Effect Analysis of Dimensional Tolerances on the Dynamic Characteristics of Hydrodynamic Journal Bearing System

2013 ◽  
Author(s):  
Yuan Wei ◽  
Zhaobo Chen ◽  
Wubin Xu ◽  
Yinghou Jiao
Keyword(s):  
Dynamic Viscosity ◽  
Journal Bearing ◽  
Dynamical Behavior ◽  
System Stability ◽  
Force Model ◽  
Threshold Velocity ◽  
Effect Analysis ◽  
Negative Effect ◽  
Hydrodynamic Journal Bearing ◽  
Bearing System

According to the exist of dimensional tolerances on hydrodynamic journal bearing system, a nonlinear oil film force model was developed, emphasis on the different dimensional tolerances in the system, the tolerances of dynamic viscosity, bearing width, bearing diameter and journal diameter along with its interaction effect to the dynamics characteristics of the hydrodynamic journal bearing system were analyzed. By using the eccentricity corresponding to the stability threshold velocity, the effects of the stiffness and damping coefficients, carrying capacity, system stability and friction power loss brought by the dimensional tolerances of the dynamic viscosity, bearing width, bearing diameter and journal diameter was quantitative analyzed. The results show that in contrast to the impacts of the tolerances in bearing diameter, dynamic viscosity and bearing width, the journal diameter tolerance would lead to a negative effect, and the dimensional tolerances have different degrees of impacts on the journal bearing system. The energy decreased as the eccentricity increased, when the eccentricity is 0.6948 the friction energy reach to a minimum. It provides a theoretical basis to select reasonable parameter, find the best solution and control varieties of nonlinear dynamical behavior.

Comparison of Effects of Dimensional Manufacturing Tolerances and Journal Out-of-Roundness on Stability of Hydrodynamic Journal Bearing System

2011 ◽  
Vol 121-126 ◽  
pp. 1966-1971
Author(s):  
Wu Bin Xu ◽  
De Jian Zhou ◽  
Peter Ogrodnik ◽  
Mike Goodwin
Keyword(s):  
Theoretical Analysis ◽  
Taguchi Method ◽  
Journal Bearing ◽  
Journal Bearings ◽  
System Stability ◽  
Design Stage ◽  
Analysis Method ◽  
Manufacturing Tolerances ◽  
Hydrodynamic Journal Bearing ◽  
Bearing System

The manufacturing tolerances of a hydrodynamic journal bearing system are inevitable in manufacturing process. To examine and understand the effect of manufacturing tolerances on the system stability can help engineers to confidently choose reasonable tolerances at design stage. This study presented a theoretical analysis method to determine and compare the effects of dimensional manufacturing tolerances and journal out-of-roundness on system stability by Taguchi method. The results show that the journal out-of-roundness has the most significant effect on the system stability and the journal out-of-roundness appears to stabilize the system. The authors suggest that both dimensional manufacturing tolerances and journal roundness should be taken into account in the design of cylindrical journal bearings.

Effect of journal cylindricity error with saddle or drum distribution on the performance of hydrodynamic journal bearing systems

2019 ◽  
Vol 234 (7) ◽  
pp. 1092-1105
Author(s):  
Bing Li ◽  
Dejian Zhou ◽  
Peter Ogrodnik ◽  
Wubin Xu
Keyword(s):  
Journal Bearing ◽  
System Stability ◽  
Analysis Method ◽  
Shape Distribution ◽  
Hydrodynamic Journal Bearing ◽  
The Stability ◽  
Cylindricity Error ◽  
Saddle Shape ◽  
Fourier Model ◽  
Bearing System

The present study investigates the effect of cylindricity error on the performance of hydrodynamic journal bearing systems. Two types of cylindricity errors of the journal, namely the drum shape distribution cylindricity error (DCE) and the saddle shape distribution cylindricity error (SCE), are considered. The Legendre–Fourier model is used to characterize the profile of each journal. Based on the nonlinear analysis method, the dynamic characteristics and stability of hydrodynamic journal bearing systems are analyzed. The results indicate that cylindricity error affects the system stability, and the effect is related to the type and level of the error. DCE used with a certain range of operating speed and load is not harmful and is even beneficial to the stability of hydrodynamic journal bearing systems; conversely, SCE decreases the system stability. When the Sommerfeld number is between 0.02 and 0.05, cylindricity errors have a minimal effect on the system stability. Additionally, the results indicate that the effect of cylindricity error on the bearing system is more significant than that of roundness error.

Numerical and Experimental Research on Periodic Solution Stability of Inclined Rotor Journal Bearing System

2011 ◽  
Author(s):  
Dashuai Qian ◽  
Zhansheng Liu ◽  
Jiajia Yan ◽  
Liquan Sun ◽  
Yongliang Wang
Keyword(s):  
Periodic Solution ◽  
Journal Bearing ◽  
Rotor System ◽  
Experimental Results ◽  
System Stability ◽  
Response Analysis ◽  
Solution Stability ◽  
Special Cases ◽  
Rotor Journal ◽  
Bearing System

Rotor bearing systems on ships usually work in inclined states when ships are swaying in wave and wind. The inclined status will affect the lubricant condition of journal bearing and bring about changes of the dynamic characteristics of the rotor system. To study the periodic solution stability of inclined rotor journal bearing system, Capone’s short bearing model is employed to describe the journal bearing support properties. Considering the inclination induced change of bearing radial load, the dynamic equation of inclined rotor system is established by using finite element method. The periodic solution stability is discussed based on bifurcation and response analysis. With the increase of rotating speed, instability of period-1 motion happens and oil whirl occurs. The motion then develops into a kind of quasi-periodic motion. Two special cases of inclined rotor system, the horizontal and the vertical cases, are compared and discussed. Both of the numerical and the experimental results show that the periodic solution unstable threshold decreases with the increase of rotor inclination angle. At last, some experimental results about influences of experiments conditions on rotor system stability are given.

Morton Effect Induced Synchronous Instability in Mid-Span Rotor–Bearing Systems, Part 2: Models and Simulations

2011 ◽  
Vol 133 (6) ◽  
Author(s):  
Zenglin Guo ◽  
Gordon Kirk
Keyword(s):  
Journal Bearing ◽  
Negative Impact ◽  
System Stability ◽  
Stability Performance ◽  
Fluid Film Bearings ◽  
Morton Effect ◽  
Thermal Bending ◽  
Hydrodynamic Journal Bearing ◽  
The Stability ◽  
Thermal Imbalance

The mechanism of the Morton Effect induced synchronous instability has been discussed in Part 1, using an assumption of isotropic linear bearings. The second part of the current study will now focus on the more realistic systems, mid-span rotors supported by the hydrodynamic journal bearings. First, the models to calculate the thermal bending of the shaft and the temperature distribution across the journal surface are established. This can be used to calculate the equivalent thermal imbalance. The calculations of the temperature difference and its equivalent thermal imbalance using hydrodynamic plain journal bearing models are conducted and discussed with the comparison to the analytical results obtained in Part 1. It shows that the thermal imbalance induced by the Morton Effect may increase to the level of the mechanical imbalance and then its influence on the system stability should be included. The suggested thermal bending model also partially explains that the mid-span rotors are less liable to be influenced by the Morton Effect induced instability than are the overhung configurations, because of the restraining effect between two supports. Finally, a symmetric mid-span rotor - hydrodynamic journal bearing system is calculated to show its stability performance. The results show the inclusion of the Morton Effect may lead to an unstable operation of the system. Considering the existence of the oil film self-induced vibration due to the dynamic characteristics of fluid film bearings, the Morton Effect may make a further negative impact on the stability of the system. The simulation results of the unbalance response show that the Morton Effect changes the shapes of the whirling orbits and makes them no longer the standard elliptical orbits around the static equilibriums.

Development of an Active Squeeze Film Journal Bearing Using High Power Ultrasonic Transducers

2009 ◽  
Author(s):  
Su Zhao ◽  
Sebastian Mojrzisch
Keyword(s):  
High Power ◽  
Journal Bearing ◽  
Levitation Force ◽  
Acoustic Radiation ◽  
Ultrasonic Transducers ◽  
Squeeze Film ◽  
Prototype System ◽  
Force Model ◽  
Acoustic Radiation Pressure ◽  
Bearing System

A novel active squeeze film journal bearing actuated by high power piezoelectric transducers is developed aiming for non-contact suspension of axial rotating member with active error compensation and active axis positioning. A mathematical model based on acoustic radiation pressure theory is developed to predict the levitation force of the proposed bearing system. The levitation force model is then integrated into the model of the electro-mechanical system to describe the total dynamic behavior of the bearing system. Experimental results are carried out using a prototype system, which show good agreement with the calculation.

Nonlinear dynamic behaviors of rod fastening rotor-hydrodynamic journal bearing system

2015 ◽  
Vol 85 (7) ◽  
pp. 855-875 ◽  
Author(s):  
Di Hei ◽  
Yanjun Lu ◽  
Yongfang Zhang ◽  
Fuxi Liu ◽  
Chao Zhou ◽  
...  
Keyword(s):  
Nonlinear Dynamic ◽  
Journal Bearing ◽  
Dynamic Behaviors ◽  
Rod Fastening Rotor ◽  
Hydrodynamic Journal Bearing ◽  
Bearing System

Hydrodynamic journal bearing lubricated with a ferrofluid

2017 ◽  
Vol 69 (5) ◽  
pp. 754-760 ◽  
Author(s):  
Nimeshchandra S. Patel ◽  
Dipak Vakharia ◽  
Gunamani Deheri
Keyword(s):  
Design Methodology ◽  
Journal Bearing ◽  
Magnetic Bearing ◽  
Point Of View ◽  
Content Type ◽  
Test Conditions ◽  
Hydrodynamic Journal Bearing ◽  
Bearing Design ◽  
Set Up ◽  
Bearing System

Purpose This paper aims to investigate the performance of a ferrofluid-based hydrodynamic journal bearing system. Design/methodology/approach This paper presents a new design of ferrofluid-based hydrodynamic journal bearing. An experimental set-up consisting of a magnetic shaft along with a brass bearing was modified and developed. A permanent magnet was used to make the selected shaft material magnetic. The load and speed were varied to conduct the analyses for different test conditions. Findings The paper provides information about a design of ferrofluid-based journal bearing and its improved performances. For moderate to higher loads at different shaft speeds, it was found that because of the magnetization effect, the maximum film pressure in case of a ferrofluid lubricant increased up to approximately 60 per cent, compared with that of the conventional lubricant-based journal bearing system. Besides, the temperature rise was found smaller for ferrofluid lubricants, thus making the system cooler while running. Originality/value This paper offers a new design of magnetic bearing system for the experimental analysis by utilizing a magnetic shaft with a non-magnetic bearing. The present ferrofluid-based bearing design is less complicated from manufacturing point of view.

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