• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.03a
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• pp.1-5
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• 2008

An experimental study was performed to develop the rotational fuel injection system of the micro turbojet engine. In this system, fuel is sprayed by centrifugal forces of engine shaft. The test rig was designed and manufactured to get droplet information on combustion space. This experimental apparatus consist of a high speed rotational device(Air-Spindle), fuel feeder, rotational fuel injector and acrylic case. To understand spray characteristics, spray droplet size, velocity and distribution were measured by PDPA (Phase Doppler Particle Analyzer) and spray was visualized by using Nd-Yag laser-based flash photography. From the test results, the length of liquid column from injection orifice is controlled by the rotational speeds and Sauter Mean Diameter(SMD) is decreased with rotational speed. Also, Sauter Mean Diameter is increased as increasing mass flow rate at same rotational speeds.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.202-206
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• 2009

We studied the spray characteristics of the high-speed rotating fuel injection system. The diameter of in-line injection orifices are varied from 1mm to 5mm and the number of in-line injection orifices are varied from 3 to 12. Droplet size, velocity and spray distribution were measured by the PDPA(Phase Doppler Particle Analyzer) system and spray was visualized. From the test results, the liquid column generated from the injection orifice is mainly controlled by the rotational speeds. Also diameter of injection orifices and number of injection orifices have influence on the diameters of droplet. Consequently, we find out that the basic mechanism of controlling the droplet size is the liquid film thickness in the injection orifice.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.5
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• pp.51-56
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• 2010

An experimental study was performed to understand spray characteristics of the V type rotating fuel nozzle with orifice diameters by using high speed rotational system. The experimental apparatus consist of a high speed rotational system, fuel injection system and acrylic case. The droplet size and velocity were measured by PDPA(Phase Doppler Particle Analyzer) and spray was visualized by using Nd-Yag laser-based flash photography. From the test results, droplet size is reduced with increasing orifice diameter up to the critical value. When increasing orifice diameter over than this critical value, droplet size is not decreased with increasing the orifice diameter. This is due to the irregular distribution of the liquid sheet around the inner surface of injection orifice.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.258-263
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• 2010

An experimental study was performed to understand spray characteristics of the V type rotating fuel nozzle with orifice diameters by using high speed rotational system. The experimental apparatus consist of a high speed rotational system, fuel injection system and acrylic case. The droplet size and velocity were measured by PDPA(Phase Doppler Particle Analyzer) and spray was visualized by using Nd-Yag laser-based flash photography. From the test results, droplet diameters are reduced with increasing orifice diameter and the optimum injection orifice diameter is 2.6 mm. When increasing orifice diameter over than 2.6 mm, droplet diameter is not decreased with increasing orifice diameter. This is due to the irregular distribution of the liquid sheet around the inner surface of injection orifice.

• Korean Journal of Food Science and Technology
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• v.37 no.2
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• pp.164-170
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• 2005

To improve functional properties of food proteins, homologous or heterologous ${\beta}-casein$ and 11S globulin(glycinin) from animal and vegetable proteins, respectively, were bio-hybridized using transglutaminase(MTGase). Susceptibility was confirmed by SDS-PAGE, particle size analyzed, and emulsion stability tested using Reddy and Fogler method, To determine how bio-hybridized protein influences emulsion stability, protein bound on oil droplet was investigated using Scanning Electron Microscopy (SEM). formation of bio-hybridized protein band was detected among homologous and heterologous proteins, with heterologous protein forming weak band in oligomer form. Homologous ${\beta}-casein$ protein showed high emulsion stability, while homologous glycinin showed almost no stability. Stability of heterologous ${\beta}-casein$ and glycinin protein was higher than that of glycinin. SEM photographs showed even distribution of bio-hybridized proteins on oil droplet improved stability.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.914-916
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• 2009

Using gelatin and acacia as wall and electronic ink as core substance, microcapsules were prepared by complex coacervation to fabricate a flexible electronic paper display. In order to obtain the microcapsules in a narrow dispersed distribution, we focus on the interfacial tension between the hydrophobic electrophoretic ink and an aqueous polyelectrolyte solution, through controlling sodium dodecyl sulphate (SDS) concentration and stirring rate. The existence of anionic surfactant of SDS not only decreases the droplet diameters, but also reduces the diameter size distribution. And, as the stirring rate is increased, the average size of microcapsule is also decreased.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.5
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• pp.1211-1221
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• 1990

The purpose of this study is to get experimental data on the distribution of CWM (Coal- Water Mixture) droplets size and the presence of pulverized coal particles inside CWM droplets. Atomization of CWM is done by Twin-Fluid Atomizer. The operational parameters are atomizing air pressure, coal particle loading, mean size of pulverized coal particles and sampling positions across spray. Th data analysis is initiated by Impression Sampling Method(Magnesium Oxide Technique) and Photo-technique and counting works are followed. Experimental work induces following research results. The variation of particle loadings in slurry makes no appreciable effects on the mean size of CWM droplets. It is evident that atomizing air pressure has very strong effect on the atomization of slurry. The mean size of atomized fuel droplets is dramatically reduced with the increasing air pressure. The population ratio of droplets without coal particles to total number of droplets is decreased as atomizing air pressure or loading rises and the same trend is obtained as the mean size of coal particles becomes smaller but a certain tendency of coal particle presence inside droplets could not be found from the change of sampling positions.

• Journal of ILASS-Korea
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• v.5 no.1
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• pp.30-40
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• 2000

The characteristics of liquefied butane spray are expected to be different from conventional diesel fuel spray, because a kind of flash boiling spray is expected when the back pressure is below the saturated vapor pressure of the butane(0.23MPa at 298K). The ambient pressure was held at a pressure above(0.37MPa) and below(0.15MPa) the fuel vapor pressure. The axial velocities, radial velocities, and size distributions in butane sprays were measured with PDPA(Phase Doppler Particle Analyzer) system. The PDPA measurement showed a smaller SMD at the 0.15MPa chamber pressure, compared to the 0.37MPa case. Log-hyperbolic density function for the droplets size distribution can be fitted to the experimental results of a liquefied butane spray.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.4
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• pp.219-227
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• 1998

This paper describes the fuel spray characteristics of gasoline port injectors such as the breakup procedures of liquid fuel, breakup and extinction behaviors of fuel spray at nozzle tip, time history of SMD and velocity distribution of fuel spray in the direction of fuel stream. Pintle-type gasoline fuel injector was used to analyze mentioned spray characteristics. In order to visualize the fuel spray behaviors and to measure the droplet mean diameter and velocities of spray droplets, the Schlieren method, digital image processing and auto-correlation PIV were applied in this study. In addition, the spray characteristics according to the variation of time were considered. The results of fuel spray show that the liquid sheet breakup starts at 10mm downstream actively. The flying time is approximately 4msec between 50mm and 80mm down the nozzle tip. Also, SMD of fuel spray, the number of droplets and fuel velocity distribution at each point of downstream are discussed.

• Journal of Mechanical Science and Technology
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• v.18 no.7
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• pp.1177-1186
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• 2004

In this paper, the spray atomization characteristics of a gasoline direct-injection injector were investigated experimentally and numerically. To visualize the developing spray process, a laser sheet method with a Nd :YAG laser was utilized. The microscopic atomization characteristics such as the droplet size and velocity distribution were also obtained by using a phase Doppler particle analyzer system at the 5 ㎫ of injection pressure. With the experiments, the calculations of spray atomization were conducted by using the KIVA code with the LISA-DDB breakup model. Based on the agreement with the experimental results, the prediction accuracy of LISA-DDB breakup model was investigated in terms of the spray shapes, spray tip penetration, SMD distribution, and axial mean velocity. The results of this study provides the macroscopic and microscopic characteristics of the spray atomization, and prediction accuracy of the LISA-DDB model.