• Title/Summary/Keyword: emission dispersion analysis

검색결과 69건 처리시간 0.026초

대기오염 확산분석을 위한 복합모형 방법론 연구 (Studies on the Methodology of a Hybrid Model for Emission Dispersion Analysis)

  • 양충헌;구윤서;김인수;성정곤
    • 대한교통학회지
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    • 제31권2호
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    • pp.69-79
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    • 2013
  • 본 연구에서는 대기오염 물질이 대기 변화에 따라 주변 지역의 오염농도에 미치는 영향 분석에 대한 필요성과 구체적인 방법론을 제시하였다. 이에 대한 사례연구로서 경기도 포천지역 도로망을 대상으로 본 방법론을 적용하였다. 본 연구에서 제시한 방법론은 1) 교통에서 배출된 오염물질만을 고려한 확산 분석, 2) 교통에서 배출된 오염물질과 주변오염물질농도를 결합하여 분석하는 두 가지 분석 모형을 포함하고 있다. 이를 통해 교통에 의해 발생된 대기오염물질이 교통망과 교통망 주변지역에 미치는 영향을 분석하는데 유용 할 것으로 판단된다. 또한, 교통에 의해 발생된 대기오염원과 대기오염원이 인체에 미치는 영향을 본 분석에 근거하여 도로주변 고농도의 대기오염물질에 의한 위해성(危害性)을 평가하는데 유용할 것으로 판단된다.

Wind tunnel study of plume dispersion with varying source emission configurations

  • Wittwer, Adrian R.;Loredo-Souza, Acir M.;Schettini, Edith B. Camano;Castro, Hugo G.
    • Wind and Structures
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    • 제27권6호
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    • pp.417-430
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    • 2018
  • The concentration fields in the proximities of a local gas emission source are experimentally analyzed in several combinations of wind incidences and source emissions. These conditions are determined by the plume buoyancy, emission velocity and incident flow wind speed. Concentration measurements are performed by an aspirating probe in a boundary layer wind tunnel. The analysis included the mean concentration values and the intensity of concentration fluctuations in a neutral atmospheric boundary layer flow. Different configurations are tested: an isolated stack in a homogeneous terrain and a stack with a bluff body in close proximity, located windward and leeward from the emission source. The experimental mean concentration values are contrasted with Gaussian profiles and the dilution factor is analyzed with respect to the empirical curves of the minimum dilution. Finally, a study on the plume intermittency is performed in a cross-sectional plane near the emission source. It is possible to highlight the following observations: a) plume vertical asymmetry in the case of an isolated emission source, b) significant differences in the dispersion process related to the relative location of the emission source and bluff body effects, and c) different probabilistic behavior of the concentration fluctuation data in a cross-sectional measurement plane inside the plume.

산지 내 오염물질 확산의 2차원 수치해석 (Numerical Analysis of the Two-Dimensional Pollutant Dispersion Over Hilly Terrain)

  • 김현구;이정묵
    • 한국대기환경학회지
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    • 제13권5호
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    • pp.383-396
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    • 1997
  • Numerical prediction of the pollutant dispersion over a two-dimensional hilly terrain is presented. The dispersion model used in the present work is based on the gradient diffusion theory and the finite-volume method on a non-orthogonal boundary-fitted grid system. The numerical model is validated by comparing the results with the available experimental data for the flat-floor dispersion within a turbulent boundary-layer. The numerical error analysis is performed based on the guideline of Kasibhatla et al.(1988) for the elevated-source dispersion in the flat-floor boundary layer having a power-law velocity and linear eddy-diffusivity profile. The influences of the two-dimensional hilly terrain on the dispersion from a continuously released source are numerically investigated by changing the emission locations and heights. It is found that the distributions of ground-level concentration are strongly influenced by the source location and the emission height. Hence, the terrain amplification factor is greatly enhanced when the pollutant source is located within a flow separation region. Dispersion from a source of short duration is also simulated and the duration time of the pollutant is compared at several downstream locations on a hilly terrain. The results of the numerical prediction are applied to the evaluation of environmental impacts due to the automobile exhausts at the seashore highway with a parallel mountain range.

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도시계획에 따른 개발밀도에 근거한 도시 대기오염 확산분석 - 네덜란드 Delft시를 사례로 - (Emission Dispersion Analysis based on the Development Density associated with Urban Planning (a case study of the Delft city on Netherlands))

  • 김인수;양충헌;허혜정;성정곤
    • 한국도로학회논문집
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    • 제16권3호
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    • pp.21-33
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    • 2014
  • PURPOSES : This study presents a specific methodology for air dispersion analysis of urban areas methodology in accordance with urban planning and transport policy. METHODS : This study performed three alternatives including development density and public transit applying integrated urban model for the Delft city on Netherlands. Based on this result, the two types of air pollutant emissions($PM_{10}$, NOx) were calculated and analyzed the emission dispersion on that City. RESULTS : As a result, the quality of air near the City is better than that of current conditions showed that approximately from 2.1 to 7.9% according to alternatives. CONCLUSIONS : Air quality assessment in urban areas can be reasonably performed by applying a methodology when urban development and transport policy are considered.

CALPUFF and AERMOD Dispersion Models for Estimating Odor Emissions from Industrial Complex Area Sources

  • Jeong, Sang-Jin
    • Asian Journal of Atmospheric Environment
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    • 제5권1호
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    • pp.1-7
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    • 2011
  • This study assesses the dispersion and emission rates of odor form industrial area source. CALPUFF and AERMOD Gaussian models were used for predicting downwind odor concentration and calculating odor emission rates. The studied region was Seobu industrial complex in Korea. Odor samples were collected five days over a year period in 2006. In-site meteorological data (wind direction and wind speed) were used to predict concentration. The BOOT statistical examination software was used to analyze the data. Comparison between the predicted and field sampled downwind concentration using BOOT analysis indicates that the CALPUFF model prediction is a little better than AERMOD prediction for average downwind odor concentrations. Predicted concentrations of AERMOD model have a little larger scatter than that of CALPUFF model. The results also show odor emission rates of Seobu industrial complex area were an order of 10 smaller than that of beef cattle feed lots.

미시적 탄소배출량 및 대기확산 모형을 이용한 이동오염원에 의한 대기 질 영향 분석 (Impact Analysis of Air Quality of Mobile Sources using Microscopic Emission and Dispersion Model)

  • 양충헌;양인철;윤천주;성정곤
    • 한국도로학회논문집
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    • 제15권4호
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    • pp.167-175
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    • 2013
  • PURPOSES : The objective of this study is to investigate the capability of the combined model of traffic simulation, emission and air dispersion models on the impact analysis of air quality of mobile sources such as vehicles. METHODS : The improvement of the quality of life brings about the increasing interest of the public environment. Many endeavors including the travel demand management, the application of the state-of-the-art ITS technologies, the promotion of eco-friendly vehicles have been tried in transportation area to reduce the modal emissions. Especially, it is expected that the increasing number of eco-friendly vehicles in the road network would be able to reduce the pipe-tail emissions tremendously. From this perspective, we have performed a study on the impact analysis of the popularization of the eco-friendly vehicle in the place of the fossil fuel energy powered vehicles on the surrounding air quality using the combined framework of microscopic traffic simulation, emission and air dispersion model. RESULTS : The combined model successfully captured the effect of moving to the eco-friendly vehicles on the air quality, and the results showed that the increasing usage of eco-friendly vehicles can improve the surrounding air quality tremendously and that the air dispersion model plays a crucial role in the investigation of the air quality change around the main corridor. CONCLUSIONS : This study demonstrated the capability of the combined model showing the spatio-tempral change of emission concentration.

선 오염원에 의한 도로변 지역으로의 대기확산모델의 민감도 분석 - ISCST3, CALINE4 모델을 중심으로 - (Sensitivity Analysis of Air Pollutants Dispersion Model in the Road Neighboring Area Due to the Line Source -The Object on ISCST3, CALINE4 Model-)

  • 안원식;박명희;김해동
    • 한국환경과학회지
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    • 제16권6호
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    • pp.715-723
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    • 2007
  • The air pollutant emission is mainly caused by line sources in urban area. For example, the annually totaled air pollutant emission is known to consist of about 80% of line sources in Daegu. Hence, the appropriate assessment on the air pollutants of line sources is very important for the atmospheric environmental management in urban area. In this study, we made a comparative study to evaluate suitable dispersion model for estimating the air pollution from line sources. Two air pollution dispersion models, ISCST3 and CALINE4 were the subject of this study. The results were as follows; In the assessment of air pollution model, ISCST3 was found to have 4 times higher concentration than CALINE4. In addition, actual data obtained by measurement and estimated values by CALINE4 were generally identical. The air pollution assessment based on ISC3 model produced significantly lower values than actual data. The air pollution levels estimated by ISCST3 were very low in comparison with the observational values.

An improved cross-correlation method based on wavelet transform and energy feature extraction for pipeline leak detection

  • Li, Suzhen;Wang, Xinxin;Zhao, Ming
    • Smart Structures and Systems
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    • 제16권1호
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    • pp.213-222
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    • 2015
  • Early detection and precise location of leakage is of great importance for life-cycle maintenance and management of municipal pipeline system. In the past few years, acoustic emission (AE) techniques have demonstrated to be an excellent tool for on-line leakage detection. Regarding the multi-mode and frequency dispersion characteristics of AE signals propagating along a pipeline, the direct cross-correlation technique that assumes the constant AE propagation velocity does not perform well in practice for acoustic leak location. This paper presents an improved cross-correlation method based on wavelet transform, with due consideration of the frequency dispersion characteristics of AE wave and the contribution of different mode. Laboratory experiments conducted to simulate pipeline gas leakage and investigate the frequency spectrum signatures of AE leak signals. By comparing with the other methods for leak location identification, the feasibility and superiority of the proposed method are verified.

Acoustic emission source location and noise cancellation for crack detection in rail head

  • Kuanga, K.S.C.;Li, D.;Koh, C.G.
    • Smart Structures and Systems
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    • 제18권5호
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    • pp.1063-1085
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    • 2016
  • Taking advantage of the high sensitivity and long-distance detection capability of acoustic emission (AE) technique, this paper focuses on the crack detection in rail head, which is one of the most vulnerable parts of rail track. The AE source location and noise cancellation were studied on the basis of practical rail profile, material and operational noise. In order to simulate the actual AE events of rail head cracks, field tests were carried out to acquire the AE waves induced by pencil lead break (PLB) and operational noise of the railway system. Wavelet transform (WT) was first utilized to investigate the time-frequency characteristics and dispersion phenomena of AE waves. Here, the optimal mother wavelet was selected by minimizing the Shannon entropy of wavelet coefficients. Regarding the obvious dispersion of AE waves propagating along the rail head and the high operational noise, the wavelet transform-based modal analysis location (WTMAL) method was then proposed to locate the AE sources (i.e. simulated cracks) respectively for the PLB-induced AE signals with and without operational noise. For those AE signals inundated with operational noise, the Hilbert transform (HT)-based noise cancellation method was employed to improve the signal-to-noise ratio (SNR). Finally, the experimental results demonstrated that the proposed crack detection strategy could locate PLB-simulated AE sources effectively in the rail head even at high operational noise level, highlighting its potential for field application.

移動汚染源에 대한 大氣擴散模型의 感應度 分析에 관한 硏究 (HIWAY2, PAL, CALINE3 模型을 對象으로) (A Study on the Sensitivity Analysis of Line Source Air Quality Models)

  • 김선태;김병태;김정욱
    • 한국대기환경학회지
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    • 제5권1호
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    • pp.1-10
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    • 1989
  • The sensitivity analysis is a method to quantify to what extent the output of a model changes with the values of input parameters. This will lead to increase model accuracy through measurement validation. Three line source air quality models, HIWAY 2, PAL, and CALINE 3 were selected for this study. The input parameters analysed included wind speed, wind direction, stability, emission rate, mixing height, receptor distance, initial dispersion coefficient, surface roughness, and averaging time. It turned out that PAL model generally showed higher concentration than other two models, and that between CALINE 3 and HIWAY 2, CALINE 3 showed higher concentration than HIWAY 2 model near the line sources, but beyond a certain downwind distances HIWAY 2 model showed higher concentration. The modesl were very sensitive to wind speed especially in the range of 0 $\sim$ 1 m/s and to wind direction near the parallel wind to streets. In case of emission rate, the output concentration was directly proportional to these input parameters. And the sensitivity of the input parameters such as stability, mixing height, initial dispersion coefficient, surface roughness, and averaging time were not very significant.

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