• Tribology and Lubricants
• /
• 제6권2호
• /
• 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.

• 한국해양공학회:학술대회논문집
• /
• 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
• /
• 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.

• 한국윤활학회:학술대회논문집
• /
• 한국윤활학회 2001년도 제34회 추계학술대회 개최
• /
• 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.

• 한국기계가공학회지
• /
• 제9권5호
• /
• 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.

• 한국유체기계학회 논문집
• /
• 제20권2호
• /
• 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.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2002년도 추계학술대회 논문집
• /
• 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.

• Tribology and Lubricants
• /
• 제22권4호
• /
• 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.

• 에너지공학
• /
• 제25권4호
• /
• pp.37-52
• /
• 2016

석유제품은 한국 및 일본 모두에서 1차 에너지원 중 소비 비중이 가장 높다. 이에 본 논문에서는 산업연관분석을 이용하여 한국 및 일본 정유산업의 국민경제적 역할을 비교 분석해 보고자 한다. 먼저 수요유도형 모형을 이용하여 정유산업의 생산유발효과 및 부가가치 유발효과를 살펴본다. 다음으로 공급유도형 모형 및 레온티에프 가격모형을 적용하여 각각 정유산업의 공급지장효과 및 물가파급효과를 분석한다. 이 과정에서 정유산업을 내생부문이 아닌 외생부문으로 다룸으로써 정유산업을 중심으로 한 논의결과를 제시한다. 수요유도형 모형의 분석 결과, 정유산업에서의 1원 생산이 타 산업에 미치는 생산유발효과는 한국 0.2620원 및 일본 0.6537원으로 일본의 값이 더 크다. 하지만 타 산업 부가가치 유발효과를 분석한 결과 각각 0.0946원 및 0.0536원으로 한국의 값이 일본의 값보다 크다. 정유산업 산출물 1원 어치의 공급지장이 타 산업에 미치는 부정적 생산차질효과를 의미하는 공급지장효과를 살펴보면, 한국 0.9657원 및 일본 1.4476원으로 일본 정유산업의 공급지장효과가 더 큰 것으로 분석되었다. 정유산업의 산출물 가격 10% 인상으로 인한 물가파급효과는 한국 0.3819% 및 일본 0.3409%로 한국의 값이 더 큰 것으로 분석되었다.

• 자원ㆍ환경경제연구
• /
• 제17권2호
• /
• pp.381-418
• /
• 2008

동북아 3국(한국, 중국, 일본)의 원유시장 수급과, 원유수급에 영향을 주는 석유제품별 수급 현황을 살펴보는 것은 원유와 석유제품수급에서 발생할 수 있는 석유안보의 의미를 검토하는데 도움을 준다. 2006년 동북아 3국의 석유시장에서는 1,060만 배럴/일의 수급불균형이 발생하였고, 2030년에는 1,550~2,200만 배럴/일의 불균형이 발생할 것으로 전망되며, 이러한 수급불균형은 국가간 교역으로 해결되고 있다. 원유소비는 다양한 석유제품의 수요로 나타나는데, 2005년 중국은 경유>휘발유>연료유>LPG>나프타>등 항공유, 일본은 경유>휘발유>나프타>등 항공유>연료유>LPG, 한국은 나프타>경유>연료유>LPG>등 항공유>휘발유 순의 수요패턴을 보였다. 수요가 주어진 경우, 석유제품의 공급을 담당하는 각국의 주어진 정제시설규모는 공급 측면에서 석유제품의 수불균형에 영향을 미친다. 본 연구는 관련하여 3국의 상압증류시설과 이용률에 관해서 함께 살펴본다. 본 연구는 원유와 석유제품의 수급, 그리고 정제설비시장의 국가별 분포와 계획 등과 석유안보의 개념이 무관하지 않음을 실제 자료를 통해 평가해 보고, 석유안보 확보를 위한 다양한 방안마련에 대해 논의한다.

• 대한기계학회논문집
• /
• 제17권2호
• /
• 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.