H11 Governing Equations of Very High Speed Journal Bearings with Centrifugal Force and Surface Tension Acting on Oil Film being Considered

2006 ◽  
Vol 2006.59 (0) ◽  
pp. 197-198
Author(s):  
Nobuhiko ISHIBASHI ◽  
Kiyoshi HATAKENAKA
Keyword(s):  
Surface Tension ◽  
Centrifugal Force ◽  
High Speed ◽  
Journal Bearings ◽  
Governing Equations ◽  
Oil Film ◽  
Very High

Nonlinear Vibration and Bifurcation Analysis for Rotor-Seal-Bearing Systems of Centrifugal Compressors

2007 ◽  
Author(s):  
Yuefang Wang ◽  
Yong Li ◽  
Yong Zhang ◽  
Xiaoyan Wang
Keyword(s):  
High Speed ◽  
Labyrinth Seal ◽  
Journal Bearings ◽  
Coupling Vibration ◽  
Oil Film ◽  
Disc Center ◽  
Multiple Parameters ◽  
Jeffcott Rotor ◽  
Vibration Responses ◽  
The One

This paper presents the nonlinear coupling vibration and bifurcation of a high-speed centrifugal compressor with a labyrinth seal and two journal bearings. The rotor system is modeled as a Jeffcott rotor. The Muszynska’s model is used to express the seal force with multiple parameters. For the journal bearings, the model proposed by Zhang is adopted to express the excitation of unsteady oil-film force. The Runge-Kutta method is used to determine the vibration responses at the disc center and the two bearings. With parameters of rotation speed and pressure difference of the seal, bifurcation diagrams are presented to demonstrate the complexity in the rotor motions. Multiple periodic bifurcations are pointed out using two seal pressure differences. The intricate bifurcation behavior shows inherent interactions between forces of oil-film and seal, which reflect much more complicated rotor dynamics than the one with either of the excitations alone.

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.

scholarly journals A HIGH SPEED VACUUM CENTRIFUGE SUITABLE FOR THE STUDY OF FILTERABLE VIRUSES

1936 ◽  
Vol 64 (4) ◽  
pp. 503-528 ◽  
Author(s):  
Johannes H. Bauer ◽  
Edward G. Pickels
Keyword(s):  
Centrifugal Force ◽  
Yellow Fever ◽  
High Speed ◽  
Yellow Fever Virus ◽  
High Vacuum ◽  
Fever Virus ◽  
Compressed Air ◽  
Frictional Heat ◽  
High Speeds ◽  
Very High

1. A high speed centrifuge is described in which the speed is limited only by the strength of the material of which the rotor is made. It carries sixteen tubes, each of which conveniently accommodates 7 cc. of fluid. 2. The centrifuge operates in a very high vacuum and therefore requires only a small amount of driving energy. The arrangement has been found to eliminate the possibility of producing injurious frictional heat. 3. The rotating parts are supported by anair-bearing and are driven by compressed air. 4. The centrifuge has been successfully operated at a speed of 30,000 revolutions per minute, representing a maximum centrifugal force in the fluid of 95,000 times gravity. 5 Celluloid tubes used for centrifugation of fluid at high speeds are described. 6. Experiments are described in which good sedimentation of the yellow fever virus was obtained.

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