• Title/Summary/Keyword: Flow control plate

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Demonstration of a Modular Electrostatic Precipitator to Control Particulate Emissions from a Small Municipal Waste Incinerator

  • Intra, Panich;Yawootti, Artit;Tippayawong, Nakorn
    • Journal of Electrical Engineering and Technology
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    • v.9 no.1
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    • pp.239-246
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    • 2014
  • Incineration is conceptually sound as a waste treatment technology. There is, however, concern over its emissions when it is improperly designed and operated. An electrostatic precipitator is one of the most commonly used devices to control particulate emissions from boilers, incinerators and some other industrial processes. In this work, a modular electrostatic precipitator with sizing of $1m{\times}1m{\times}1m$ was developed for removal of particulate matter from the exhaust gases of a small waste incinerator. Its design was based on a simple wire-and-plate concept. The corona discharge wires were connected to a positive high-voltage pulse generator, while the collection plates were grounded. The high-voltage pulse generator was used to produce the corona discharge field between the individual discharge wire and the collection plate. The particulate-laden exhaust gas flow was directed across the corona discharge field. The charged particles were deflected outward and collected on the plate. The collection efficiency was evaluated as a mass loading ratio between the difference at the inlet and the outlet to the particulate loading at the inlet of the precipitator. The collection efficiency of this modular electrostatic precipitator design was approximately 80 %.

Flow of a low concentration polyacrylamide fluid solution in a channel with a flat plate obstruction at the entry

  • Kabir, M.A.;Khan, M.M.K.;Rasul, M.G.
    • Korea-Australia Rheology Journal
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    • v.16 no.2
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    • pp.63-73
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    • 2004
  • Flow in a channel with an obstruction at the entry can be reverse, stagnant or forward depending on the position of the obstruction. These flow phenomena have potential applications in the control of energy and various flows in process engineering. Parameters that affect this flow inside and around the test channel are the gap (g) between the obstruction geometry and the test channel, the Reynolds number (Re) and the length (L) of the test channel. The influence of these parameters on the flow behavior was investigated using a flat plate obstruction at the entry of the channel. A low concentration polyacrylamide solution (0.018% by weight) showing a powerlaw fluid behavior was used as the fluid in this investigation. The flow phenomena were investigated by the velocity measurement and the flow visualization and their results were compared with numerical simulation. These results of low concentration polyacrylamide solution are also compared with the results of water published elsewhere (Kabir et al., 2003). The maximum reverse flow inside the test channel observed was 20% - 30% of the outside test channel velocity at a g/w (gap to width) ratio of 1 for Reynolds numbers of 1000 to 3500. The influence of the test channel length (L) and the Reynolds number (Re) on the velocity ratio ($V_i$/$V_o$: inside velocity/outside velocity in the test channel) are also presented and discussed here.

The Development of Vibration Exciter Using Strain Displacement Estimator for Flow Resonance (스트레인 게이지 변위 추정기를 사용한 유동공진 가진기 개발)

  • Choi, Jae-hyuck;Nam, Yoon-su
    • Journal of Industrial Technology
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    • v.21 no.B
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    • pp.125-132
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    • 2001
  • Heat dissipation technology using flow resonant phenomenon is a kind of new concept in heat transfer area. A vibration exciter is needed to generate air turbulence which has the natural shedding frequency of heat system. A mechanical vibrating device for the air flow oscillation is introduced, which is driven by a moving coil actuator. An analytical dynamic model for this mechanical vibration exciter is presented and its' validity is verified by the comparison with experimental data. Values of some unknown system parameters in the analytic model are estimated through the system identification approach. Based on this mathematical model, the vibration exciter using strain displacement estimator is developed. And in the experiment, the feedback control is used. During the experimental verification phase, it turns out the high modal resonant characteristics of vibrating plate are the major barrier against obtaining a high bandwidth vibration exciter.

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Design and Evaluation of a Vibration Exciter for the Flow Resonance (유동공진을 위한 가진기 설계 및 평가)

  • Nam, Yoon-Su;Choi, Jae-Hyuck
    • Journal of the Korean Society for Precision Engineering
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    • v.18 no.6
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    • pp.141-147
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    • 2001
  • A heat dissipation technology using flow resonant phenomenon is a kind of new concept in heat transfer area. A vibration exciter is needed to generate an air turbulence which has the natural shedding frequency of a heat system. A mechanical vibrating device for the air flow oscillation is introduced, which is driven by a moving coil actuator. An analytical dynamic model for this mechanical vibration exciter is presented and its validity is verified by the comparison with experimental data. Values of some unko주 system parameters in the analytic model are estimated through the system identification approach. based on this mathematical model, a high bandwidth vibration exciter is designed using feedback control. During the experimental verification phased, it turns out the high frequency modal resonant characteristics of vibrating plate are the major barrier against obtaining a high bandwidth vibration exciter.

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Prediction of the Diffusion Controlled Boundary Layer Transition with an Adaptive Grid (적응격자계를 이용한 경계층의 확산제어천이 예측)

  • Cho J. R.
    • Journal of computational fluids engineering
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    • v.6 no.4
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    • pp.15-25
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    • 2001
  • Numerical prediction of the diffusion controlled transition in a turbine gas pass is important because it can change the local heat transfer rate over a turbine blade as much as three times. In this study, the gas flow over turbine blade is simplified to the flat plate boundary layer, and an adaptive grid scheme redistributing grid points within the computation domain is proposed with a great emphasis on the construction of the grid control function. The function is sensitized to the second invariant of the mean strain tensor, its spatial gradient, and the interaction of pressure gradient and flow deformation. The transition process is assumed to be described with a κ-ε turbulence model. An elliptic solver is employed to integrate governing equations. Numerical results show that the proposed adaptive grid scheme is very effective in obtaining grid independent numerical solution with a very low grid number. It is expected that present scheme is helpful in predicting actual flow within a turbine to improve computation efficiency.

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Reduction of the Cavity Flow Oscillations at Supersonic Speeds (초음속 공동유동에서의 진동감소)

  • Kang, Min-Sung;Shin, Choon-Sik;Kwon, Joon-Kyung;Kim, Heuy-Dong
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.11a
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    • pp.345-348
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    • 2008
  • The subcavity passive control technique is used in present study. Cavity-induced pressure oscillation has been investigated numerically for a supersonic three-dimensional flow over rectangular cavities at Mach number 1.83 at the cavity entrance. The three-dimensional, compressible Navier-stokes equations are numerically solved based on a fully implicit finite volume scheme. The results showed that the resultant amount of attenuation of cavity-induced pressure oscillations was dependent on the length and thickness of the flat plate.

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A Study on the Optimal Water Flow Rate of the Solar Heating System (태양열 난방시스템의 최적 유량에 관한 연구)

  • Seong, Kwan-Jae;Kim, Hyo-Kyung
    • The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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    • v.12 no.1
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    • pp.2-11
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    • 1983
  • The solar energy retention rate of a flat plate collector can be increased by increasing water flow rate through the collector which also increases the pumping energy incurred in obtaining that solar energy. The problem of optimal flow rate is formulated to fit within the framework of pontryagin's maximum principle and with a few simplifying assumptions, an optimal solution that can be easily implemented is obtaincd, The optimal solution is used in the simulation of a solar heating system using actual climatological data and the results are compared with that of on-off control. The result that not only the object function but, In some cases, also the solar energy retention rate the collector is increased. In is also found that the optimal control gets more advantageous as the solar insolation level gets lower, and also as tile cost of auxiliary heating fuel gets higher.

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A Study on Vibration Power Flow of 2-Dimension Structure Travelling from the Source (진동원으로부터 전달되는 2차원 구조물의 진동파워흐름에 관한 연구)

  • 노영희;김동영;홍도관;권용수;안찬우;한근조
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2002.10a
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    • pp.879-882
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    • 2002
  • To control the vibration and sound of structure, it is important to analyze the dynamic action of structure. And through those analysis, the vibration source and the flow path is understood. To grasp that, when the two-dimension plate structure is shaken by a harmonic point excitation with the natural frequency using the finite element method, this paper presents the relation between vibration power flow and mode shape. As those results present to vector flow, the vibration power flow is visualized.

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Enhancement of Impinging Jet Heat Transfer Using Triangular Multi-Tabs (삼각형 멀티 탭을 이용한 충돌제트 열전달 향상 연구)

  • Lee Jeong-Wook;Lee Sang-Joon
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.28 no.10
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    • pp.1139-1146
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    • 2004
  • The effect of triangular tabs attached at the perimeter of jet nozzle on heat transfer enhancement was investigated experimentally. The modified flow structure was visualized using a smoke-wire method. Four different types of jet nozzle having 0, 4, 6 and 8 tabs were tested at jet Reynolds number Re=15,000 to investigate the effect of tabs on the variation of heat transfer rate. The local and average Nusselt numbers are increased with increasing the number of tabs. At nozzle-to-plate distance of L/D=4, the average Nusselt number was increased about 9.9% at Re=15,000 in the impingement region for the case of 8 tabs attachment. As the nozzle-to-plate distance increases, however, the heat transfer enhancement effect of triangular tabs is reduced. For the case of 4 tabs, the heat transfer enhancement is not so distinctive at L/D=8. As the protrusion depth of tabs into the jet flow increases, the heat transfer rate is also enhanced when the nozzle-to-plate distance is smaller than L/D=6.

Solar District Heating System (지역난방용 태양열시스템)

  • Baek, Nam-Choon;Lee, Jin-Kook;Yoon, Eung-Sang;Yoon, Suk-Man;Sin, U-Chul
    • Proceedings of the SAREK Conference
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    • 2008.06a
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    • pp.663-668
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    • 2008
  • This study was carried out solar heating system design for district heating and it's the performance analysis by experiment. This experimental system was installed in Bundang district heating area in the end of 2006. The flat plate and vacuum tube solar collector are combined in one system. So district heating water is heated first by flat plate solar collector and than by vacuum tube solar collector. This solar heating system has not a solar buffer tank and is operating with variable flow rate to obtain a setting temperature of $90{\sim}95^{\circ}C$. As a result, the daily solar thermal collection efficiency is about 30 to 40% for the plate type and 50 to 55% for the vacuum tube solar collector. It varied especially depend on the weather condition like as solar radiation and ambient temperature. This variable flow rate system can be also reduced much pumping power more than 50%.

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