• 제목/요약/키워드: Micro-mixing

검색결과 259건 처리시간 0.034초

상하좌우 복합유동 유도를 통한 고효율 HVM 마이크로 믹서 설계에 관한 연구 (A Study on Design of an Effective Micromixer using Horizontal and Vertical Multi-mixing (HVM) Flow Motion)

  • 유원설;김성진;강석훈;김판근;박상후
    • 한국정밀공학회지
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    • 제28권6호
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    • pp.751-757
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    • 2011
  • Subminiature devices such as Lab-on-a-chip and p-TAS(Micro Total Analysis System) have been intensively studied in biotechnology and chemistry, In many cases, a micromixer was widely used to mix different solutions for synthesizing novel materials. However, in microfluidic system, there is generally a laminar flow under very small Reynolds number so it is difficult to mix each solution perfectly. To settle this problem, we propose a new mixing mechanism which generates a horizontal and vertical multi-mixing (HVM) flow for effective mixing within a short mixing section. We evaluated the proposed mechanism using CFD analysis, and the results showed that the HVM mechanism had a relative high-effectiveness comparing to the existing methods.

마이크로 가스터빈을 위한 하이브리드/이중 선회제트 연소기의 개발 (Part II: 비반응 유동구조에 관한 수치해석) (Development of a Hybrid/Dual Swirl Jet Combustor for a Micro-Gas Turbine (Part II: Numerical Analysis on Isothermal Flow Structure))

  • 문선여;황해주;황철홍;이기만
    • 한국연소학회:학술대회논문집
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    • 한국연소학회 2012년도 제44회 KOSCO SYMPOSIUM 초록집
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    • pp.201-202
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    • 2012
  • The isothermal flow structure and mixing characteristics of a hybrid/dual swirl jet combustor for micro-gas turbine were numerically investigated. Location of pilot nozzle, angle and direction of swirl vane were varied as main parameters with constant fuel flow rates for each nozzle. As a result, the variation in location of pilot nozzle resulted in significant change in turbulent flow field near burner exit, in particular, center toroidal recirculation zone (CTRZ) as well as turbulent intensity, and thus flame stability and emission characteristics might be significantly changed. The swirl angle of $45^{\circ}$ provided similar recirculating flow patterns in a wide range of equivalence ratio (0.5~1.0). Compared to the co-swirl flow, the counter-swirl flow leaded to the reduction in CTRZ and fuel-air mixing near the burner exit and a weak interaction between the pilot partially premixed flame and the lean premixed flame. With the comparison of experimental results, it was confirmed that the case of co-swirl flow and swirl $angle=45^{\circ}$ would provided an optimized combustor performance in terms of flame stability and pollutant emissions.

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Defocusing 기법을 이용한 마이크로 믹서내의 3 차원 유동장 측정연구 (The study of three dimentional flow field using defocusing method in micromixer)

  • 김수헌;윤상열;김경천
    • 한국가시화정보학회:학술대회논문집
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    • 한국가시화정보학회 2005년도 추계학술대회 논문집
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    • pp.99-102
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    • 2005
  • This study was conducted for obtaining the optimized data to build the mixer or micro fluid device as measuring the three dimensions flow field in micro mixer. To acquire the rapid diffusion on the region of low Reynolds (Re < 100), the staggered herringbone mixer using chaotic advection was selected in this case. At first, by conducting the numerical analytical virtual experiment using CFD-ACE+, three dimensions flow field in the micro mixer was estimated As this flow field was proven using defocusing particle tracing method, the behavior of micro flow with three dimensional aspects could be analyzed. Numerical analysis and flow pattern in the micro mixer by experimental verification made to be able to analyze the chaotic advection. These can be important sources for building more optimized form. Verifying the information of three dimensional flow structure, these information can be used as the data for developing and improving the $\mu$ -TAS.

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Micro-PIV measurement of internal flow in a micro droplet

  • KINOSHITA Haruyuki;KOBAYASHI Toshio;OSHIMA Marie
    • 한국가시화정보학회:학술대회논문집
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    • 한국가시화정보학회 2004년도 Proceedings of 2004 Korea-Japan Joint Seminar on Particle Image Velocimetry
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    • pp.141-145
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    • 2004
  • Visualization and PIV measurements of the symmetrical recirculation flow in a nanoliter-sized droplet have been performed using the micro PIV system. The airflow sweeps over the nanoliter-sized liquid droplet fixed in a microchannel and the frictional force drags the liquid on the round interface, which causes the symmetrical recirculation flow in the droplet. The internal recirculation flow in the droplet has been visualized and measured successfully. The results of micro PIV measurement show the maximum speed of the recirculation flow is up to 10 mm/s. The high-speed recirculation can enhance a stirring effect and generate strong shear in the droplet, resulting in acceleration of mixing.

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상수원수의 혼화 및 응집 조건에 따른 DAF pump 장치의 부상분리효율 (Flotation Efficiency of the DAF Pump System for Mixing and Coagulation Conditions in Raw Drinking Water)

  • 안갑환;이창한
    • 한국환경과학회지
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    • 제20권5호
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    • pp.639-645
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    • 2011
  • This study found that flotation efficiencies for removing algae and micro particles in raw water were optimized on mixing intensity and time of the mixing and flocculation conditions with a continuous DAF system. It is more efficient for mixing intensity at 23.1 $s^{-1}$ and time at 660 s(Gt value : 15246) to float flocculated floc with the raw water in M water treatment plant. Flotation efficiency was more than about 0.9 when operated pressure and A/S ratio were sustained at 5 $kg_f{\cdot}cm^{-2}$ and up to 0.056 $mL{\cdot}mg^{-1}$. The continuous DAF system made by the study could be continuously operated for 20 days and sustained not exceeding 4 NTU with raw water with low turbidity(13.4~9.8 NTU).

마이크로 채널 내 국소적 전위 인가에 따른 전기삼투 유동 및 혼합 특성에 대한 수치해석적 연구 (A Numerical Study on Electro-osmotic Flow and Stirring Characteristics in a Microchannel with Local Adjustment of Electric Potential)

  • 서용권;허형석
    • 한국가시화정보학회지
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    • 제4권1호
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    • pp.31-40
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    • 2006
  • In this study a newly designed electro-osmotic micro-mixer is proposed. This study is composed of a channel and metal electrodes attached locally on the side wall surface ultimately to control the mixing effect. To obtain the flow patterns, numerical computation was performed by using a commercial code, CFD-ACE. The fluid-flow solutions are the cast into studying the characteristics of stirring in terms of the mixing index. It was shown that the local control of the electric potential can indeed contribute to the enhancement of mixing effect.

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엇갈림 배플 구조의 마이크로 채널 내 유동 및 혼합 특성에 관한 수치해석적 연구 (A NUMERICAL STUDY ON FLOW AND STIRRING CHARACTERISTICS IN A MICROCHANNEL WITH PERIODIC ARRAY OF CROSS BAFFLES)

  • 허성규;허영근;허형석;서용권
    • 한국전산유체공학회:학술대회논문집
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    • 한국전산유체공학회 2006년도 추계 학술대회논문집
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    • pp.159-162
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    • 2006
  • In the microfluidics devices the most important thing is mixing efficiency of various fluids. In this study a newly designed mixer is proposed to enhance the mixing effect with the purpose to apply it to microchannel mixing in a short future. This design is composed of a channel with cross baffles periodically arranged on the both bottom and top surfaces of the channel. To obtain the flow patterns, the numerical computation was performed by using a commercial code, ANSYS CFX 10.0. To evaluate the mixing performance, we computed Lyapunov exponent and obtained Poincare sections.

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Micro EDM을 이용한 Lab-on-a-chip금형의 미세 패턴 제작에 관한 연구 (A Study on the Micro Pattern Fabrication of Lab-on-a-chip Mold Master using Micro EDM)

  • 신봉철;김규복;조명우;김보현;정우철;허영무
    • 소성∙가공
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    • 제20권1호
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    • pp.17-22
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    • 2011
  • Recently, analyzing system is studying for applying to biomedical engineering field, actively. Micro fluidics control system has been manufactured using LIGA (Lithographie Galvanoformung und Abformung), Etching, Lithography and Laser etc. However, it is difficult that above-mentioned methods are applied to fabrication of precision mold master efficiently because of long processing time and rising cost of equipments. Therefore, in this study, micro EDM and micro WEDG system were developed to analyze machining characteristics with tool wear, surface roughness and process time. Then, optimal machining conditions could be obtained from the results of analysis. As the results, mold master of staggered herringbone mixer which has a high mixing efficiency, one of passive mixer of Lab-on-a-chip, could be fabricated from micro pattern(< 50um) using micro EDM successfully.

화상분석기와 CLSM을 이용한 침.활엽수 섬유의 배합비에 따른 인쇄화상 분석 (Analysis of Printed Image Depending on Mixing Ratios of Softwood and Hardwood fibers Using Image Analyzer and CLSM)

  • 이장호;박종문
    • 펄프종이기술
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    • 제34권3호
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    • pp.25-31
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    • 2002
  • The purpose of this study was to analyze how the fiber properties and mixing ratio of softwood and hardwood pulp affect on roundness of printed image. Softwood pulp and hardwood pulp were refined to 400 and 600ml CSF by Valley beater and handsheets of 70 g/$m^2$ basis weight were made at different mixing ratios of hardwood and softwood pulp. The roundness, dot area, and shape of the printed dot were measured by Image Analyzer. The depths and shapes of the acridine orange penetration into paper were measured by CLSM. With higher mixing ratio of hardwood pulp, the paper showed higher air-permeability and better formation, especially at lower freeness. The roundness of the printed image became better and the dot size became smaller when the amount of hardwood pulp increased. Penetration depth of acridine orange by CLSM became greater and roundness increased to real circle when the amount of hardwood pulp increased. It was thought that higher mixing ratio of hardwood fibers resulted in efficient penetration by better formation with uniform micro-pore distribution and it increased roundness. It was thought that fiber properties and mixing ratio affected the structure of paper and the shape of the printed dot. This study showed that the measurement of depth of the liquid penetration into paper without destruction and contact was feasible. Moreover, this method showed that the shape of the liquid penetration was measurable.

DAF 공정에서 부상속도 향상을 위한 플럭형성 조건 평가 (Evaluation of Floc Formation Conditions for Increasing Flotation Velocity in DAF Process)

  • 권순범;민진희;박노석;안효원
    • 상하수도학회지
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    • 제20권2호
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    • pp.245-255
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    • 2006
  • Dissolved air flotation is a solid-liquid separation system that uses fine bubbles rising from bottom to remove particles in water. In order to enhance the flotation velocity and removal efficiency of flocs in the flotation process, we tried to obtain pretreatment conditions for the optimum DAF process operation by comparing and evaluating features of actual floc formation and flotation velocity etc, according to coagulant types and conditions for flocculation mixing intensity by using PIA, PDA, and FSA. Accordingly, generating big flocs that have low density at low flocculation mixing intensity may reduce treatment efficiency. In addition, generating small flocs at high flocculation mixing intensity makes floc-bubbles smaller, which reduces flotation velocity, In this study, it was found that high flocculation mixing intensity could not remove the remaining micro-particles after flocculation, which had negative effects on treated water quality, Therefore, in order to enhance treatment efficiency in a flotation process, flocculation mixing intensity around $50sec^{-1}$ is effective.