• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 1999.05a
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• pp.75-79
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• 1999

순환유동층은 주탑에서 비말 동반된 입자를 cyclone과 같은 입자 포집장치에서 회수하여 다시 주탑으로 재 주입함으로써 입자의 순환이 일어나는 외부 순환계와 종래의 유동층내에 원형관(Draft tube)이나 평판을 설치하여 두개의 층으로 분리한 후 가스 분산판 위의 간격을 통해 입자들을 두 구역 사이로 강제 순환시키는 내부순환계로 분류할 수 있다. 드래프트 관을 갖는 내부순환유동층 반응기는 기체와 고체의 적절한 접촉을 통해 반응이 이루어지는 반응기 형태이다.(중략)

• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1756-1760
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• 2004

Circulating Fluidized-Bed (CFB) boilers which have been operated in Korea were manufactured by the design technology of foreign leading companies. As they are not active to transfer their technology, domestic companies don't have the enough ability to design it independently yet. Doosan Heavy Industries & Construction Co. Ltd. and Korean Institute of Energy Research are trying to develop and improve the particle re-circulating device among the components of CFB boiler. Our purpose is to control the amount of particles leaving the re-circulating system by adjusting utility air and reuse the heat of circulating particles. The results of experiments with cold model system show that a fluidization state in the particle re-circulating device is very stable when the amount of utility air is supplied to its wind box with 2.29 times of minimum fluidization velocity. Also the amount of particles entering the riser don't increase linearly when the amount of utility air is supplied over 2.5 times of minimum fluidization velocity. Now we are testing its functional run with the hotstate experiment set-up.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.6
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• pp.577-583
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• 2011

To meet the requirements of the Tier 4 interim regulations for off-road vehicles, emissions of particulate matter (PM) and nitrogen oxides (NOx) must be reduced by 95% and 30%, respectively, compared to current regulations. In this research, both the DPF and HPL EGR systems were investigated, with the aim of decreasing the PM and NOx emissions of a 56-kW off-road vehicle. The results of the experiments show that the DOC-DPF system is very useful for reducing PM emissions. It is also found that the back pressure is acceptable, and the rate of power loss is less than 5%. By applying the HPL EGR system to the diesel engine, the NOx emissions under low- and middle-load conditions are reduced effectively because of the high differential pressure between the turbocharger inlet and the intake manifold. The NOx emissions can be decreased by increasing the EGR rate, but total hydrocarbon (THC) emission increases because of the increased fuel consumption needed to compensate for the power loss caused by EGR and DPF.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.8
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• pp.755-760
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• 2010

In this study, we mainly focused on the PM (Particulate Matter) emission characteristics of a diesel engine. To analyze particle behavior in the tail-pipe, particle emission was measured on the engine-out (downstream of turbocharger), each upstream and downstream both of DOC (Diesel Oxidation Catalyst) and DPF (Diesel Particulate Filter). Moreover, particle emission contours on each sampling point were constructed. The reduction efficiency of particle number concentration and mass through the DOC and DPF was studied. Parameters such as EGR (Exhaust Gas Recirculation) and the main injection timing were varied in part load conditions and evaluated using the engine-out emissions. The DMS500 (Differential Mobility Spectrometer) was used as a particle measurement instrument that can measure particle concentrations from 5 nm to 1000 nm. Nano-particles of sizes less than 30 nm were reduced by oxidation or coagulated with solid particles in the tail-pipe and DOC. The DPF has a very high filtration efficiency over all operating conditions except during natural regeneration of DPF.

• Korean Chemical Engineering Research
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• v.54 no.5
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• pp.706-711
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• 2016

Characteristics of solid circulation rate in the liquid-solid circulating fluidized beds with viscous liquid medium were investigated. Effects of primary and secondary liquid velocities, particle size, liquid viscosity and height of solid particles piled up in the solid recycle device on the solid circulation rate were considered. The solid circulation rate increased with increasing primary and secondary liquid velocities, liquid viscosity and height of solid particles in the downcommer, but it decreased with increasing particle size. The particle rising velocity in the riser decreased with increasing the ratio of $U_{L1}/U_{L2}$ and particle size. The slip velocity of liquid and particle, $U_L/U_S$, decreased with increasing liquid viscosity but it increased with increasing particle size. The values of solid circulation rate were well correlated in terms of operating variables and dimensionless groups.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.766-774
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• 2017

Software has been developed for simulating particle dispersion in a circular pipe with sudden-expansion, which models the fuel feeding system of a combustor that uses metal powder like aluminum as fuel. The Lagrangian based discrete tracer point method was employed for a plug flow of particles that satisfies local turbulent velocity fluctuations. A radial velocity component was created to improve the flow turning outwards in the recirculation zone. The particle distribution patterns from both with and without the component were directly compared with the experiments near the reattachment.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.2
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• pp.159-164
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• 2009

Cooled EGR system is an effective method for the reduction of $NO_x$ emission and PM emission from a diesel engine. Proper choice of wavy cooling fins and gas tubes is a key factor of cooled EGR system. As a part of solutions for energy crisis and environmental problems, hybrid vehicles mounted with diesel engines are under development globally. This study investigates the cooled EGR systems for hybrid diesel engine with the specifications of both optimized wavy cooling fins and improved shape of structure to verify the heat exchange efficiency, outlet temperature and gas pressure drop of cooler by means of numerical analyses and rig performance tests. The output of this study will be applied to a 2.0L hybrid diesel engine which is being developed for domestic and overseas market.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.3
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• pp.183-188
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• 2007

Recently, diesel engine has been frequently applied to RV, SUV and light duty truck due to the good fuel economy and high thermal efficiency. $NO_x$ and PM, environmental pollution materials are basically produced in diesel combustion process. The most important target in diesel engine research is the development of system to reduce the emissions of $NO_x$ and PM. Cooled EGR system is an effective method for the reduction of $NO_x$ emission and PM emission from a diesel engine and EGR cooler is the key component of the system. This study investigates the EGR cooler of oval gas tubes compared with the EGR cooler of shell & tubes to verify the heat exchange efficiency of cooler by means of engine dynamometer tests, rig performance tests and numerical analyses.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.242-242
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• 2004

원자력발전소의 운전과정에서 계획적 혹은 비계획적으로 방출되는 미량의 입자상 방사성 물질들은 대부분 원전 부지내 토양에 침적되게 된다. 이러한 과정 속에서 오염토양이 발생하게 되면 수거되어 단순 격리관리하고 있는 실정이지만 앞으로 원전의 해체과정 등으로 인한 오염토양이 상당량 발생할 것으로 예상되기 때문에 적절한 제염을 통하여 폐기물량을 최소화시킬 필요가 있다. 이를 위해 오염토양 제염공정으로 물을 이용한 토양세척법을 선정하여 제염장치를 제작하였으며 실증시험을 수행하였다.(중략)

• Nuclear Engineering and Technology
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• v.18 no.4
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• pp.273-280
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• 1986

The purpose of this study is to obtain the experimental data of the forced flow dryout heat flux in a heat generating debris bed which simulates the degraded nuclear reactor core after severe accident. An experimental investigation has been conducted of dryout heat flux in an inductively heated bed of steel particles with upward forced flow rising coolant circulation system under atmospheric pressure. The present observations were mainly focused on the effects of coolant mass flux, particle size, bed height, and coolant subcooling on the dryout heat flux The data were obtained when carbon steel particles in the size distribution 1.5, 2.5, 3.0 and 4.0 mm were placed in a 55 mm ID Pyrex glass column and inductively heated by passing radio frequency current through a multiturn work coil encircling the column. Distilled water was supplied with variation of mass flux from 0 to 3.5 kg/$\textrm{cm}^2$ s as a coolant in the tests, while the bed height was selected as 55 mm and 110 mm. Inlet temperature of coolant varied by 2$0^{\circ}C$ and 8$0^{\circ}C$. The principal results of the tests are: (1) Dryout heat flux increases with increase of upward forcing mass flux and particle size; (2) The dryout heat flux at the zero mass flux obviously depends on the Particle size as Previous studies; (3) The forced flow dryout heat flux in the shallow bed is somewhat higher than that in the deep bed,