality/value The present study focuses on the static and dynamic characteristics of GFCB and investigates the effects of misalignment on the bearing performance. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-04-2020-0117

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