scholarly journals A Study on the Dynamic Characteristics of High Speed Journal Bearing with Axial Oil Film Rupture and Its Application to Stability Analysis of Floating Bush Bearing.

1999 ◽  
Vol 65 (640) ◽  
pp. 4840-4845 ◽  
Author(s):  
Kiyoshi HATAKENAKA ◽  
Masato TANAKA ◽  
Kenji SUZUKI
Keyword(s):  
Stability Analysis ◽  
Dynamic Characteristics ◽  
High Speed ◽  
Journal Bearing ◽  
Film Rupture ◽  
Oil Film

Experimental Investigation on Cavitation Characteristics of a Three-Groove Journal Bearing

2013 ◽  
Vol 420 ◽  
pp. 47-50
Author(s):  
Ying Yang ◽  
Jing Hua Dai
Keyword(s):  
Experimental Investigation ◽  
High Speed ◽  
Journal Bearing ◽  
Rupture Zone ◽  
Work Characteristics ◽  
Oil Film ◽  
Rotating Speed ◽  
Clear Effect ◽  
Supply Pressure

Under high and super-high speed, oil film of the journal bearing is easy to crack and then becomes cavitation. The existence of cavitation has an important effect on the work characteristics of the shaft. On the journal bearing experiment rig the cavitation characteristics of the three-groove journal beaing were studied. The influences of the shaft rotating speed and supply pressure on cavitation shape were investigated. The results show that rotating speed and supply pressure have a clear effect on the cavitation shape, and the number of cavitation strip in the rupture zone decreases when the supply pressure increases.

Experimental Research on Cavitation Characteristics of a Novel Hybrid Journal Bearing

2013 ◽  
Vol 420 ◽  
pp. 74-77
Author(s):  
Ying Yang ◽  
Jing Hua Dai ◽  
Xu Li
Keyword(s):  
Experimental Research ◽  
High Speed ◽  
Work Performance ◽  
Journal Bearing ◽  
Rupture Zone ◽  
Oil Film ◽  
Rotating Speed ◽  
Supply Pressure ◽  
Experimental Rig

Under high and super high speed, the oil film of a journal bearing is easy to crack and then becomes cavitation. The existence of cavitation has a great effect on the work performance of the bearing. The cavitation mechanism of a spiral oil wedge journal bearing was investigated on the experimental rig. The effects of rotating speed and supply pressure on the cavitation shape of oil film and the number of cavitation strip in the rupture zone were analyzed. The results show that the cavitation shape of oil film is a long strip. The number of cavitation strip increases when supply pressure has been improved, and the location of oil outlet must be designed optimally.

Experimental Study on Cavitation Boundary of Journal Bearing

2013 ◽  
Vol 378 ◽  
pp. 362-366
Author(s):  
Ying Yang ◽  
Li Xu ◽  
Wen Qing Liu
Keyword(s):  
Experimental Study ◽  
High Speed ◽  
Journal Bearing ◽  
Theory Model ◽  
Work Characteristics ◽  
Oil Film ◽  
Rotating Speed ◽  
Supply Pressure ◽  
Rupture Area ◽  
Experimental Rig

Under high and super-high speed conditions, oil film of the journal bearing is easy to crack and then becomes cavitation. The existence of cavitation has a great effect on the work characteristics of the bearing. Cavitation boundary of a three-groove journal beaing was investigated on the journal bearing experimental rig. The influences of rotating speed and supply pressure on cavitation boundary were studied. And experimental equations of reformation location and the percent of rupture area are established. The results show that rupture location of oil film is not related with rotating speed and supply pressure, otherwise reformation location of oil film is effected greatly by them. The experimental equations lay foundations for next research on cavitation theory model and stability.

Linear stability analysis of finite hydrodynamic journal bearing under turbulent lubrication with coupled-stress fluid

2016 ◽  
Vol 68 (3) ◽  
pp. 386-391 ◽  
Author(s):  
Abhishek Ghosh ◽  
Sisir Kumar Guha
Keyword(s):  
Stability Analysis ◽  
Newtonian Fluid ◽  
High Speed ◽  
Journal Bearing ◽  
Slenderness Ratio ◽  
Linear Perturbation ◽  
Content Type ◽  
Hydrodynamic Journal Bearing ◽  
The Stability ◽  
Coupled Stress

Purpose Several researchers have observed that to satisfy modern day’s need, it is essential to enhance the characteristics of journal bearing, which is used in numerous applications. Moreover, the use of Newtonian fluid as a lubricant is diminishing day by day, and the use of Non-Newtonian fluids is coming more into picture. Furthermore, if turbo-machinery applications are taken into account, then it can be seen that journal bearings are used for high speed applications as well. Thus, neglecting turbulent conditions may lead to erroneous results. Hence, this paper aims to present focuses on studying the stability characteristics of finite hydrodynamic journal bearing under turbulent coupled-stress lubrication. Design/methodology/approach First, the governing equation relevant to the problem is generated. Then, the dynamic analysis is carried out by linear perturbation technique, leading to three perturbed equations, which are again discretized by finite difference method. Finally, these discretized equations are solved with the help of Gauss-Seidel Iteration technique with successive over relaxation scheme. Consequently, the film response coefficients and the stability parameters are evaluated at different parametric conditions. Findings It has been concluded from the study that with increase in value of the coupled-stress parameter, the stability of the journal may increase. Whereas, with increase in Reynolds number, the stability of the journal decreases. On the other hand, stability increases with increasing values of slenderness ratio. Originality/value Researches have been performed to study the dynamic characteristics of journal bearing with non-Newtonian fluid as the lubricant. But in the class of non-Newtonian lubricants, the use of coupled-stress fluid has not yet been properly investigated. So, an attempt has been made to perform the stability analysis of bearings with coupled-stress fluid as the advanced lubricant.

Power Loss of Tilting 5-Pad Journal Bearing Operating With Turbulent Oil Film

2005 ◽  
Author(s):  
S. Strzelecki
Keyword(s):  
Power Loss ◽  
High Speed ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Heavy Duty ◽  
Safe Operation ◽  
Oil Film ◽  
Full Knowledge

Journal bearings of high speed turbocompressors, compressors and heavy duty high speed turbine gearboxes operate at journal peripheral speeds like 150 m/s. The flow of lubricant in such bearings is not laminar but super laminar or turbulent. It results in the increase in power loss and in the decrease of the bearing stability. The ground for the safe operation of high speed journal bearings at proper oil film temperature and with less power loss is the full knowledge of bearing performances at the turbulent oil film.

An Experimental Study on Opening Delay of a Reed Valve for Reciprocating Compressors

2011 ◽  
Author(s):  
Fumitaka Yoshizumi ◽  
Yasuhiro Kondoh ◽  
Kazunori Yoshida ◽  
Takahiro Moroi ◽  
Masakazu Obayashi ◽  
...  
Keyword(s):  
High Speed ◽  
Gas Flow ◽  
Valve Seat ◽  
Film Rupture ◽  
Air Conditioners ◽  
Oil Film ◽  
Gas Compression ◽  
Valve Opening ◽  
Reed Valve ◽  
Opening Process

Automatic reed valves are widely used to control refrigerant gas flow in reciprocating compressors for automotive air conditioners. The oil film in the clearance between the reed and the valve seat causes a delay in opening of the valve. This opening delay of the discharge valve leads to over compression, which increases losses such as friction in sliding components and gas overheating. Therefore it is important to understand the behavior both of the oil film and the elastic reed deformation in order to reduce losses due to the delay. This study aims to develop an experimental setup that enables simultaneous visualization of the oil film rupture and measurement of the reed deformation, and to observe this behavior during the valve opening process. The gas-compression stroke is simulated by controlling compressed air with an electromagnetic valve. The oil film rupture is visually observed using a high speed camera through a special valve seat made of glass. The total deformation of the cantilever reed is identified by multipoint strain measurement with 12 strain gauges. The experiment finds that the opening process is divided into four stages. In the first stage, the reed remains stuck to the seat and deforms while the bore pressure increases. In the second stage, cavitation occurs in the oil film and the film starts to rupture. In the third stage, the oil film ruptures and the bore pressure starts to decrease. Finally, in the fourth stage, the reed is separated from the seat and the gas flows through the valve. Reducing the reed/seat contact area changes the reed deformation in the first stage, thereby increasing the reed/seat distance and realizing an earlier oil film rupture and a shorter delay.

Modeling and Analysis of High-Speed Journal Bearing Based on Thermal Hydrodynamic Lubrication Theory

2013 ◽  
Vol 380-384 ◽  
pp. 82-86 ◽  
Author(s):  
Song Sheng Li ◽  
Yu Xin Lu ◽  
Ma Li Dong ◽  
Juan Shao ◽  
Feng Yu
Keyword(s):  
High Speed ◽  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Lubrication Theory ◽  
Engineering Practice ◽  
Isothermal Model ◽  
Modeling And Analysis ◽  
Oil Film ◽  
Rotating Speed ◽  
Hydrodynamic Lubrication Theory

Journal bearing in high-speed working conditions will generate a lot of heat, which affects its working performance. Based on hydrodynamic lubrication theory, a model of the thermal hydrodynamic lubrication was built, and the distributions of temperatures and pressures of the oil film were obtained from the simultaneous solution of generalized Reynolds, energy and viscosity-temperature equations. The results show that the temperature will increase and the pressure decrease of the lubrication oil film with the rising of the rotating speed, which will make the the bearing capacity decrease. Compared with the traditional isothermal model, the thermal hydrodynamic lubrication model is more consistent with the engineering practice.

Stability of Jeffcott Rotor Operating in Tilting 3-Pad Journal Bearings with Turbulent Oil Film

2009 ◽  
Vol 147-149 ◽  
pp. 450-455
Author(s):  
Stanislaw Strzelecki ◽  
Sobhy M. Ghoneam
Keyword(s):  
Theoretical Investigation ◽  
Dynamic Characteristics ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Oil Film ◽  
Temperature Distributions ◽  
Jeffcott Rotor ◽  
Oil Flow ◽  
The Stability ◽  
Oil Film Pressure

This paper introduces the results of theoretical investigation on the dynamic characteristics of tilting 3-pad journal bearing that operates with turbulent oil film. The Reynolds, energy, viscosity and geometry equations determine the oil film pressure, temperature distributions, and oil film resultant force that are the grounds for the dynamic characteristics of bearing. These equations were solved simultaneously on the assumption of adiabatic laminar or adiabatic turbulent oil flow in the bearing gap. The stability and system damping of Jeffcott rotor operating in tilting 3-pad journal bearing was determined.

scholarly journals Simultaneous Pressure Measurement and High-Speed Photography Study of Cavitation in a Dynamically Loaded Journal Bearing

1993 ◽  
Vol 115 (1) ◽  
pp. 88-95 ◽  
Author(s):  
D. C. Sun ◽  
D. E. Brewe ◽  
P. B. Abel
Keyword(s):  
Pressure Measurement ◽  
Cavitation Bubble ◽  
High Speed ◽  
Journal Bearing ◽  
Operating Conditions ◽  
High Speed Photography ◽  
Pressure Data ◽  
Oil Film ◽  
Dynamically Loaded ◽  
Insight Into

Cavitation of the oil film in a dynamically loaded journal bearing was studied using high-speed photography and pressure measurement simultaneously. Comparison of the visual and pressure data provided considerable insight into the occurrence and non-occurrence of cavitation. It was found that (1), cavitation typically occurred in the form of one bubble with the pressure in the cavitation bubble close to the absolute zero; and (2), for cavitation-producing operating conditions, cavitation did not always occur; with the oil film then supporting a tensile stress.

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