• Title/Summary/Keyword: liquid drop size

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Prediction of drop size by analysis of conical liquid sheet breakup (원추형 액막분열 해석에 의한 액적 크기 예측)

  • Yoon, S.J.;Cho, D.J.
    • Journal of ILASS-Korea
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    • v.2 no.1
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    • pp.8-17
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    • 1997
  • A study has been carried out on the instability of a conical liquid sheet by using the linear instability theory. Various analytical methods using the Kelvin-Helmholtz instability theory were tried to examine the wave growth on cylindrical liquid sheets. Cylinderical liquid sheets were extended to the case with the conical sheets. Perturbations due to tangential motion as well as longitudinal one were taken into account. And it was assumed the the breakup occurs when amplitude ratio exceeds exp(12), drop sizes were predicted only by theoretical approach. The predicted drop size agreed well with the measured Sauter mean diameter, $D_{32}$.

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A Study on the Prediction of the Drop Size Distribution of Pressure-Swirl Atomizer (압력식 스월 노즐의 액적 크기분포 예측에 관한 연구)

  • Cho, D.J.;Yoon, S.J.;Kim, D.W.
    • Journal of ILASS-Korea
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    • v.1 no.1
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    • pp.44-54
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    • 1996
  • A theoretical and experimental study was carried out on the prediction of drop size distribution of the pressure swirl atomizer. Drop size distribution was obtained by using maximum entropy formal ism. Several constraints in the form of the definition of mean diameter were used in this formulation in order to avoid the difficulties of the estimating source terms. In this study $D_{10}$ was only introduced into the formulation as a constraint. A drop size obtained by using linear Kelvin-Helmholtz instability theory was considered as an unknown characteristic length scale. As a result, the calculated drop size was agreed well with measured mean diameter, particularly with $D_{32}$. The predicted drop size distribution was agreed welt with experimental data measured wi th Malvern 2600.

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Spray Characteristics on Shape of Twin Fluid atomizer by Internal Mixing Chamber Type (내부혼합형 2유체 분사노즐의 형상에 따른 분무특성)

  • 윤수환;정대인;하종률
    • Journal of Advanced Marine Engineering and Technology
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    • v.18 no.4
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    • pp.43-52
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    • 1994
  • I investigated experomentally the spray characteristics to the operating conditions and the shapes of internal mixing twin fluid atomizer. The wide variations of air per liquid ratio are conducted to predit the influences of the Sauter mean diameter(SMD), spray angle, distribution of drop size, the flowing condition of gas and length, flowing, area of gas and liquid, and diameter, number and place of the orifice. In this experiment, air per liquid raio, mixing chamber length per diameter, orifice diameter, and the flowing area ratio of gas and fluid influences greatly on SMD, spray angle, distribution of drop size and intermittent fluctuation region.

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An Experimental Study on the Behavior of Twin-Spray with Flow Interaction in a Condensable Environment (주위기체내에서의 두 액체분무간의 유동간섭현상에 대한 정상적 고찰)

  • 이상룡;정태식;한기수
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.10 no.3
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    • pp.326-334
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    • 1986
  • The effects of flow interaction between adjacent sprays in twin-spray system on the spatial distribution of injected liquid (water) and drop size distribution in condensable (steam) environment were carefully observed through experiments. The spatial distribution of injected liquid in twin-spray system appears to be more uniform than the simple superposition of the spatial distributions of liquid obtained from each individual spray. Drop size distribution was obtained by using the immersion sampling technique. It was found that, in the twin-spray, the larger numbers of small drops are collected throughout the spraying region due to the increase of entrainment velocity of ambient steam compared with the case of simple superposition of each individual spray. Moreover, in the overlapped portion of the twin-spray, the drop size distribution was changed also due to the collision between large drops. As a result, the behavior of twin-spray system (and eventually multiple-spray system) can not be predicted precisely by simple superposition of the behaviors of each constituting spray. Hence, for the design of multiple spray system, the effect of flow interaction between sprays should be taken into account seriously.

Drop Size Measurement using Image Processing Method under High Ambient Pressure Condition (고압환경에서 이미지 프로세싱 기법을 이용한 액적크기 측정)

  • Lim Byoungjik;Khil Taeock;Jung Kihoon;Yoon Youngbin
    • 한국가시화정보학회:학술대회논문집
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    • 2003.11a
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    • pp.111-114
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    • 2003
  • Drop size is one of the most important parameters which are control the performance of the engine using liquid fuel/oxidizer and drop formation is mainly controlled by aerodynamic force caused by ambient gas. Because of this, empirical data and correlation acquired under standard ambient condition are not valid. So experiments under high ambient pressure condition to measure the drop size using image processing method And find the empirical correlation between SMD and chamber pressure(density), injection velocity.

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Raindrop Size Distribution Over Northeastern Coast of Brazil

  • Tenorio Ricardo Sarmento;Kwon Byung-Hyuk;Silva Moraes Marcia Cristina da
    • Journal of information and communication convergence engineering
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    • v.4 no.1
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    • pp.46-52
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    • 2006
  • Precipitation measurement with ground-based radar needs an information of the raindrop size distribution (RSD) characteristics. A 10-month dataset was collected in tropical Atlantic coastal zone of northeastern Brazil where the weather radar was installed. The number of drop was mainly recorded in 300 - 500 drop $mm^{-3}$, of which the maximum was registered around 1.1 mm drop diameter.

Atomization of Shear-Thinning Liquid Slurry Discharging from Fan Spray Nozzles (고형성분이 포함된 전단희석 유체의 선형(扇形) 분무노즐을 통한 미립화)

  • An, S.M.;Ryu, S.U.;Lee, S.Y.
    • Journal of ILASS-Korea
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    • v.13 no.1
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    • pp.42-50
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    • 2008
  • In the present work, atomization characteristics of shear-thinning liquid slurry discharging from fan spray nozzles were studied experimentally for spray painting applications. The effects of solid particle size and concentration on the properties (especially on the viscosity) of suspensions and mean drop size were examined by using model fluids. In the range of low particle concentration (below 3 wt%), the fluid viscosity was primarily determined by the particle size. On the other hand, in the range of high particle concentration (higher than 10 wt%), the agglomeration phenomenon and the oil absorption capability of solid particles played major roles in determining the fluid viscosity. In the high concentration region, which most of the paints belong to, the fluid became more viscous and the shear thinning behavior appeared more prominent as the particle concentration was increased. In this region, mean drop size(SMD) decreased more rapidly with the increase of the injection pressure. Also, SMD became larger with the higher particle concentration and the larger particle size.

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Correlation between size and velocity of drops in a spray from an internal mixing twin-fluid atomizer (내부혼합형 이류체 분사노즐에서 발생한 분무내 액적들의 크기와 속도의 상관관계)

  • Kim, Sang-Jin;Hiroyasu, H.
    • Journal of ILASS-Korea
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    • v.3 no.1
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    • pp.27-33
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    • 1998
  • Correlations of drop size and velocity in a spray from the disintegration of liquid jet and liquid film from an internal mixing twin-fluid atomizer, were determined by phase Doppler method. The distribution pattern of Sauter mean diameter(SMD) in a spray was changed by a behavior of liquid flow. As smaller droplets became faster and slower easily by the surrounding conditions, the correlation between drop size and mean velocity was found to be varied as next 3 steps; firstly smaller droplets have a higher mean velocity at the area near atomizer, droplets have almost the same mean velocity and finally larger droplets have a higher mean velocity at the area far from an atomizer.

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An Experimental Study on the Drop Size of a Twin-Fluid Swirl Jet Nozzle (이유체 선회분사 노즐의 액적크기에 관한 실험적 연구)

  • Oh, J.H.;Kim, W.T.;Kang, S.J.;Rho, B.J.
    • Journal of ILASS-Korea
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    • v.1 no.1
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    • pp.21-27
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    • 1996
  • This experimental study was to investigate spray angles and drop sizes in an external mixed twin-fluid swirl jet nozzle. Twin-fluid swirl jet nozzle with swirlers designed four swirl angles such as $0^{\circ},\;22.5^{\circ},\;45^{\circ},\;64.2^{\circ}$ was employed. A PDA system was utilized for the measurement of drop size and mean velocity. Water and air were used as the working fluids in this experiment. The mass flow rate of water was fixed as 0.03 kg/min, and air flow rates were controlled to have the air/liquid mass ratio from 1.0 to 6.0. As a result, swirl angle controlled to spray angles and drop sizes. It was found that swirl angle was increased with spray angle and with decreased SMD. However, the effect of swirl angle was reduced at large air/liquid mass ratio(Mr=6.0).

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An Experimental Study on Droplet Size Characteristics of Liquid Jets in Subsonic Crossflow (아음속 수직분사제트에서 액적크기 특성에 대한 실험적 연구)

  • Kim, Min-Ki;Song, Jin-Kwan;Kim, Jin-Ki;Hwang, Yong-Seok;Yoon, Young-Bin
    • Journal of ILASS-Korea
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    • v.12 no.2
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    • pp.115-122
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    • 2007
  • The spray characteristics and drop size measurements have been experimentally studied in liquid jets injected into subsonic crossflow. With water as fuel injection velocity, injection angle and atomize. internal flows were varied to provide of jet operation conditions. The injector internal flow was classified as three modes such as a non-cavitation flow, cavitation, and hydraulic flip flows. Pulsed Shadowgraph Photography measurement was used to determine the spatial distribution of the spray droplet diameter in a subsonic crossflow of air. And this study also obtains the SMD (Sauter Mean Diameters) distribution by using Planar Liquid Laser Induced Fluorescence technique. The objectives of this research are get a droplet distributions and drop size measurements of each condition and compare with the other flow effects. As the result, This research has been showned that droplet size were spatially dependent on air-stream velocity, fuel injection velocity, injection angle effects, and normalized distance from the injector exit length(x/d, y/d). There are also different droplet size characteristics between cavitation, hydraulic flip and the non-cavitation flows.

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