• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.1184-1189
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• 2008

This paper is a study about characteristics of the SSC-1 nozzle, which is used in a fire extinguishing system in a ship. Through this paper, we can find that the traces and elements’ distributions obtained from experiments are as the same as the simulation analysis results of CFD program. At the point of 100mm, the $\alpha$ is 34.9 in the CFD analysis, and it is 32.5 in the experiment. This shows that there is no big different between the CFD analysis and the experiment result. And the average elements velocity is similar to the SMD.

• 한국대기환경학회지
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• 제12권4호
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• pp.449-457
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• 1996

The main purpose of this study was to investigate sulfur dioxide removal performance of flue gas desulfurization system utilizing a Spray Absorption/Drying Reactor. In this system, the size of droplets was considered the most significant factor and tested using a PDA system. Lime slurry flow rate, operating temperature, calcium/sulfur (Ca/S) ratio and applied air pressure were selected as major operation variables and tested/analyzed in terms of system performance. The results are as follows. 1. The $SO_2$ removal efficiencies were 49%, 74%, 85% for Ca$(OH)_2$ slurry flow rate of 10, 20, 30 ml/min, which implies that the increase of slurry flow rate improves removal efficiency. The optimum slurry flow rate in this study was, however, considered 20 ml/min because of constraints of system troubles and absorbent utilization. 2. As Ca/S ratio increased, $SO_2$ removal efficiency was observed to increase. 3. As air pressure, at the atomizing nozzole, increased from 3 to 5 $kg/cm^2, SO_2$ removal efficiency increased from 74% to 80%, because of droplet size reduction due to pressure increase during atomizing process and the increase of surface area, helping mass transfer between gas and liquid phase.

• 한국분무공학회지
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• 제6권1호
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• pp.9-17
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• 2001

The effect of air entrainment in twin-fluid spray structure is investigated experimentally by varing the amount of itemizing air. The air entrainment is expected to affect on droplet size and velocity, droplet number density, turbulent kinetic energy and vorticity. PDA(Phase Doppler Anemometer) and PIV(Particle Image Velocimetry) system are used to measure those important factors in analyzing spray structure. The results show that spray structure consists of three distinctive regions ; the atomizing region near nozzle, characterizing strong convective effect, the central core region where droplets are accelerated, and the spray sheath region where droplets are decelerated due to air entrainment. The local air entrainment rate is largest near nozzle, characterizing strong turbulent kinetic energy and vorticity but deceases along axial distance.

• 한국산학기술학회논문지
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• 제18권6호
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• pp.1-7
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• 2017

분무식 노즐(spray nozzle)은 액체의 표면을 증가시키기 위해 에너지를 공급하여 액체를 다수의 액적으로 미립화시키는 장치로 연소과정에서의 연료의 미립화 또는 표면이나 입자의 코팅 등 여러 산업분야에 다양한 목적으로 응용된다. 초음파 미립화 노즐은 진동 발생장치로부터 고진동수의 전기에너지를 받아 같은 진동수의 기계적 에너지로 변환시키는 변환기를 갖고 있다. 변환된 에너지를 액체에 부가하여 고주파 진동에 의해 미세한 액적을 생성하여 분사한다. 코팅작업에서 가압되지 않은 저속의 분무는 액적이 튕겨나가지 않고 표면에 달라붙어 과도하게 분사되는 양을 줄일 수 있다. 초음파 미립화 노즐은 초음파 진동부 외벽에 공기를 공급해 줄 수 있는 공간을 통해 생성된 보조 공기흐름을 이용하여 저속의 액적을 운반하여 분무특성이나 분무형상을 조절할 수 있다. 따라서 주위 공기의 흐름을 이용하여 원하는 분무특성을 얻을 수 있다. 본 연구에서는 액적의 분사 운동을 모사하기 위해 라그랑지안 분산상 모델(DPM)을 적용한 상용코드 FLUENT를 사용하여 액적 주위의 공기흐름을 동반하는 초음파 미립화 노즐을 해석하였다. 노즐 수축부 형상, 액적의 크기 그리고 공기 측 압력차의 크기를 변화시키며 수치해석을 수행하여 코팅용 분무를 위한 최적 조건을 연구하였다.

• Journal of Biosystems Engineering
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• 제21권2호
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• pp.117-122
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• 1996

Droplet sizes produced from a mist blower should be adequate to get highly biological effects with a reasonable level of work performance. However the droplet sizes from the conventional nozzles of the mist blower were around VMD 95 to 469$\mu$ which were relatively large as compared with the recommended droplet sizes in liquid flow rate of 17.2 m$/ell$s with air flow rate of 16660$m^3$/s on the maximum travel distance of about 4.0 m. The velocity of air stream at the point where two fluids, air and liquid, impact each other, was tried to maximize as much as possible in order to enhance the atomization performance of a newly designed twin fluid nozzles with the same or better level of performance of the conventional mist blower, The configuration of nozzle orifice should be designed to enlarge the contact area between air and liquid to enhance the atomization.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2004년도 하계학술대회 논문집 C
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• pp.1900-1902
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• 2004

The degradation systems of non degradable waste water consist of the arc plasma torch, power supply, a feeder of liquid waste and reactors. Output of stable plasma torch, suitable air flux, microscopic atomizing state of waste water and long reaction section must be to degrade waste water more efficiently. In this paper, we are designed the stable power system, the microscopic atomizing state of waste water and the efficient reactors to satisfy various conditions. Non degradable wast water used in this work was $Na_2$EDTA of 1.0 mol. The concentration of $CO_2$ and EDTA was analyzed using GC (Gas Chromatography) and HPLC (High Performance Liquid Chromatography). In the result show that $CO_2$ concentration was about 96% and EDTA was degraded approximately 96%.

• 한국분무공학회지
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• 제3권2호
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• pp.14-23
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• 1998

The negative pressure as much as 10's mmHg is demanded at nozzle inside, in case of atomizing the large density molten materials. by conventional air jet nozzle. In this study, suction type fluid nozzle is designed by applying the ejector principle in order to clarify the air flow of nozzle inside, mechanism of liquid suction and liquid film formation. The results of this experimental study areas follows. Suction force of liquid is magnified by using liquid nozzle, and it is able to supply the liquid stable. Negative pressure at nozzle inside is varied by throttle angle of liquid nozzle, position and outer diameter of air jet nozzle, and have a influence on liquid suction quantity and liquid film formation.

• 대한기계학회논문집
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• 제15권6호
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• pp.2147-2159
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• 1991

본 연구에서는 가장 다순한 내부혼합형 이류체분사노즐의 기류속도, 액체유량, 노즐직경 및 혼합길이, 기액접촉각을 변화시켜 평균입경(SMD), 분무각, 입도분포, 분 무분사량분포 등을 조사하여 노즐형상에 따른 분무특성의 변화를 자세히 밝혀, 분무특 성을 조절할 수 있는 이류체분사 노즐의 설계에 대한 기초적 자료를 제시하고자 한다.

• 한국가시화정보학회지
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• 제12권2호
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• pp.9-12
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• 2014

Conventional electrospray and air spray methods have the vulnerabilities of limited flow rate (throughput) and droplet size, respectively. Since high throughput with uniform size of droplet is required for various applications, an improved technique should be adopted. Here, we report a combined system of an air pressure and an electric field and evaluate the atomization performance of it. The air flow allowed applying high flow rate range and the electric field reinforced the atomization process to generate fine droplets. A correlation between two forces was investigated by comparing the droplet produced by each method. The atomized droplets were measured and visualized by image processing and a particle image velocimetry (PIV). The quantitative results were achieved from the parametric space and the effect of both forces was analyzed. The motion of charged droplets followed the outer electric field rather than the complex vortex in the shear layer so that the droplets accelerated directly toward the grounded collector.

• 한국분무공학회지
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• 제18권1호
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• pp.9-15
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• 2013

Wall thinning of pipeline in power plants occurs mainly by flow acceleration corrosion (FAC), cavitation erosion (C/E), liquid droplet impingement erosion (LDIE). Wall thinning by FAC and C/E has been well investigated; however, LDIE in plant industries has rarely been studied due to the experimental difficulty of setting up a long injection of highly-pressurized air. In this study, we designed a long-term experimental system for LDIE and investigate the behavior of LDIE for three kinds of materials (A106B, SS400, A6061). The main control parameter was the air-water ratio (${\alpha}$), which was defined as the volumetric ratio of water to air (0.79, 1.00, 1.72). In order to clearly understand LDIE, the spraying velocity (${\nu}$) of liquid droplets was controled larger then 160 m/s and the experiments were performed for 15 days. Therefore, this research focuses relation between erosion rate and air-water ratio on the various pipe-flow materials. NPP(nuclear power plant)'s LDIE prediction theory and management technique were drawn from the obtained data.