• 한국분무공학회지
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• 제4권1호
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• pp.19-26
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• 1999

An experimental study of twin-fluid atomization for powder metallurgy has been conducted using a specially designed atomizer in which liquid is first spread into a thin sheet and then exposed on both sides to high-velocity air. Inner air jet worked for supplying liquid and outer air jets disintegrated liquid sheet. The first result of this study were confined to the effect of atomizing quality through experiments with water. The experimental data will be extend to include the influence of atomizing air velocities on mean particle size through experiments with molten material. An experimental equation on the relationship between SMD and the related parameters was taken out; $$SMD=0.00302\frac{{(\sigma_L\;\rho_L\;D_L)}^{0.5}}{\rho_A(V_1+1.155\;V_2)/2}(1+\frac{W_L}{(W_{A1}/3.33)+W_{A2}})+0.0148(\frac{{\mu_L}^2}{\sigma_L\;\rho_L})^{0.425} \;{D_L}^{0.575}(1+\frac{W_L}{(W_{A1}/3.33)+W_{A2}})^2$$.

• 한국분무공학회지
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• 제4권3호
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• pp.32-41
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• 1999

In this research, internal-mixing twin-fluid atomizer using sonic energy is designed and manufactured. We are trying to intimate high efficiency twin-fluid atomizer to obtain good liquid atomization in the low pressure region. Define of geometric form of atomizer, characteristics of spray is influenced by position, depth and height variation of cavity resonator, variation of sound intensity and resonant sound frequency with liquid flow rate. The liquid atomization is promoted by multi-stage disintegration of mixing flow of gas with liquid and the optimum condition of position and depth of cavity resonator according to sonic energy is obtained from the condition at a=2.5mm and L=2mm. The velocity distribution of droplets shows negative value due to recirculation region at the center of axial, and as the radial direction distance is far, the velocity distribution of droplets decrease slowly after having a maximum value. However velocity and SMD show nearly uniform distribution at the down stream and as result compared to Nukiyama and Tanasawa's equation. atomization of mixing flow with air and liquid dispersing from the outlet of the nozzle is promoted by the effect of collision at the cavity resonator.

• 한국분무공학회지
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• 제19권3호
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• pp.101-108
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• 2014

The current paper reviews the main characteristics and the operating principles of major fuel atomizers used for gas turbine combustors, including various empirical SMD equations for each atomizers. We have summarized various methodologies for evaluation of the combustion efficiency and for combustor sizing from the selected SMD data. It is found that the combustor sizing as well as the combustion efficiency are totally dependent upon the SMD calculation results, which means that special cares should be taken in choosing the SMD empirical equations.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2004년도 추계 학술대회논문집
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• pp.37-41
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• 2004

Liquid injection in a Venturi Scrubber creates great effect on the dust-collection efficiency and operation cost of venturi scrubbers. We have developed a model that can numerically simulate atomization of the liquid jet in the Venturi Scrubber. This simulation consists of models on liquid column, jet surface breakup, column fracture and secondary droplet breakup. These models have been embedded in the KIVA3-V code. We have calculated such parameters as the jet penetration, jet trajectory, droplet size, velocity field and the volume flux distribution. The results are compared with the experimental data in this paper.

• Korean Journal of Chemical Engineering
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• 제35권11호
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• pp.2164-2171
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• 2018

Heavy duty diesel vehicles deteriorate urban air quality by discharging a large volume of air pollutants such as soot and nitrogen oxides. In this study, a newly introduced auxiliary device a fuel activation device (FAD) to improve the combustion efficiency of internal engines by utilizing the cavitation effect was closely investigated by the fluid flow mechanism via a numerical analysis method. As a result, the FAD contributed to fuel atomization from the injection nozzle at lower inlet pressure by reducing the pressure energy. The improved cavitation effect facilitated fuel atomization, and ultimately reduced pollutant emission due to the decrease in fuel consumption. The axial velocity along the flow channel was increased 8.7 times with the aid of FAD, which improved the primary break-up of bubbles. The FAD cavitation effect produced 1.09-times larger turbulent bubbles under the same pressure and fuel injection amount than without FAD.

• 한국생산제조학회지
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• 제24권1호
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• pp.23-30
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• 2015

The scanning quality can be influenced by reflective abilities of a surface. Transparency and glossiness of a surface can highly limit the scanning results. Various techniques have been developed to solve problems of reflective and transparent surfaces. As one of the most feasible and convenient solutions, a thin layer of coating with proper specifications is sprayed on surface for eliminating the problems of the surfaces. As the main goal is to keep the object geometry unchanged, then it is important to coat the surface with layers less than one micrometer in thickness. For this purpose, a newly designed atomization-based spray system has been developed and tested in sets of experiments to study its efficiency on scanning results while objects with the surface are in use. This paper presents the spray design process and then studies and compares the 3D scanning results of the surfaces coated with atomization-based and aerosol sprays.

• 한국식품저장유통학회지
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• 제30권4호
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• pp.589-601
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• 2023

Malaysian honey is rich in nutrients and bioactive compounds, which can be a healthy alternative to refined sugar in food production. However, liquid honey's viscous and sticky nature makes it unpreferable in industrial handling. This study, an atomization system coupled with vacuum drying to produce honey powders to overcome the problem. Three types of Malaysian honey, namely Acacia, Gelam, and Tualang, were encapsulated in Ca-alginate gel beads using the atomization system. The density viscosity, and surface tension of the honey-alginate solutions were measured, and the concentration of honey and alginate influenced the physical properties of the solutions. Honey-encapsulated gel beads in the size range of 2.16-2.92 mm were produced using the atomization system with the air-liquid mass flow rate ratios of 0.22-0.31, Weber number (We) of 112-545, and Ohnersorges number (Oh) of 0.35-10.46. Gel bead diameter can be predicted using a simple mathematical model. After vacuum drying, the honey gel powder produced was in the size range of 1.50-1.79 mm. Results showed that honey gel powders with good encapsulation efficiency and high honey loading could be produced using the atomization system and vacuum drying.

• 한국항공우주학회지
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• 제33권1호
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• pp.62-68
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• 2005

액체로켓 가스발생기를 위한 인젝터를 설계하여 분사특성을 살펴보았다. 인젝터는 F-O-F triplet impinging이고 모의 추진제로 kerosene/물을 사용하였다. 인젝터의 형상설계 변수는 충돌각과 충돌거리이며 이를 이용하여 5가지의 후보 요소 인젝터를 설계하였으며, 모의 추진제를 사용하여 분사 특성을 실험하였다. 분사특성을 측정하기 위한 인자는 혼합효율과 분사각으로 모의 추진제 운동량비 0.2~1.3 범위에서 분사유량과 국부 O/F비를 측정하고 혼합효율을 계산하였다. 가스발생기용 인젝터는 농염한계의 O/F비 때문에 가장 높은 효율과 적절한 분사 각을 갖는 요소 인젝터를 선정하였고 연소 특성을 연구하기 위하여 연소실험을 실시하였다.

• 한국대기환경학회지
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• 제25권3호
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• pp.211-218
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• 2009

Feasibility study of using $Ti0_2$ mist generated by ultrasonic atomization for photocatalytic degradation of gaseous toluene was attempted in this study. For this, the photocatalytic reactor consisting of mist generator and photo-reactor was designed. Most of experimental results showed that steady state reached about 30 minutes after the start of experiments. The effects of $Ti0_2$ concentration, toluene concentration, and UV wavelength on toluene removal ratio were investigated. It was found that the highest removal efficiency was obtained when $Ti0_2$ concentration was 0.6 g/L in slurry. At this condition, it was found that the toluene removal efficiency increased as toluene concentration in feed decreased. In order to investigate the effect of UV wavelength, experiments were carried out using three UV lamps with different UV wavelength. The results showed that the highest removal efficiency was achieved when the lamp with the shortest wavelength were employed.

• Journal of Biosystems Engineering
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• 제27권4호
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• pp.317-326
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• 2002

Characteristics of a twin-fluid spray with ultrasonic vibration were examined in order to obtain a high efficiency of cold-fog spray of the automatic pest control machine which has been widely used in protected horticulture recently. An electrostrictive vibrator of PZT BLT and a magnetostrictive $\pi$-type vibrator were used applied as the ultrasonic transducers with a frequency of 28 kHz. All experiments were conducted in 4 methods of spray ; a conventional spray method without ultrasonic forcing, an indirect vibration method with ultrasonic forcing, an improving-quality method by ultrasonic forced within liquid, and a combined-use method with both of the indirect vibration method and the improving quality method. It was found that the ultrasonic energy increased the atomization efficiency of spray droplets about 10% and especially much more in the case of the combined-use method.