scholarly journals Experimental Stability Studies of the Herringbone-Grooved Gas-Lubricated Journal Bearing

1969 ◽  
Vol 91 (1) ◽  
pp. 52-57 ◽  
Author(s):  
Robert E. Cunningham ◽  
David P. Fleming ◽  
William J. Anderson
Keyword(s):  
Journal Bearing ◽  
Experimental Studies ◽  
Ambient Air ◽  
Fair Agreement ◽  
Radial Clearance ◽  
Radial Load ◽  
Test Results ◽  
Stability Studies ◽  
Theory And Experiment

Experimental studies were conducted on six rotors, 1 1/2 in. dia by 12 1/4 in. long operating in ambient air to high compressibility numbers. Herringbone-groove geometries and clearances were varied to determine their effect on half-frequency whirl (HFW). All rotors were operated vertically and without any applied radial load. Results show that half-frequency-whirl onset is very sensitive to radial clearance. Limited test results indicate that a fully grooved bearing is more stable than a partially grooved one, other parameters being equal. Generally fair agreement between theory and experiment was achieved for predicting HFW onset speeds.

Behavior of a Two-Lobe Journal Bearing With a Scratched Shaft: Comparison Between Theory and Experiment

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Jean Bouyer ◽  
Michel Fillon ◽  
Mathieu Helene ◽  
Jérôme Beaurain ◽  
Célia Giraudeau
Keyword(s):  
Experimental Data ◽  
Pressure Field ◽  
Journal Bearing ◽  
Experimental Tests ◽  
Radial Clearance ◽  
Test Rig ◽  
Different Depths ◽  
Geometrical Defects ◽  
Bearing Preload ◽  
Theory And Experiment

Using the experience acquired within our lab in terms of both thermohydrodynamic (THD) and thermoelastohydrodynamic (TEHD) numerical simulations, a new THD code has been improved by adding the possibility of taking into account geometrical defects, and particularly scratches, which are often discovered by turbine users during maintenance operations. To examine this issue, two numerical codes were coupled to provide the TEHD analysis presented in this work. To validate the numerical results, experimental tests were conducted using the Pprime Institute bearing test rig. The performance of the same two-lobe journal bearing (preload 0.524) as used in a previous study, lubricated with ISO VG 46 oil, was evaluated. Scratches of different depths (varying as a function of the radial clearance) were directly machined onto the shaft. TEHD solutions and experimental data were compared for various rotational speeds and applied loads. Pressure and temperature comparisons for the three scratch depths show good correlation, and give the expected results for cases with a scratch. It was also found that the asymmetry in the pressure field created by the presence of a scratch led to a slight misalignment. The comparisons were improved by taking into account this misalignment, using the balance of momentum.

Experimental and Theoretical Rotordynamic Characteristics of a Hybrid Journal Bearing

1997 ◽  
Vol 119 (1) ◽  
pp. 132-141 ◽  
Author(s):  
J. T. Sawicki ◽  
R. J. Capaldi ◽  
M. L. Adams
Keyword(s):  
Journal Bearing ◽  
Operating Conditions ◽  
Dynamic Force ◽  
Test Results ◽  
Force Measurements ◽  
Lubrication Equation ◽  
Load Cells ◽  
Theoretical Predictions ◽  
Stiffness And Damping

This paper describes an experimental and theoretical investigation of a four-pocket, oil-fed, orifice-compensated hydrostatic bearing including the hybrid effects of journal rotation. The test apparatus incorporates a double-spool-shaft spindle which permits independent control over the journal spin speed and the frequency of an adjustable-magnitude circular orbit, for both forward and backward whirling. This configuration yields data that enables determination of the full linear anisotropic rotordynamic model. The dynamic force measurements were made simultaneously with two independent systems, one with piezoelectric load cells and the other with strain gage load cells. Theoretical predictions are made for the same configuration and operating conditions as the test matrix using a finite-difference solver of Reynolds lubrication equation. The computational results agree well with test results, theoretical predictions of stiffness and damping coefficients are typically within thirty percent of the experimental results.

Performance Analysis of a Nonrecessed Hybrid Conical Journal Bearing Compensated With Capillary Restrictors

2015 ◽  
Vol 138 (1) ◽  
Author(s):  
Prashant G. Khakse ◽  
Vikas M. Phalle ◽  
S. S. Mantha
Keyword(s):  
Performance Analysis ◽  
Film Thickness ◽  
Journal Bearing ◽  
Fluid Film ◽  
Load Parameter ◽  
Radial Load ◽  
Wide Range ◽  
Bearing Stiffness ◽  
Fluid Film Thickness ◽  
Film Stiffness

The present paper deals with the performance analysis of a nonrecessed hole-entry hydrostatic/hybrid conical journal bearing with capillary restrictors. Finite element method has been used for solving the modified Reynolds equation governing the flow of lubricant in the clearance space of journal and bearing. The hole-entry hybrid conical journal bearing performance characteristics have been depicted for a wide range of radial load parameter (W¯r  = 0.25–1.5) with uniform distribution of holes at an angle of 30 deg in the circumferential direction. The numerically simulated results have been presented in terms of maximum fluid film pressure, minimum fluid film thickness, lubricant flow rate, direct fluid film stiffness coefficients, direct fluid film damping coefficients, and stability threshold speed. However, the proposed investigation of nonrecess hole-entry hybrid conical journal bearing shows important performance for bearing stiffness and minimum fluid film thickness at variable radial load and at given operating speed.

scholarly journals HUBUNGAN PIJAT BAYI DENGAN PERKEMBANGAN MOTORIK BAYI USIA 1 – 12 BULAN DI DESA PUNDUNGSARI BULU SUKOHARJO

2015 ◽  
Vol 3 (1) ◽  
Author(s):  
Rahayu Setyaningsih ◽  
Kristiani Eka Prasetyo Wat ◽  
Asri Utami
Keyword(s):  
Rapid Growth ◽  
Experimental Studies ◽  
Sampling Technique ◽  
Test Results ◽  
Infant Massage ◽  
Chi Square ◽  
The Public ◽  
Touch Therapy ◽  
Mother And Child ◽  
Long Time

AbstractIntroduction: Infant massage is a touch therapy oldest known to the public. Infant massage is one of the communication between mother and child is communication through touch. Infant massage has been known to man for a long time and reduced down - generations. Age 1-12 months is a period of rapid growth that is traversed by the child, including motoric development. Infant massage can provide a stimulus to promote weight and to increase motoric development.The purpose: Of this study was to correlate of infant massage and motoric development in infants aged 1-12 months in District Pundungsari Bulu Sukoharjo.The subjects: Were mother with infants aged 1-12 months, in the District Pundungsari. Sampling is done with total sampling technique. They are 33 sample in this research.Methods: This study was a non-experimental studies, correlation approach. Data obtained by the method of questionare, which is mother has filled the questionare about baby massage in infants aged 1-12 months and motoric development. The data have been collected and analyzed by chi square with p= 0.05. The research found that respondents do baby massage with continue and not continue and motoric development found delayed, normal and advance. After the test results obtained chi square p 0.000 to p <0.05, which means Ha accepted and Ho rejected.The conclusion: Of this study is infant massage correlate with motoric development in infants aged 1-12 months in District Pundungsari Bulu Sukoharjo.Keywords: Infant massage, motoric development

Influence of geometric parameters and operating conditions on the thermohydrodynamic behaviour of plain journal bearings

2000 ◽  
Vol 214 (5) ◽  
pp. 445-457 ◽  
Author(s):  
I Pierre ◽  
M Fillon
Keyword(s):  
High Speed ◽  
Journal Bearing ◽  
Three Dimensional ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Thermal Dissipation ◽  
Radial Clearance ◽  
Geometric Factors ◽  
Essential Components ◽  
Mass Flowrate

Hydrodynamic journal bearings are essential components of high-speed machinery. In severe operating conditions, the thermal dissipation is not a negligible phenomenon. Therefore, a three-dimensional thermohydrodynamic (THD) analysis has been developed that includes lubricant rupture and re-formation phenomena by conserving the mass flowrate. Then, the predictions obtained with the proposed numerical model are validated by comparison with the measurements reported in the literature. The effects of various geometric factors (length, diameter and radial clearance) and operating conditions (rotational speed, applied load and lubricant) on the journal bearing behaviour are analysed and discussed in order to inform bearing designers. Thus, it can be predicted that the bearing performance obtained highly depends on operating conditions and geometric configuration.

scholarly journals Air Pollution Monitoring and Control System for Subway Stations Using Environmental Sensors

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Gyu-Sik Kim ◽  
Youn-Suk Son ◽  
Jai-Hyo Lee ◽  
In-Won Kim ◽  
Jo-Chun Kim ◽  
...  
Keyword(s):  
Air Quality ◽  
Air Pollutants ◽  
Linear Regression Analysis ◽  
Experimental Studies ◽  
Ambient Air ◽  
Pollution Monitoring ◽  
Scattering Method ◽  
Environmental Sensors ◽  
Monitoring And Control ◽  
Subway Stations

The metropolitan city of Seoul uses more energy than any other area in South Korea due to its high population density. It also has high emissions of air pollutants. Since an individual usually spends most of his/her working hours indoors, the ambient air quality refers to indoor air quality. In particular, PM10concentration in the underground areas should be monitored to preserve the health of commuters in the subway system. Seoul Metro and Seoul Metropolitan Rapid Transit Corporation measure several air pollutants regularly. In this study, the accuracy of an instrument for PM measurement using the light scattering method was improved with the help of a linear regression analysis technique to continuously measure thePM10concentrations in subway stations. In addition, an air quality monitoring system based on environmental sensors was implemented to display and record the data of PM10, CO2, temperature, and humidity. Through experimental studies, we found that ventilation fans could improve air quality and decrease PM10concentrations in the tunnels effectively by increasing the air flow rate.

Analysis of Fatigue of Cylindrical Roller Bearing in Printing Press

2013 ◽  
Vol 312 ◽  
pp. 25-28
Author(s):  
Ji Mei Wu ◽  
Yan Chen ◽  
Bo Gao ◽  
Tuan Yong Yi
Keyword(s):  
Fatigue Life ◽  
Roller Bearing ◽  
Flow Chart ◽  
Printing Press ◽  
Radial Clearance ◽  
Radial Load ◽  
Double Row ◽  
Rotating Speed ◽  
Cylindrical Roller Bearing ◽  
Cylindrical Roller

By means of considering improved Lundberg-Palmgren (L-P) fatigue life theory and rollers and other comprehensive factors, a model of fatigue life is setup for eccentric double row cylindrical roller bearing under rotation. On this basis, the calculation flow chart is given and the fatigue life is calculated. Then come to the conclusions that the fatigue life of bearing is influenced by radial load, rotating speed, radial clearance.

Mechanical Behaviour of Steel-Concrete Twin I-Girder Bridges

2018 ◽  
Author(s):  
Weiwei Lin ◽  
Heang Lam ◽  
Teruhiko Yoda
Keyword(s):  
Load Transfer ◽  
Mechanical Performance ◽  
Experimental Studies ◽  
Test Results ◽  
Loading Test ◽  
Girder Bridges ◽  
Bridge Model ◽  
Symmetrical Loading ◽  
Unsymmetrical Loading ◽  
Girder Bridge

<p>Steel-concrete composite twin I-girder bridges have been built a lot in both Europe and Japan, but the lack of redundancy has always been a concern in U.S. and many other countries. In addition, few experimental studies have been performed on the mechanical performance of such bridges, particularly for the intact bridges. On this background, a steel-concrete composite twin I-Girder bridge model was designed according to the current highway bridge design specification in Japan and tested in the laboratory. The static loading tests were performed, and two loading conditions including both symmetrical loading and unsymmetrical loading were applied. Load versus deflection relationships were measured in the loading test, and the failure mode of the test specimen was discussed. The flexural strain development on bottom flanges of two main girders was also reported in this paper to confirm the load transfer between two main girders. In addition, the theoretical results on the basis of the classic theory were also provided to compare with the test results. The comparison indicates that the theoretical analyses can predict the behaviour of the twin I-girder bridges very well in the elastic stage by considering the effective width of the slab. The load transfer paths in such bridges were also discussed on the basis of the test results under un-symmetrical loading.</p>

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