• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.4-5
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• 2006

An update and the latest results on molten metal atomization using a Pressure-Gas-Atomizer will be given. This atomizer combines a swirl-pressure atomizer, to generate a liquid hollow cone film and a gas atomizer to atomize the film and/or the fragments of the film. The paper is focused on powder production, but this atomization system is also applicable for deposition purposes. Different alloys (Sn, SnCu) were atomized to study the characteristics of the Pressure-Gas-Atomizer.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.10-11
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• 2006

The use of hot gas in melt atomization has been widely reported, but little detailed experimental data on its precise effects and no satisfactory theory to explain them have been published. In this paper the authors present experimental data on the atomization of metals with gas at temperatures from ambient to 1000C, a semi-empirical equation relating particle size to gas temperature and flow rate, and an analysis of the gas dynamics of the atomization process that allows some insight into the process.

• 에너지공학
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• 제7권1호
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• pp.17-23
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• 1998

본 실험은 고점성 미강유의 액체 미립화를 향상시키기 위해 초음파 에너지를 적용하여 미립화 특성을 규명하고자 수행하였다. 식물유의 미립화 실험장치는 유사하게 1마력의 구동모터와 노즐을 장착할 수 있는 인젝터 및 소형분사 펌프 등으로 구성되어 있는 분사장치, 액적의 분산을 막기 위한 포집장치, 공급되는 연료에 초음파 진동을 가해주는 초음파 장치, 그리고 미립화 정도를 측정하기 위한 PDPA 시스템으로 구성되어 있다. 핀틀형 노즐에서 된끝각을 5$^{\circ}$ $10^{\circ}$ 15$^{\circ}$이며, 분사압력은 10, 13, 16 Mpa의 조건으로 실험하였다. 이 때 포집거리 300mm로 하였다. 노즐 분사 압력에 따른 분무 평균입경을 측정하기 위하여 노즐테스터를 대기압 상태에서 핀틀링 노즐의 스프링 크기를 조절하여 분무 평균입경(SMD)은 상용연료 공급장치 보다 초음파 연료공급 장치의 경우 Pintle형 노즐에서는 SMD를 기준으로 하여 10% 미립화 상승효율을 얻을 수 있었다. 따라서 본 실험에서는 초음파 진동에너지를 연료에 공급함으로써 고점성연료의 미립화 개선이 이루어지고 있음을 확인할 수 있었다.

• International Journal of Automotive Technology
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• 제4권4호
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• pp.157-164
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• 2003

An experimental and numerical study was performed to investigate the macroscopic and microscopic atomization characteristics of high-speed diesel spray issued from the common-rail injection system. For the experiments, spray visualization system and a phase Doppler particle analyzer system were utilized to obtain the spray atomization characteristics such as the process of spray development, spray tip penetration, and SMD distribution. In order to analyze the process of spray atomization with KIVA-3 code, the TAB breakup model is changed to the KH-DDB competition model, which assumes the competition between the wave instability and droplet deformation causes the droplet breakup above the breakup length. The calculated results were also compared with the experiments in terms of spray tip penetration and SMD distribution. The results provide the process of spray development, axial and radial distribution of SMD, and calculated overall SMD as a function of time after start of injection.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.943-946
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• 2002

This paper presents atomization characteristics of cutting fluids. To analyze the behavior characteristics of cutting fluid, analytical approach and experimental measurement were performed to predict the aerosol size, velocity and concentration due to cutting fluid atomization mechanism in machining operation. The established analytical model which is based on atomization theory analyzes the cutting fluid motion and aerosol generation in machining process. The predictive models can be used as a basis for environmental impact analysis on the shop floor. It can be also facilitate the optimization of cutting fluid usage in achieving a balanced consideration of productivity and environmental consciousness.

• 한국연소학회지
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• 제7권1호
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• pp.44-51
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• 2002

This paper presents an atomization model for sprays under flash boiling conditions. The atomization is represented by the secondary breakup of a bubble/droplet system, and the breakup is considered as the results of two competing mechanisms, aerodynamic force and bubble growth. The model was applied to predict the atomization of a hollow-cone spray from pintle injector under flash boiling conditions. In the regimes this study considered, sprays are atomized by bubble growth, which produces smaller SMD#s than aerodynamic forces alone. With decreasing ambient pressures, the spray thickness, fuel vaporization rate and vapor radial penetration increases, and the drop size decreases. With increasing the fuel and ambient temperatures to some extent, the effect of flash boiling and air entrainment completely change the spray pattern.

• 한국분무공학회지
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• 제12권1호
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• pp.45-57
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• 2007

This paper presents both experimental and numerical studies regarding nozzles used for the SI engine application, particularly for the intake-port fuel injection type. The atomization mechanism of the multi-hole plate nozzle was investigated experimentally. It was found that the nozzle design added turbulence into the liquid-film jet and the jet disintegrated rapidly. Based on the results, various plate types for the nozzle were developed and tested; six hole nozzle for liquid jet interaction, plate-type nozzle with flat duct channel, and the simpler structured nozzle. The spray characteristics of the prototype nozzles were examined experimentally while the internal flow of the nozzle was investigated computationally. It was shown that turbulent liquid-film was injected and atomization quality was improved by controlling the internal flow condition of the plate-type nozzle.

• 한국분무공학회지
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• 제12권2호
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• pp.108-114
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• 2007

This study investigates the influence of energizing duration on the fuel atomization characteristics of biodiesel injected through a high pressure common-rail injector. In order to analyze the effect of energizing duration on the fuel injection rate performance, the injection rate of biodiesel fuel is obtained from the pressure variation in the tube filled with fuel in injection measuring system. On the other hand, the atomization characteristics of biodiesel was measured and compared in terms of Sauter mean diameter(SMD), arithmetic mean diameter(AMD), droplet mean velocity, and detected droplets number by applying a phase Doppler particle analyzer(PDPA). It was revealed that the injection mass and maximum injection rate increase with increase of the energizing duration. Moreover, the increase of energizing duration improves the atomization performance of biodiesel fuel because it induces higher droplets momentum and velocity.

• 한국분무공학회지
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• 제8권3호
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• pp.1-9
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• 2003

The objective of this study is to compare 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 compared experimental and numerical results. In this investigation, the measurement and numerical analysis of spray droplet are to analyze the effects of ultrasonic energy on the agricultural atomization spray system in order to protection of dispersion droplets. It is clarified that ultrasonic energy forcing into a nozzle is valid to obtain atomization enchancement. As the result of comparing the experimental and numerical result, it is confirmed that nozzle type is highest efficiency than that of tube type and conventional type, also well fit, respectively.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2006년도 추계 학술대회논문집
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• pp.7-8
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• 2006

The governing equations for high-speed lateral atomizing injector nozzle flow based on the LES-VOF model in conjunction with the CSF model are presented, and then an integrated parallel computation are performed to clarify the detailed atomization process of a high speed nozzle flow and to acquire data which is difficult to confirm by experiment such as atomization length, liquid core shapes, droplets size distributions, spray angle and droplets velocity profiles. According to the present analysis, it is found that the atomization rate and the droplets-gas two-phase flow characteristics are controlled by the turbulence perturbation upstream of the injector nozzle, hydrodynamic instabilities at the gas-liquid interface, shear stresses between liquid core and periphery of the jet. Furthermore, stable and a high-resolution computation can be attained in the high density ratio (pl/ pg = 554) conditions conditions by using our numerical method.