• Tribology and Lubricants
• /
• v.6 no.2
• /
• pp.76-87
• /
• 1990

It is known that the effects of oil supply conditions on the characteristics of plain journal bearings are significant and especially the dynamic characteristics are affected by cavity region. For various shapes (axial groove, spiral groove, X-shape groove) and positions of oil grooves, the pressure distribution and the static performance of plain journal bearings are obtained with numerical methods. Elrods algorithm which implements JFO oil rupture/reformation boundary condition is used in order to take into account the effect of cavity region. It is shown that in the cases of axial groove or X-shape groove the load capacity and the attitude angle are affected by the groove position but the effect of spiral groove position is less significant.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
• /
• 2006.11a
• /
• pp.269-272
• /
• 2006

The use of packaged skid in oil and gas plant has increased dramatically over the decades, replacing loose supply equipment. Most equipment is installed on structural skid in manufacturer's shop. As Oil and Gas Plants are constructed at inaccessible area, the demands of packaged skids are increased. The packaged skid have advantages comparing to loose supply equipment in inaccessible area. The packaged skid is small complex plant consists of process, mechanical, piping, instrument, electrical and structural steel. This paper examines advantages and problems of packaged skid, based on previous experience. EPC company consider key factors such as manufacturing period, construction periods, equipment quality and costs.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
• /
• 2001.11a
• /
• pp.186-193
• /
• 2001

In the high pressure state, the leakage flow rate of hydraulics is one of serious problems and the great reason to decrease the volume efficiency. In this paper, I tried to clarify tribology characteristics for the slipper hydrostatic bearing in swash plate type axial piston pumps and motors by means of experiment . I measured the leakage flow rate between swash plate and piston shoe with change the supply pressure and oil temperature at a swash plate angle of 0。 . And I also investigated the slipper pocket pressure and calculated oil film thickness for theoretical method. So. 1 have analyzed the tribology characteristics of hydrostatic bearing for leakage flow rate and oil film thickness with oil temperature and supply pressure.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.9 no.5
• /
• pp.64-69
• /
• 2010

This study is the machining of fuel supply pipe used in large vessels. The fuel supply pipe of large vessels have effects to reduce engine exhaust because of common rail system and show excellent fuel efficiency so it is in the limelight as a vessel engine of next generation. At present, the shape of fuel supply pipe of common rail used for huge two-stroke & low-speed vessels is like a peanut hole so the second machining is necessary after the first machining. There is high error rate for machining and the materials waste caused by machining error is serious. Also, in this time the request for increasing the length of fuel supply pipe is suggested in the world market, it's judged that current methods will show higher error rate for machining. Therefore, the purpose of this study is to improve the machining process used originally. For that, the system controlling the process was developed as well as surface roughness and straightness which are evaluation items of fuel supply pipe were measured so that improved process can be observed in real time.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.10a
• /
• pp.254-257
• /
• 2002

As the large Coolant amount used of a machine holds mass serious trouble recently, an environment pollution is increased, and a machine is conquering large specific gravity in an empty cost plane. It is the stage that must reexamine the parts washing that processing is later with this current way or a problem of a liquid waste treatment back. The environmental problems by using coolant demanded the new cooling methods. As one of them, the studies on the grinding with compressed cold air and oil mist have been done. The cooling method using compressed cold air was effective through going down the temperature of compressed air supplied below -$25^{\circ}C$ and increasing the amount of compressed cold air, but had not enough cooling effect due to the low performance of lubrication. Therefore, the cooling methods using oil mist newly were suggested. This method can satisfy both cooling effect and lubrication with only small amount of coolant, also have the benefit in the point of decreasing the environmental pollution. This paper focused on analyzing the grinding characteristics of the cooling method using oil mist. The grinding test according to compressed cold air and oil mist supply direction were done.

• The KSFM Journal of Fluid Machinery
• /
• v.20 no.2
• /
• pp.53-62
• /
• 2017

In this paper, the effect of oil conditions in rotor dynamic behaviors of a FFRB (Fully-Floating Ring Bearing) is investigated. Through the characteristic of a FFRB has two films, it has several advantages such as less friction loss and better stability over a wide speed range. However, it is difficult to supply a oil to the inner film. Thus, turbocharger makers have been paid significant attention to the lubrication of a FFRB because of its importance. This work focuses on the influence of oil inlet pressure and temperature. The methodologies of computational simulation and experimental test were used to estimate the rotor dynamic behaviors. In experimental test, the single-scroll turbocharger for the 1.4L diesel engine was used. The results show that the oil inlet pressure and temperature will place considerable influence on the rotor response. Oil conditions affect RSR (Ring Speed Ratio) which is cause of sub-synchronous vibrations, which also cause of oil whirling and whip even a critical speed. At higher speed range, the phenomenon of self-excited vibrations which is cause of instability of fluid whirl is investigated through the orbit shapes that consist of small orbit and large amplitude orbit. It is shown that some performance of a FFRB can be controlled by the conditions of oil supply. Finally, it was revealed that the oil induced operating conditions will strongly affect the turbocharger rotor dynamics behaviors.

• Tribology and Lubricants
• /
• v.22 no.4
• /
• pp.203-210
• /
• 2006

Two kinds of crankshaft oil supply system which were called continuous and discontinuous oil sup-ply system have recently been adopted in engine developing process. In order to clarify the lubrication characteristics for theses systems, in this paper, the comparison studies on supplied oil temperature, pressure, aspect ratio of bearings, and radial clearance were carried out for the main and the connecting rod bearing using computational fluid dynamic analysis.

• Journal of Energy Engineering
• /
• v.25 no.4
• /
• pp.37-52
• /
• 2016

This study attempts to compare the role of the oil refinery industry in the Korean and Japanese national economy using an inter-industry analysis. First of all, the study conducts a comparative analysis on production-inducing effects and value-added creation effects of the oil refinery industry based on demand-driven model. Moreover, we investigate the supply shortage effects and sectoral pervasive effects of price change by using supply-driven model and Leontief price model, respectively. These analyses have been done by specifying the oil refinery industry as not endogenous but exogenous. The results show that1 won of production or investment in the oil refinery industry induces 0.2620 won and 0.6537 won of production in other industries of Korea and Japan, respectively. The former is less than the latter. It also creates 0.0946 won and 0.0536 won of value-added in other industries of Korea and Japan, respectively. The first is larger than the second. The effects of 1 won of supply shortage in oil refinery industry on other industries are computed to be 0.9657 won and 1.4476 won for Korea and Japan, respectively, and thus the former is smaller than the latter. Finally, the pervasive effects of 10% price change in oil refinery industry are estimated to be 0.3819% and 0.3409% in Korea and Japan, respectively, and thus the first is larger than the second.

• Environmental and Resource Economics Review
• /
• v.17 no.2
• /
• pp.381-418
• /
• 2008

This study revisits the meaning of energy security by examining the oil market supply and demand conditions of petroleum products and refinery capacity of three Northeast Asian countries(Korea, China, Japan). In 2006, 10.6 million bid of excess demand occurred and is expected to be 15~22 million bid by the year 2030 in this regional oil market. Different oil demand is caused mainly by the different demands for various petroleum products based on each country's economic structures. If the demands are ranked according to their petroleum products, Chinese case shows gasoil > gasoline > fuel oil> LPG > naphtha > Kero/jet and Japanese case shows gasoil > gasoline> naphtha> Kero/jet > fuel oil > LPG, while Korean case shows naphtha> gas oil > fuel oil > LPG > Kero/jet > gasoline, respectively. Total CDU(Crude Distillation Unit) capacity of three northeast asian countries also have been examined in this respect. This study points out the importance of the information on oil demand and supply, on petroleum products and refinery capacities of the three Northeast Asian countries to enhance the security of the oil market in this region.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.17 no.2
• /
• pp.351-358
• /
• 1993

Recently a high speed spindle system for machine tools has attracted considerable attention to reduce the machining time, to improve the machining accuracy, to perform the machining of light metals and hard materials and to unite the cutting and grinding processes. In this study, a high speed spindle system is developed by applying the oil-air lubrication method, angular contact ball bearings, injection nozzles with dual orifices and so on. And a lubrication experiment for evaluating the performance of the spindle system is carried out. Especially, in order to establish the lubrication conditions related to the development of a high speed spindle system, the effects of oil supply rate, rotational spindle speed and so on are studied and discussed on the bearing temperature rise, bearing temperature distribution and frictional torque. And the effect of spindle system structure on the bearing temperature distribution is investigated.