Hydraulic Jacking

1971 ◽  
Vol 13 (6) ◽  
pp. 384-396
Author(s):  
E. T. Eliasson
Keyword(s):  
High Pressure ◽  
Approximate Solution ◽  
Analytical Solution ◽  
Finite Length ◽  
Experimental Verification ◽  
Journal Bearing ◽  
Small Diameter ◽  
Load Carrying ◽  
Bearing Design ◽  
Hydraulic Jacking

The trend in modern plain journal bearing design is towards a reduction in the relative bearing width; this results in reduced machine bulk and bearing losses, but has the disadvantage of increased bearing wear, particularly at starting, stopping and the reversal of motion. A method of reducing this wear problem is by means of hydraulic jacking, or the separation of the load carrying surfaces by the introduction of high pressure oil into the clearance space, through suitable feed grooves. The article describes an analytical solution to the problem of hydraulic jacking. The following solutions are presented, giving full performance characteristics. (1) Single- and twin-axial feed grooves, end leakage neglected. (2) Single- and twin-axial feed grooves, concentric journal, finite length bearing (approximate solution). (3) Single- and twin-axial feed holes, concentric journal, small diameter feed holes (approximate solution). Some experimental verification is given for the theory of the axial feed groove arrangement, both the single grooved and the twin grooved arrangement.

Theoretical Analysis of Externally Pressurized Air Journal Bearing

1970 ◽  
Vol 12 (2) ◽  
pp. 123-129 ◽  
Author(s):  
B. C. Majumdar
Keyword(s):  
Experimental Data ◽  
Carrying Capacity ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Design Parameters ◽  
Load Carrying Capacity ◽  
Load Carrying ◽  
Dimensional Parameters ◽  
Bearing Design

A theoretical investigation is made to predict the performance of an externally pressurized air journal bearing having several pressure sources. The pressure distribution, which leads to the determination of load-carrying capacity and flow requirement, is obtained by solving Reynolds equation numerically. The load and flow, expressed in non-dimensional parameters, are presented for different bearing design parameters (dimensionless). The results predicted by this method are compared with others' experimental data.

scholarly journals A superlinear iteration method for calculation of finite length journal bearing's static equilibrium position

2017 ◽  
Vol 4 (5) ◽  
pp. 161059 ◽  
Author(s):  
Wenjie Zhou ◽  
Xuesong Wei ◽  
Leqin Wang ◽  
Guangkuan Wu
Keyword(s):  
Finite Length ◽  
Carrying Capacity ◽  
Equilibrium Position ◽  
Journal Bearing ◽  
Secant Method ◽  
Static Equilibrium ◽  
Computational Time ◽  
Load Carrying Capacity ◽  
Dynamic Coefficients ◽  
Load Carrying

Solving the static equilibrium position is one of the most important parts of dynamic coefficients calculation and further coupled calculation of rotor system. The main contribution of this study is testing the superlinear iteration convergence method—twofold secant method, for the determination of the static equilibrium position of journal bearing with finite length. Essentially, the Reynolds equation for stable motion is solved by the finite difference method and the inner pressure is obtained by the successive over-relaxation iterative method reinforced by the compound Simpson quadrature formula. The accuracy and efficiency of the twofold secant method are higher in comparison with the secant method and dichotomy. The total number of iterative steps required for the twofold secant method are about one-third of the secant method and less than one-eighth of dichotomy for the same equilibrium position. The calculations for equilibrium position and pressure distribution for different bearing length, clearance and rotating speed were done. In the results, the eccentricity presents linear inverse proportional relationship to the attitude angle. The influence of the bearing length, clearance and bearing radius on the load-carrying capacity was also investigated. The results illustrate that larger bearing length, larger radius and smaller clearance are good for the load-carrying capacity of journal bearing. The application of the twofold secant method can greatly reduce the computational time for calculation of the dynamic coefficients and dynamic characteristics of rotor-bearing system with a journal bearing of finite length.

Stability, Load Capacity, Stiffness, and Damping Advantages of the Double Pocket Journal Bearing

1985 ◽  
Vol 107 (1) ◽  
pp. 53-58
Author(s):  
J. C. Nicholas
Keyword(s):  
Journal Bearing ◽  
Load Capacity ◽  
Load Carrying Capacity ◽  
Rigid Rotor ◽  
Instability Problem ◽  
Oil Whirl ◽  
Load Carrying ◽  
Bearing Design ◽  
The Stability ◽  
Stiffness And Damping

The double pocket bearing design is discussed and compared to the plain three axial groove bearing. Rigid rotor stability, load capacity, and stiffness and damping curves are shown for the two bearing designs illustrating the stability and load capacity advantages of the double pocket bearing. Results show that placing double opposing stepped pockets in the top pads of a three axial groove bearing is a simple, inexpensive, expedient modification that is effective in suppressing oil whirl instability. Furthermore, the bottom plain pad retains the load carrying capacity of the original three axial groove design. Frequency spectrums substantiating the stabilizing ability of the double pocket design are shown for a test stand instability problem.

An approximate solution of oil film forces of turbulent finite length journal bearing

2014 ◽  
Vol 74 ◽  
pp. 110-120 ◽  
Author(s):  
Yongfang Zhang ◽  
Di Hei ◽  
Cheng Liu ◽  
Bingjun Guo ◽  
Yanjun Lu ◽  
...  
Keyword(s):  
Approximate Solution ◽  
Finite Length ◽  
Journal Bearing ◽  
Oil Film

Zur Lösung der BETHE-GOLDSTONE-Gleichung bei nicht-verschwindendem Gesamtimpuls I

1963 ◽  
Vol 18 (4) ◽  
pp. 531-538
Author(s):  
Dallas T. Hayes
Keyword(s):  
Approximate Solution ◽  
Analytical Solution ◽  
Nuclear Matter ◽  
Analytical Solutions ◽  
Projection Operator ◽  
Center Of Mass ◽  
Separable Potential ◽  
Localized Solutions ◽  
Non Local ◽  
Square Well

Localized solutions of the BETHE—GOLDSTONE equation for two nucleons in nuclear matter are examined as a function of the center-of-mass momentum (c. m. m.) of the two nucleons. The equation depends upon the c. m. m. as parameter due to the dependence upon the c. m. m. of the projection operator appearing in the equation. An analytical solution of the equation is obtained for a non-local but separable potential, whereby a numerical solution is also obtained. An approximate solution for small c. m. m. is calculated for a square-well potential. In the range of the approximation the two analytical solutions agree exactly.

scholarly journals Pivoted-Pad Journal Gas Bearing Performance in Exploratory Operation of Brayton Cycle Turbocompressor

1968 ◽  
Vol 90 (4) ◽  
pp. 687-696 ◽  
Author(s):  
R. Y. Wong ◽  
W. L. Stewart ◽  
H. E. Rohlik
Keyword(s):  
Experimental Study ◽  
Journal Bearing ◽  
Inert Gas ◽  
Brayton Cycle ◽  
Ambient Conditions ◽  
Operating Characteristics ◽  
The Third ◽  
Loading Device ◽  
Bearing Design ◽  
Gas Bearing

This paper describes findings obtained to date in the area of journal gas bearings from an experimental study of a Brayton cycle turbocompressor designed for the requirements of a two-shaft 10-kw space power system. The journal bearing design utilizes three pads pivoted on conforming balls and sockets. Two of the pivots are rigidly mounted to the frame, and the third pivot is mounted to the frame through a low-spring-rate diaphragm. This paper describes the salient package and bearing design features and then presents the principal results obtained from testing the package in both a spin calibration rig and operation at design temperature conditions with an inert gas. The results discussed include (a) the successful use of a pneumatic loading device to vary pad load during operation, (b) the operating characteristics of the bearings as obtained over a range of pad loads and ambient conditions, (c) structural and dynamic behavior of the bearing-support system during design temperature operation and (d) a discussion of the wear characteristics of the conforming ball-and-socket pivot as obtained from the tests made to date.

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