• 한국분무공학회지
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• 제11권4호
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• pp.244-250
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• 2006

Of the macroscopic spray characteristics of non-reacting diesel fuel sprays, the spray angle reflects directly the atomization and air entrainment processes downstream the nozzle. In addition, spray angle is important because it will be closely related to the spray penetration. The existing definitions for the measurement of spray angle as well as the correlations for the prediction of spray angle are, therefore, summarized and reviewed. The existing definition of spray angle can be classified into four groups: distance based on orifice diameter, distance based on spray tip penetration, definition based on surface wave, and definition based on atomization. It is strongly required to specify the definition and measurement method when the data for spray angle is reported. The existing correlations for spray angle can be classified into two groups: theoretical and empirical correlations. The study on the evaluation of the existing correlations fer spray angle is required.

• 한국분무공학회지
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• 제5권3호
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• pp.17-26
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• 2000

The main parameter commonly used to evaluate spray distribution is spray angle. Spray angle is important because it influences the axial and radial distribution of the fuel. Spray angles were measured and compared for the two non-air assisted injectors such as 2hole-2stream 4hole-1stream injectors used for port fuel injection gasoline engines with n-heptane as a fuel by three different measuring techniques, i.e., digital image processing, shadowgraphy, and spray patternator, respectively. Fuel was injected with the injection pressures of 0.2-0.35 MPa into the room temperature and atmospheric pressure environment. In digital image processing approach, the selection of the transmittance level is critical to obtain the edge of spray and hence to measure the spray angle. From the measurement results by the shadowgraphy technique, it is dear that the spray angle is varied during the spray injection period. The measurement results from spray patternator show that the different spray angles exist in different region. Spray angle increases with the increase in the injection pressure. it is suggested that the spray angle and stream separated angle should be specified when spray is characterized for 2hole-2stream injector, because spray angle is much different though stream separated angle is same. It was also considerably affected by the measurement techniques introduced in this experimental work. However, the optimal axial distance for measuring the spray angle seems to be at least 60-80 mm from the injector tip for two non-air assisted injectors.

• 대한기계학회논문집B
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• 제28권11호
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• pp.1459-1466
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• 2004

The purpose of this study is to investigate the effect of swirler angle and the aspect ratio of swirl chamber of nozzle on the characteristics of single and twin spray. The characteristics of sprays have been investigated by measuring the spray angle, droplet size and velocity. Visualization of spray was conducted to obtain the spray angle and breakup process. The spray characteristics such as droplet size and velocity were measured by Phase Doppler Anemometry(PDA). It was found that the spray angle was increased with increasing the swirler angle. For both sprays, the axial velocity and SMD were decreased with increasing the swirler angle. It was also shown that the axial velocity and SMD were decreased with increasing the aspect ratio of swirl chamber, but for the twin spray, the axial velocity and SMD were not influenced significantly by the changing the aspect ratio of swirl chamber. The effect of swirler angle on the spray characteristics was greater than the aspect ratio of swirl chamber for single spray. The nozzle pitch was one of the important factors affecting the spray characteristics of twin spray.

• 한국분무공학회지
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• 제16권4호
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• pp.201-209
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• 2011

Optimum engine performance is obtained when the spray characteristics is well matched to the geometry of a combustion chamber. Among many parameters governing the combustion performance in internal combustion engine, fuel supply characteristics and atomization are important performance factors. Therefore, spray characteristics of high pressure multi-hole injector has been studied experimentally. An experimental test system has been made to operate high pressure injection system and to visualize spray behavior. Spray visualization has been performed to analyze spray formation, spray cone angle, bent angle and penetration length. Spray interaction with piston has been analyzed with various injector installation angle, injection pressure and ambient pressure. Test results show that penetration length is greatly influenced by the injection pressure. Penetration length is decreased as ambient pressure increased. Spray cone angle is increased as injection pressure and ambient pressure increased. However, bent angle is not influenced by the change of injection pressure and ambient pressure. Spray cone angle distribution map is plotted using the experimental data. Fuel movement around the spark-plug has been enforced as increasing injector installation angle.

• 한국분무공학회지
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• 제26권1호
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• pp.9-17
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• 2021

Six shear coaxial injectors with different recess length and taper angle were manufactured. Cold-flow tests on the injectors were performed at room temperature and pressure using water and air as simulants. By changing the water mass flow rate and air mass flow rate, spray images were taken under single-injection and bi-injection. Breakup length and spray angle were analyzed from instantaneous and averaged spray images using image processing techniques. For all the injectors, the breakup length generally decreased as the momentum flux ratio increased at the same gas mass flow rate. The injectors with 7.5° taper angle usually had the longest breakup length and the smallest spray angle. When the taper angle was 15° or more, it hardly affected breakup length and spray angle. The recess length did not influence breakup length but its effect on spray angle depended on the taper angle.

• 한국분무공학회지
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• 제10권4호
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• pp.1-7
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• 2005

The purpose of this study is to investigate the effect of swirler vane angle and the aspect ratio of swirl chamber of nozzle on the characteristics of single spray. The characteristics of sprat's have been investigated by measuring the spray angle, droplet size and velocity Visualization of spray was conducted to obtain the spray angle and breakup process. The spray characteristics such as droplet size and velocity were measured by Phase Doppler Anemometry(PDA). It was found that the spray angle was increased with increasing the swirler angle. For both sprays, the axial velocity and SMD were decreased with increasing the swirler vane angle. It was also shown that the axial velocity and SMD were decreased with increasing the aspect ratio of swirl chamber The effect of vane angle un the spray characteristics was greater than the aspect ratio of swirl chamber for single spray.

• 한국자동차공학회논문집
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• 제6권5호
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• pp.182-190
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• 1998

Behaviour of ultra-high pressure diesel spray in a constant-volume pressure chamber was studied with injection pressure ranging from 20 to 160㎫. Sprays were observed by the right angle scattering method. As a result, the spray tip penetration is first proportional to a time, and after that, it is proportional to 0.52 of the time during at the time of injection pressure and back pressure increase. An empirical correlation was made for the parameters of injection pressure, air-fuel density ratio, spray tip distance, spray angle, jet angle of spray and max. spray width.

• 한국분무공학회지
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• 제4권4호
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• pp.9-16
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• 1999

Spray angle, a parameter which is most commonly used to evaluate. spray distribution, is important because it affects the axial and radial distribution of the fuel. Spray angles were measured and compared for the pintle-type gasoline fuel injector with n-heptane as a test fuel with the three different measuring techniques, i.e. digital image processing, shadowgraphy and spray patternator, respectively. Fuel was injected with the injection pressures of 0.2-0.35MPa into the room temperature and atmospheric pressure environment. In digital image processing method, the transmittance level greatly influences the spray angle with the axial distance from the injector. From the experimental results by the shadowgraphy technique, it is obvious that the spray angle vary during the injection period. The results of spray angle from the spray patternator show that there exist the different spray angles in the different areas. The spray angles increase with the increase in the injection pressure for the three measurement techniques considered in this study. The spray angle is widely different, especially in the near region from the injector, according to the measurement techniques used in this experimental work.

• 한국분무공학회지
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• 제12권1호
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• pp.11-17
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• 2007

The swirl spray for direct-injection spark-ignition (DISI) engines was investigated using a nozzle whose exit surface shape was cut with a certain tapered angle. The reason for the change in spray's characteristics at various tapered angles was explained by the data correlating the taper and flow angles. The spray tended to shift its characteristics from the symmetric to asymmetric when the tapered angle was increased; furthermore, the spray penetration and spray cone angle were also increased. When the tapered angle was greater than the $90^{\circ}$ minus flow angle, an opened hollow cone spray was formed because of the fuel impingement against the tapered surface area of the nozzle exit. This behavior indicates that the reduction in the air pressure difference between the inner and outer spray of the spray can be achieved. This behavior also promises the potential use of the tapered nozzle for the case where the independence of the spray performance from atmospheric pressure and fuel temperature is desired.

• 한국마린엔지니어링학회:학술대회논문집
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• 한국마린엔지니어링학회 2002년도 춘계학술대회논문집
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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.