• 한국분무공학회지
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• 제9권3호
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• pp.29-34
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• 2004

To investigate characteristics and micro-explosion of single-droplets of emulsified fuel, water is mixed with diesel oil by using ultrasonic energy fuel feeding system. The fuel characteristics is analysed through H-NMR spectrum and micro-explosion phenomena of the emulsified fuel is also investigated. The life times of droplets of conventional diesel fuel, ultrasonic energy added diesel fuel and emulsified fuel we obtained additionally. According to this study, the micro-explosion phenomena of single-droplets happen in atmospheric pressure condition, a curve form of emulsified fuel's life tim is different from diesel fuel's one and the change of chemical structures is a cause of ultrasonic-energy-added diesel fuel effect.

• 한국기후변화학회지
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• 제9권4호
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• pp.313-318
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• 2018

The growth rate of international aviation is expected to be higher than that of most industries and the proportion of carbon emissions from the aviation industry will become very significant as the year 2050 approaches. Constraining the growth of this industry is not desirable because it is essential for human welfare as well as the development of related industries. However, reduction of carbon due to aviation is not easy because it is difficult to improve fuel efficiency in a significant way. The ICAO (International Civil Aviation Organization), which is the main organization responsible for handling this problem, developed a program named CORSIA (Carbon Offsetting and Reduction Scheme for International Aviation). The present study analyzes various strategies for countries and airlines to comply with CORSIA using a fuel-efficient system. We conclude that countries should improve their airspace utilization systems, airport facilities, and air navigation systems. Additionally, based on the results of a flight data analysis, airlines should improve their operational efficiency in terms of operations control, flight operation, and maintenance management.

• 한국도로학회논문집
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• 제12권1호
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• pp.55-59
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• 2010

높은 차량운행비용(VOC : Vehicle Operating Cost)은 포장도로 복구작업의 주요한 원인이고, 차량운행비용(VOC)은 연료소모량, 오일소모량, 부품교체비용 등으로 구성된다. 이중 연료소모량이 VOC에서 차지하는 비중이 높고, 다른 도로조건에 비해 도로 표면 거칠기가 도로의 노화 정도를 대표적으로 지시하는 값이기 때문에, 본 연구에서는 포장도로의 표면 거칠기(IRI : International Roughness Index) 변화에 따른 차량의 연료소모량 변화를 측정하였다. 차량의 연료분사 인젝터의 전압변화를 측정하여 연료소모량을 계산하였고, 속도는 GPS센서를 사용하여 측정하였다. 본 실험 결과를 이용하여 IRI 변화에 대한 연료소모량의 변화율을 계산할 수 있었다. 계산 결과, 40~100km/h 속도영역에서 중형 및 대형 승용차의 연료소모량(L/100km)은 3.5m/km 정도의 IRI 수준에서 IRI(m/lm) 증가율의 7배 정도로 증가하였고, 60km/h의 속도에서 가장 연비가 우수하였다.

• 한국자동차공학회논문집
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• 제19권2호
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• pp.26-34
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• 2011

Hybrid powertrain systems have been developed to improve the fuel efficiency of internal combustion engines. In the case of a parallel hybrid powertrain system, an engine and a motor are directly coupled. Because of the hardware configuration of the parallel hybrid system, friction and the pumping losses of internal combustion engines always exists. Such losses are the primary factors that result in the deterioration of fuel efficiency in the parallel-type hybrid powertrain system. In particular, the engine operates as a power consumption device during the fuel-cut condition. In order to improve the fuel efficiency for the parallel-type hybrid system, cylinder deactivation (CDA) technology was developed. Cylinder deactivation technology can improve fuel efficiency by reducing pumping losses during the fuel-cut driving condition. In a CDA engine, there are two operating modes: a CDA mode and an SI mode according to the vehicle operating condition. However, during the mode change from CDA to SI, a serious fluctuation of the air-fuel ratio can occur without adequate control. In this study, an air-fuel ratio control algorithm during the mode transition from CDA to SI was proposed. The control algorithm was developed based on the mean value CDA engine model. Finally, the performance of the control algorithm was validated by various engine experiments.

• 한국항공우주학회지
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• 제48권11호
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• pp.927-933
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• 2020

본 논문에서는 항공기 자세 변화를 고려한 항공기 보조연료탱크 연료량측정시스템을 제시하였다. 개발된 연료량측정시스템은 연료센서, 데이터 처리장치, 계기 및 센서 데이터로부터 연료량을 추정하는 소프트웨어로 구성되었다. 지상에서의 롤 및 피치 자세 변화를 모사하기 위해 모사시험 장치가 개발되었다. 모사시험장치를 이용하여 다양한 연료량, 롤 및 피치 각도의 센서 데이터를 자동으로 측정하여 트레이닝 데이터 세트를 획득하였다. 연료량을 추정하는 연료량 측정 소프트웨어를 트레이닝 데이터 세트와 함께 삼선형보간법을 사용하여 개발하였다. 개발된 연료량측정시스템은 참값을 알고 있는 테스트 데이터 세트의 연료 추정 오차를 측정하여 검증하였다. 테스트를 통해 개발된 연료량측정시스템의 오차가 TSO-C55 문서의 기준을 충족하는 것을 확인하였다.

• Journal of Radiation Protection and Research
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• 제21권1호
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• pp.27-39
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• 1996

DUPIC핵연료주기로 인해 변화되는 경수로 사용 후 핵연료 물질의 핵종별 농도, 방사능, 붕괴열, 위해지수 및 방사선원항등을 시간의 함수로 그 변화특성을 분석하고, 각 인자별로 크게 영향을 미치는 주요핵종의 거동을 물질농도 측면에서 추적 분석평가하였다. 방사성물질 농도에 있어서 연소도 19,000 MWD/MTU의 사용 후 DUPIC핵연료에 존재하는 악티나이드 양은 연소도 35,000 MWD/MTU의 경수로 사용후 핵연료에 비해 약 2% 감소한 반면 핵분열생성물의 양은 약 20% 증가된 것으로 나타났다. 그리고 사용 후 DUPIC핵연료의 방사능 및 붕괴열은 일반적인 사용후핵연료 특성과는 달리, 방사성물질 농도 변화와 비례하지 않는 것으로 나타났다. 사용후 DUPIC핵연료가 갖는 감마 스펙트럼을 경수로핵연료의 경우와 비교해 볼 때, 전체적인 특징은 사용후 DUPIC핵연료의 경우가 $0.01{\sim}0.575MeV$의 낮은 에너지 범위에서는 경수로핵연료 보다 약 $40{\sim}50%$ 낮은 감마선 세기를 보여주고 있으나, 3.5 MeV이상의 높은 에너지 범위에서는 사용후 DUPIC핵연료의 감마선 세기가 휭씬 크게 나타났다. 중성자 선원항은 모두 악티나이드 물질의$({\alpha},\;n)$ 반응 및 자발핵분열에 의해 결정되고 있고, 특히 Cm-244의 자발 핵분열에 의한 중성자선원이 지배적인 것으로 나타났다. 이런 이유 때문에 Cm-244의 농도가 약 3.3배 큰 사용후 DUPIC핵연료의 중성자 선원이 경수로핵연료보다 4배 이상 크게 나타났다.

• 항공우주시스템공학회지
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• 제4권1호
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• pp.10-14
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• 2010

The Fuel system of T-50 Advanced Trainer is equipped with two boost pump and fuel flow proportioner for feeding fuel to turbo jet engine. when an unexpected failure occurs, they can feed the fuel to turbo jet engine which fuel quantity required. fuel quantity control method is applied for minimizing the center of gravity change. and fuel quantity control method is controlled by FQMS(Fuel Quantity Measuring System) and FFP(Fuel Flow Proportioner). This paper presents life cycle extension plans of FFP hydraulic motor by design improvements of connecting and arrangement of pipe comparing with KF-16.

• 대한기계학회논문집B
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• 제28권10호
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• pp.1172-1177
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• 2004

The emission control of automobile has been intensified as a part of the countermeasure to decrease air pollution in the world. As the cars with an alternative fuel starts to get into the spotlight, the cars with low emission has been introduced and exhaust gas regulation forced in this country. These days, LPG vehicles, which infrastructure of fuel was already built up, and CNG vehicles are recognized for alternative fuel cars in this country. In this study, the constant volume combustion chamber was manufactured and used for experiments to obtain the combustion characteristics of propane mixture. The combustion characteristics was analyzed, with the change of supply conditions of propane fuel. Inside the combustion chamber, the maximum temperature increase with the initial pressure is going up. The burning velocity also seems to have the same characteristic as the temperature. However, the heat flux do not change much according to the theoretical correct mixture but it changes with the various initial temperature of the combustion chamber.

• 한국화재소방학회:학술대회논문집
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• 한국화재소방학회 2008년도 춘계학술논문발표회 논문집
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• pp.333-336
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• 2008

This study is the result between the variation of fuel moisture and the risk of forest fire through measuring the change of moisture containing ratio on-site and its average analysis for each diameter of surface dead fuels in the forest. The measurement was performed on six days from the day after a rainfall. The fuel moisture on-site was measured on the day when the accumulated rainfall was above 5.0mm, and the measurements was 2 times in spring. From the pine forest which were distributed around Samcheok and Donghae in Kangwondo, three regions were selected by loose, medium, and dense forest density, and the fuel moisture was measured on the ranges which are less than 0.6cm, 0.6-3.0cm, 3.0-6.0cm, and more than 6.0cm in the forest for six days from the day after a rainfall. The study showed that the moisture containing ratio converged on 3 - 4 days for surface deads fuels which diameter are less than 3.0cm and the convergence was made more than six days for ones which diameters are more than 3.0cm except the surface dead fuel of 3.0-6.0cm diameter of loose forest density.

• Nuclear Engineering and Technology
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• 제53권11호
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• pp.3704-3710
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• 2021

The characteristics of the external radiation on the surface of the casks for spent nuclear fuel (SNF) storage by dry method are investigated for the case when the spatial distribution of SNF in the basket changes due to the destruction of the fuel rod claddings. The surface areas are determined, where the changes in fluxes of neutrons, produced by ²⁴⁴Cm actinide, and γ-quanta, produced by long-lived isotopes, are maximum in the result of the decrease in the height of the SNF area. Concrete (VSC-24) and metal (SC-21) casks are considered as examples. The procedure of periodic measurement of the dose rate of neutrons or γ-quanta at the specified points of the cask surface is proposed for identifying the fuel rod cladding destruction. Under normal operation, the decrease in the dose rate produced by neutrons as the function of SNF storage duration is determined by the half-life of ²⁴⁴Cm, and for γ-quanta - by the half-lives of long-lived SNF isotopes. Consequently, a stepwise change in the dose rate of neutrons or γ-quanta, detected by the measurements, as compared to the previous one, would indicate the destruction of the fuel rod claddings.