• 제목/요약/키워드: 반응유체

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Gas and Temperature Distribution during MCFC Stack Operation (용융탄산염 연료전지 스택내에서의 온도/농도 분포 및 운전 특성)

  • 고준호;안교상;강병삼;김동형;임희천
    • Proceedings of the Korea Society for Energy Engineering kosee Conference
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    • 1998.05a
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    • pp.253-258
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    • 1998
  • 연료 전지 시스템에서의 스택은 화학 공장의 반응기에 해당한다. 화학 공장에서 반응 생성물의 생산성을 최적화하기 위해 반응기 해석이 매우 중요한 것과 마찬가지로, 연료 전지 스택의 특성을 해석하고 최적 조건으로 설계 및 운전하는 것은 필수적이다. 스택에서 전기를 생산하는 과정에서 중요한 두 가지 운전 변수는 기체의 조성과 온도이며, 이론적인 해석을 위해서는 유체의 이동시에 열전달 및 각 성분별 물질 수지식과 전기 화학 반응식이 사용될 수 있다.(중략)

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Preparation of Thin TiO$_2$ Photocatalytic Filter for Waste Gas Treatment (폐가스 처리를 위한 박막형 TiO$_2$ 광촉매 필터 제조)

  • 조영민;윤정호
    • Proceedings of the Korea Air Pollution Research Association Conference
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    • 2002.04a
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    • pp.311-312
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    • 2002
  • 환경분야에서 광촉매는 주로 오염물질의 광분해처리에 이용되고 있는데, 기존에 사용되고 있는 광분해 방법은 광촉매 미립자를 수용액에 슬러리 형태로 분산시키거나 fixed bed, fluidized bed에 부착시킨 형태의 반응기들이다. 실험적 수준의 연구로부터 얻어진 여러 연구 결과에 의하면 슬러리 형태의 반응기가 고정화 촉매 반응기보다 효율이 더 높은 것으로 보고되고 있다. 그러나 엔지니어링 관점에서 슬러리형 반응기는 촉매의 재활용과 정화 처리 후 촉매입자를 유체로부터 분리해야하는 결점이 있다. (중략)

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Practical Packaging Technology for Microfluidic Systems (미소유체시스템을 위한 실용적인 패키징 기술)

  • Lee, Hwan-Yong;Han, Song-I;Han, Ki-Ho
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.34 no.3
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    • pp.251-258
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    • 2010
  • This paper presents the technology for the design, fabrication, and characterization of a microfluidic system interface (MSI); the purpose of this technology is to enable the integration of complex microfluidic systems. The MSI technology can be applied in a simple manner for realizing complex arrangements of microfluidic interconnects, integrated microvalves for fluid control, and optical windows for on-chip optical processes. A microfluidic system for the preparation of genetic samples was used as the test vehicle to prove the effectiveness of the MSI technology for packaging complex microfluidic systems with multiple functionalities. The miniaturized genetic sample preparation system comprised several functional compartments, including compartments for cell purification, cell separation, cell lysis, solid-phase DNA extraction, polymerase chain reaction, and capillary electrophoresis. Additionally, the functional operation of the solid-phase extraction and PCR thermocycling compartments was demonstrated by using the MSI.

CaCO3 Biomineralization in Microfluidic Crystallizer (미세유체 결정화기를 이용한 탄산칼슘 Biomineralization)

  • Seo, Seung Woo;Ko, Kwan Young;Lee, Chang Soo;Kim, In Ho
    • Korean Chemical Engineering Research
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    • v.51 no.1
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    • pp.151-156
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    • 2013
  • Crystallization of $CaCO_3$ is practiced on a polymethylsiloxane (PDMS) - based microfluidic system. Liquid- liquid reaction was investigated by mixing calcium chloride ($CaCl_2$) and sodium carbonate ($Na_2CO_3$) solution to crystallize $CaCO_3$. Aspartic acid (Asp) was added to investigate the morphology change such as vaterite and calcite. Suitable ratio of $Na_2CO_3$ and $CaCl_2$ was searched for initial seed formation. Christmas tree model was used as microfluidic device to form concentration gradient of $Na_2CO_3$ and $CaCl_2$. After observing microfluidic channel by using optical microscope, we found that seeds of $CaCO_3$ were formed under the condition that the ratio of $Na_2CO_3$ and $CaCl_2$ was 2:1. Morphology of crystals were also observed as $CaCO_3$ crystals grow. When Asp was added, vaterite crystal was more frequently found in two morphologies (vaterite and calcite) and seed formation and crystal growth were inhibited.

A Review on nuclear magnetic resonance logging: fundamental theory and measurements (자기공명검층: 기본 이론 및 자료 측정)

  • Jang, Jae Hwa;Nam, Myung Jin
    • Geophysics and Geophysical Exploration
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    • v.15 no.4
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    • pp.235-244
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    • 2012
  • Nuclear magnetic resonance (NMR) logging has been considered one of the most complicated nevertheless, one of the most powerful logging methods for the characterization on of both rocks and natural fluids in formation. NMR measures magnetized signals (polarization and relaxation) between the properties of hydrogen nucleus called magnetic moment and applied magnetic fields. The measured data set contains two important petrophysical properties such as density of hydrogen in the fluids inside the pore space and the distinct decay rate for fluid type. Therefore, after the proper data processing, key petrophysical information, not only the quantities and properties of fluids but also supplies of rock characterization in a porous medium, could be archived. Thus, based on this information, several ongoing researches are being developed in estimating aspects of reservoir productivity information, permeability and wettability since it is the key to having correct interpretation. This study goes through the basic theory of NMR at first, and then reviews NMR logging tools as well as their technical characteristics. This paper also briefly discusses the basic knowledge of NMR simulation algorithm by using Random walk.

Droplet Based Microfluidic System (액적 기반의 미세유체 시스템의 현황)

  • Jung, Jae-Hoon;Lee, Chang-Soo
    • Korean Chemical Engineering Research
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    • v.48 no.5
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    • pp.545-555
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    • 2010
  • Recently, droplet-based microfluidic systems are widely used in various areas ranging from fundamental science including chemistry, biology, and physics to material science and engineering. This article reviews recent development in the droplet based microfluidic system from basic fabrication of tiny device, principle of droplet formation, merging, mixing, control of droplets, and application for the synthesis of novel functional materials. We discuss strong advantages of the droplet based microfluidics in point of control of particle size, morphologies, shapes, and structures.

Numerical Analysis of Two-Phase Aluminum Dust Combustion according to Single Aluminum Particle Combustion Model (단일 알루미늄 입자 연소 모델에 따른 2상 알루미늄 분말 연소장 시뮬레이션)

  • Kim, Sang-Min;Yang, Hee-Sung;Yoon, Woong-Sup
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2010.05a
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    • pp.460-466
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    • 2010
  • 단일 알루미늄의 연소 모델을 사용하여 알루미늄 분말의 점화 과정에 대한 전산유체 해석 기법을 개발하였다. 유동의 계산은 Reynolds averaged Navier-Stokes식을 사용하였으며, $k-{\epsilon}$ 난류모델을 적용하였다. 입자는 Eulerian-Lagrangian 방법을 사용하여 유동과 독립적으로 계산을 수행하였으며 상용 전산유체해석 프로그램인 Fluent 6.3을 사용하여 해석을 수행하였다. 단일 모델에서 사용한 대류 및 복사 열전달, 표면이상반응, 알루미늄의 용융열을 입자 가열원으로 고려하였다. 같은 조건을 사용하여 단일 입자 모델 계산과 전산유체해석을 수행하였으며, 두 결과는 5% 이내로 잘 일치 하였다. 이를 통해 전산유체해석에서 알루미늄의 점화를 모사할 수 있음을 확인하였다.

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Laboratory Experiment of Two-layered fluid in a Rotating Cylindrical container (원통형 이층유체의 회전반 실험)

  • 나정열;최진영
    • 한국해양학회지
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    • v.28 no.1
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    • pp.17-23
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    • 1993
  • A right cylindrical tank with sloping bottom and top (${\beta}-effect$) is filled with two-layered fluid and is put on the rotating table. External fluid of same density as the lower-layer fluid is continuously injected to drive the lower-layer current. By minimizing the interfacial stress between two layers the motion in the lower-layer deformed the shape of interface such that the upper-layer adjust itself to the variations of the interface in terms of its direction of flow patterns .The most significant parameter is the internal Froude Number($F_1$) and when $F_1$ is greater than 6 two-cellular circulation of the upper-layer changes its direction, there by creates a separation of Western boundary current. The separation position moves to the most northward when $F_1$ equals to 6.

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THE CHARACTERISTICS OF HEAT TRANSFER AND CHEMICAL REACTION FOR THERMAL CRACKING OF ETHANE IN TUBULAR REACTOR (에탄 열분해 반응이 동반된 관형 반응기에서의 열전달 및 화학반응 특성 연구)

  • Shin, C.Y.;Ahn, J.
    • Journal of computational fluids engineering
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    • v.21 no.1
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    • pp.43-49
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    • 2016
  • Thermal cracking is commonly modeled as plug flow reaction, neglecting the lateral gradients present. In this paper, 2-dimensional computational fluid dynamics including turbulence model and molecular reaction scheme are carried out. This simulation is solved by means of coupled implicit scheme for stable convergence of solution. The reactor is modeled as an isothermal tube, whose length is 1.2 m and radius is 0.01 m, respectively. At first, The radial profile of velocity and temperature at each point are predicted in its condition. Then the bulk temperature and conversion curve along the axial direction are compared with other published data to identify the reason why discussed variations of properties are important to product yield. Finally, defining a new non-dimensional number, Effect of interaction with turbulence, heat transfer and chemical reaction are discussed for design of thermal cracking furnace.

Numerical Study of Aggregation and Breakage of Particles in Taylor Reactor (테일러 반응기 내의 입자응집과 분해에 관한 수치 연구)

  • Lee, Seung Hun;Jeon, Dong Hyup
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.40 no.6
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    • pp.365-372
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    • 2016
  • Using the computational fluid dynamics (CFD) technique, we simulated the fluid flow in a Taylor reactor considering the aggregation and breakage of particles. We calculated the population balance equation (PBE) to determine the particle-size distribution by implementing the quadrature method-of-moment (QMOM). It was used that six moments for an initial moments, the sum of Brownian kernel and turbulent kernel for aggregation kernel, and power-law kernel for breakage kernel. We predicted the final mean particle size when the particle had various initial volume fraction values. The result showed that the mean particle size and initial growth rate increased as the initial volume fraction of the particle increased.