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.

Effect of non-Newtonian magneto-elastohydrodynamic on performance characteristics of slider-bearings

2019 ◽  
Vol 71 (10) ◽  
pp. 1158-1165
Author(s):  
Mouhcine Mouda ◽  
Mohamed Nabhani ◽  
Mohamed El Khlifi
Keyword(s):  
Friction Coefficient ◽  
Design Methodology ◽  
Reynolds Equation ◽  
Load Capacity ◽  
Transverse Magnetic ◽  
Finite Width ◽  
Two Dimensional ◽  
Content Type ◽  
Slider Bearings ◽  
First Time

Purpose This study aims to examine the magneto-elastohydrodynamic effect on finite-width slider-bearings lubrication using a non-Newtonian lubricant. Design/methodology/approach Based on the magneto-hydrodynamic (MHD) theory and Stokes micro-continuum mechanics, the modified two-dimensional Reynolds equation including bearing deformation was derived. Findings It is found that the bearing deformation diminishes the load-capacity and increases the friction coefficient in comparison with the rigid case. However, the non-Newtonian effect increases load-capacity but decreases the friction coefficient. Moreover, the use of a transverse magnetic field increases both the friction coefficient and load capacity. Originality/value This study combines for the first time MHD and elastic deformation effects on finite-width slider-bearings using a non-Newtonian lubricant.

Finite Element Analysis of the Static Performance of a Self-Slot-Compensating Aerostatic Bearing

2011 ◽  
Vol 199-200 ◽  
pp. 749-753
Author(s):  
Xiao Bo Zuo ◽  
Jian Min Wang ◽  
Chao Liang Guan ◽  
Juan Li
Keyword(s):  
Finite Element ◽  
Reynolds Equation ◽  
Geometric Parameters ◽  
Load Carrying Capacity ◽  
The Finite Element Method ◽  
Aerostatic Bearing ◽  
Element Analysis ◽  
Consistent Condition ◽  
Load Carrying ◽  
Static Performance

The static performance of an aerostatic bearing with angled surface self-slot-compensation is analyzed. The consistent condition was applied to unitize the Reynolds equation of different forms and the finite element method (FEM) was used to solve the equation. The load carrying capacity (LCC) and the stiffness of the bearing was obtained and the influence of the geometric parameters was discussed. It is concluded that this self-compensating aerostatic bearing can achieve a good performance; the geometric parameters of the gap are interactive, and should be rationally matched.

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.

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

Analysis on the steady state performance of a multi pad externally adjustable fluid film bearing

2019 ◽  
Vol 71 (6) ◽  
pp. 803-809 ◽  
Author(s):  
Girish Hariharan ◽  
Raghuvir Pai
Keyword(s):  
Steady State ◽  
Reynolds Equation ◽  
Load Capacity ◽  
Fluid Film ◽  
Finite Difference Approximation ◽  
Difference Approximation ◽  
Content Type ◽  
Bearing Load ◽  
Performance Capability ◽  
Film Profile

Purpose This study aims to investigate the performance characteristics of an externally adjustable bearing with multiple pads in steady state conditions. The proposed adjustable bearing geometry can effectively control the hydrodynamic operation in bearing clearances by adjusting the pads in radial and tilt directions. These pad adjustments have a significant role in improving the bearing characteristics such as load capacity, attitude angle, side leakage, friction variable and Sommerfeld number, which will be analysed in this paper. Design/methodology/approach The adjustable bearing is designed with circumferentially spaced four bearing pads subjected to similar radial and tilt adjustments. Tilt angles are applied along the leading edges of bearing pads. A modified film thickness equation is used to incorporate the pad adjustments and accurately predict the variation in film profile. Finite difference approximation is adopted to solve the Reynolds equation and discretize the fluid film domain. Findings For negative radial and tilt adjustments, higher hydrodynamic pressures are generated in bearing clearances, which increases the bearing load capacity at different eccentricity ratios. From comparative analysis for different pad adjustments, superior bearing performance is observed for bearing pads under negative radial and negative tilt adjustments. Originality/value This research presents a detailed theoretical approach to analyse the performance capability of a four pad adjustable bearing geometry, which is not available in literatures. Improved bearing performances with negative pad adjustments can attract bearing designers to implement the proposed adjustability-bearing concept in rotating machineries.

Structural design of high-speed rolling bearing test rig spindle with cantilever

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Hui Li ◽  
Hao Li ◽  
Rongfeng Zhang ◽  
Yi Liu ◽  
Shemiao Qi ◽  
...  
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Critical Speed ◽  
Testing Machine ◽  
Structure Design ◽  
Installation Space ◽  
The Finite Element Method ◽  
Content Type ◽  
First Order ◽  
Element Method

Purpose The purpose of this paper is to introduce the structure design process of the cantilever spindle with limited installation space and wishing to increase its critical speed. Design/methodology/approach In this paper, the finite element method was used to analyze the influence of the supporting stiffness and the structure of the spindle on the critical speed, and then the structure of the spindle was designed; moreover, the experiment was accomplished and the experiment results show that the spindle can work stably. Findings Through analyzing the influence of the supporting stiffness and the structure of the spindle on the critical speed, the following conclusions could be obtained: the shape of the first-mode is the bend vibration of the cantilever of the spindle; the first-order critical speed of the spindle gradually decreases with the diameter and length of the cantilever increasing; the first-order critical speed of the spindle increases with the depth and diameter of the blind hole increasing; and the experiment was accomplished and the experiment results show that the spindle can work stably. Originality/value In this paper, the finite element method was used to design the spindle of the testing machine, and satisfactory results were obtained. It can provide a theoretical reference for the design of a similar spindle.

Effect of starting time on hydro-viscous drive speed regulating start

2015 ◽  
Vol 67 (4) ◽  
pp. 320-327 ◽  
Author(s):  
Qingrui Meng
Keyword(s):  
Reynolds Equation ◽  
Load Capacity ◽  
Practical Application ◽  
Upward Trend ◽  
Content Type ◽  
Oil Film ◽  
Starting Time ◽  
Drive Speed ◽  
Research Findings ◽  
Starting Process

Purpose – The purpose of this paper is to reveal the effect of starting time on hydro-viscous drive speed regulating start. Design/methodology/approach – The modified transient Reynolds equation, thermal energy equation and temperature–viscosity equation were solved simultaneously by using finite element method. And then variations of the oil film load capacity, variations of temperature and variations of the torque generated by the oil film during the starting process were obtained. Findings – The results show that during the starting process, both the oil film load capacity and the temperature show an upward trend, the torque increases during the beginning period and then decreases during the latter part of the starting process. When the starting time is less than 60 s, variations of the oil film load capacity and temperature show fluctuations, which decrease with the starting time. For any output speed, the corresponding oil film load capacity, temperature and torque decrease with the starting time, and the decreasing amplitude also decreases with the starting time. Originality/value – This paper indicates that the starting time can be set to 60-90 s to obtain a perfect starting process. The simulation results are verified by the speed regulating start experiments. Research findings of this work provide theoretical basis for the design and practical application of the hydro-viscous drive equipments.

Design optimization of a high-sensitive absolute micro-pressure sensor

Sensor Review ◽  
2014 ◽  
Vol 34 (3) ◽  
pp. 312-318 ◽  
Author(s):  
Zhongliang Yu ◽  
Yulong Zhao ◽  
Lili Li ◽  
Cun Li ◽  
Xiawei Meng ◽  
...  
Keyword(s):  
Pressure Sensor ◽  
Optimization Problems ◽  
High Sensitivity ◽  
Optimization Method ◽  
Structure Design ◽  
Content Type ◽  
Design And Optimization ◽  
Nonlinear Fitting ◽  
Silicon Bulk ◽  
Dynamic Performances

Purpose – The purpose of this study is to develop a piezoresistive absolute micro-pressure sensor for altimetry. For this application, both high sensitivity and high overload resistance are required. To develop a piezoresistive absolute micro-pressure sensor for altimetry, both high sensitivity and high-overload resistance are required. The structure design and optimization are critical for achieving the purpose. Besides, the study of dynamic performances is important for providing a solution to improve the accuracy under vibration environments. Design/methodology/approach – An improved structure is studied through incorporating sensitive beams into the twin-island-diaphragm structure. Equations about surface stress and deflection of the sensor are established by multivariate fittings based on the ANSYS simulation results. Structure dimensions are determined by MATLAB optimization. The silicon bulk micromachining technology is utilized to fabricate the sensor prototype. The performances under both static and dynamic conditions are tested. Findings – Compared with flat diaphragm and twin-island-diaphragm structures, the sensor features a relatively high sensitivity with the capacity of suffering atmosphere due to the introduction of sensitive beams and the optimization method used. Originality/value – An improved sensor prototype is raised and optimized for achieving the high sensitivity and the capacity of suffering atmosphere simultaneously. A general optimization method is proposed based on the multivariate fitting results. To simplify the calculation, a method to linearize the nonlinear fitting and optimization problems is presented. Moreover, a differential readout scheme attempting to decrease the dynamic interference is designed.

Static and dynamic performances of an offset bearing under a micropolar lubricant

2021 ◽  
pp. 135065012110100
Author(s):  
Sanyam Sharma ◽  
Chimata M Krishna
Keyword(s):  
Reynolds Equation ◽  
Diameter Ratio ◽  
Dynamic State ◽  
The Finite Element Method ◽  
Static And Dynamic Characteristics ◽  
Dynamic Performances ◽  
Micropolar Lubrication ◽  
Theoretical Performance ◽  
Bearing System ◽  
Increasing Load

In this research paper, the theoretical performance of a circular offset bearing is evaluated. The objective of this paper is to discuss the effects of eccentricity ratios and micropolarity parameters on the static and dynamic characteristics of an offset bearing with respect to micropolar lubrication. The modified Reynolds' equation for a dynamic state is solved using the finite-element method and Galerkin technique. The performance of an offset bearing is computed for a chosen range of eccentricity ratios (0.4–0.6) and for a length–diameter ratio (2.4). Enhancement in the performance of a bearing system is achieved in terms of increasing load and decreasing whirling at the higher values of eccentricity and offset especially at higher micropolarity.

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.

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