• Title/Summary/Keyword: Liquid Droplet Behavior

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An experimental study on the atomizing characteristics of liquid column type coaxial sprays (액주형 동축노즐 분무의 무화특성에 관한 실험적 연구)

  • 노병준;강신재;오제하
    • Journal of the korean Society of Automotive Engineers
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    • v.14 no.5
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    • pp.41-53
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    • 1992
  • The main purpose of this study is to investigate the atomizing characteristics of a two phase spray by using a liquid column type coaxial nozzle. The experiments have been carried out to analyze the atomization behavior, the droplet size distributions, and the statistical properties of droplet size distributions. Immersion sampling method and the image processing technique were adapted for the measurements of particles, and the distributions of the droplet sizes were statistically analyzed. In the experiments, the mass ratio defined as Mr= $M_{\sigma}$/ $M_{1}$ has been changed from 1.0 to 3.4 and the measurements have been performed along the axis of the spray. As a result of this experimental study, the distributions of droplet size were satisfied with the Log-Normal distributions and arithmetic mean diameter and deviation of mass ratio. Droplet volume-surface mean diameter was denoted by a exponential function of mass-ratio and the exponent was denoted by linear relation according to the central axis from the nozzle. Dispersions, skewness factors and flatness factors had comparatively constant values regardless of mass ratio and location.

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DEVELOPMENT OF A NUMERICAL TECHNIQUE FOR CAPILLARY SPREADING OF A DROPLET CONTAINING PARTICLES ON THE SOLID SUBSTRATE (미세입자분산 액적의 고체면에서 모세퍼짐 현상에 관한 직접수치해석 기법개발)

  • Hwang, Wook-Ryol;Jeong, Hyun-Jun;Kim, See-Jo;Kim, Chong-Youp
    • Journal of computational fluids engineering
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    • v.12 no.4
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    • pp.14-19
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    • 2007
  • We present a direct numerical simulation technique and some preliminary results of the capillary spreading of a droplet containing particles on the solid substrate. We used the level-set method with the continuous surface stress for description of droplet spreading with interfacial tension and employed the discontinuous Galerkin method for the stabilization of the interface advection equation. The distributed Lagrangian-multipliers method has been combined for the implicit treatment of rigid particles. We investigated the droplet spreading by the capillary force and discussed effects of the presence of particles on the spreading behavior. It has been observed that a particulate drop spreads less than the pure liquid drop. The amount of spread of a particulate drop has been found smaller than that of the liquid with effectively the same viscosity as the particulate drop.

Experimental investigation of growth and transport behavior of single water droplet in a simplified channel of PEM fuel cell (PEM 연료전지의 단순화된 공기극 채널 내 단일 물방울의 성장 및 이동 특성에 대한 실험적 연구)

  • Kim, Bok-Yung;Kim, Han-Sang;Min, Young-Doug
    • 한국신재생에너지학회:학술대회논문집
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    • 2006.06a
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    • pp.81-84
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    • 2006
  • To investigate the characteristics of water droplet on the gas diffusion layer from both upper-view and side-view of flow channel, a rig test apparatus was designed and fabricated with L-shape acryl plate in a $1mm{\times}1mm$ micro-channel. This experimental device is used to simulate the single droplet growth and its transport process under fuel cell operating condition. As a first step, we investigated the growth and transport of single water droplet with working temperature and air flow velocity. The contact angle and its hysteresis of water droplet at departing moment are measured and analyzed. It is expected that this study can provide the basic understanding of liquid water droplet behavior in gas flow channel and GDL interface during the PEM fuel cell operation.

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Study on the Dissolution Behavior of Liquide $CO_2$ Hydrate Injected at the Intermediate Depth of the Ocean (중층심해에 분사된 액체 이산화탄소 하이드레이트 용해에 대한 연구)

  • Kim, Nam-Jin;Park, Sung-Seek;Seo, Hyan-Min
    • New & Renewable Energy
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    • v.4 no.2
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    • pp.12-20
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    • 2008
  • Calculations for the dissolution behavior of liquid CO2 droplets released in the East Sea and the Clipperton Clarion from a moving ship and a fixed pipeline have been carried out in order to estimate the CO2 dissolution characteristics in the ocean. The results show that the injection of liquid CO2 from a moving ship in a high temperature point is an effective method for dissolution. Also, it is noted that the ultimate plume generated from CO2 bubbles repeatsand shrinking due to the peeling from a fixed pipeline, and the presence of hydrate layer on a liquid CO2 droplet acts as a resistant layer in dissolving liquid CO2.

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Study on the Dissolution Behavior of Liquide $CO_2$ Hydrate Injected at the Intermediate Depth of the Ocean (중층심해에 분사된 액체 이산화탄소 하이드레이트 용해에 대한 연구)

  • Kim, Nam-Jin;Seo, Hyang-Min;Park, Sung-Seek
    • 한국신재생에너지학회:학술대회논문집
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    • 2008.05a
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    • pp.597-601
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    • 2008
  • Calculations for the dissolution behavior of liquid $CO_2$ droplets released in the East Sea and the Clipperton Clarion from a moving ship and a fixed pipeline have been carried out in order to estimate the $CO_2$ dissolution characteristics in the ocean. The results show that the injection of liquid $CO_2$ from a moving ship in a high temperature point is an effective method for dissolution. Also, it is noted that the ultimate plume generated from $CO_2$ bubbles repeatsand shrinking due to the peeling from a fixed pipeline, and the presence of hydrate layer on a liquid $CO_2$ droplet acts as a resistant layer in dissolving liquid $CO_2$.

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A Study on the Behavior of Droplets Colliding with Parallel Wires (평행 와이어와 충돌하는 액적 거동에 관한 연구)

  • Na, J.K.;Noh, D.H.;Jung, Y.J.;Kang, B.S.
    • Journal of ILASS-Korea
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    • v.26 no.3
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    • pp.149-156
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    • 2021
  • In this study, the behavior of the droplet colliding with parallel wires was analyzed by time-delay photography. The impact behavior modes and the critical capture speed were analyzed by changing fluids, the droplet velocity, the wire diameter and the distance between wires. Seven typical modes of impacting droplet on parallel wires were observed. The tendency of mode change was generally similar when the wire diameter was changed, but the increase of the wire diameter caused the increase of the droplet velocity at which the mode changed. The modes at the highest droplet velocity were the splitting mode when the wires were closest, the passing and splitting mode in the middle, and the passing mode when the wires were farthest apart. The critical capture speed increased as the wire diameter increased and the distance between wires decreased. The ethanol droplet showed the lowest critical capture speed.

An Experimental Study on the Dynamic Behavior of Spray Droplets in the Wind Tunnel (관내 분무액적의 유동특성에 관한 실험적 연구)

  • Park, Dae-Sick;Choi, Heok-Jun;Park, Sang-Gyun;Kim, Myoung-Hwan;Oh, Cheol;Yun, Seok-Hun
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • 2002.05a
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    • pp.95-100
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    • 2002
  • This study was experimentally performed to investigate flow characteristics of spray droplets in the wind tunnel. Behavior of the spray droplets in the pipe was observed and the deposition rate of droplets on the surface of pipe as liquid film was measured. The experiments were carried out for a variety of parameter, such as velocity of feed air, spray angle of nozzle, and diameter of droplet. From the visual observation of the spray droplets in the pipe and the measurement of deposition rate on the pipe, the general understanding of droplets behavior for desuperheater was provided.

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Charging of an Ionic Liquid Droplet in a Dielectric Medium (비전도성 매질 내 이온성 액체 액적의 충전 현상)

  • Im, Do Jin
    • Clean Technology
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    • v.20 no.4
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    • pp.354-358
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    • 2014
  • Ionic liquid (IL) is a salt presents in a liquid form at room temperature. Recently, it attracts huge attention due to its possibilities as a clean solvent, electrolyte, and catalyst. In the present work, the charging behavior of six different ILs were investigated using droplet contact charging phenomenon in a dielectric medium. Basically, the charging of an IL droplet can be explained by a perfect conductor theory. However, there were several different features depending on the species of ions of ILs, which requires rigorous molecular level modeling of charge transport through electrochemical reaction of IL. We hope the present results contribute to build up fundamental understanding of electrochemical charge transport of IL.

Analysis of Unstable Droplet Behavior of Liquid Rocket Engine (액체로켓엔진의 불안정 액적 거동의 해석)

  • 이윤용;노태성
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2003.05a
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    • pp.141-144
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    • 2003
  • For the analysis of combustion instabilities of a liquid locket engine, a simple spray combustion model has been analyzed by the Euler-Lagrange method. Gas temperature, droplet trajectory, and droplet radius have been evaluated on 2-D axisymmetric coordinates. The Euler-Lagrange method has been shown to have a good tendency of gas temperature distribution as well as droplet trajectory and radius change.

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An Experimental Study of Breakup of Impinging Droplets on a Hot Surface (표면 충돌 액적의 분열에 관한 실험적 연구)

  • Ko, Y.S.;Chung, S.H.
    • Transactions of the Korean Society of Automotive Engineers
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    • v.2 no.5
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    • pp.85-92
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    • 1994
  • Characteristics of breakup of a liquid droplet impinging on a hot surface has been investigated experimentally by using decane fuel. Factors influencing droplet breakup are surface temperature, impinging velocity, droplet diameter and incident angle. Droplets impinging on a hot surface begins to breakup at $220{\sim}235^{\circ}C$. This temperature varies with impinging Velocity, droplet diameter and incident angle. For wall temperature of $220{\sim}245^{\circ}C$ and above $270^{\circ}C$, breakup probability increases as impinging velocity increases showing S shape curve. For $245{\sim}265^{\circ}C$, a local minimum heat transfer rate occurs. In this temperature range, breakup probability shows nonmonotonous behavior as functions of impinging velocity. As droplet diameter decreases, impinging velocity required for droplet breakup increases. An optimum impinging angle for droplet breakup exists which are found to be about $75^{\circ}$.

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