• Title/Summary/Keyword: 전기 유동유체

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Opto-electrokinetic Technique for Microfluidic Manipulation of Microorganism (광-전기역학 기술을 이용한 미생물의 미세유체역학적 제어)

  • Kwon, Jae-Sung
    • Journal of the Korean Society of Visualization
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    • v.17 no.1
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    • pp.69-77
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    • 2019
  • This paper introduces microfluidic manipulation of microorganism by opto-electrokinetic technique, named rapid electrokinetic patterning (REP). REP is a hybrid method that utilizes the simultaneous application of a uniform electric field and a focused laser to manipulate various kinds and types of colloidal particles. Using the technique in preliminary experiments, we have successfully aggregated, translated, and trapped not only spherical polystyrene, latex, and magnetic particles but also ellipsoidal glass particles. Extending the manipulation target to cells, we attempted to manipulate saccharomyces cerevisiae (S. cerevisiae), the most commonly used microorganism for food fermentation and biomass production. As a result, S. cerevisiae were assembled and dynamically trapped by REP at arbitrary location on an electrode surface. It firmly establishes the usefulness of REP technique for development of a high-performance on-chip bioassay system.

A COMPARATIVE STUDY OF TWO AND THREE DIMENSIONAL LOW REYNOLDS NUMBER FLOW (2차원 및 3차원 저레이놀즈수 유동 해석 비교 연구)

  • Lee, Jae-Hun;Jung, Kyoung-Jin;Lee, Kil-Tae;Kang, In-Mo
    • 한국전산유체공학회:학술대회논문집
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    • 2009.11a
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    • pp.3-7
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    • 2009
  • In this study, two and three dimensional low Reynolds number flows are compared. For the two dimensional flow, an airfoil was considered and for the three dimensional low wing and full-body aircraft were considered. Because a flight condition of the aircraft is in a low Reynolds number flow, itl requires reflecting flow transition. In the two dimensional analysis, transition is predicted using en method. In the three dimensional flow, the effect of transition is included using k-w SST turbulence models.

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Performance Comparison Between ER and MR Clutches with Same Gap Size (동일한 간극을 갖고 있는 ER 및 MR 클러치의 성능 비교)

  • Hong, Sung-Ryong;Choi, Seung-Bok
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.23 no.6 s.165
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    • pp.1055-1064
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    • 1999
  • In this wort ER(electro-rheological) clutch and MR(magneto-rheological) clutch are devised and their performance characteristics such as response time and controllability are compared. As a first step, field-dependent yield stresses of ER and MR fluids are distilled in shear mode. For reasonable comparison between two clutches, a nondimensional design model is established by choosing same design parameters of gap size and number. Following the manufacturing of two clutches, field-dependent torque level, response time to step input, mechanical Power generation to electric power consumption are experimentally measured and compared. In addition, in order to investigate torque controllability of the clutches a sliding mode controller is formulated and experimentally realized. Control bandwidths of two clutches are identified and tracking control responses for desired torque trajectories are presented.

Prediction of MCFC Performance Using Three Dimensional Heat and fluid Flow Analysis with Electrochemical Reaction (전기 화학 반응을 포함한 3차원 열유동 해석을 이용한 용융탄산염 연료전지의 성능예측)

  • Cho H. M.;Lee K. W.;Choi D. H.
    • 한국전산유체공학회:학술대회논문집
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    • 2003.08a
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    • pp.219-224
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    • 2003
  • An analysis procedure for the MCFC channel flow has been developed to predict the fuel cell performance. As for the electrochemical reaction, among several chemical reaction models, one that fits the data best is adopted after a comprehensive comparative study. The Wavier-Stokes, energy, and species equations are solved to obtain the velocity, temperature and concentration fields for a specified average current density. The procedure is iterative as the local current density, or the reaction rate, is allowed to vary with the gas composition. A series of calculations are then carried out to examine the effects of gas flow rate, gas composition, gas usage rate, inlet gas temperature, and average current density on the fuel cell performance. The fuel cell characteristics, such as the temperature, current density distributions, and the concentration fields, for various operating conditions are presented and discussed.

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The Flow Visualization of ER Fluid Between Two Parallel-Plate Electrodes Separated by Small Distance (좁은 평행평판전극 사이의 ER유체 유동의 가시화)

  • Park, Myeong-Kwan;Rhee, Eun-Jun;Oshima, Shuzo;Yamane, Ryuichiro
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.23 no.7
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    • pp.801-810
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    • 1999
  • The purpose of present research was to get characteristics and basic knowledges of electrorheological(ER) suspension. To observe behaviors of the ER suspensions. transparent conductive plates were used to visualize the flow of ER suspensions between two parallel plate electrodes. The influence of flowing speed and intensity of electric field on the ER fluid were examined in circle-shaped electric field, and it takes several hundred milliseconds that suspensions in flow cluster. The present study also conducts a numerical analysis adopting the Bingham model. It is found that simple Bingham model can not property describe the flow behavior in the parallel plates.

Numerical modeling of ICP-nitriding system using CFD-ACE+ (CFD-ACE+를 이용한 ICP-nitriding system의 수치 모델링)

  • Ju, Jeong-Hun
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2009.05a
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    • pp.268-268
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    • 2009
  • 고밀도 유도 결합 플라즈마를 이용한 연료 전기 분리판용 질화 장치를 플라즈마를 모사할 수 있는 3차원 전산 유체 역학 프로그램인 CFD-ACE+를 이용하여 해석하였따. 내장형 안테나 타입의 유도 결합 플라즈마의 전자 온도, 밀도 균일성, 가스 유동, 얇은 기판이 촘촘히 적재 되었을 경우의 플라즈마 특성을 모사하였다.

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Three Dimensional Electro-Fluid-Structural Interaction Simulation for Pumping Performance Evaluation of a Valveless Micropump (무밸브 마이크로 펌프의 성능평가를 위한 3차원 전기-유체-구조 상호작용 해석)

  • Pham, My;Phan, Van Phuoc;Han, Cheol-Heui;Goo, Nam-Seo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.37 no.8
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    • pp.744-750
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    • 2009
  • In this study, the pumping performance of a piezoelectric valveless micropump is simulated. The micropump, which was developed in the previous work, is composed of a four-layer lightweight piezocomposite actuator, a polydimethylsiloxane (PDMS) pump chamber, and two diffusers. The piezoelectric domain, the fluid domain and the structural domain are coupled in the three-dimensional simulation. We used ANSYS for the piezoelectric and structural domains and ANSYS CFX for the fluid domain. The effects of driven frequency on the flow rate have been investigated by simulating the flow characteristics for 10 Hz and 40 Hz driven frequencies. The flow rates with respect to driven frequencies up to 300 Hz have been calculated.

Flow Rate-Pressure Drop Characteristics of Dispersive ER Fluid According to Change of Electric Field Strength in Clearance between Parallel Plates (평행평판 간극에서 전기장의 강도변화에 따른 분산계 ER유체의 유량-압력강하 특성)

  • 장성철;염만오;김도태
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.12 no.1
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    • pp.78-83
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    • 2003
  • Electro-rheological(ER) fluids are suspensions in which rheological properties show an abrupt change with variation of electric fields. We modeled the parallel-plates relating to ER-Valve system and yielded shear stress according to the strength of electric field. The purpose of the present study is to examine the flow characteristics of ER fluids according to the strength of electric field between parallel-plates. Then the steady relationship between pressure drop and flow rate of the ER fluids between parallel-plates under application of an electric fields was measured. The pressure drop and flow rates of ER fluids under the application of electric fields for steady flow were measured. For the experiment, we used the ER fluids, 35w% zeolite having hydrous particles and differential pressure gauge. This test reviewed experiment for the special changes of ER fluids in the steady flow condition.

Electrohydrodynamic Flow around a Circular-Cylindrical Rod Submerged in a Dielectric Liquid (비전도성 액체에서의 실린더 막대 주변에 생기는 전기동역학적 유체흐름)

  • Park, Hyun-Jin;Ryu, Jae-Chun;Kang, Kwan-Hyoung
    • 한국가시화정보학회:학술대회논문집
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    • 2007.11a
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    • pp.51-54
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    • 2007
  • The induced-charge electroosmosis (ICEO) is a kind of electroosmotic flow which is generated by the electrical charge induced by an externally-applied electric field. That kind of electrokinetic phenomenon provides a nonmechanical technique to handle microscale flows and particles. In this work, we report that the ICEO-like flow is observed around two kinds of circular-cylindrical rod submerged in a dielectric liquid. The conductivity of the solution is varied by adding a surfactant. The flow field is visualized by the PIV method, and average flow speed shows a remarkable dependence on electrical input frequency. Interestingly, the characteristics of the flow are quite different from the conventional ICEO with respect to the flow direction and the locations of center of vortices.

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