• 설비공학논문집
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• 제19권6호
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• pp.447-456
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• 2007

Suspended particles behavior when they go through a vertical riser with heat transfer is of significant concern to system designers and operators in pneumatic transport, various processes such as in chemical, pharmaceutical and food industries. When it comes with the energy system, that knowledge is critical to the reliable design practices of related equipment as heat exchangers, especially in the phase of system scale-up. Without haying a good understanding of the related physics, many scale-up practices based on their pilot plant experience suffer from unexpected behaviors and problems of unstable fluidization typically associated with excessive pressure drop, pressure fluctuation and even unsuccessful particle circulation. In the present study, we try to explain the observed phenomena with related physics, which may help understanding of our unanswered experiences and to provide the designers with more reliable resources for their work. We selected hot exhaust gas with solid particle that goes through a heat exchanger riser as our model to be considered. The effect of temperature change on the gas velocity, thermodynamic properties, and eventually on the particles motion behavior is reviewed along with some heat transfer analyses. The present study presents an optimal riser length at full scale under given conditions, and also defines the theoretical limiting length of the riser. The field data from the numerical analysis was validated against our experimental results.

• 한국전산유체공학회지
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• 제13권4호
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• pp.58-65
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• 2008

In the present study, a numerical analysis on electrohydrodynamics (EHD) of the flow and the collection mechanisms inside a electrostatic precipitator with a spiral spike electrode were investigated. The phenomena of the electrostatic precipitator include complex interactions between the electric field, the fluid flow and the particle motion. To validate the numerical method, the numerical computation for the electric field of a simple wire-pipe type electrostatic system having an analytic solution were performed. Using this numerical method, the electric field of the spiked electrostatic precipitator was simulated. And the fluid flow and the particle motion inside the spiked electrostatic precipitator were numerically analyzed.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년도 학술대회
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• pp.276-282
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• 2008

In the present study, a numerical analysis on electrohydrodynamics (EHD) of the flow and the collection mechanism inside a electrostatic precipitator were investigated. The phenomena of the electrostatic precipitator include complex interactions between the electric field, the fluid flow and the particle motion. To validate the numerical method, the numerical computation for the electric field of a simple wire-pipe type electrostatic system having an analytic solution were performed. Using this numerical method, the electric field of the spiked electrostatic precipitator was simulated. And the fluid flow and the particle motion inside the spiked electrostatic precipitator were numerically analyzed.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2008년 추계학술대회논문집
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• pp.276-282
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• 2008

In the present study, a numerical analysis on electrohydrodynamics (EHD) of the flow and the collection mechanism inside a electrostatic precipitator were investigated. The phenomena of the electrostatic precipitator include complex interactions between the electric field, the fluid flow and the particle motion. To validate the numerical method, the numerical computation for the electric field of a simple wire-pipe type electrostatic system having an analytic solution were performed. Using this numerical method, the electric field of the spiked electrostatic precipitator was simulated. And the fluid flow and the particle motion inside the spiked electrostatic precipitator were numerically analyzed.

• 한국분무공학회지
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• 제3권4호
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• pp.58-64
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• 1998

In the gasoline engine of fuel injection type, atomization of fuel droplet and its distribution has directly influenced the performance of engine and harmful emission. To investigate atomization characteristics of fuel spray, in this paper fuel spray of air-assisted injector is observed at the various initial conditions of ambient air temperature and air assisted pressure. Behavior of fuel spray is photographed with microscopic visualization system. The SMD of fuel droplet is measured with PMAS (Particle Motion Analysis System). The effect of air-assisted pressure and temperature of ambient air resulted in the decrement of SMD and its variation. Finally, It was found that It was found that from spray angle at the two-hole injector had measured $20{\pm}4$ degree the result of photographs by shadow graphy. The mean diameter of suns decreased and the of droplets increased with increasing the temperature in the spray fields by the results of PMAS measurement. It was found that the characteristics of sprays became finer by increasing the temperature of spray fields about 373K without the delivery of air-assistance.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 동계학술발표대회 논문집
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• pp.546-550
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• 2008

In this study, 3-dimensional Computational Fluid Dynamics (CFD) analysis was induced to simulate air flow and particle motion in the axial flow cyclone separator. The commercialized CFD code FLUENT was used to visualize pressure drop and particle collection efficiency inside the cyclone. We simulated 4 cyclone models with different shape of vane, such as turning angle or shape of cross section. For the air flow simulation, we calculated the flow field using standard ${\kappa}-{\varepsilon}$ turbulence viscous model. Each model was simulated with different inlet or outlet boundary conditions. Our major concern for the flow filed simulation was pressure drop across the cyclone. For the particle trajectory simulation, we adopted Euler-Lagrangian approach to track particle motion from inlet to outlet of the cyclone. Particle collection efficiencies of various conditions are calculated by number based collection efficiency. The result showed that the rotation angle of the vane plays major roll to the pressure drop. But the smaller rotation angle of vane causes particle collection efficiency difference with different inlet position.

• 한국자동차공학회논문집
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• 제9권5호
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• pp.54-61
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• 2001

It is reported that during the cold starting, especially in gasoline engine, the engine response and the effect of HC emission can be improved by prompting atomization and reducing the quantity of fuel adhered to the range of injector tip, inlet port, and inlet valve. The purposes of this study are to promote atomization of fuel before air-fuel mixture in the inlet port. In order to achieve its goal, the glow plug is to evaluate the feasibility of for the early fuel evaporator and the spray behavior characteristics of gasoline, injected on the surface of glow plug with room temperature(2$0^{\circ}C$) and high temperature(25$0^{\circ}C$) is to examine. Particle motion analysis system(PMAS) was used to measure the SMD and the dropsize distribution of impinging spray and free spray. The results of this experiment, evaporation rate of impinging spray was higher than that of free spray, and the higher evaporation rate win, the smaller peak dropsize was. Especially, during early spray SMD of impinging spray was still smaller than that of fee spray.

• 한국가스학회지
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• 제13권5호
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• pp.7-14
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• 2009

본 연구는 석탄화력발전소 노의 연소효율 향상을 위하여 미분탄 수송배관의 공기-입자 유동장의 압력손실 특성을 분석하여 미분탄 수송장치 내에 설치되어 유량을 제어하는 오리피스의 설계에 적용하고자 하는 것이다. 통상의 미분탄 수송배관장치는 관의 형태에 따라 직선관, 곡선관 및 엘보우로 구성된다. 본 연구에서는 공기유동과 입자운동의 상호작용 해석을 통하여 직선관과 곡선관을 갖는 미분탄 수송배관장치 내의 압력손실을 분석하였다. 총 압력손실은 공기-미분탄 입자의 마찰 손실 증가와 배관의 길이, 곡선관 각도의 증가에 따라 증가하는 것으로 확인되었다. 연구결과로 압력손실과 유량제어를 위한 최적화된 오리피스 설계 프로그램이 개발되었으며 그 계산 결과를 기존의 실험결과와 비교, 분석하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1057-1062
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• 2007

The purpose of this study is to find out design parameters of vibrating screen, such as particles motion, specific gravity, shape, and kinetic friction. In order to approach this problem, four materials of construction wastes, wood, styrofoam, concrete, and sand are used for dynamic modeling. To present friction between the particles material and tilt plates material, these particles model is applied in order to verify effectively. Generally, the vibrating screen is composed of three assemblies such as screen, wastes guide, supported of screen. This model regards vibrator as system of screen fixed tilt plates. The model is analyzed to present what kind of particles motion while the system is vibrating. and this vibration system has been implemented in a ADAMS dynamaic program. This modeling is consist of dynamic model separation state on particle size. This study make good technique to verify in theory.

• 한국분무공학회지
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• 제7권2호
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• pp.7-15
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• 2002

A particle flow visualization, electrostatic charging measurement and separation of triboelectrically charged particles in the external electric field by a fluidized bed tribocharger are conducted for the removal of PVC particles from mixed waste plastics. The laboratory-scale triboelectrostatic separation system consists of the fluidized bed tribocharger, a separation chamber, a collection chamber and a controller. PVC and PET particles can be imparted negative and positive surface charges respectively due to the difference of triboelectric charging series between particles and particles in the fluidized bed tribocharger, and can be separated by passing them through an external electric field. To visualize these charged particles, He-Ne laser is used with cylindrical lenses to generate a sheet beam. In the charging measurement, the particle motion analysis system (PMAS), capable of determining particle velocity and diameter. is used to non-intrusively measure particle behavior in high strength electric field. The average charge-to-mass ratios of PVC and PET particles are $1.4\;and\;1.2{\mu}C/kg$, respectively. The highly concentrated PVC (91.9%) can be recovered with a yield of about 96.1% from the mixture of PVC and PET materials for a single-stage processing. The triboelectrostatic separation system using the fluidized tribocharger shows the potential to be an effective method for removing PVC from mixed plastics for waste plastic recycling.