• Title/Summary/Keyword: Mean drop size

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

  • 조대진;윤석주;김동우
    • 한국분무공학회지
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    • 제1권1호
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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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액주형 이류체노즐의 반경반향 분무특성에 관한 연구 (A Study on the Radial Spray Performance of a Plaint-Jet Twin-Fluid Nozzle)

  • 최진철;노병준;강신재
    • 대한기계학회논문집
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    • 제18권3호
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    • pp.662-669
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    • 1994
  • In the combustion system, the optimum spray conditions reduce the pollutant emission of exhaust gas and enhance the fuel efficiency. The spray characteristics-the drop size, the drop velocity, the number density and the mass flux, become increasingly important in the design of combustor and in testifying numerical simulation of spray flow in the combustor. The purposes of this study are to clarify the spray characteristics of twin-fluid nozzle and to offer the data for combustor design and the numerical simulation of a spray flow. Spatial drop diameter was measured by immersion sampling method. The mean diameter, size distribution and uniformity of drop were analyzed with variations of air/liquid mass flow ratio. The results show that the SMD increases with the liquid supply flow rate and decreases with the air supply velocity. The radial distribution of SMD shows the larger drops can diffuse farther to the boundary of spray. And the drop size range is found to be wider close to the spray boundary where the maximum SMD locates.

와류 분무 노즐에 의해 형성되는 액적들의 균일도에 액체의 점도가 미치는 영향 (Effect of liquid viscosity on the degree of uniformity of drops from swirl spray nozzles)

  • 이상용;김인구;조한권
    • 대한기계학회논문집
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    • 제13권3호
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    • pp.538-546
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    • 1989
  • 본 연구에서는 분사액체의 점도가 분무액적의 평균크기뿐만 아니라 표준편차 의 역수적 개념을 가지는 균일도에 주는 영향을 실험을 통하여 살펴보았다.

분무특성 예측을 위한 이론적 접근과 실험적 연구 (A numerical analysis and experimental study on the prediction of spray characteristics)

  • 윤석주;조대진
    • 한국분무공학회지
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    • 제3권2호
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    • pp.1-13
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    • 1998
  • A theoretical and experimental study was carried out to predict the drop size distribution of the pressure swirl atomizer. 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 that the breakup occurs when amplitude ratio exceeds exp(12), drop sizes were predicted only by theoretical approach. Drop size distribution was obtained by using maximum entropy formalism. Seven constraints in the form of the definition of mean diameter were used in this formulation in order to avoid the difficulties of estimating source terms. In this study $D_{10}$ only was introduced into the formulation as a constraint. The predicted drop size and drop size distribution agreed well with the measured data.

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현탁중합의 계면안정에 따른 폴리스티렌 입자 제조 (Preparation of Polystyrene particles based on interfacial stability of suspension polymerization)

  • 이진호;이상남;박문수;김은경;문명준
    • 한국인쇄학회지
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    • 제20권1호
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    • pp.65-78
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    • 2002
  • The suspension polymerization of styrene was carried out to obtain the narrow-size distribution of particle by using poly(vinyl alcohol) (PVA) as suspension stabilizer according to the degree of hydrolysis and the molecular weight. The stabilizing properties of suspension are also dependent on the interfacial tension of aqueous solution when PVA is added. When the polymerization process was carried out with low hydrolyzed PVA, it gave single, well-defined particles, while high hydrolyzed PVA gave clusters. The size of particle produced in this study ranged between 5${\mu}{\textrm}{m}$ and 10${\mu}{\textrm}{m}$. The suspending agent, PVA, influences on the drop size and drop stability, When the molecular weight of PVA is increased, the drop size decreases and the drops become more stable toward coalescence. An increase in the PVA concentration decreases the mean drop size and narrows the drop size distribution.

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

  • 김상진;히로야스 히로유키
    • 한국분무공학회지
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    • 제3권1호
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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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고형성분이 포함된 전단희석 유체의 선형(扇形) 분무노즐을 통한 미립화 (Atomization of Shear-Thinning Liquid Slurry Discharging from Fan Spray Nozzles)

  • 안상모;류성욱;이상용
    • 한국분무공학회지
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    • 제13권1호
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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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내부혼합형 2유체 분사노즐의 형상에 따른 분무특성 (Spray Characteristics on Shape of Twin Fluid atomizer by Internal Mixing Chamber Type)

  • 윤수환;정대인;하종률
    • Journal of Advanced Marine Engineering and Technology
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    • 제18권4호
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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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입도와 흑연 첨가제에 따른 유해 입자 및 가스 동시제거용 세라믹필터 특성평가 (Characteristics of the Ceramic Filter with the Control of Particle Size and Graphite Additive for the Hazardous Particle and Gas Removal)

  • 조을훈;이근재
    • 한국분말재료학회지
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    • 제21권6호
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    • pp.454-459
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    • 2014
  • In this study, the porous ceramic filter was developed to be able to remove both dust and hazardous gas contained in fuel gas at high temperature. The porous ceramic filters were fabricated and used as a catalyst support. And the effects have been investigated such as the mean particle size, organic content and addition of foaming agent on the porosity, compressive strength and pressure drop of ceramic filters. With the increase of mean powder size and the organic content for the cordierite filter, the porosity was increased, but the compressive strength and pressure drop were decreased. From the results of the research, the optimum condition for the fabrication of ceramic filters could be acquired and they had the porosity of 58%, the compressive strength of 13.4 MPa and the pressure drop of 250 Pa. It was expected that this ceramic filter was able to be applied to the glass melting furnace, combustor, and dust/toxic gas removal filter.

Gaussian 액적 크기 분포 함수를 이용한 분무형 화재 현상 해석 (Analysis of Sodium Spray Fire Using Gaussian Droplet Size Distribution)

  • 김병호;한도희;서숭혁
    • 한국수소및신에너지학회논문집
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    • 제15권1호
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    • pp.72-81
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    • 2004
  • Study on the analysis of sodium spray fire using Gaussian drop size distribution, which redistributes a droplet spectrum with given mean diameter if its size classes with critical diameter(D>8mm) occur, was carried out. In this case, the oversized droplets were reduced to a stable diameter. Results calculated by the code using Gaussian drop size distribution were in better agreement with AI experimental results than those of NACOM and SPRAY code. The effect of variance on pressure in the test cell appeared greatly by introducing Gaussian function, which could represent various sodium droplet size distribution. The increase of the variance with mean droplet size resulted had an important effect upon the pressure in the test cell.