• Journal of ILASS-Korea
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• v.24 no.3
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• pp.145-151
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• 2019

Viscoelastic fluid is used in various industrial sites because its cost reduction and environmental benefits by preventing formation of fine droplets that scattered around. However, viscoelastic fluids, unlike newtonian fluids, contain a shear thinning characteristic that decrease in viscosity as shear rate increases and elastic characteristic, making it difficult to predict spray breakup process. In this study we made three test fluids. Boger fluid with viscoelastic characteristics, and two newtonian fluids, were prepared to exclude shear thinning characteristics and study the effects of elastic characteristic only. Flow visualization, spray angle, and SMD were measured for three test fluids using laboratory scale impinging jet test apparatus. As a result, it was confirmed that Boger fluid, unlike the newtonian fluid, was not formed fine droplets that scattered around and the breakup process appeared differently. In addition, SMD was found to be large in Boger fluid, and the SMD according to pressure was confirmed that there is no significant difference.

• Journal of Power System Engineering
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• v.5 no.3
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• pp.17-24
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• 2001

In order to investigate a characteristic of the behavior of spray pattern in accordance with running conditions for a DI diesel engine, the PLN Injection system with changeable revolution speed of fuel injection cam was set up, and through this, history curves of injection pressure for a similar real DI diesel engine were able to be displayed. Authors visualized and analyzed the sprays at various revolution speed of fuel injection cam, and found out that fuel distributions of the sprays in the low speed condition were bad, fuel with air was injected from the hole of nozzle at the beginning of injection, and wide spray angle at the early stage of injection became narrower with elapsed time, but wider again at the end of injection.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2002.05a
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• pp.67-73
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• 2002

The characteristics of fuel spray influence on the engine performances such as power, fuel economy and emissions. therefore, the measurement of fuel spray characteristics is very important for the improvement of heat engine. The factor which controls the fuel spray is injection pressure, ambient pressure, engine speed et al.. In :his study, We measured spray angle, spray penetration and spray tip velocity considering injection pressure(10,14㎫), ambient pressure(3,4,5㎫), fuel pump speed(500,700,900rpm) in the high temperature and pressure chamber. Experimental results are summarized as follows: 1) Injection pressure influence on the characteristics of spray namely As Injection pressure Is increased, spray angle is decreased but spray penetration and spray tip velocity is increased. 2) Spray angle, spray penetration is increased by increasing the fuel pump speed. 3) Ambient pressure plays an important role in spray characteristics.

• Proceedings of the KSME Conference
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• 2001.11b
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• pp.946-951
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• 2001

This experimental study is to investigate the intermittent spray characteristics of a pintle nozzle. High speed camera used in this expreiment with 9000fps. The factor, which controls the diesel spray, is the Injection pressure, ambient pressure and ambient temperature. In this paper, experiments were conducted free spray for the ambient pressure(3, 4, 5Mpa), nozzle Injection pressure(10, 14, 18MPa) and ambient temperature(293, 473K). With the higher opening pressure, the spray tip velocity and spray penetration increases while the spray angle decreases, On the other hand, With the higher ambient pressure, the spray angle increase while the spray tip penetration and spray tip velocity decrease. also, With the higher ambient temperature, the spray penetration decrease while the spray angle decrease.

• Journal of ILASS-Korea
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• v.25 no.2
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• pp.51-59
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• 2020

The purpose of this study is to propose and compare methods for measuring individual spray cone angles using spray cross-section images. In direct injection gasoline engines, it was believed that the distribution of air-fuel mixture in the combustion chamber directly affected combustion performance and emission formation. However, since gasoline direct injection (GDI) injectors have a small injection angle, interference between individual spray plumes occurs. Therefore, GDI injectors have only measured the spray angle of the entire spray. To overcome these limitations, three methods of indirectly measuring the spray cone angles of individual spray plume were presented and compared by forming sheet beams using Nd:YAG laser and acquiring spray cross-section images. Each method currently has advantages and disadvantages, and research to apply the method suitable for various GDI injectors needs to be continued.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.2076-2081
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• 2004

Future exhaust gas limits for diesel-driven passenger cars will force the automotive industry to significantly improve the performance of engine. Since modern common-rail injection systems deliver more degrees of freedom referring to the injection process, again the optimization of the injection process could offer a possibility to meet the exhaust gas limits. This study describes the characteristic the pilot spray structure of piezo-driven injector for a passenger car common-rail system to be applicable multiple injection caused by fast response rather than solenoid-driven injector. The piezo-driven injector is prototype injector with same needle chamber of solenoid injector and the solenoid-driven one is commercial injector. The pilot spray characteristic such as spray tip penetration, spray speed, spray angle were obtained by spray images, which is measured by the Mie scattering method with optical system for high-speed temporal photography. It was found that piezo-driven injector effected electric change as important factor and showed faster response than solenoid-driven injector.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.1
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• pp.67-73
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• 2011

The purpose of this study is to investigate experimentally the spray-atomization and combustion-emission characteristics of biodiesel-DME blended fuel. In this study, two types of test fuels pure biodiesel (BD100) and blended fuel (B-DME20) were used, and the spray and combustion characteristics of different fuel compositions were analyzed. DME constitutes 20% and biodiesel constitutes 80% (by mass fraction) of the blended fuel. The overall spray characteristics, spray tip penetration, and cone angle were evaluated using frozen spray images. In addition, the combustion and emission characteristics were analyzed on the basis of the evaluated data for a single-cylinder CI engine with common-rail injection system. It was revealed that the injection profiles of both the test fuels for a given injection pressure showed similar trends. However, the injection profiles of the blended fuel (B-DME20) indicated shorter ignition delay than those of biodiesel.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.841-844
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• 2006

Recently, tunnels being constructed in korea with the increased construction of highways, high-speed railways and hydro structure. shotcrete and spray is one of the major processes in that construction. So general Shotcrete and spray has many problems on strength property, environmental pollution and human body noxiousness as the use of accelerater. However, In this paper using HES-LMS(High Early Strength Latex Modified Spray) without accelerater can solve problems which are mentioned above. problems that the hish early cement has can be solved by modifying material with latex. Therefore HES-LMS mortar is Classify by High performance and High ability. Analysis according to the variables such as W/C, Latex content and sand content is conducted. Studied about mechanical characteristic of material such as each parameter characteristic, and rebound characteristic is completed.

• International Journal of Automotive Technology
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• v.6 no.3
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• pp.215-219
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• 2005

Liquefied petroleum gas (LPG) has been used as motor fuel due to its low emissions and low cost. A liquid direct injection system into a cylinder was suggested as a next generation system to maximize a fuel economy as well as a power. This study addresses the analysis of the LPG spray injecting from single hole injector. Two different test conditions are given, which are a fully developed spray case with various injection pressures and a developing spray case with ambient pressure variation. The LPG spray photographs are compared with the sprays of gasoline and diesel fuel at the same conditions, and the spray angles and penetration lengths are also compared, and then the spray behavior is analyzed. The LPG spray photos show that the dispersion characteristic depends very sensitively on the ambient pressure soon after injection. The spray angle is very wide in a low ambient pressure condition until the saturated pressure, but the angle is quickly reduced at the condition over the pressure. However, the down stream of the LPG spray shows much wider dispersion and less penetration than those of gasoline and diesel sprays regardless ambient pressure condition.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.11a
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• pp.217-220
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• 2009

This paper presents experimental results of Recess Characteristic of Swirl Coaxial Injector of fuel-rich gas generators. It was revealed that the internal impinging phenomenon played an important role in the spray characteristics, such as spray angle and breakup length.