• 제목/요약/키워드: 입자(particulate)

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DPF의 배기가스 유동 및 포집에 관한 다차원 모델링 연구 (Study on Multi-Dimensional Simulation of the Flow and Filtration Characteristics in Diesel Particulate Filters)

  • 김동균;윤천석
    • 한국자동차공학회논문집
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    • 제18권3호
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    • pp.60-68
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    • 2010
  • In order to understand the flow and filtration characteristics in a wall-flow type DPF(Diesel Particulate Filter), 0-D, 1-D, and 3-D simulations are preformed. In this paper, three model are explained and validated with each other. Based on the comparisons with 1-D and 3-D results for the steady state solution, 3-D CFD analysis is preferable to 1-D for the prediction of wall velocity at the inlet and exit plane. Because PM loading process is transient state phenomena, the combination of full 3-D and time dependent simulation is crucial for the configuration of wall channels. New coupling technique, which is the connection between calculated permeability from 0-D lumped parameter model and UDF(User Defined Functions) of main solver, is proposed for the realisti

파울링 예측을 위한 가스-입자 이상 유동 해석(1)-고온 풍동 설계 및 성능실험- (Particulate Two-Phase Flow Analysis for Fouling Prediction(I)-Design of Hot Wind Tunnel and Its Performance Experiment-)

  • 하만영;이대래
    • 대한기계학회논문집B
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    • 제20권11호
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    • pp.3695-3705
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    • 1996
  • We designed the hot wind tunnel to reproduce the conditions of utility boiler and carried out its performance test, in order to investigate the particulate two-phase flow behaviour, the fouling and heat transfer characteristics to the heat exchanger. The hot wind tunnel introduces the control system to control the temperature in the test section. The particle is injected into the hot gas stream. The fouling probe (cylindrical tube) is positioned normal to the particulate gas-particle two-phase flow and cooled by the air. The temperature of gas and cooling air, and temperature in the fouling probe are measured as a function of time, giving the local and averaged heat transfer and fouling factor. The shape of particulate deposition adhered to the fouling probe is also observed.

부유선별법에 의한 폐수 함유 입자성 유기 물질 처리에 대한 기초 연구 (Fundamental Studies on the Treatment of Particulate Organic Substances Contained in Wastewater by Flotation)

  • 유정민;김동수
    • 한국물환경학회지
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    • 제29권5호
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    • pp.674-680
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    • 2013
  • Basic studies for the treatment of particulate organic substances contained in wastewater by flotation have been conducted. Four kinds of plastics were chosen as the possibly existing organic particles in wastewater and the Zisman plots for these substances were constructed by measuring the contact angle of liquids on their surfaces. The critical surface tensions for these organic substances were estimated based on the constructed Zisman plot and the floatability of organic substances were regarded to be related with their molecular structure. The existence of dissolved organic substances such as a surfactant was observed to affect the extent of flotation of particulate organics. In addition, the consideration of work of adhesion was thought to be better than adopting the critical surface tension as the analytical basis in the operational design of flotation process of organic particles.

광역논에서의 용존성과 입자성 영양물질의 거동 특성 (Behavior of the Dissolved and Particulate Nutrient at Paddy Field Area)

  • 오승영;김진수;정구영
    • 한국수자원학회:학술대회논문집
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    • 한국수자원학회 2004년도 학술발표회
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    • pp.543-546
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    • 2004
  • Nutrients behavior were investigated at a paddy fields area(Soro-ri) with large-scaled plots on loam soil during irrigation seasons of $2001\~2003$. The average concentration of TN, TDN and TDP in drainage water was higher than that in irrigation water. On the other hand, the average concentration TP in irrigation water was higher than in drainage water. The ratio of TDN to TN accounted (or over $90\%$ and the ratio of TDP to TP accounted for $50\~70\%$. Especially the ratio of TDP to TP in drainage water was higher than that in irrigation water, suggesting that much of particulate component was reduced due to sedimentation and adsorption in paddy fields plots. Overall, particulate phosphorus usually account for 44 to $77\%$ of tile total phosphorus during storm events.

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낙동강 하구역 입자성 유기 규소의 계절적 변화 (Seasonal Variations of Particulate Biogenic Silica in the Nakdong River Estuary)

  • 문창호;권기영
    • 한국해양학회지
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    • 제29권1호
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    • pp.5-16
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    • 1994
  • 1991년 3월부터 1992년 4월까지 낙동강 하구에서 입자성 유기규소(PBSi), 규조류 및 규산염의 시공간적 변화를 조사하였다. 입자성 유기 규소의 양은 0.40∼11.45 ug-at/l의 범위에 있었으며 춘계 및 추계에 놓고 동계에 낮았으며 일반적으로 외해보 다는 내만에서 더 높았다. 수심별로는 상충이 가장 높고 중층에서 낮았으며 저층에서 다소 증가하는 양상이었다. 입자성 유기 규소는 규조류의 현존량과 밀접한 관계가 있 었으나 입자성 유기 규소와 개체수의 비율(약 500pgSi·cell/SUP -1/)이 높아 조사해 역에 많은 detritus성 유기규소가 존재하고 있음을 시사하고 있다. 규산염은 담수유입 이 주요 공급원이었으며 조사 해역에서 규조류의 성장 제한 요소로는 작용하지 않았 다. 다만 저층의 규산염 농도는 담수 유입외에 조사시기 직전의 표층의 입자성 유기 규소량과도 관계가 있는 것으로 예상된다. 비교적 낮은 입자성 유기 규소와 탄소(POC) 의 비(평균 0.20gSi·gC/SUP -1/), 높은 POC와 엽록소 a 의 비율 (약 900)로 볼 때 POC중 상당부분이 detrital POC 임을 시사하고 있다.

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디젤 승용차량 시험모드별 극미세입자 배출 특성 해석 (Analysis of Diesel Nano-particle Characteristics for Different Vehicle Test Mode in Diesel Passenger Vehicle)

  • 이진욱;정민원;정용일;차경옥
    • 한국자동차공학회논문집
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    • 제16권1호
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    • pp.114-120
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    • 2008
  • Recently, the nano-PM's number concentration emitted by diesel internal combustion engine has focused on attention because this particulate matters are suspected being hazardous of human health. In this study, The nano-PM mass and size of diesel passenger vehicles were measured on chassis dynamometer test bench. The particulate matters(PM) emissions of these vehicles were investigated by number concentration too. A condensation particle counter(CPC) system was applied to measure the particle number and size concentration of diesel exhaust particles at the end of dilution tunnel along the NEDC(ECE15+EUDC) and CVS-75 vehicle test mode. As the research result, the characteristic of vehicle test mode on the diesel nano-particle number and size distribution was investigated in this study.

국내 아파트의 미세먼지 유입 특성 (Infiltration Characteristics of Particulate Matter at a Korean Apartment House)

  • 주상우;지준호
    • 한국입자에어로졸학회지
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    • 제15권4호
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    • pp.149-157
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    • 2019
  • Infiltration characteristics of airborne particulate matter had been investigated in real-life for about 90 days over 2 years in a Korean apartment building where a 3-person household had lived and the exclusive private area was 84.9 ㎡. Airtightness was measured by fan depressurization, and the ACH50 was 2.41 times per hour. In and outdoor particle concentrations were measured by optical particle counters. Infiltration factors and filtration efficiencies of the house, which reflect the removal of outdoor particles penetrating building envelope and the deposition inside a building, were obtained from data screened based on an empirical evaluation process. Infiltration factor of fine particles showed a range from about 42% at 0.4 m/s of wind speed to 72% at 4.2 m/s of wind speed with closed windows and doors. Filtration efficiency was like a MERV 13 grade filter with an open window outside at a balcony at low outdoor wind speed under 1 m/s. The grade decreased to MERV 11 by opening another outside window at the other balcony. Filtration efficiencies decreased as much as 29% in average at a range of 0.3~2.5 ㎛.

단방향 플러싱에 의한 입자성 물질의 제거에 관한 연구 (A study on the removal of particulate matters using unidirectional flushing)

  • 김두일;천수빈;현인환
    • 상하수도학회지
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    • 제29권3호
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    • pp.371-380
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    • 2015
  • Particulate matters in a water distribution system are main causes of turbidity and discoloration of tap water. They could be removed by conventional or uni-directional flushing in a water distribution system. The behaviors and required flow velocity of particles are not well known for their flushing. A model water main and hydrant were made from transparent acrylic pipe of 30mm and 16mm in diameter, respectively. We analyzed the effect of flushing velocity, particle density, and particle diameter. We found that the existence of break-though velocities at which particles begin to be removed, and which are affected by their physical properties. The removal efficiencies seemed to be influenced by resuspension capabilities related to their upward movement from the bottom. Heavy particles like scale were hard to remove through upflow hydrant because the falling velocity, calculated using Stokes' law, was higher. Particle removal efficiencies of upward hydrant and downward drain showed minor differences. Additionally, the length between hydrant and control valve affected flushing efficiency because the particulate matters were trapped in this space by inertia and recirculating flow.

승용디젤엔진의 과도구간 입자상물질 저감 및 운전성능 향상을 위한 연료분사량 및 커먼레일압력 제어전략 (A Control Strategy of Fuel Injection Quantity and Common-rail Pressure to Reduce Particulate Matter Emissions in a Transient State of Diesel Engines)

  • 홍승우;정동혁;선우명호
    • 한국자동차공학회논문집
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    • 제23권6호
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    • pp.623-632
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    • 2015
  • This study proposes a control strategy of the common rail pressure with a fuel injection limitation algorithm to reduce particulate matter (PM) emissions under transient states. The proposed control strategy consists of two parts: injection quantity limitation and rail pressure adaptation. The injection limitation algorithm determines the maximum allowable fuel injection quantity to avoid rich combustion under transient states. The fuel injection quantity is limited by predicting the burned gas rate after combustion; however, the reduced injection quantity leads to deterioration of engine torque. The common rail pressure adaptation strategy is designed to compensate for the reduced engine torque. An increase of the rail pressure under transient states contributes to enhancement of the engine torque as well as reduction of PM emissions by promoting atomization of the injected fuel. The proposed control strategy is validated through engine experiments. The rail pressure adaptation reduced the PM emission by 5-10% and enhanced the engine torque up to 2.5%.

광산란 계측기의 미세먼지 측정 정확도 향상을 위한 수분제거 전처리 기술 개발 (Development of Drying Systems for Accurate Measurement of Particulate Matter by means of Optical Particle Measuring Instruments)

  • 강두수;오정은;이상열;신희준;봉하경;최주현;김대성
    • 한국입자에어로졸학회지
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    • 제14권4호
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    • pp.191-203
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    • 2018
  • IIn this study, we have developed drying systems for reducing the error by humidity on measuring particulate matter (PM) in the ambient air with optical particle measuring instruments. Two types of drying systems were designed: drying systems using heating and dilution methods. In addition, 3 types of drying systems using a heating method were designed: Type A (1 hole), B (3 holes) and C (7 holes). After making them, the laboratory and field tests were carried out to evaluate the developed drying systems. As a result, it was shown that the PM concentrations obtained by PM monitoring devices with drying systems agree well with that of the reference devices. Therefore, it could be concluded that the drying systems can be applied to PM monitoring devices for real-time monitoring of the ambient aerosols.