• 한국가스학회지
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• 제27권1호
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• pp.13-22
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• 2023

현재 통용되고 있는 화석연료로부터 발생되는 환경오염에 대한 대안으로써 대기오염이 발생하지 않는 수소를 사용하기 위한 연구가 활발히 이루어지고 있다. 하지만, 최근까지도 수소 누출에 의한 화재 및 폭발사고가 발생함에 따라 특수한 환경인 선박에서 수소를 상용화하기 위해 안전에 관한 연구가 더욱 필요하다. 따라서 본 연구에서는 수소저장탱크가 설비된 수소연료전지 추진선박이 울산 장생포항을 운항하던 중 누출사고가 발생할 경우의 계절별 대안 시나리오와 최악의 시나리오를 가정하였다. 또한, 환경변수를 고려하기 위하여 기상청 2021년도 연평균 기상자료와 통계청 지리정보 자료를 토대로 ALOHA와 프로빗 분석을 통해 피해 영향 범위를 도출하였다. 복사열이 대안 시나리오와 최악의 시나리오 모두에서 과압과 화염의 피해 영향범위 보다 넓은 피해범위가 나타났고 프로빗 분석 결과 가정한 모든 구역에서 99%의 사망률을 확인하였다.

• 한국대기환경학회지
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• 제30권6호
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• pp.545-554
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• 2014

In general, odorant was added to fuel gases, such as LPG, LNG and city gas, to prevent gas poisoning, ignition, explosion, or other accident caused by fuel gases, and to enable immediate and easy detection of fuel-gas leakage by emitting an offensive smell. This study describes a study on the exhaust emissions characteristics and fuel economy of liquefied petroleum gas (LPG) vehicle using LPG fuel with new sulfur free odorant. New sulfur free odorant was added to LPG to reduce sulfur content of the LPG. Its performance and exhaust emission were compared to those of LPG with sulfur containing odorant (EM, ethyl mercaptan). Engine performance using LPG with sulfur free odorant was similar to that with sulfur-containing odorant. Exhaust emissions from the LPG vehicle with LPG including sulfur free odorant were also similar to those with LPG including sulfur containing odorant in the FTP 75 and NEDC mode. There experimental results suggest that the sulfur free odorant may substitute for the sulfur containing odorant in LPG fuel.

• 한국압력기기공학회 논문집
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• 제16권2호
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• pp.18-24
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• 2020

When a damage occurs in the nuclear fuel burning in the reactor, fission products that should be in the nuclear fuel rod are released into the reactor coolant. In this case, sipping test, a series of non-destructive inspection methods, are used to find leakage in nuclear fuel assemblies during the power plant overhaul period. In addition, the sipping test is also used to check the integrity of the spent fuel for moving to an intermediate dry storage, which is carried out as the first step of nuclear decommissioning, . In this paper, the principle and characteristics of the sipping test are described. The structure of the sipping inspection equipment is largely divided into a suction device that collects fissile material emitted from a damaged assembly and an analysis device that analyzes their nuclides. In order to make good use of the sipping technology, the radioactive level behavior of the primary system coolant and major damage mechanisms in the event of nuclear fuel damage are also introduced. This will be a reference for selecting an appropriate sipping method when dismantling a nuclear power plant in the future.

• Tribology and Lubricants
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• 제27권5호
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• pp.275-280
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• 2011

Automotive wheel bearing grease helps to reduce stresses and prevent wear of wheel bearings. But it is easily contaminated by water and other contaminants. In this study, we investigated the property change of automotive wheel bearing grease under water contamination. The result showed that some properties such as dropping point, work penetration and oxidation stability were not influenced by water content. However, most of properties such as work stability, water washout characteristics, leakage tendency, oil separation, evaporation loss and rust protection became worse after water was added. This is thought that added water makes the interaction weak between thickener and base oil of grease.

• 한국자동차공학회논문집
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• 제9권1호
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• pp.63-74
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• 2001

In this study, a cycle simulation program of a Unit-Injection(UI) system was developed to estimate the injection performance of newly designed injection system. A fundamental theory of the simulation program is based on the conservation law of mass. Loss of fuel mass in the system due to leakage, compressibility effect of the liquid fuel and friction loss in the control volume was considered in the algorithm f the program. For the evaluation of the simulation program developed, the experimental result which was offered by the Technical Research Center of Doowon Precision Industry Co. was incorporated. Two main parameters; the maximum pressure in the plunger chamber and total fuel mass(kg) injected into the engine cylinder per cycle, were measured and compared with the simulation results. It was found that the maximum error rate of the simulation result to the experimental output was less than 3% in the rated rotational speed (rpm) range of the plunger cam.

• Nuclear Engineering and Technology
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• 제53권11호
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• pp.3517-3527
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• 2021

New 80-MW (electric) ultra-long-life sodium cooled fast reactor core having inherent safety characteristics is designed with heterogeneous fuel assemblies comprised of driver and blanket fuel rods. Several options using upper sodium plenum and SSFZ (Special Sodium Flowing Zone) for reducing sodium void reactivity are neutronically analyzed in this core concept in order to improve the inherent safety of the core. The SSFZ allowing the coolant flow from the peripheral fuel assemblies increases the neutron leakage under coolant expansion or voiding. The Monte Carlo calculations were used to design the cores and analyze their physics characteristics with heterogeneous models. The results of the design and analyses show that the final core design option has a small burnup reactivity swing of 618 pcm over ~54 EFPYs cycle length and a very small sodium void worth of ~35pcm at EOC (End of Cycle), which leads to the satisfaction of all the conditions for inherent safety with large margin based on the quasi-static reactivity balance analysis under ATWS (Anticipated Transient Without Scram).

• International Journal of Automotive Technology
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• 제7권4호
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• pp.407-413
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• 2006

The liquefied petroleum gas(LPG), mixture of propane and butane, has the potential to reduce toxic hydrocarbon emissions and inhibit ozone formation due to its chemical composition. Conventional mixer systems, however, have problems in meeting the future lower emission standards because of the difficulty in controlling air-fuel ratio precisely according to mileage tar accumulation. Liquid Phase LPG injection(LPLi) system has several advantages in more precise fuel metering and higher engine performance than those of the conventional mixer type. On the other hands, leakage problem of LPLi system at the injector tip is a main obstacle for meeting more stringent future emission regulations because these phenomena might cause excessive amount of THC emission during cold and hot restart phase. The main focus of this paper is the development of a leaked fuel recirculation system, which can eliminate the leaked fuel at the intake system with the activated carbon canister. Leaked fuel level was evaluated by using a fast response THC analyzer and gas chromatography. The result shows that THC concentration during cold and hot restart stage decreases by over 60%, and recirculation system is an effective method to meet the SULEV standard of the LPLi engine.

• International Journal of Precision Engineering and Manufacturing
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• 제6권3호
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• pp.51-55
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• 2005

This study addresses the contamination sensitivity test of a typical fuel pump for an automotive vehicle. The objective of the study is to find the contamination sensitivity coefficient of a fuel pump on specific contaminant particle sizes so that an optimal fuel filter could be selected. To achieve the objective, the degradation of discharge flow rate of the fuel pump is measured under the experiments of various contaminants size ranges of ISO test dust up to $80\;{\mu}m$. The fundamental theory of contamination sensitivity is introduced and the contamination sensitivity coefficients are estimated using the experimental data. Maximum contamination sensitivity coefficient of $5\chi\;10^{-6}\;L/min{\cdot}Ea$ is found in the contaminant size range of $40\;{\mu}m\~50\;{\mu}m$. The magnified picture of the surface of vane disc reveals that the abrasive wear is the principal cause of discharge flow rate degradation. Hence, this study reveals that a high efficiency filter for contaminant particles especially in the size range of $30\;{\mu}m\~70\;{\mu}m$ especially should be used to maintain the service life of the fuel filter.

• 한국정밀공학회지
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• 제21권6호
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• pp.102-108
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• 2004

This study addresses the contamination sensitivity test of a typical fuel pump for automotive vehicle. The objective of the study is to find the contamination sensitivity coefficient of fuel pump on specific contaminant particle sizes so that optimal fuel filter could be selected. To achieve the objective, the degradation of discharge flow rate of fuel pump was measured under the experiments of various contaminants size ranges of ISO test dust up to 80${\mu}{\textrm}{m}$. The fundamental theory of contamination sensitivity was introduced and the contamination sensitivity coefficients were estimated using the experimental data. Maximum contamination sensitivity coefficient of $5{\times}10^{-6}$ L/minㆍEa was found on the contaminant size range of 40${\mu}{\textrm}{m}$∼50${\mu}{\textrm}{m}$. The magnified picture of the surface of vane disc revealed that the abrasive wear was the principal cause of discharge flow rate degradation. Hence, this study revealed that high efficiency filter on the contaminant particle size range of 30${\mu}{\textrm}{m}$∼70${\mu}{\textrm}{m}$ especially should be used to maintain the service lift of the fuel filter.

• 한국가스학회지
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• 제16권2호
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• pp.38-44
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• 2012

근래 들어 강화되는 배출가스 규제에 대응하기 위한 대책으로 LPG 차량에 적용되고 있는 제3세대 LPG 연료공급방식인 LPi(Liquid phase LPG injection)는 펌프를 이용해서 고압의 액상연료를 공급하는 것이 가장 핵심적인 기술이다. LPi 시스템은 액상연료분사의 전자식 정밀제어를 통해 출력이 상승하고 유해배출가스가 현저하게 저감되는 장점이 있으나, 가장 핵심적인 부품인 연료펌프 및 인젝터의 경우 대부분 수입에 의존하고 있어 시스템 설계에 유연하지 못하다. 본 연구에서는 인젝터의 국산화 개발을 위해 LPi 시스템에 적합한 연료공급방법의 인젝터 디자인 및 최적의 작동조건 확보를 목표로 LPi용 인젝터의 설계 및 시작품을 제작하여 누설 및 유량특성을 살펴보았다.