• 제목/요약/키워드: atomization

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음향 부양장(acoustic levitation field)에서 초음파 주파수(ultrasonic frequency)에 따른 단일 액적의 미립화 특성 (Effect of Ultrasonic Frequency on the Atomization Characteristics of Single Water Droplet in an Acoustic Levitation Field)

  • 서현규
    • 한국분무공학회지
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    • 제18권3호
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    • pp.126-131
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    • 2013
  • This paper describes the effect of ultrasonic frequency(f) on the atomization and deformation characteristics of single water droplet in an acoustic levitation field. To achieve this, the ultrasonic levitator that can control sound pressure and velocity amplitude by changing frequency was installed, and visualization of single water droplet was conducted with high resolution ICCD and CCD camera. At the same time, atomization and deformation characteristics of single water droplet was studied in terms of normalized droplet diameter($d/d_0$), droplet diameter(d) variation and droplet volume(V) variation under different ultrasonic frequency(f) conditions. It was revealed that increase of ultrasonic frequency reduces the droplet diameter. Therefore, it is able to levitate with low sound pressure level. It also induces the wide oscillation range, large diameter and volume variation of water droplet. In conclusion, the increase of ultrasonic frequency(f) can enhance the atomization performance of single water droplet.

분사 압력 변화에 따른 농업용 노즐의 분무 및 미립화 특성 (Spray and Atomization Characteristics of an Agricultural Nozzle by Changing the Injection Pressures)

  • 상몽소;박수한
    • 한국분무공학회지
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    • 제26권4호
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    • pp.189-196
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    • 2021
  • Spray drift of agricultural nozzles has become a big issue because it causes low precision targeting and environmental pollution. In order to reduce the spray drift, study spray characteristics of agricultural nozzles is virtually important. In this study, shadowgraph and Mie-scattering visualization techniques were used to study the macroscopic spray and atomization characteristics of an agricultural nozzle. PDPA was used to measure the atomization characteristics of spray. The injection pressure is set to 1 bar, 3 bar and 5 bar, which covers the working range of the nozzle. For the PDPA experiment, 75 points were measured in an area of 160 mm × 120 mm at 10 mm intervals directly below the nozzle to grasp the overall atomization characteristics of the spray. It was found that the spray width and sheet width showed a linear correlation. As the injection pressure increased, the sheet expansion in the 0-degree direction and the sheet swing in the 90-degree direction jointly promoted the breakup of the sheet. In addition, the area close to the central axis had a large droplet velocity, and since a large droplet velocity promoted atomization of spray, the area close to the central axis had a smaller spray droplet diameter than the left and right regions.

Atomize법에 의한 용융소재의 고효율 미세화에 관한 연구 (제3보 : 애토마이저의 미립화 기구와 특성) (A STUDY ON HTGH-EFFICIENCY ATOMIZATION OF MOLTEN MATERIALS (PART 3 : MECHANISM AND CHARACTERISTICS OF ATOMIZATION))

  • 오재건;권순익
    • 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; $$SMD=0.00302\frac{{(\sigma_L\;\rho_L\;D_L)}^{0.5}}{\rho_A(V_1+1.155\;V_2)/2}(1+\frac{W_L}{(W_{A1}/3.33)+W_{A2}})+0.0148(\frac{{\mu_L}^2}{\sigma_L\;\rho_L})^{0.425} \;{D_L}^{0.575}(1+\frac{W_L}{(W_{A1}/3.33)+W_{A2}})^2$$.

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디젤분무에 대한 액체미립화모델들의 영향 (The Influence of Liquid Atomization Models on Diesel Sprays)

  • 이성혁;유홍선;홍기배
    • 한국자동차공학회논문집
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    • 제8권6호
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    • pp.22-30
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    • 2000
  • The present article deals with comparisons of published liquid breakup models for diesel sprays to analyze the influence of breakup models on various spray parameters. The three different models tested in this study are the surface wave instability (Wave) model, the Taylor analogy breakup (TAB) model, and the drop drag model(DDM). The numerical results using these models are compared with several experimental data to assess the prediction capabilities of breakup models. Additional task in this study is to investigate effects of the breakup time constant in the Wave model on the spray parameters because the spray behavior is sensitive to the breakup time constant. It is seen that there is uncertainly about the breakup time constant indicating that the suitable acceptance of the constant is important, and the TAB model generally shows significant under-prediction of Sauter Mean Diameter(SMD). In addition, it may be indicated that differences between the DDM and Wave model are not significant, showing that the DDM may be suitable for air-assisted atomization rather than pressure atomization.

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