Modelling a New Three-Pad Active Bearing

2004 ◽  
Author(s):  
Janusz M. Krodkiewski ◽  
Gregory J. Davies
Keyword(s):  
Pressure Distribution ◽  
Reynolds Equation ◽  
Dynamic Properties ◽  
Oil Film ◽  
Active Devices ◽  
System Of Matrix Equations ◽  
Stiffness Matrices ◽  
Oil Flow ◽  
Lower Chamber ◽  
Non Linear System

This paper describes investigations into a new type of active bearing to be implemented in the field of rotating machinery. Active bearings are based on the concept that journal oil flow can be modified during operation by active devices. Here, the concepts of the flexible pads and the oil-filled chambers that control their deflection are used. Three active pads are positioned around the journal with three oil-filled chambers positioned behind them. One of them, the load-bearing pad located at the bottom of the bearing, acts as a passive device and is equipped with a very thin film chamber, which acts as a source of damping. Such a damper was found in previous work to be effective in dissipating energy. Here, in a departure from previous work, two additional small pads with deep oil-filled chambers have been added in order to allow control theory to be implemented. They are located in the upper part of the active bearing. A non-linear system model is developed for the rotor-bearing system that includes the described active bearing. The flow inside the upper chambers that control motion of the active pads was neglected due to their large volume. It results in a uniform pressure distribution along the upper pads. The pressure distribution within the damper oil film (inside the lower chamber) and the journal oil film was modeled with the aid of the Reynolds equation. They were solved by means of the finite difference method and Gauss-Seidel technique. The same mesh used for solution of the Reynolds equation was used for the division of the flexible pads into the finite elements. The same approach was adopted for the modelling of the dynamic properties of the rotor. The mass and stiffness matrices for the pads and rotor were condensed down to 12 master generalized coordinates using Guyan condensation. The obtained system of matrix equations was converted to a system of first order equations and solved via the Runge-Kutta method. Some results of the numerical testing of the mathematical model developed are provided.

Modelling and Analysis of the Dynamic Behavior of an Active Journal Bearing

1994 ◽  
Author(s):  
Linxiang Sun ◽  
Janusz M. Krodkiewski ◽  
Nong Zhang
Keyword(s):  
Pressure Distribution ◽  
Reynolds Equation ◽  
Hydrodynamic Pressure ◽  
Chamber Pressure ◽  
Oil Film ◽  
Simulation Based ◽  
Rotor Bearing ◽  
New Type ◽  
The Stability ◽  
Bearing System

Modelling and analysis of a rotor-bearing system with a new type of active oil bearing are presented. The active bearing basically consists of a flexible sleeve and a pressure chamber. The deformation of the sleeve can be controlled by the chamber pressure during the operation, and so can the pressure distribution of the oil film. Finite Element Methods (FEMs) and the Guyan condensation technique were utilised to create mathematical models for both the rotor and the flexible sleeve. The hydrodynamic pressure distribution of the oil film, for the instantaneous positions and velocities of the flexible sleeve and rotor, was approximated by Reynolds equation. The influence of the chamber pressure on the stability of the rotor system was investigated by numerical simulation based on the nonlinear model. The results showed that the stability of the rotor-bearing system can be improved effectively by implementation of the active bearing.

Nonlinear Dynamic Behaviors of an Imbalance Rotor Supported on Fixed-Tilting Pad Journal Bearings

2011 ◽  
Vol 291-294 ◽  
pp. 1941-1951
Author(s):  
Xiao Bing Qi ◽  
Lei Feng ◽  
Yong Fang Zhang ◽  
Yan Jun Lu
Keyword(s):  
Pressure Distribution ◽  
Reynolds Equation ◽  
Axial Direction ◽  
Journal Bearings ◽  
Nonlinear Phenomena ◽  
Dynamic Behaviors ◽  
Oil Film ◽  
Tilting Pad ◽  
Field Dynamic ◽  
Tilting Pad Journal Bearings

Based on the unsteady Reynolds equation with Reynolds boundary, two-dimensional (2D) Reynolds equation is transformed into one-dimensional (1D) by taking the assumption of parabolic pressure distribution in axial direction in oil film field. Finite difference method was employed to solve 1D Reynolds equation, and the approximate pressure distribution was obtained in oil film field. Dynamic behaviors of a flexible rotor system with fixed-tilting pad journal bearings support were analyzed while the inertia of the pads was taken into consideration in the model. Imbalance responses of a symmetrical rotor-combination journal bearings (fixed-tilting pad journal bearings) system were investigated using Poincaré map and self-adaptive Runge-Kutta method. Numerical results reveal rich and complex nonlinear phenomena, such as periodic, quasi-periodic motion, etc.

Numerical Simulation of Oil Film State and Mechanical Performance of Heavy Hydrostatic Thrust Bearings

2013 ◽  
Vol 318 ◽  
pp. 148-152
Author(s):  
Yao Yao Hong ◽  
Li Jun Du ◽  
She Miao Qi
Keyword(s):  
Numerical Simulation ◽  
Temperature Distribution ◽  
Film Thickness ◽  
Pressure Distribution ◽  
Reynolds Equation ◽  
Mechanical Performance ◽  
The Finite Element Method ◽  
Oil Film ◽  
Thrust Bearings ◽  
Temperature And Pressure

The finite element method (FEM) is applied in the numerical simulation of heavy hydrostatic thrust bearings to study the influence of pressure and temperature on bearing deformation. The pressure distribution and the temperature distribution are obtained by solving the Reynolds equation and the energy equation. The bearing deformations caused by temperature and pressure are computed by imposing the two obtained distributions on the bearing. Because the pressure distribution and the temperature distribution are influenced by the oil film thickness and the oil film thickness is influenced by the bearing deformation, the numerical simulation is a process of iteration. The numerical results demonstrate that, in heavy hydrostatic thrust bearings, the thermal deformation and the mechanical deformation are both significant and can not be neglected. The influence of operation parameters on the anti-capsizing capability of heavy hydrostatic thrust bearings is also discussed. The obtained results reveal that, the anti-capsizing moment of the bearing increases with the decrease of the central thickness of the oil film.

scholarly journals Influence of Centrifugal Forces on Oil Flow in Journal Bearing of Planetary Gear

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Mikhail Temis ◽  
Alexander Lazarev
Keyword(s):  
Mathematical Model ◽  
Pressure Distribution ◽  
Reynolds Equation ◽  
Stokes Equations ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Centrifugal Forces ◽  
Element Discretization ◽  
Oil Flow ◽  
Wheel Bearing

Mathematical model of oil flow in fluid film bearing in field of centrifugal forces is developed. Centrifugal forces for planet wheel bearing sliding surfaces and oil gap are formulated. This model is based on modification of two-dimensional Reynolds equation taking into account inertia centrifugal forces for oil film. Required modification of Reynolds equation is received from Navier–Stokes and continuity equations taking into account centrifugal forces acting on planet wheel bearing. Modified two-dimensional Reynolds equation is solved numerically using finite element discretization. Developed mathematical model, based on modified Reynolds equation, is verificated at comparison with solution of full Navier–Stokes equations system obtained in commercial software package. Results for pressure distribution in bearing with fixed axis and in planet wheel bearing are received and compared. The sufficient influence of centrifugal inertia forces in oil layer of planet wheel bearing on pressure distribution, bearing carrying force, and attitude angle is shown for specific shaft journal eccentricity ratio, eccentricity direction, and rotation velocity.

scholarly journals Study of Injection Method for Maximizing Oil-Cooling Performance of Electric Vehicle Motor with Hairpin Winding

Energies ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 747
Author(s):  
Taewook Ha ◽  
Dong Kyu Kim
Keyword(s):  
Electric Vehicle ◽  
Flow Rate ◽  
Film Formation ◽  
Formation Rate ◽  
Cooling Performance ◽  
Oil Film ◽  
Injection Method ◽  
Cooling Method ◽  
Oil Flow ◽  
Oil Injection

The oil injection method was studied to maximize the cooling performance of an electric vehicle motor with a hairpin winding. The cooling performance of the motor using the oil cooling method is proportional to the contact area of the oil and the coil. A numerical analysis was conducted to examine the effect of the spray nozzle type on the oil flow. The dripping nozzle forms the thickest oil film on the coil, making it the most effective for cooling of hairpin-type motors. Subsequently, an experimental study was conducted to optimize the nozzle diameter and number of nozzles. When the inlet diameter and number was 6.35 mm and 6, the oil film formation rate was 53%, yielding the most uniform oil film. Next, an experiment was performed to investigate the effects of the oil temperature and flow rate on the oil flow. The oil film formation rate was the highest (83%) when the oil temperature was 40 °C and the flow rate was 6 LPM.

The Numerical Analysis of the Velocity and Pressure Distribution of the Oil Film in Heavy Hydrostatic Thrust Bearing

2014 ◽  
Vol 541-542 ◽  
pp. 658-662
Author(s):  
Jian Li ◽  
Yuan Chen ◽  
Yang Chun Yu ◽  
Zhu Xin Tian ◽  
Yu Huang
Keyword(s):  
Mathematical Model ◽  
Numerical Analysis ◽  
Pressure Distribution ◽  
Working Conditions ◽  
Thrust Bearing ◽  
Rotation Speed ◽  
The Other ◽  
Surface Load ◽  
Oil Film ◽  
Volume Method

To study the velocity and pressure distribution of the oil film in a heavy hydrostatic thrust bearing, a mathematical model of the velocity is proposed and the finite volume method (FVM) has been used to simulate the flow field under different working conditions. Some pressure experiments were carried out and the results verified the correctness of the simulation. It is concluded that the pressure distribution varies small under different rotation speed when the surface load on the workbench is constant. But the velocity of the oil film is influenced greatly by the rotation speed. When the rotation speed of the workbench is as quick as enough, the velocity of the oil film on one radial side of the pad will be zero, that is to say the lubrication oil will be drained from the other three sides of the recess.

Numerical Simulation on Velocity Profiles of Mill Bearing Lubrication

2010 ◽  
Vol 145 ◽  
pp. 282-286
Author(s):  
Qing Xue Huang ◽  
Jian Mei Wang ◽  
Yu Gui Li ◽  
Li Feng Ma ◽  
Chun Jiang Zhao
Keyword(s):  
Cross Section ◽  
Velocity Profiles ◽  
Flow State ◽  
Oil Film ◽  
Velocity Gradients ◽  
Oil Flow ◽  
The Mathematical Model ◽  
The Relationship ◽  
General Velocity ◽  
Oil Film Pressure

No 460 oil-film bearing oil as the dedicated lubricant is regarded as the incompressible Newtonian fluid. To comprehensively analyze the real oil flow state, the mathematical model on velocity profiles, together with its dimensionless equations, is established, and the calculating program is developed to simulate the 3D velocity profiles and velocity gradients at different oil flow layers. The relationship between velocity profiles and the oil film pressure is discussed, and the velocity tendency is consistent with the general velocity profile of wedge cross section. The conclusions are beneficial to the further study on lubricating performances of heavy contact components and to prolong their service lives.

scholarly journals Pressure Distribution of Oil Film Caused by Unbalanced Whirl

1966 ◽  
Vol 32 (242) ◽  
pp. 1500-1508
Author(s):  
Kyosuke ONO ◽  
Akiyoshi TAMURA
Keyword(s):  
Pressure Distribution ◽  
Oil Film

A Theoretical Analysis of Floating Bush Journal Bearing With Axial Oil Film Rupture Being Considered

2002 ◽  
Vol 124 (3) ◽  
pp. 494-505 ◽  
Author(s):  
Kiyoshi Hatakenaka ◽  
Masato Tanaka ◽  
Kenji Suzuki
Keyword(s):  
Steady State ◽  
Reynolds Equation ◽  
Speed Ratio ◽  
Shaft Speed ◽  
Film Rupture ◽  
State Behavior ◽  
Oil Film ◽  
Rotordynamic Coefficients ◽  
The Stability ◽  
Very High

A new modified Reynolds equation is derived with centrifugal force acting on the hydrodynamic oil film being considered. This equation, together with a cavitation model, is used to obtain the steady-state equilibrium and calculate the rotordynamic coefficients of lightly loaded floating bush journal bearings operating at very high shaft speeds. The bush-to-shaft speed ratio and the linear cross-coupling spring coefficients of the inner oil film is found to decrease with the increase in shaft speed as the axial oil film rupture develops in the inner oil film. The present model can give reasonable explanation to the steady-state behavior and the stability behavior of the bearing observed in actual machines.

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