• Landscaping Tree
• /
• s.111
• /
• pp.8-9
• /
• 2009

지구 평균 기온은 이미 19세기 비하여 0.75$^{\circ}C$ 상승해 있는 상태이며, 이 시점에서 화석연료를 사용하는 모든 스위치를 내린다 해도 앞으로 지구의 온도는 추가로 0.6$^{\circ}C$ 상승할 거이라고 한다. 왜냐하면 우리가 이미 대기 중에 방출해 놓은 온실가스의 온난화 효과가 시간차를 두고 나타나기 때문이다. 그러나 현실적으로 화석연료를 사용하는 스위치를 내려 놓을 수도 없고, 획기적 탄소 저감 기술이 없다면 당분간은 대기중에 온실가스의 배출량은 줄이지 못할 것이라는데 이의가 없다. 따라서 온난화 효과는 가속화되고 기온은 계속 상승할 것이라는 것은 쉽게 예측할 수 있다. 더구나 최근 우리나라는 세계 평균 기온상승에 비하여 2배의 높은 수치를 보인다.

• Journal of Energy Engineering
• /
• v.1 no.1
• /
• pp.49-52
• /
• 1992

전 세계적으로 사용되고 있는 에너지의 90% 정도가 화석 연료로서 현재의 에너지 사용추세로 보아 21세기초에는 석유와 천연가스가 고갈되고 이후 예측되는 석탄의 가속적인 이용을 감안하면 석탄에너지 자원도 21세기를 넘기기 어려울 것으로 전망된다. 이에 대처하기 위하여 화석연료 대체에너지자원 및 기술개발이 활발히 진행되고는 있으나 핵연료비가 발전원가에 차지하는 비용이 낮고(15%, 석유 약 57%, 석탄 약 60%) 기술집약형으로 복합기술의 파급효과, 그리고 산성비 온실효과 등의 환경오염을 유발하지 않는 청정에너지라는 점에서 현재로는 원자력이 에너지 문제 해결을 위한 대안이라고 하겠다. (중략)

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.20 no.2
• /
• pp.624-631
• /
• 1996

This study describes extinguishment mechanism of the purely buoyant diffusion flame using the water spray. Experiments are systematically carried out for the oul pool fire with the six different atomizing nozzles. From the measurement of burning rate which represents the combustion intensity of fire, it is observed that the water spray is able to act to enhance fire rather than to extinguish fire. The air entertainment due to the water spray is visualized to understand this phenomenon, acting to enhance fire. In order to observe effects of droplet size on fire extinguishment, and amount of water which reaches the flame base, fuel surface, and mean diameter of droplets are measured. When water droplets are too small, they do not reach the flame base because they can the water spray having too small doplets is ineffective for extinguishment of the oil fire.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.16 no.6
• /
• pp.23-31
• /
• 2012

Present work deals three families of $SiO_2$ gelling agents which have been used to produce gel fuel based on Kerosene. Jet A-1 is chosen as fuel where power-law rheological model is used to confirm whether or not the gelification is achieved depending on the %wt of gellant. It was confirmed that the produced jelly-like substance have shear-thinning effect, and that its apparent viscosity increases as $SiO_2$ concentration increases. Compared to other gellants, gel with Aerosil(R) R972 fits most to the power-law model, while gels with Silica 230 and Silica 530 deviate from the power-law model. The rheological characteristics behaved differently depending on the mixing method(vortex mixing and manual mixing) when gellant concentration is increased.

• Journal of Energy Engineering
• /
• v.14 no.3 s.43
• /
• pp.173-179
• /
• 2005

Fuel injection system has more benefits in power, fuel consumption and emission than carburetor system even in high speed small engine. Up to date fuel injection system is used in motor car but is not used in motorcycles in Korea. EFI (Electronic fuel injection) system which has ECU can control precise fuel supply to variable RPM in engine. The purpose of this study is the investigation of effects of fuel injection system to improve the engine performance and efficiency in variable revolution of high speed small engine which is 4 Valves SOHC single cylinder engine used in motorcycle.

• Journal of the Computational Structural Engineering Institute of Korea
• /
• v.16 no.1
• /
• pp.77-86
• /
• 2003

Dynamic response of baffled fuel-storage tank in turnaround motion is simulated using the ALE finite element method. Fuel-storage tank undergoes abrupt impact load caused by inertia force of internal fuel in turnaround motion. Also, large dynamic force and moment caused by this load influence structural stability and control system. In this paper, ring-type baffles are adopted to suppress the dynamic influence. Through the parametric analysis with respect to the baffle number and location, the effects of baffle on the dynamic response of baffled fuel-storage tank is analyzed. The ALE finite element method is adopted for the accurate and effective simulation of the hydrodynamic interaction between fluid and structure.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.49 no.4
• /
• pp.273-279
• /
• 2021

Winglets are specialized wingtip devices to reduce induced drag, and they have been installed on Boeing-made aircraft since the 1980s, Airbus has also developed a winglet named 'Sharklet' since 2009 and has started providing them as an option to the A320 Family. The winglet has the effect of improving take-off performance, reducing fuel consumption, increasing payload, and increasing flight distance by reducing the induced drag generated at the tip of the wing. The purpose of this study is to analyze the actual flight data of the sharklet-installed and non-sharklet-installed models of the A321 aircraft to verify the fuel efficiency improvement due to the winglet installation, and to analyze the economic analysis accordingly. Through this, it can be used to determine the winglet installation when introducing an aircraft or to make a decision for upgrading the existing aircraft. To this end, a case study on the aerodynamic characteristics and effects of the winglet installation was conducted, and the economic analysis was verified.

• Environmental and Resource Economics Review
• /
• v.29 no.4
• /
• pp.443-468
• /
• 2020

Broad effects of fuel-transition in all type of ground transportation have occurred with the help of the advances in electric vehicle (EV) technologies and the increases in EV supply. This research estimates the economic benefit of air environmental improvements, which results from the fuel-transition of high-mileage business cars(taxies) in metropolis. If we consider power production sector for EV operation, some air pollutants will be produced. In this respect, this research takes both the mixture of power sources in power production level and the driving pattern of business cars into account when investigating the economic benefit in air environment resulted from the fuel-transition of business cars(taxies). According to our results, the business cars' fuel transition from LPG to electricity brings about 21.5￦/km (8.6million won/year) of economic benefit in air environment. These results emphasize the necessity and appropriateness of public polices for expanding power production with renewable energies and facilitating EV distribution.

• 한국신재생에너지학회:학술대회논문집
• /
• 2005.11a
• /
• pp.307-319
• /
• 2005

인류에게 있어 가장 중요한 연료의 역할을 충실히 해왔던 임산자원이 화석계 에너지원의 고갈과 환경오염 문제의 급부상으로 임산자원의 신재생에너지원으로서의 잠재력이 다시 관심의 대상이 되고 있다. 본 연구에서는 임산자원의 에너지화와 그 산업적 응용을 위하여 원료의 수급체계를 검토, 확립하는 한편, 폐목질자원을 펠릿화한 목재펠릿 연료의 제조공정을 국내 환경을 고려하여 고효율화하는 동시에 본 연료를 효과적으로 이용할 수 있는 시스템을 개발하고자 하였다.

• Bulletin of Korea Environmental Preservation Association
• /
• s.399
• /
• pp.20-21
• /
• 2012

우리나라는 좁은 국토에 많은 인구가 밀집한 관계로 단위면적당 폐기물의 발생량이 세계 최고 수준이며, 해양 오염 방지를 위해 유기성 폐기물 해양 배출을 금지한 런던협약 등 기후변화 관련 규제가 강화되고 있다. 또한 화석연료의 고갈화로 대체에너지 개발이 시급한 현시점에서 폐자원 에너지화 사업의 인프라 구축 및 대응책 수립이 요구되고 있다. 이에 우리나라는 2008년 5월 "폐기물 에너지화 종합대책" 이후 2009년 7월 "폐자원 및 바이오매스 에너지 대책" 실행계획 수립으로 폐기물 에너지화 사업 도입을 적극 추진하고 있다. 폐자원 에너지화 기술은 화석연료 대체로 인한 온실가스 감축효과가 있어 폐기물 처리, 화석연료 대체, 온실가스 감축이라는 일석삼조의 기술이다.