• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2001년도 제16회 학술발표회 논문초록집
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• pp.86-89
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• 2001

본 연구는 화재를 효과적으로 진압하기 위한 비활성가스제너레이터의 성능 해석 및 실험에 관한 연구의 내용을 담고 있다. 비활성가스제너레이터는 가스터빈을 이용하여 화재를 진압하기 위한 비활성가스를 제조한다. 일반적으로 연소화합물 속에 산소함유량이 낮을수록 화재진압이 용이한 것으로 알려져 있다. 비활성가스제너레이터 시스템에 급수 노즐을 설치하여 물을 분사하는 경우 화재진압에 필요한 냉각 및 질식효과를 갖는 다는 점에서 유리하다. 비활성가스제너레이터 성능에 미치는 몇몇 중요한 인자인 압축비, 과급 공기지수, 연소기 입출구 온도, 공기 유량 및 급수량에 관한 영향을 조사하였다.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2012년도 전기공동학술대회 논문집
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• pp.123-124
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• 2012

Effervescent atomizer in which the liquid is ejected from nozzle with bubble caused by gas injection into the liquid is one of twin-fluid atomizers. Effervescent atomizer is operated with the lower injection pressure and the smaller air flow rate when compared with those of other twin-fluid atomizers. In this study, we attempted experiment study to investigate the atomization characteristics of effervescent atomizer related with the internal flow condition. The nozzle was made with acrylic material to investigate the nozzle internal flow. The macroscopic spray analysis was conducted with internal flow images and spray images. Furthermore, SMD was measured by using the laser diffraction method. According to this study, the internal flow condition changed from bubbly flow to annular flow as the air-liquid mass ratio(ALR) increases. At that time, the atomization characteristics were improved.

• 설비공학논문집
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• 제14권10호
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• pp.863-870
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• 2002

Fossil fuels have been depleted gradually and new energy resource which can solve this shortage is needed now. Methane hydrate, non-polluting new energy resource, satisfies this requirement and considered the precious resource prevent the global warming. Fortunately, there are abundant resources of methane hydrate distribute in the earth widely, so developing the techniques that can use these gases effectively is fully valuable. the work presented here is to develop the skill which can transport and store methane hydrate. As a first step, the equilibrium point experiment has been carried out by increasing temperatures in the cell at fixed pressures. The influence of gas consumption rates under variable degree of subcooling, stirring and water injection has been investigated formation to find out kinetic characteristics of the hydrate. The results of present investigation show that the enhancements of the hydrate formation in terms of the gas/water ratio are closely related to operational pressure, temperature, degrees of subcooling, stirring rate, and water injection.

• 설비공학논문집
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• 제28권8호
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• pp.311-315
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• 2016

The efficiency of manure treatment was investigated in terms of the pH, BOD, COD, SS, T-N and TP with a variation in the injection amount of PAC, polymer and ozone. The wastewater flow rate to the AOF is of $7.4m^3/hr$ with a reaction time of 30 minutes. The amount of PAC and polymer changed by 30, 35, 40 ml/min, and 30, 40, 50 ml/min, respectively. The amount of ozone injected varied from 110, 125, and $150kg-O_3/hr$. The optimum manure treatment performance was found for a PAC of 35 ml/min for the COD and SS, with polymer of 30 ml/min, and ozone injection of $150kg-O^3/hr$. A substantially optimum dose for each PAC, polymer, and ozone was also found to exist.

• 설비공학논문집
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• 제19권5호
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• pp.386-393
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• 2007

This paper studies the ventilation characteristics according to the jet fan location at the long road tunnel using the CFD software 'FLUENT' which is based on the finite volume method. The tunnel model used in the analysis has a length of 1600m, a cross sectional area of $120m^3$, and is composed of 3 lanes and one way. The velocity profile, the distribution of CO concentration and the ventilation flow rate within the tunnel are analyzed, respectively. In the analysis, it is found that the dependence of the ventilation flow rate upon the jet fan location is small, but the CO concentration in the tunnel is at the lowest when the jet fans are installed near the tunnel outlet. An air stream right below the jet fan is almost inactive due to the strong stream injection near the jet fan. Thus, the pollution level below the jet fan must be higher than the other area.

• 한국수소및신에너지학회논문집
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• 제25권6호
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• pp.636-642
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• 2014

As environment problem became a worldwide issue, countries are tightening regulations regarding greenhouse gas reduction and improvement of air pollution problems. With these circumstances, one of the renewable energies produced from biomass is getting attention. Bio-ethanol, which is applicable to SI engine, showed a positive effect on the PFI (Port Fuel Injection) type. However, Ethanol has a problem in homogeneous mixture formation because it has high latent heat of vaporization characteristics and in the GDI (Gasoline Direct Injection) type, mixture formation is required quickly after fuel injection. Particularly, South Korea is one of the countries with great temperature variation among seasons. With this reason, South Korea supply fuel additive for smooth engine operation during winter. Therefore, experimental study and investigation about application possibility of blending fuel is necessary. This paper demonstrates the spray characteristics by using the CVC direct injection and setting the bio-ethanol blending fuel temperature close to the temperature during each seasons: -7, 25, $35^{\circ}C$. The diameter and the width of the CVC are 86mm and 39mm. High-pressure fuel supply system was used for target injection pressure. High-speed camera was used for spray visualization. The experiment was conducted by setting the injection pressure and ambient pressure according to each temperature of bio-ethanol blending fuel as a parameter. The result of spray visualization experiment demonstrates that as the temperature of the fuel is lower, the atomization quality is lower, and this increase spray penetration and make mixture formation difficult. Injection strategy according to fuel temperature and bio-ethanol blending rate is needed for improving characteristics.

• 동력기계공학회지
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• 제19권3호
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• pp.29-35
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• 2015

Environmental pollution is produced by consumption of fossil fuel, therefore alternative fuels is interested for development of new energy resources and reduction of exhaust emissions for air pollution prevention. Biofuels are produced from new vegetable oil and animal fat, may be used as fuel without change of engine structure in diesel engine. In this paper, the test results on specific fuel consumption, combustion characteristics of neat diesel oil and biodiesel blends(10 vol.% biodiesel and 20 vol.% biodiesel) were presented using four stroke, direct injection diesel engine, especially this biodiesel was produced from biodiesel fuel at our laboratory by ourselves. This study showed that specific fuel consumption is increased slightly, on the other hand cylinder pressure, rate of pressure rise, rate of heat release and soot were decreased slightly in the case of biodiesel blends than neat diesel oil.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 총회 및 춘계학술발표회
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• pp.47-50
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• 2003

We carried out rock pneumatic fracturing test which to increase groundwater yield by injection of highly pressured air in artificially under the surface every four borehole. The result of test performing shows that effect of increasing groundwater was not found in three testhole around igneous and metamorphic formation area, but we can realized that about 15 percent increased wateryield appeared in number P-5 test hole at sedimmentary rock formation.

• 한국안전학회지
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• 제10권3호
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• pp.120-129
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• 1995

직접분사엔진에서 기상과 분무액적간의 유동특성 및 분무특성에 미치는 선회비의 영향에 대하여 수치해석 하였다. 정적인 환경에서는 분무초기를 제외하고는 계산과 실험결과가 잘 일치하였다. 운전상태에서는 연료분사 기간동안 속도장의 영향이 증가하여 스쿼시유동의 중요성이 상대적으로 감소하였다. 선회비가 증가할수록 높은 난류에너지가 연소실내에 분포되며 분무액적이 확산되고 기상과의 상호작용이 강해져서 증발률이 증가하였다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제10권4호
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• pp.45-53
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• 2005

본 연구의 목적은 실제 디젤유로 오염된 불포화 토양을 복원하기 위해 수행되었던 고온공기 주입 파일롯 테스트에서 토양온도 변화가 생분해 속도에 미치는 영향을 알아보고자 히는 것이었고, 이것을 토대로 현장 생분해 속도, 최적의 생분해 온도 및 1차 분해 속도 상수를 도출하고 총복원기간을 예측해 보았다. 실험은 과거 디젤유 누출 사고가 있었던 고농도 오염지역에 대해 토양의 온도별 현장 호흡률(in-situ respiration)을 약 10일 간격으로 측정하는 식으로 진행되었다. 적용된 복원공법은 고온공기를 주입/추출하여 1차적으로 오염된 디젤 성분을 휘발, 추출하고 이어서 토양의 잔열과 미생물 생분해를 이용하여 토양내 잔류 디젤을 제거하는 후속공정으로 이루어졌다. 토양온도 $26\sim60^{\circ}C$ 범위에서 산소소비속도는 $2.2\sim46.3%/day$ 값을 보였고 $32^{\circ}C$에서 가장 빠른 46.3%/day를 나타냈다. 산소소비속도를 기준으로 하여 계산한 0차반응 생분해 속도(biodegradation rate)는 $6.5\sim21.3mg/kg-day$ 이었고 역시 토양온도 $ 32^{\circ}C$ 에서 최대값을 보였고 그 이전과 이후는 각각 감소된 값을 나타냈다. 주기적으로 측정된 현장호흡률을 바탕으로 계산한 1차 분해속도 k는 몇가지 온도 범위에서 즉, $0.0027\;d^{-1}(@32.8^{\circ}C),\;0.0013\;d^{-1}(@41.1^{\circ}C)$ 그리고 $0.0006\;d^{-1}(@52.7^{\circ}C)$ 이었다. 토양의 초기 TPH 농도 대비목표 농도를 870 mg/kg으로 가정했을 경우 소요 복원기간은 $2\mu9$년 정도 소요되는 것으로 예측되었다.