• 대한토목학회논문집
• /
• 제31권6B호
• /
• pp.507-514
• /
• 2011

본 논문에서는 하천에 유입되는 열 오염물질의 혼합거동을 분석하기 위해 2차원 수심 평균된 이송-분산방정식에 유한요소법을 적용하여 수치 모형을 개발하였다. 유한요소법의 여러 수치기법 중 SUPG법을 적용하였으며, 복잡한 하천경계를 보다 정확히 재현할 수 있도록 삼각 및 사각 요소망의 혼용이 가능하도록 하였다. 열 오염물질의 거동을 표현하기 위해서 열 교환을 묘사하는 반응항을 평형온도와 수온과의 차이에 비례하는 식으로 나타내고, 열교환 계수 및 평형온도에 따라 수온의 변화가 적용되도록 방정식을 구성하였다. 모형의 검증을 위하여 직사각형 수로에 선원으로 연속주입하여 얻은 수치해와 1차원 정상상태의 해석해를 비교하였다. 비교결과 수치해와 해석해의 결과가 서로 일치하는 것으로 밝혀졌다. 모형의 현장적용을 위해 상수원 보호구역인 팔당댐 하류부터 잠실수중보까지 22.5 km 구간을 대상영역으로 하였다. 구리하수처리장 방류수에 의한 수온 변화를 모의한 결과 수질측정망 측정자료와 비교적 비슷한 경향이 나타났다. 본 연구에서 개발한 수치모형이 열 오염원 유입으로 인한 수온 변화를 잘 표현하는 것을 알 수 있었다.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
• /
• pp.452-455
• /
• 2008

The co-combustion of coal and three kinds of RDFs(Refuse Plastic Fuel) mixture has been experimented in a commercially operating CFB coal boiler respectively and the pollutant emissions such as SOx, NOx, TSP and dioxine were measured at the stack. The mixing ratio with coal was 7.5% RPF, 7.5% RDF and 10% SDF respectively. During co-combustion, dioxine emission level was very low and SOx, NOx and TSP were decreased comparing the single coal combustion. Emitting dioxine concentration was proportioned to the chlorine content of RDF. These RPF, SDF and RDF could be determined to be a good alternative fuel of general coal.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
• /
• 제10권S_2호
• /
• pp.65-71
• /
• 2001

The chemical behavior and properties related to the redox state of environmental pollutants were investigated using electrochemical methods. Measurements were taken of variations in the redox potential and cyclic polarization current. The results established the influence of various factors, including concentration, temperature, salt, and pH, on the redox potential and current. These factors were determined to effect the result of the redox reaction. Optimum conditions were also established for each case. It was clearly established that the electrode reaction was from a reversible to an irreversible process, plus it was also mixing reaction current controlled.

• 한국환경과학회지
• /
• 제9권1호
• /
• pp.57-64
• /
• 2000

The sensitivity analysis of two short-term models (ISCST3, INPUFF2.5) is performed to improve the model accuracy. It appears that the sensitivities on the changes of wind speed, stack height and stack inner diameter in the near distance from source, stability and mixing height in the remote distance form source, are significant. Also the gas exit velocity, stack inner diameter, gas temperature and air temperature which affect the plume rise have some effects on the concentration values of each model within the downwind distance where final plume rise is determined. And in modeling for the atmospheric dispersion of point pollutant source INPUFF2.5 can calculate amount, trajectory of puff and concentration versus time at each receptors. So, it is compatible to analyze distribution of point pollutants concentration at modeling area.

• 한국건축시공학회:학술대회논문집
• /
• 한국건축시공학회 2017년도 춘계 학술논문 발표대회
• /
• pp.113-114
• /
• 2017

Recently, Subway workers have died from lung cancer. According to the Epidemiological Survey of the Welfare Corporation Institute of Pulmonary Disease of the Welfare Corporation, the family members applied for industrial accidents. The radon concentration in the subway work area was found to exceed 10 times the recommended standard value of 148 becquerels (Bq/㎥) in domestic multipurpose facilities. In addition, as a result of the national indoor radon concentration survey conducted by the Ministry of Environment in 2010 and 2013, housing was found to be over 100 becquerels (Bq/㎥) in 41% of the surveyed subjects. In addition, it was found that in 2012, 16.3% of villages exceeded the radon standard value in the survey on natural radioactive materials containing groundwater.

• 한국대기환경학회지
• /
• 제9권4호
• /
• pp.278-287
• /
• 1993

In order to calssify smog type durnig the summer season in Seoul, air Quality and meterorological data were analyzed by multivariate analysis. Among 15 variables relating to visibility, 10 variables were selected by multiple regression analysis for clustering of smog types; total suspended particle, sulfur dioxide, ozone, ntrogen dioxide, total hydrocarbon, south-north wind component, ralative humidity, precipitable water, mixing height and air temperature. Somg types were grouped into three clusters using cubic clustering criterion and the mumbers of days in each cluster were contained 74, 28 and 16 days. Each cluster was seperated clearly by sulfur dioxide, precipitable water and air teperature. The first cluster was representative of high ozone concentration and prevailing meterological conditions for ozone formation. Therefore, visibility in the first cluster was considered to be affected by photochemical smog. The third cluster showed characteristics of sulphurous smog type due to the higher concentration of primary pollutant, based on the dry condition than that in another cluster. On the other hand, the characteristic of the second cluster was not relatively clear, but considered to be in an intermediate characteristic between photochemical smog and sulphurous smog type.

• 한국환경과학회지
• /
• 제11권2호
• /
• pp.131-137
• /
• 2002

The chemical behavior and properties on the redox state of environmental pollutant has been investigated by electrochemical methods. We carried out to measure the variations in the redox reaction of differential pulse polarogram and cyclic voltammogram. The results observed the influences on redox potential and current of various factors with temperature and pH. These were established factors as the effect of the redox reaction. It can be clearly recognized that the electrode reaction are from qusi-reversible to irreversible processes. Also, it was mixing with reaction current controlled. The bits-phenol A in the waste water was made to compound with cobalt ion and it take away from the separation into compound. The $Co(BPA)_2$ compound was not found to be dissociation in waste water. However, this compound is avery unstable(K=1.02) and for a while, it was to be a dissociation. Therefore, we believed that it was likely to a toxic substance.

• 한국자동차공학회논문집
• /
• 제7권7호
• /
• pp.94-103
• /
• 1999

A model for the prediction of combustion and exhaust emissions of DI diesel engine has been formulated and developed . This model is a quasi-dimensional phenomenological one and is based on multi-zone combustion modelling concept. It takes into consideration, on a zonal basis ,detailed of fuel spray formation, droplet evaporation, air-fuel mixing, spray wall interaction, swirl , heat transfer, self ignition and burning rate . The emission model is considered with chemical equipment , as well as the kinetics of fuel. NO and soot reactions in order to calculate the pollutant concentrations within each zone and the whole of cylinder . The accuracy of prediction versus experimental data and the capability of the model in predicting engine heat release, cylinder pressure and all the major exhaust emissions on zonal and cumulative basis., is demonstrated. Detailed prediction results showing the sensitivity of the model bv various injection rates are presented and discussed.

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 2013년도 제46회 KOSCO SYMPOSIUM 초록집
• /
• pp.123-126
• /
• 2013

Combustor development requires high fidelity simulation capable of predicting recirculation zone (RZ), temperature field, and pollutant emission. Swirling flow is widely used in combustor for its benefits in efficient mixing and flame stabilization by RZ. Large eddy simulation (LES) is used to calculate swirling flow in an expanding pipe [1], and shows higher accuracy than RANS. Reactive flow modeling using LES and flamelet model is validated with experiments by Barlow et al. [4] and Masri et al. [3]. Finally, heat transfer simulation of Samsung Techwin's combustor liner is presented.

• 한국방재학회:학술대회논문집
• /
• 한국방재학회 2008년도 정기총회 및 학술발표대회
• /
• pp.799-802
• /
• 2008

General behaviors based on hydraulic characteristics of natural streams and channels have been recently analyzed and developed via various numerical models. However in the states of natural hydraulics, an experimental research must be performed simultaneously with the mathematical analysis due to effects of hydraulic properties such as meander, sediment, and so on. In this study based on 2-D advection-dispersion equation, flow and tracer experiments were performed in the S-curved meandering laboratory channel with a rectangular cross-section. The channel was equipped with instrument carriages which was equipped with an auto-traversing system to be used with velocity measuring sensors throughout the depth and breadth of the flow field. To measure concentration distribution of the salt solution was adjusted to that of the flume water by adding methanol and a red dye (KMnO4) was added to aid the visualization of the tracer cloud, the tracer was instantaneously injected into the flow as a full-depth vertical line source by the instantaneous injector and the initial concentration of the tracer was 100,000 mg/l. The secondary current as well as the primary flow pattern was analyzed to investigate the flow distribution in the meandering channels. The velocity distribution of the primary flow for all cases skewed toward the inner bank at the first bend, and was almost symmetric at the crossovers, and then shifted toward the inner bank again at the next alternating bend. Thus, one can clearly notice that the maximum velocity occurs taking the shortest course along the channel, irrespective of the flow conditions. The result of the tracer tests shows that pollutant clouds are spreading following the maximum velocity lines in each cases with various mixing patterns like superposition, separation, and stagnation of pollutant clouds. Flow characteristics in each cases performed in this study can be compared with tracer dispersion characteristics with using evaluation of longitudinal and transverse dispersion coefficients(LDC, TDC). As expected, LDC and TDC in meandering parts have been evaluated with increasing distribution and straight parts have effected to evaluate minimum of LDC and TDC due to symmetric flow patterns and attenuations of secondary flow.