• Title/Summary/Keyword: Twin-Fluid Spray

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Spray Flow Characteristics of Twin-fluid Water Mist Nozzle for Fire Suppression (2유체 미세 물분무 소화노즐의 분무유동 특성)

  • Kim, Bong-Hwan;Choi, Hyo-Sung;Kim, Dong-Keon
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.10 no.3
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    • pp.60-66
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    • 2011
  • In the present investigation, experimental studies were conducted on the fire suppression performance of twin-fluid water mist spray which is subjected to thermal radiation in a closed space. Downward-directed water-mist sprays, interacting with an under kerosene pool fire, were investigated in a test facility. The mass mean diameter of water-mist droplets were measured by PMAS under various flow conditions. The developed twin-fluid water mit spray nozzle satisfied the criteria of NFPA 750, Class 1. The mechanism of fire suppression by fine water mist was concluded to be the cooling of the fire surface which leads to the suppression of fuel evaporation. It was proved that the automatic twin-fluid water mist spray system under lower pressures could be applied to an industrial facilities.

An Experimental Study on The Effect of Ultrasonic Atomization in Agricultural Twin-fluid Nozzle (농업용 액체 분무용 초음파 분사효과에 관한 실험적 연구)

  • Chung, J.D.;Lim, Y.J.
    • Journal of ILASS-Korea
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    • v.8 no.4
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    • pp.1-8
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    • 2003
  • The objective of this study is to investigate experimentally atomization characteristics for differently made an ultrasonic twin-fluid nozzle. A spray system, an ultrasonic system, and three different type(Nozzle type, Tube type, Conventional type)are made and tested by applied with ultrasonic energy. In this investigation, the measurement and calculation of spray droplet are to analyze the effects of ultrasonic energy on the agricultural atomization system. Through the measurement of suray angle, spray column using, high speed camera and PDA, it is found that nozzle type is highest efficiency than that of tube type and conventional type. It was found that the ultrasonic energy increased the atomization efficiency of spray droplets about 9% respectively and spray angle was wide spray.

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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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A Study on Ultrasonic Effects for the Atomization in a Twin-Fluid Spray (2-유체 분무에서 액체미립화에 대한 초음파의 영향에 관한 연구)

  • Ju, E.S.;Chung, J.D.;Song, M.G.
    • Journal of ILASS-Korea
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    • v.3 no.4
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    • pp.50-57
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    • 1998
  • The utilization of resonance should be considered to get the maximum effect of ultrasonic to atomize liquid. The ultrasonic generator, transducer, horn, and all attached parts are used to produce the resonance, and specially the characteristics of liquids such as liquid load, property, and etc., for the liquid atomization affinity are considered. In this study, the variable device of liquid load was made and distilled water and city water selected as experimental liquids were sprayed by a twin-fluid spray method and their diameters, distributions, and spray quantum of spray droplets were measured by the light scattering system. And all data were observed, compared and considered relatively. In results, a lot of phenomena of liquid atomization affinity by ultrasonic appeared in accordance with liquid loads, namely head h.

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An Experimental Study on Structure of Twin-Fluid Spray with Air Entrainment (공기 유입을 고려한 2유체 분무의 구조에 관한 실험적 연구)

  • Chae, Hyo-Cheol;Kim, Dong-Il;Oh, Sang-Heun
    • Proceedings of the KSME Conference
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    • 2000.04b
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    • pp.925-930
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    • 2000
  • This paper is investigated the entrainment of air into sprays which has significant effects on the combustion efficiency, stability of flame using the air-assisted twin-fluid nozzle in non-burning. The factors which may be expected to affect the entrainment of air by a liquid spray are: Relative velocity of droplet and ambient gas; Drop size and size distribution; Density and other property of the liquid. Here, axial, radial velocity and turbulent kinetic energy of spray droplet was measured with the PIV(Particle Image Velocimetry). Spray characteristics were also visualized using CCD camera. The results indicate that the entrainment rate increases more or less non-linearly with the downstream region.

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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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Behavior Characteristics of Swirl-Twin Spray with Changing Swirl Angle (선회각도변화에 따른 2유체 선회분무의 거동특성)

  • Kang, Wan-Bong;Cha, Keun-Jong;Kim, Duck-Jool
    • Proceedings of the KSME Conference
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    • 2000.04b
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    • pp.943-948
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    • 2000
  • The Twin-fluid Swirl Nozzles are used in many parts of the industry to produce homogeneous spray. This study is to investigate the effects of outer air swiller and inner water swiller on atomization of liquid.. The experiment was carried out with increasing air-flow rate at constant liquid-flow rate and with changing outer air swiller angle and inner water swiller angle. A Particle Dynamics Analyzer(PDA) was used to measure drop size, mean and ms values of axial velocity, number density and Sauter mean diameter(SMD). The axial mean velocity and SMD of droplets were measured along the center line and radial directions. It was found that the higher air flow-rate resulted in the smaller Sauter mean diameter of liquid spray and the higher axial mean velocity of droplets. This experimental results will be conveniently used for the preliminary design stage of twin-fluid nozzle development.

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Performance Evaluation of Automatic Self-Cleaning Filter System using Twin-Fluid Nozzles for Air Cleaning in the Subway Stations (지하철 공기청정을 위한 2유체노즐형 자동세정 공기청정 시스템 개발에 관한 연구)

  • Ahn, Y.C.;Lee, J.K.
    • Journal of ILASS-Korea
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    • v.9 no.3
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    • pp.15-21
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    • 2004
  • The removal of the dusts in the subway stations, tunnels, factories and buildings becomes issue for comfortable indoor and outdoor conditions. There has been used an automatic self-cleaning filter system to collect the dusts. In general, the collected particles are removed by water spray nozzles. The new design for improving the cleaning efficiency of collected dusts and reducing the supplied water is the concept of the plane array of demister filters and the twin-fluid nozzle for mixing compressed air and water in the automatic self-cleaning filter system. Results show that the cleaning efficiency of twin-nozzle filter systems is 99.1%, compared to 47% in the conventional filter system. Therefore the automatic self-cleaning filter system using twin-fluid nozzle filter systems reduces water supplied in the filter system, and increases cleaning efficiency and drying efficiency.

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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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Spray characteristics on mixing region scale of twin fluid atomizer (이류체 분사노즐의 혼합영역 형상에 따른 분무특성)

  • 김병문;김혁주;이충원
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.15 no.6
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    • pp.2147-2159
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    • 1991
  • The effects of principal dimensions of internal mixing twin-fluid atomized and operating conditions on the atomizing characteristics are experimentally investigated. The tests are conducted over the wide range of air/liquid ratio to predict influences of the diameter and length of nozzle, contacting angle between air and liquid in the mixing chamber, and air orifice diameter on the mean drop size(SMD), spray angle, distribution of drop size, and spray dispersion, And also, initial distribution of liquid column by air stream within the mixing chamber are observed through the transparent nozzles. A He-Ne laser particle sizer(MALVERN Model 2604) was used to measure the Sauter.s mean diameter( $D_{321}$) and droplet sizes distribution. In this experiment the air/liquid ratio, mixing length and nozzle diameter have a great influence on SMD, spray angle, droplet sizes distribution and spray dispersion.