• Transactions of the Korean Society of Mechanical Engineers
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• v.11 no.5
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• pp.828-836
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• 1987

The inclusion of thermophoresis in particle deposition studies has often been treated separately from deposition due to flow characteristics. Also previously reported experimental results on thermophoresis have been studied in the regions of relatively small temperature gradients. In this study, using real-time laser light reflectivity method, we measured the angular dependence of the deposition rates of particles of the cylindrical collector surface, which immerged in laminar flow of a hot gas suspension of small particles. And we extended the previous narrowband results of thermophoretic deposition rates to the regions of large temperature gradients between the hot gas stream and the collector surface. Based on the obtained data, the cylinder's forward stagnation-point region is considerably enriched in particle 'phase' density owing to the compressibility effect, which leads to locally enhanced deposition while the downstream region from the stagnation point inertial force acts in the opposite direction, which tends to centrifuge particles away from the wall, thus the local deposition rates by thermophoresis are reduced.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.14 no.10
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• pp.792-800
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• 2002

A grease filter is used to remove grease generated from a cooking appliance in a kitchen. This numerical study has been conducted to investigate the particle collection characteristics of a grease filter having nominal flowrate of $100m^3$/h. The flow field and particle trajectories in the grease filter with a flow chamber were simulated by using the commercial code of STAR-CD. The air velocity and pressure distributions were discussed in detail. The pressure drop of a grease filter rapidly increases with increasing the air flowrate. The numerical values of the pressure drop are slightly lower than the experimental values when the air flowrates are 50, 75, and 100㎥/h. The particle collection efficiency of a grease filter increases with increasing the particle diameter, the particle density, and the air flowrate, which means that the inertial impaction is a dominant particle removal mechanism in a grease filter. The cut-off diameter of the tested grease filter representing 50-% collection efficiency is about 11.6$\mu$m for water droplets at $100m^3$/h.

• Particle and aerosol research
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• v.9 no.1
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• pp.23-29
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• 2013

Inertial impaction type mist eliminators are the most effective instruments to separate mist from the gas. In this work, the effect of the horizontal chevron type mist eliminators is characterized experimentally. Droplet size distribution and evaluation of removal efficiency of the chevron type mist eliminators at different gas flows were investigated using an aerosol particle size analyzer and a portable aerosol spectrometer, respectively. The experimental investigations showed that the mist removal efficiency in these instruments is dependent in the droplet size, and the pressure drop is nil.

• Resources Recycling
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• v.9 no.4
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• pp.28-36
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• 2000

This study describes to analyze the characteristics for separation and recovery of both the dried particles and the purified solvent from the waste solvent through the vaporization process by the continuous and instantaneous vacuum drying system. The vacuum drying system for the waste solvents recovery consists of a feeding pump, a double pipe heat exchanger, a vacuum spray chamber, and a condenser. The vacuum drying system heats the waste solvent to the vapor in the double pipe heat exchanger and the expanded vapor is sprayed at the end of the tube. The vaporized solvent in the condenser are recovered. The particles in the waste solvent are separated and dried from the vapor in the vacuum spray chamber. Performance evaluation of the vacuum drying system was conducted using the mixture of the dried pigment particles and benzene or alkylbenzene as test samples. For the mixture of 10 wt% pigment particles an 90% benzene, the recovery efficiency of benzene was 88% with the purity of 99% and the recovery efficiency of dried particles was 94% with the moisture of 1.1 wt%. The size of pigment particles was decreased from $6.5\mu\textrm{m}$ to $5.6\mu\textrm{m}$ in diameter due to high speed spraying and dispersion in the vacuum drying system during drying process. Therefore, the vacuum drying system showed to be an effective method for separating particles and solvent in the waste solvent.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2000.11a
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• pp.145-146
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• 2000

도시와 산업의 발달 및 인구증가로 인하여 다양한 종류의 대기오염물질이 대기 중으로 대량 배출되고 있다. 대기 중의 입자상 및 가스상 오염물질들은 강수, 안개 및 응축 등에 의한 습식침착(wet deposition)과 강수의 영향없이 진행되는 중력침강, 확산, 관성충돌 등에 의한 건식침착(dry deposition) 의 과정에 의해 대기 중에서 제거된다(Legge and Krupa, 1990). 일반적으로 습식침착은 구름 내에서 응핵(nuclei)으로 작용하여 오염물질이 제거되는 rain-out 과정과 비 또는 눈 등의 강하시 충돌, 간섭, 흡수 및 흡착과정에 의해 제거되는 세정과정(wash-out)으로 분류될 수 있다. (중략)

• Proceedings of the KAIS Fall Conference
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• 2012.05a
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• pp.371-374
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• 2012

본 연구는 "사이클론과 관성충돌 및 백필터의 제진원리를 일체화한 고효율 멀티 제진시스템의 최적화 설계를 위한 수치 해석적 연구(I) : 집진기 입구 최적화 설계"에 이은 일련의 연구로서 앞선 연구에서 도출된 사이클론부 하단 벤츄리(Venturi)에서의 강한 하향 기류의 가속에 따른 분진 재비산 가능성에 대한 추가적 검토를 위한 연구이다. 사이클론부를 통과한 기류가 상향 흐름으로 방향을 전환할때 좀 더 가속시켜 빠르게 곡률반경을 형성하여 조대 입자의 분리를 극대화시키기 위한 목적으로 사이클론부 하단을 벤츄리 형상으로 설계하였으나, 유동장 분석 결과 벤츄리를 통과한 처리가스 흐름이 가속되면서 호퍼 하단까지 약 4~5 m/s의 강한 하향 흐름을 형성하고 호퍼 하부의 말단 부근에서 상향 흐름으로 방향 전환을 하고 있는 것으로 예측됨에 따라 설계 의도와는 달리 벤츄리 설치시 호퍼 하단에 포집된 분진의 재비산을 예방하는데는 크게 역할을 하지 못하는 것으로 나타났다.

• Journal of the Korean Ceramic Society
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• v.40 no.12
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• pp.1202-1207
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• 2003

Using a recently developed Hybric Plasma-Particle Accelerating Impact Deposition (HP-PAID) process, synthesis of nanostructured silicon coatings has been investigated by injecting vapor-phase TEOS (tetraethosysilane, (C$_2$H$\_$5/O)$_4$Si) into an Ar hybrid plasma. The plasma jet with reactants was expanded through nozzle into a deposition chamber, with the pressure dropping from 700 to 10 torr. Ultrafine particles accelerated in the free jet downstream of the nozzle, deposited by an inertial impaction onto a temperature controlled substrate. By using this process, nanostructured amorphous silicon coatings with grain size smaller than 10 nm could be synthesized. These samples were annealed in an Ar and crystallized at 900$^{\circ}C$ for 30 min. TEM analysis showed that the annealed coatings were also composed of nanoparticles smaller than 10 nm, which showed a good consistency that the average grain size of 7 nm was also estimated from a peak shift of 2.39 cm$\^$-1/ and Full Width at Half Maximum (FWHM) 5.92 cm$\^$-1/ of Raman analysis. The noteworthy is that a strong PL peak at 398 nm was also obtained for this sample, which indicates that the deposited coatings also contained 3∼4 nm nanostructured grains.

• Particle and aerosol research
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• v.9 no.4
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• pp.247-252
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• 2013

Removal of water contents in a gas is needed in industrial field of gas processing related on energy production/conversion, and environmental treatment. Inertial separators are economic devices for separating droplets from the gas stream. For design and incorporation of inertial pre-treatment separator, characteristics of removal of water contents with various operation conditions are needed. In this study, removal efficiency of water droplets at various flowrates (5-14 SCMM) and relative humidity (R.H.) conditions (40%, and 90%) has been investigated. At low R.H. condition, the removal characteristic is similar to the removal of solid particles. But, droplet growth resulting from the condensation of water vapor at high R.H. condition, is significant and it made increase in removal efficiency of droplet phase of water contents. For rapid removal of water contents, an effective method to enhancing condensation growth of water droplets is highly needed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.41 no.4
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• pp.221-228
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• 2017

We proposed a novel method to remove PM2.5 dusts without HEPA filters aiming at applications in kitchens or enclosed work spaces generating PM2.5 at high concentrations. Many workers are exposed to PM2.5 owing to lack of air purification because the high replacement costs of HEPA filters make their application impractical. A key idea is to use the condensational growth of nanoparticles. Once particles grow to the size of a few micrometers, it is much easier to remove them because of their increased inertia. We developed and tested a prototype consisting of an air saturator (equipped with water spray nozzles), a condenser in which humid air was cooled down to make the particles grow, and a multi-impactor assembly for collecting the grown particles.

• Journal of Korean Society of Water and Wastewater
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• v.22 no.1
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• pp.159-168
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• 2008

A special field experiment has been carried out from March 2001 to June 2001 at the Changhowon in Kyunggi to investigate a better methodology for the estimation of dry deposition of pollutions applicable in Korea. In this study, dry deposition plate was used to measure of total and water soluble acidic mass fluxes, and CPRI(Coarse Particle Rotary Impactor), CI(Cascade Impactor) were also used to measure ambient concentrations in various particle size ranges. Sehmel-Hodgson model was used to estimate dry depostion velocity and Weibull probability distribution function was applied to get generalized particle size distribution for the size fractioned concentration data sampled by CPRI and CI. Atmospheric dry deposition fluxes of mass and ionic matters estimated by the various techniques(one-step, multi-step, equi-concentration, subdivision for only the coarse particle range, applying Weibull distribution function, etc.) were compared to flux data sampled by DDP. It was found out that the deposition fluxes estimation methodology calculated by the each particle size range devided by particle size distribution characteristics and the rapidly changed points of deposition velocity using Weibull probability distribution function was the most applicable.