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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society of Tribologists and Lubrication Engineers
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Journal DOI :
The Korean Society of Tribologists and Lubrication Engineers
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Volume & Issues
Volume 24, Issue 6 - Dec 2008
Volume 24, Issue 5 - Oct 2008
Volume 24, Issue 4 - Aug 2008
Volume 24, Issue 3 - Jun 2008
Volume 24, Issue 2 - Apr 2008
Volume 24, Issue 1 - Feb 2008
Selecting the target year
In-line Smart Oil Sensor for Machine Condition Monitoring
Kong, H. ; Ossia, C.V. ; Han, H.G. ; Markova, L. ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 3, 2008, Pages 111~121
An integrated in-line oil monitoring detector assigned for continuous in situ monitoring multiple parameters of oil performance for predicting economically optimal oil change intervals and equipment condition control is presented in this study. The detector estimates oil deterioration based on the information about chemical degradation, total contamination, water content of oil and oil temperature. The oil oxidation is estimated by "chromatic ratio", total contamination is measured by the changes in optical intensity of oil in three optical wavebands ("Red", "Green" and "Blue") and water content is evaluated as Relative Saturation of oil by water. The detector is able to monitor oils with low light absorption (hydraulic, transformer, turbine, compressor and etc. oils) as well as oils with rather high light absorption in visible waveband (diesel and etc. oils). In a case study that the detector is applied to a diesel engine oil, it is found that the detector provides good results on oil chemical degradation as well as soot concentration.
The Effects of Surface Porfiles and Coatings on the Tribological Behaviors of the Surfaces of Piston Skirt
Cho, Dae-Hyun ; Chung, Soon-Oh ; Won, Young-Duck ; Han, Man-Cheol ; Lee, Young-Ze ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 3, 2008, Pages 122~128
To reduce the friction losses and the wear amounts in the piston assembly two methods were proposed. One is the modification of surface profile of the skirt part. The surface coating is another method to protect the sliding surfaces. To modify the profile of the skirt surfaces the surfaces were ground to have three different shapes of profiles. Also, several coatings, such as graphite, TiN, and
, and DLC, were used to protect the surfaces of the piston skirts. The specimens of the skirt and the cylinder bores were tested with the reciprocating wear tester. SAE 5W40 engine oil was used in boundary lubrication regime. Among several coatings the graphite and DLC coatings were very effective to reduce the friction forces. Especially, DLC film represented much better tribological performances than the others. The friction coefficient of the graphite coating was the lowest, but the graphite coating was not effective to protect the surfaces.
Fretting Wear Characteristics of the Corroded Fuel Cladding Tubes for Nuclear Fuel Rod against Supporting Girds
Lee, Young-Ze ; Kim, Jin-Seon ; Park, Se-Min ; Kim, Yong-Hwan ; Lee, Seung-Jae ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 3, 2008, Pages 129~132
Fuel cladding tubes in nuclear fuel assembly are held up by supporting grids because the tubes are long and slender. Fluid flows of high-pressure and high-temperature in the tubes cause oscillating motions between tubes and supports. This is called as FIV (flow induced vibration), which causes fretting wear in contact parts of tube and support. The fretting wear of tube and support can threaten the safety of nuclear power plant. Therefore, a research about the fretting wear characteristics of tube-support is required. The fretting wear tests were performed with supporting grids and cladding tubes, especially after corrosion treatment on tubes, in water. The tests were done using various applied loads with fixed amplitude. From the results of fretting tests, the wear amounts of tube materials can be predictable by obtaining the wear coefficient using the work rate model. Due to stick phenomena the wear depth was changed as increasing load and temperature. The maximum wear depth was decreased as increasing the water temperatures. At high temperatures there are the regions of some severe adhesion due to stick phenomena.
Pin-Boss Bearing Lubrication Analysis of a Diesel Engine Piston Receiving High Combustion Pressure
Chun, Sang-Myung ; Ha, Dae-Hong ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 3, 2008, Pages 133~139
In recently designed diesel engines, the running conditions for piston pin bearings have become very severe due to combustion pressure and temperature increase. In this paper, it will be investigated the tendency of piston pin rotating motion by calculating the friction coefficient at piston pin bearings, the oil film thickness and the frictional torques induced by hydrodynamic shear stress. Finally, the pressure distributions on the oil film of piston pin bearings will be found by two-dimensional lubrication analysis in order to help the optimum design of the bearings of piston pin. Specially, it is investigated the effects on the film pressure distribution due to the change in maximum combustion pressure.
Theoretical research of Static Characteristics of Bump Floating Ring Seal
Kim, Kyoung-Wook ; Chung, Jin-Taek ; Kim, Chang-Ho ; Lee, Young-Bok ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 3, 2008, Pages 140~146
The floating ring seal which is used in the high pressure turbo pump is frequently used in the oxidizer pump and the fuel pump of the turbo pump of the liquid propulsion rocket, because it is able to minimize clearance to decrease the leakage flow rate. But, the floating ring seal has a tendency to increase instability in decreasing eccentricity ratio. To complement this weakness, it is devised bump floating ring seal which is inserted bump in the outer surface. It has various experiment results. But the theoretical study of the bump floating ring seal didn't investigated yet. In this paper, we analyse about static characteristics of bump floating ring seal, compared previous experimental results. To analyze the characteristic of bump floating ring seal, we coupled perturbation method of floating ring seal and FEM of bump foil.
The Effect of Oil Supply Pressure on the Performance of Vapor Cavitated Short Squeeze Film Dampers
Jung, Si-Young ;
Journal of the Korean Society of Tribologists and Lubrication Engineers, volume 24, issue 3, 2008, Pages 147~153
The effect of oil supply pressure on the performance of vapor cavitated short squeeze film dampers is examined. Vapor cavitation is characterized by film rupture occurring as a result of evaporating oils. The pressure of vapor cavity in the film is almost zero in absolute pressure and nearly constant. Pan's model about the shape of vapor cavity is utilized for studying the effect of vapor cavitation on the damping capability of a short squeeze film damper. As the level of oil supply pressure is increasing, vapor cavitation is suppressed so that the direct damping coefficient increases and the cross coupled damping coefficient decreases. Futhermore, the analysis of the unbalance responses of a rigid rotor supported on cavitated squeeze film dampers shows that a significant reduction in rotor amplitude and force transmissibility is possible by controlling the oil supply pressure into short squeeze film dampers.