Modeling and Identification of Gas Journal Bearings: Self-Acting Gas Bearing Results

2002 ◽  
Vol 124 (4) ◽  
pp. 716-724 ◽  
Author(s):  
G. Belforte ◽  
T. Raparelli ◽  
V. Viktorov
Keyword(s):  
Mathematical Model ◽  
Dynamic Characteristics ◽  
Transfer Functions ◽  
Analytical Data ◽  
Journal Bearings ◽  
Rotating Shaft ◽  
Static And Dynamic Characteristics ◽  
Gas Bearings ◽  
Wide Range ◽  
Analytical Relations

A mathematical model is elaborated with analytical relations for transfer functions and for gas-film stiffness and damping coefficients for self-acting and externally pressurized gas journal bearings with four supply orifices positioned at the center plane for rotating shaft displacements near the bearing center. Averaging and corrective coefficients are elaborated. In this paper static and dynamic characteristics of self-acting gas bearings are investigated. Results derived using the developed mathematical model are compared with the results derived from numerical computations of a non-linear distributed parameter model of the gas bearings. The results obtained demonstrate that analytical data are in good agreement with the numerical data for wide range of parameters and the mathematical model developed makes the simple calculation of static and dynamic characteristics of self-acting gas bearings possible. Derived analytical relations for transfer functions and for gas-film coefficients of gas bearings provide an efficient means for designing rotor-bearing systems.

Modeling and Identification of Gas Journal Bearings: Externally Pressurized Gas Bearing Results

2004 ◽  
Vol 127 (3) ◽  
pp. 548-556 ◽  
Author(s):  
V. Viktorov ◽  
G. Belforte ◽  
T. Raparelli
Keyword(s):  
Mathematical Model ◽  
Dynamic Characteristics ◽  
Transfer Functions ◽  
Analytical Data ◽  
Numerical Data ◽  
Journal Bearings ◽  
Rotating Shaft ◽  
Static And Dynamic Characteristics ◽  
Gas Bearings ◽  
Wide Range

Static and dynamic characteristics of externally pressurized gas journal bearings with four supply orifices positioned at the central cross section for rotating shaft displacements near the bearing center are investigated. Results for transfer functions and for gas-film coefficients derived using the developed mathematical model are compared with the results derived from numerical computations of a nonlinear distributed parameter model of the gas bearings. Averaging and corrective coefficients are elaborated. The results obtained demonstrate that analytical data are in good agreement with the numerical data for the wide range of parameters and the mathematical model developed makes the simple calculation of static and dynamic characteristics of this type of externally pressurized gas bearings possible. Derived analytical relations for transfer functions and for gas-film coefficients of gas bearings provide an efficient means for designing rotor-bearing systems.

Analysis of static and dynamic characteristics of spiral-grooved gas journal bearings in high speed

2019 ◽  
Vol 233 (19-20) ◽  
pp. 6774-6792 ◽  
Author(s):  
Laiyun Song ◽  
Kai Cheng ◽  
Hui Ding ◽  
Shijin Chen ◽  
Qiang Gao
Keyword(s):  
Dynamic Characteristics ◽  
High Speed ◽  
Load Capacity ◽  
Structural Parameters ◽  
Dynamic Stiffness ◽  
Journal Bearings ◽  
Linear Perturbation ◽  
Static And Dynamic Characteristics ◽  
Gas Bearings ◽  
Spiral Grooves

The spiral grooves structures could promote load capacity and improve stability of the gas journal bearings working in high-speed condition. In this study, the unsteady Reynolds equation is solved by linear perturbation method and finite difference method in which the mesh of the groove region is specially treated. The static and dynamic characteristics of spiral grooves journal gas bearings are investigated in different working conditions and the pumping effect caused by spiral-groove structure is revealed and analyzed. Further, the influences of groove structural parameters on the dynamic stiffness and damping coefficients are studied and discussed, which provides guidelines for the design of the journal gas bearings with spiral grooves.

The static and dynamic characteristics of a pressure relief valve with a proportional solenoid-controlled pilot stage

2002 ◽  
Vol 216 (2) ◽  
pp. 143-156 ◽  
Author(s):  
R Maiti ◽  
R Saha ◽  
J Watton
Keyword(s):  
Mathematical Model ◽  
Dynamic Characteristics ◽  
Dynamic Behaviour ◽  
Practical Experience ◽  
Pressure Relief Valve ◽  
Relief Valve ◽  
Pressure Relief ◽  
Static And Dynamic Characteristics ◽  
Good Comparison ◽  
The Mathematical Model

The steady state and dynamic characteristics of a two-stage pressure relief valve with proportional solenoid control of the pilot stage is studied theoretically as well as experimentally. The mathematical model is studied within the MATLAB-SIMULINK environment and the non-linearities have been considered via the use of appropriate SIMULINK blocks. The detailed modelling has resulted in a good comparison between simulation and measurement, albeit assumptions had to be made regarding the solenoid dynamic characteristic based upon practical experience. The use of this characteristic combined with additional dynamic terms not previously considered allows new estimations of internal characteristics to be made such as the damping flowrate. The overall dynamic behaviour has been shown to be dominated by the solenoid characteristic relating force to applied voltage.

Analysis of a Centrally Loaded 120 Degree Partial Porous Journal Bearing Taking Tangential Velocity Slip into Account

1981 ◽  
Vol 23 (4) ◽  
pp. 171-178 ◽  
Author(s):  
M. Malik ◽  
M. Chandra ◽  
R. Sinhasan
Keyword(s):  
Porous Medium ◽  
Aspect Ratio ◽  
Dynamic Characteristics ◽  
Journal Bearing ◽  
Tangential Velocity ◽  
Velocity Slip ◽  
Fluid Film ◽  
Static And Dynamic Characteristics ◽  
Wide Range ◽  
Permeability Parameter

This paper presents the analysis of a partial porous journal bearing for its static and dynamic characteristics. Tangential velocity slip at the interface of the fluid film and the porous medium has been taken into account. The analysis is general and can be easily adapted to plane journal and non-circular bearing configurations. The results reported in the paper are for centrally loaded 120 degree partial bearings of aspect ratio equal to unity. These results include static as well as dynamic characteristics of the bearing. A wide range of permeability parameter and R/C ratio has been covered making the data quite comprehensive for design purposes.

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