• Title/Summary/Keyword: Micro Lattice

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Numerical Study on The Pressure Drop of Immiscible Two-Phase Flow in The Pressure Driven Micro Channel Using Lattice Boltzmann Method (Lattice Boltzmann 방법을 이용한 압력구동 미세채널 내 비혼합 2상 유체 흐름의 압력강하에 대한 수치적 연구)

  • Jeong, Soo-In;Kim, Kui-Soon;Kang, Beom-Soon
    • 한국전산유체공학회:학술대회논문집
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    • 2008.03b
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    • pp.436-439
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    • 2008
  • Computer simulation of multiphase flows has grown dramatically in the last two decades. In this work, we have studied the flow characteristics of immiscible two fluids in a 2-D micro channel driven by pressure gradient using multi-phase lattice Boltzmann method suggested by Shan and Chen(1993) considering the fluid-surface interaction. we tried to examine the effects of parameters related to the two phase flow characteristics and pressure drop in the micro channel like contact angle and channel configuration by changing their value. The results of current study could show the lattice Boltzmann method can simulate the behaviors of two phase flow in the region of micro fluidics well.

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A Novel Cell Count Method Using Micro Lattice Engraved On A Culture Dish (미세 격자가 형성된 배양 접시를 이용한 새로운 세포 계수 방법)

  • Son, Sang-Uk;Choi, Yo-Han;Lee, Seung-Seob
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.8 s.227
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    • pp.1183-1189
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    • 2004
  • A novel cell count method, which can improve the count efficiency and reduce contamination problem, was presented using micro lattice engraved on culture dish. The micro lattice has feature of $50{\mu}m{\times}50{\mu}m$ rectangular shape, $2{\mu}m$ line width, and $2{\mu}m$ depth in $3mm{\times}3mm$ area. In this paper, nickel mold was fabricated with thickness of 3mm and diameter of 80 mm, and transcription of the micro lattice on a polystyrene cell culture dish was performed by hot embossing at $200\;^{\circ}C$. The tedious and error-prone harvest/load processes of conventional cell counts with a hemocytometer could be omitted, and these advantages became magnified during periodical counts involving long-term cultures. SupT1 cells and HeLa cells were cultivated with the dish for 7 days in $CO_2$ incubator and counted as $371.84/mm^2$ and $123.36/mm^2$, respectively, during the cultivation without harmful effects on the cells.

Optimization of Passive Mixer for Enhanced Mixing in a Micro-channel by Using Lattice Bloltzmann Method (격자 볼츠만 방법을 이용한 미소 채널에서의 혼합효율 증가를 위한 수동형 믹서의 최적화)

  • Han Gyu suk;Byun Sung Joon;Yoon Joon Yong
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.5 s.236
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    • pp.707-715
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    • 2005
  • In this work, Scalar Passive code in Lattice Boltzmann Method is employed to simulate two-phase flow of low Reynolds number in a micro-channel. The mixing characteristics in a micro-channel is a function of Peclet number. The mixing length increases with the Peclet number. It is found that with the inclusion of static elements at the channel, rapid mixing of two liquids can be achieved, as shown by the results of computer simulations. The enhancement in mixing performance is thought to be caused by the generation of eddies and by lateral velocity component when the mixture flows past static elements. The results indicate that the size of static element has more effect on the mixing than the number of static element.

Numerical simulation and experimental study of quasi-periodic large-scale vortex structures in rod bundle lattices

  • Yi Liao;Songyang Ma;Hongguang Xiao;Wenzhen Chen;Kehan Ouyang;Zehua Guo;Lele Song
    • Nuclear Engineering and Technology
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    • v.56 no.2
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    • pp.410-418
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    • 2024
  • Study of flow behavior within rod bundles has been an active topic. Surface modification technologies are important parts of the design of the fourth generation reactor, which can increase the strength of the secondary flow within the rod bundle lattices. Quasi-periodic large-scale vortex structure (QLVS) is introduced by arranging micro ribs on the surface of rod bundles, which enhanced the scale of the secondary flow between the rod bundle lattices. Using computational fluid dynamics (CFD) and water experiments, the flow field distribution and drag coefficient of the rod-bundle lattices are studied. The secondary flow between the micro-ribbed rod-bundle lattice is significantly enhanced compared to the standard rod-bundle lattice. The numerical simulation results agree well with the experimental results.

Effect of surface roughness on laminar flow in a micro-channel by using lattice Boltzmann method (격자 볼츠만 방법을 이용한 미소채널 내에서의 층류 유동에 대한 표면 거칠기의 영향)

  • Shin, Myung-Seob;Yoon, Joon-Yong;Byun, Sung-Joon;Kim, Kak-Joong
    • 유체기계공업학회:학술대회논문집
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    • 2006.08a
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    • pp.179-183
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    • 2006
  • Surface roughness is present in most of the microfluidic devices due to the microfabrication techniques. This paper presents lattice Boltzmann method (LBM) results for laminar flow in a microchannel with surface roughness. The surface roughness is modeled by an array of rectangular modules placed on top and bottom side of a parallel-plate channel. In this study, LBGK D2Q9 code in lattice Boltzmann Method is used to simulate flow field for low Reynolds number in a micro-channel. The effects of relative surface roughness, roughness distribution, roughness size and the results are presented in the form of the product of friction factor and Reynolds number. Finally, a significant increase in Poiseuille number is detected as the surface roughness is considered, while the effect of roughness on the microflow field depends on the surface roughness.

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Numerical Study on the Droplet Flows in a Cross-Junction Channel Using the Lattice Boltzmann Method (Lattice Boltzmann 법을 이용한 Cross-Junction 채널 내의 droplet 유동에 관한 수치해석적 연구)

  • Park, Jae-Hyoun;Suh, Young-Kweon
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2006.11a
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    • pp.407-410
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    • 2006
  • This study describes a simulation of two-dimensional bubble forming and motion by the Lattice Boltzmann Method with the phase field equation. The free energy model is used to treat the interfacial force and deformation of binary fluids system, drawn into a T-junction the micro channel. A numerical simulation of a binary flow in a cross-junction channel is carried out by using the parallel computation method. The aim in this investigation is to examine the applicability of LBM to numerical analysis of binary fluid separation and motion in the micro channel.

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Numerical Analysis on Heat Transfer Characteristics in Silicon Boated by Picosecond-to-Femtosecond Ultra-Short Pulse Laser (펨토초급 극초단 펄스레이저에 의해 가열된 실리콘 내의 열전달 특성에 관한 수치해석)

  • 이성혁;이준식;박승호;최영기
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.26 no.10
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    • pp.1427-1435
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    • 2002
  • The main aim of the present article is numerically to investigate the micro-scale heat transfer phenomena in a silicon microstructure irradiated by picosecond-to-femtosecond ultra-short laser pulses. Carrier-lattice non-equilibrium phenomena are simulated with a self-consistent numerical model based on Boltzmann transport theory to obtain the spatial and temporal evolutions of the lattice temperature, the carrier number density and its temperature. Especially, an equilibration time, after which carrier and lattice are in equilibrium, is newly introduced to quantify the time duration of non-equilibrium state. Significant increase in carrier temperature is observed for a few picosecond pulse laser, while the lattice temperature rise is relatively small with decreasing laser pulse width. It is also found that the laser fluence significantly affects the N 3 decaying rate of Auger recombination, the carrier temperature exhibits two peaks as a function of time due to Auger heating as well as direct laser heating of the carriers, and finally both laser fluence and pulse width play an important role in controlling the duration time of non-equilibrium between carrier and lattice.

Experimental and Numerical Study on the Binary Fluid Flows in a Micro Channel (마이크로 채널 내의 이상유동에 대한 실험 및 수치해석적 연구)

  • Park, Jae-Hyoun;Heo, Hyeung-Seok;Suh, Young-Kweon
    • 한국가시화정보학회:학술대회논문집
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    • 2006.12a
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    • pp.86-91
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    • 2006
  • In this parer, we present the bubble forming and motion in the micro channel by using the two-dimensional numerical computation and experiment. In the numerical computation, The Lattice Boltzmann method(LBM) and free-energy model is used to treat the interfacial force and deformation of binary fluid system, drawn in to a micro channel and a numerical simulation is carried out by using the parallel computation method. The urn in this investigation is to examine the applicability of LBM to numerical analysis and experimental method of binary fluid separation and motion in the micro channel.

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Numerical Analysis on Mixing Efficiency in a Micro-channel with Varied Geometry (미소 채널의 형상변화에 의한 혼합효율에 관한 수치 해석적 연구)

  • Yoon, Joon-Yong;Han, Gyu-suk;Byun, Sung-Joon
    • Applied Chemistry for Engineering
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    • v.16 no.2
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    • pp.275-281
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    • 2005
  • In this work, Scalar Passive code in Lattice Boltzmann Method was employed to simulate mixing performance of Passive mixer in a micro-channel. It physically analyzed stream line and Pressure drop for passive mixer in a micro-channel. The flow characteristics in a micro-channel was a function of Peclet number. The results indicated that the size of static element was more effect on the mixing than the number of static element and the distance of static elements.

Application of the lattice Boltzmann method to multiphase flow and combustion analysis (다상 유동 및 연소 해석에서 Lattice Boltzmann 방법의 응용 가능성에 대한 고찰)

  • Huh, Kang-Yul
    • 한국연소학회:학술대회논문집
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    • 2001.06a
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    • pp.3-8
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    • 2001
  • LBM은 분자 운동을 직접 모사하지 않고 통계 역학적 원리에 기초하여 주어진 격자 구조 아래서 입자들의 단순 이동, 충돌 과정의 반복에 의해 유동을 모사하는 방법이다. 이미 다양한 열유동 현상들에 대한 응용 결과가 발표되었으며 병렬화, 단순한 프로그래밍 등의 장점으로 인해 앞으로 연소, 다상 유동, micro/nano 스케일 유동 등의 해석에 많은 가능성을 지니고 있다. 아직 국내에서는 이에 대한 소개가 제대로 이루어지지 못해 관련 분야의 연구자들이 충분한 관심을 갖고 있지 않은 것으로 생각되어 본 논문에서 LBM 방법에 대한 개략적인 소개를 시도하였다.

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