• 대한기계학회:학술대회논문집
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• 대한기계학회 2002년도 학술대회지
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• pp.385-388
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• 2002

The researches of a two-phase atomizers have been carried out in the field of automotive and aerospace industries in order to improve the atomization performance of the liquid droplets ejecting from these nozzles. The smaller droplets have the advantages of the reduction of environmental pollution matter and effective use of energy through the improvement of heat and mass transfer efficiency. Thus, to propose the basic information of two-phase flow, an internal mixing atomizer was designed, its shape factor was 0.6 and the liquid feeding hole was positioned at the center of the mixing tube which was used to mix the air and liquid. The experimental work was performed in the field after the nozzle exit orifice. The measurement of the liquid droplets was made by PDPA system. This system can measure the velocity and size of the droplets simultaneously. The number of the droplets used in this calculation was set to 10,000. The flow patterns were regulated by ALR (Air to Liquid mass Ratio). ALR was varied from 0.1024 to 0.3238 depending on the mass flow rate of the air. The analysis of sampling data was mainly focused on the spray characteristics such as flow characteristics distributions, half-width of spray, RMS, and turbulent kinetic energy with ALR.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2012년도 전기공동학술대회 논문집
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• pp.123-124
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• 2012

Effervescent atomizer in which the liquid is ejected from nozzle with bubble caused by gas injection into the liquid is one of twin-fluid atomizers. Effervescent atomizer is operated with the lower injection pressure and the smaller air flow rate when compared with those of other twin-fluid atomizers. In this study, we attempted experiment study to investigate the atomization characteristics of effervescent atomizer related with the internal flow condition. The nozzle was made with acrylic material to investigate the nozzle internal flow. The macroscopic spray analysis was conducted with internal flow images and spray images. Furthermore, SMD was measured by using the laser diffraction method. According to this study, the internal flow condition changed from bubbly flow to annular flow as the air-liquid mass ratio(ALR) increases. At that time, the atomization characteristics were improved.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제29회 추계학술대회논문집
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• pp.159-162
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• 2007

아음속 유동 내에 수직으로 분사된 액체제트의 액적분열 분포 특성을 알아보기 위해 이유체 노즐을 사용하여 실험적으로 연구하였다. 노즐은 L/d=3의 외부혼합형으로 공기와 액체의 비를 0 ${\sim}$ 59.4%까지 변화시키면서 분사하였다. 분무형상의 변화를 이미지화 하였으며 분무의 궤적과 액주의 형상을 관찰하였다. 액체제트 분열의 단면분포 특성을 PDPA를 사용하여 측정하였며 SMD, 액적속도, 그리고 체적유속을 측정하였다. 그 결과 노즐로 공급되는 공기의 양이 많아질수록 Y/d방향의 관통거리는 증가하였고 액적의 미립화는 가속화되는 것을 관찰할 수 있었다.

• 한국추진공학회지
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• 제12권1호
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• pp.16-22
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• 2008

액체제트의 액적분열 분포특성을 알아보기 위해 아음속 유동 내로 수직 분사된 이유체 분무를 실험적으로 연구하였다. 노즐은 L/d=3의 외부혼합형을 사용하였으며 공기와 액체의 비를 $0\;{\sim}\;59.4%$까지 변화시키면서 분사하였다. 분무형상을 이미지화 하여 분무의 궤적과 분열특성을 관찰하였다. PDPA를 사용하여 액체제트 분열의 단면분포 특성을 측정하였으며 SMD, 액적속도, 그리고 체적유속을 측정하였다 이유체 분무로부터 공급되는 공기의 유량이 증가할수록 액체 제트의 충돌점은 노즐 입구와 좀 더 가까워졌으며, 침투거리는 증가하였고, 기체 액체 비를 증가시킴에 따라 좀 더 무화된 액체제트의 분포를 얻을 수 있었다.

• 한국추진공학회지
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• 제8권2호
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• pp.39-45
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• 2004

선회형 미립화기의 분무거동에 관한 논의는 현재 여러 연구자들에 의해 활발히 논의되고 있다. 본 연구에서는 이류체 내부혼합형 선회노즐의 특성을 파악하고자 공기와 액체의 질량 비를 바꿔가며 최적의 미립화 조건을 알아보기 위하여 실시되었다. 이를 위하여 분무 유동장의 평균속도, 파동속도 및 액적크기에 관한 비교를 정량적으로 분석하였다. 각 유동조건에 따른 지수함수를 만족하는 상관관계 또한 도출하였는데, 이는 질량 비에 관계없이 거의 동일함을 알 수 있었고, 질량비가 높을수록 선회 각이 30o인 경우가 미립화 특성이 가장 우수하였다. 따라서, 본 연구에서 이루어진 결과에서는 노즐의 형상이 분무유동에 미치는 여러 인자 중 가장 중요한 것이라 여겨진다.

• 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.

• International Journal of Automotive Technology
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• 제1권2호
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• pp.95-100
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• 2000

The droplet and the turbulent characteristics of a counterflowing internal mixing pneumatic nozzle mainly focused. The measurements were made using a Phase Doppler Particle Analyzer under the different air pressures. The nozzle with tangential-drilled holes at an angle of 30 to the central axis has been designed. The spatial distributions of velocities, fluctuating velocities, droplet diameters and SMD were quantitatively and qualitatively fluctuating velocities were substantially higher than the radial and the tangential ones. This implies that the disintegration process is enhanced with the higher air pressure. The larger droplets were detected near the spray centerline at the upstream while the smaller ones were generated at the downstream. This was attributed to the lower rates of spherical particles which were not subject to instantaneous breakup. However, substantial increases in SMD from the central part tower spray periphery were predictable in downstream regions.