• 한국농공학회지
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• 제36권1호
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• pp.141-152
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• 1994

Our experiment investigated the degree of soil contaimination caused by oil leakage. Each soil sample was taken by boring 5, 8m below the test areas, located 5 to 30m from storage tanks at oil stations. According to the results from a series of laboratory tests(both soxhiet extract test and gas chromatograph test), Traces of a light oil were found in all samples except in Dj8, rocky soil and gasoline and petroleum were not detected. We concluded that soil contamination was caused by the corrosion of storage tanks or alternatively by oil overflow caused during the flooding of underground water seeping into the tank during heavy rain fall or the spillage caused by carelessness during lubrication. Old stations without a concrete box enclosing their metal tanks run a greater risk of oil leakage. To research the effect of oil leakage on plant growth and underground water, We examined the results of research conducted overseas. According to these results, when oil leakage occurs, plant growth is repressed and agricultural crops experience low productivity levels. Also, the contamination of underground water can be serious when oil spreads to the aquifer layer. As a result of these problems, to prevent oil leakage and minimize its contaminating effects at oil stations, it is necessary to improve facilities of storage tanks and have the monitoring system of oil leakage.

• 대한토목학회논문집
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• 제2권4호
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• pp.33-38
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• 1982

지하류비축동굴의 성패는 지하수에 의하여 공동(空洞) 주위에 유지되는 수밀성(水密性)에 있다. 수밀성(水密性)이 보장되면 동굴에 저장된 유류의 gas가 유출되지 않으며 인접공동(空洞)이 비어 있을 시 이곳으로 이동하지 않는다. 본 연구에서는 전기상사모형실험(電氣相似模型實驗)을 통하여 동굴형태가 gas누출에 미치는 영향과 여러 가지 형태에서 유류이동을 방지하는 지하수위, 동굴내의 유류수준, 동굴간격 등이 검토되었다. 연구결과 동굴의 천정이 큰 곡율을 갖고 있으면 gas누출이 방지될 수 있음이 입증되었고 유류이동을 방지하는데 필요한 자연지하수위, 공동내의 유류수준 및 공동간격이 도표로 주어졌다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2006년도 춘계학술논문 발표대회 제6권1호
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• pp.177-180
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• 2006

The accidents of oil leakage is increasing in the Underground Concrete structures for Oil Storege. In the result, the waterproofing in the underground structures is melt down and cannot fulfil its Performance. This study shows an experimental study in the effects of the oil leakage to on the performance of Waterproofing Materials. In order to investigate the actual condition and the problems, a comparative analyses were conducted considering the various types of leakage. Utilizing the obtained results at the basic data for test methods and the standard of quality, we intended to propose a strategy to develop an innovated waterproofing Materials and improve the clean environment of underground structures.

• 한국가스학회지
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• 제12권2호
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• pp.7-11
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• 2008

본 논문은 LPG 차량의 주행거리에 따른 스템시일의 오일누설 특성에 대한 실험적 연구결과를 제공하고자 한다. 캠축의 속도와 오일의 온도가 증가하여도 40,000 km 이하의 주행거리를 갖는 스템시일에서는 엔진오일의 누설에 큰 영향을 미치지 못하는 것으로 나타났다. 반면에 주행거리가 50,000 km 이상 100,000 km 정도에서 사용한 스템시일의 경우는 스템시일의 밀봉성에 영향을 미쳐 누설이 급격하게 증가하는 것으로 나타났다. 이것은 포핏밸브와 스템시일 사이의 미끄럼마찰 접촉면을 따라서 오일이 누설되기 때문에 발생한 것이다. 실험결과에 의하면, 현재 LP차량에서 사용하고 있는 스템시일은 주행거리가 $50,000{\sim}60,000\;km$ 정도에서 교환하는 것이 누유특성을 고려하면 바람직하다. 따라서 포핏밸브의 누유를 차단하기 위해 사용하고 있는 스템시일은 보다 향상된 내구성과 수명연장을 위해 재설계되어야 한다.

• 대한기계학회논문집A
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• 제24권9호
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• pp.2159-2166
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• 2000

Recently, high performance machining center requires special type of sealing mechanism that prevent a leakage of oil jet or oil mist lubrication system. Sealing of oil-air mixture plays important r oles to have an enhanced lubrication for performance machining center. Current work emphasizes on investigations of the air jet effect on the protective collar type labyrinth seal. To improve sealing capabilities of conventional labyrinth seals, air jet is injected against the leakage flow. In this study, an adapted model is introduced to improve sealing capability of conventional non-contact type seals. It has a combined geometry of a protective collar type and an air jet type. Both of a numerical analysis by CFD (Computational Fluid Dynamics) and experimental measurements are carried out to verify sealing improvement. The sealing effects of the leakage clearance and the air jet magnitude aic studied in various parameters. Gas or liquid has been used as a working fluid for most of nori-contact types seals including the labyrinth seal. However, it is more reasonable to regard two-phase flows because oil mist or oil jet are used for high performance spindle's lubrication. In this study, working fluid is regarded as two phases that are mixed flow of oil and air phase. Both of turbulence and compressible flow model are also introduced in a CFD analysis to represent an isentropic process. Estimation of non-leaking property is determined by amount of pressure drop in the leakage path. Results of pressure drop in the experiment match reasonably to those of the simulation by introducing a flow coefficient. Effect of the sealing improvement is explained as decreasing of leakage clearance by air jetting. Thus, sealing effect is improved by amount of air jetting even though clearance becomes larger

• Ocean Systems Engineering
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• 제8권1호
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• pp.41-55
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• 2018

Accidental oil and gas leak is a critical concern for the offshore industry because it can lead to severe consequences and as a result, it is imperative to evaluate the probabilities of occurrence of the consequences of the leakage in order to assess the risk. Event Tree Analysis (ETA) is a technique to identify the consequences that can result from the occurrence of a hazardous event. The probability of occurrence of the consequences is evaluated by the ETA, based on the failure probabilities of the sequential events. Conventional ETA deals with events with crisp failure probabilities. In offshore applications, it is often difficult to arrive at a single probability measure due to lack of data or imprecision in data. In such a scenario, fuzzy set theory can be applied to handle imprecision and data uncertainty. This paper presents fuzzy ETA (FETA) methodology to compute the probability of the outcomes initiated due to oil/gas leak in an actual offshore-onshore installation. Post FETA, sensitivity analysis by Fuzzy Weighted Index (FWI) method is performed to find the event that has the maximum contribution to the severe sequences. It is found that events of 'ignition', spreading of fire to 'equipment' and 'other areas' are the highest contributors to the severe consequences, followed by failure of 'leak detection' and 'fire detection' and 'fire water not being effective'. It is also found that the frequency of severe consequences that are catastrophic in nature obtained by ETA is one order less than that obtained by FETA, thereby implying that in ETA, the uncertainty does not propagate through the event tree. The ranking of severe sequences based on their probability, however, are identical in both ETA and FETA.

• 한국가스학회지
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• 제26권6호
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• pp.24-29
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• 2022

이 논문은 LPG 자동차의 캠축베어링 시일의 오일누설, 컴퓨터커넥터 핀 손상에 의한 접촉불량, 베이퍼라이저 배부불량으로 인한 고장사례에 대하여 현상을 분석, 연구한 것이다. 첫 번째 사례는 실린더 헤드를 분해하여 확인한 결과 타이밍 시스템에서 가까운 엔진의 흡기캠축의 베어링과 시일의 조립부 손상으로 인해 이 부위로 엔진오일이 누설되는 것을 확인하였다. 두 번째 사례는 엔진컴퓨터로 공급되는 자동차의 시동을 제어하는 전원선의 커넥터 핀이 손상되어, 전원이 공급되지 않아 시동이 꺼진 것을 확인하였다. 세 번째 사례는 베이퍼라이저 내부에 이물질의 퇴적으로 인해 가스의 흐름이 원활하지 못하여 엔진의 부조화현상이 발생되었다. 결국, 베이퍼라이저에서 믹서로 적은 양의 가스를 공급하게 되고, 믹서의 스로틀 열림량을 제어하는 컴퓨터는 그 열림량만큼 공기를 공급하게 됨으로써 연소실에서 혼합기는 희박한 상태가 되어 엔진의 적정출력을 내지 못하는 것을 확인하였다. 따라서, 자동차가 최적의 운전조건이 될 수 있도록 자동차관련 시스템의 관리를 철저하게 해야한다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.613-617
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• 2001

The test items like as endurance, air leakage and oil endurance test is requested for reliability evaluation about O-ring which is a kind of core machinery accessories of semi-conduct manufacturing equipment. For verification of these, we design and manufactured a test system for endurance, air leakage and oil endurance of O-ring for semi-conduct manufacturing equipment, and also performed the test for two kinds of O-ring, as it were Viton and Kalretz. The characteristics of this test equipment consist in realization of the test conditions of semi-conduct manufacturing equipment and satisfying the test method. The test conditions are cut gas, vacuum grade, temperature and revolution numbers in the endurance test system, vacuum grade and temperature in the air leakage test system, temperature and time in the oil endurance test system. The separating test results for wearing which is an oil endurance test item, the wearing index of domestic produced Viton O-ring is higher than foreign product by 2%, wearing rate of Kalretz O-ring better than Viton O-ring by 17%, and particles existed in various place. The test result of air leakage which is measured through the RGA sensor used Helium, the vacuum grade was $10^-3$Torr. And the test result of oil endurance, the volume change rate was 7~15%. Hereafter, we intend to analysis the reliability test evaluation and to utilize for domestic manufacturing companies by establishing data base and developing reliability softwares.

• 한국가스학회지
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• 제11권4호
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• pp.1-6
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• 2007

본 논문은 LPG 엔진에서 밸브스템의 표면거칠기가 오일 누설에 미치는 영향에 대한 실험적 결과를 제공하고자 한다. 밸브스템시일은 밸브스템과의 미세한 밀봉간극을 통해 유출하는 오일을 차단하기 위한 부품이다. 이들 두개의 부품사이에서 발생되는 밀봉성은 밸브스템과 밸브스템시일의 누유안전성과 수명연장에 관련된 중요한 요소이다. 본 실험결과에 의하면, 밸브스템의 표면거칠기를 중심선 표면거칠기, Ra로 나타낼 경우 $0.4{\sim}0.5{\mu}m$가 최적의 가공조건이고, 표면의 거칠기 단면형상은 균일하게 분포되도록 가공하는 것이 가장 이상적인 설계조건이 될 것이다. 기본적으로 매끄러운 밸브표면과 균일하게 분포된 거칠기 형상을 유지하는 것이 밸브스템과 밸브스템 시일장치의 간극을 통해 빠져나가는 누유량을 줄일 수 있다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2002년도 proceedings of the second asia international conference on tribology
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• pp.411-412
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• 2002

Piston-cylinder system are widely used in power engineering applications. In reciprocating refrigeration compressors, where extremely low friction losses are required, ringless pistons are being used to diminish the friction between piston rings and cylinder wall. Since the ringless piston has the freedom of lateral motion there is a potential danger that it will occasionally hit the cylinder wall while moving up and down along it's axis. A good design must therefore provide a smooth and stable reciprocating motion of the piston and ensure that the fluid film separating the piston from the cylinder wall is maintained all times. And the compromise between refrigerant gas leakage through the piston-cylinder clearance and the friction losses is required utilizing a dynamic analysis of the secondary motion for the high efficiency compressor. To this end, the computer program is developed for calculating the entire piston trajectory and the lubrication characteristics as functions of crank angle under compressor running conditions. The results explored the effects of some design parameters and operating conditions on the stability of the piston, the oil leakage, and friction losses.