• 대한기계학회논문집B
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• 제31권3호
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• pp.283-291
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• 2007

The static pressure distribution, atomization characteristics and velocity distribution of tapered nozzle swirl spray is analyzed and then compared with original swirl spray. The static pressure distribution inside the swirl spray is measured using a piezoresistive pressure transducer. Phase Doppler anemometry (PDA) is applied to measure and analyze the droplet size and velocity distribution of tapered nozzle and original swirl spray. The static pressure inside the spray shows the lower value compared to the atmospheric pressure and this pressure drop is getting attenuated as the taper angle is increased. The droplet size of tapered nozzle spray shows similar value compared to the original swirl spray at the horizontal mainstream while it shows increased value at vertical mainstream. The deteriorated atomization characteristics of tapered nozzle spray is improved by applying high fuel temperature injection without causing the spray collapse. The velocity results show that the larger portion of fuel is positioned with higher injection velocity, and the smaller portion of fuel is positioned with lower injection velocity with causing spatially non-uniform mixture distribution.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2002년도 제24회 KOSCO SYMPOSIUM 논문집
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• pp.16-23
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• 2002

Electrostatic pressure-swirl nozzle for practical oil burner application has been designed. The charge injection method has been used in this design, where the nozzle consists of a sharp pointed tungsten wire as a charge injector and the nozzle body grounded. The spray characteristics of the nozzles have been investigated by using an insulating liquid, i.e. kerosene without active surface agent. Breakup length of liquid decreased with an increase in applied voltage and injection pressure, while the spray angle increased with an increased in both applied voltage and injection pressure. An empirical equations have been suggested to predict the breakup length for electrostatic pressure-swirl atomizer. The experimental result was within the range of the predicted equations. The SMD decreased between the ranges of 2.8 ${\sim}$ 33% when the conventional nozzle was compared to the electrostatic with -10 kV applied to the electrode at a radial distance from 5 to 20 mm.

• 한국분무공학회지
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• 제4권4호
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• pp.24-29
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• 1999

In the pressure swirl atomizer, the liquid is injected through tangential passages into a swirl chamber, from which it emerges with both tangential and axial velocity components to form a thin conical sheet at the nozzle exit. This sheet rapidly attenuates, finally disintegrating into ligaments and then drops. The purpose of this study is to measure the spray characteristics according to variation of viscosity of the spray produced by the pressure swirl atomizer. The nozzle tested here were especially designed for this investigation. The discharge coefficient is determined by measuring the volume flow rate with a flow meter and the cone angle of the liquid sheets issuing from the nozzle is obtained from series of photographs of the sheet for various liquid viscosity and injection pressure. And mean drop size is measured by image processing method. It is found that the geometrical characteristics of the nozzle and the variation of viscosity were the influential parameters to determine the spray characteristics such as the cone angle, discharge coefficients and SMD.

• 한국자동차공학회논문집
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• 제21권4호
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• pp.89-95
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• 2013

In this work, the evaluation of swirl nozzle injector performance was conducted by investigating effective area ($A_{eff}$), injection mass ($m_{inj}$), injection rate ($Q_{inj}$), and injection delay ($t_{delay}$) under various test conditions. To achieve these, fuel injection analysis system which was composed of fuel supply system, injection system, and control system was installed. At the same time, the swirl nozzle that had 12 orifice hole with $120^{\circ}$ injection angle was used in this work. It was revealed that the difference of injection mass ($m_{inj}$) between base and swirl nozzle injector increased as the injection pressure ($P_{inj}$) and energizing duration ($t_{eng}$) decreased under the same test conditions. The maximum injection rate ($Q_{inj}$) of swirl nozzle injector was higher than base nozzle injector about 2~5%. The injection performance of swirl nozzle was better than base nozzle at low injection pressure ($P_{inj}$) and short energizing duration ($t_{eng}$) conditions.

• 한국농공학회지
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• 제17권4호
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• pp.3991-4000
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• 1975

It is the aim of this study to investigate the influence of the factors in the sprayer nozzle for the travelling distance and to get nozzle design data in relation to the nozz1e with and without swirl plate. The factors of sprayer nozzle are composed of the spraying pressure, the helical angle of swirl plate, the helical groove depth of swirl plate, the distance of vortex chamber the slope of nozz1e cap, the curvature of nozzle cap and the hole diameter of nozz1e cap. The travelling distance and the size of sprayed particle are experimeted indoors by the factorial arrange-ment according to the 5 each level of the above factors. The results of this stupy are summarized as follows; 1. In the nozzle with swirl p1ate there were remarkable significance among factors each other, while without swirl plate were no significance. 2. The helical angle and groove depth in the nozzle with swirl plate were the highest effective factors. The effect of helical angle was very remarked in the quadratic curve with minium value. 3. The correlation betweenthe travelling distance and the sprayed particle size was no high and under 250 micron in the case with swirl plate, and there was higher correlation in the case without swirl plate. 4. The new ideal development of the swirl plate using of the most effective helical angle and groove depth will probably show the possiblities to make effective travelling distance over 8 meters and more over and to make average particle diameter under 300 micron.

• 한국분무공학회지
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• 제12권4호
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• pp.211-219
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• 2007

The liquid film thickness inside a pressure-swirl nozzle was measured, and then the measured liquid film thickness was compared with the results from previous empirical equations. The liquid film inside the nozzle was visualized using extended transparent nozzles and a microscopic imaging system, and then the measurement error was evaluated using optical geometry analysis. The high injection pressures up to 7MPa were adopted to simulate the injection conditions of the direct-injection spark-ignition engines. The totally different two injectors with different fuels, nozzle lengths, nozzle diameters and swirlers were utilized to obtain the comprehensive equations. The results showed that the liquid film thickness very slightly decreased at high injection pressures and the empirical equations overestimated the effect of injection pressure. Most of empirical equations did not include the effect of nozzle length and swirler angle, although it caused significant change in liquid film thickness. A new empirical equation was suggested based on the experimental results with the effects of fuel properties, injection pressure, nozzle diameter, nozzle length and swirler angle.

• 한국분무공학회지
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• 제16권4호
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• pp.210-214
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• 2011

This paper presents the spray characteristics of the gun type burner nozzle with bio-diesel blending rate. The burner nozzle used in this experiment is a pressure swirl type nozzle. For the spray characteristics, visualization of spray was conducted to obtain the spray angle, and laser diffraction spectroscope (LDS) was used for the measurement of the droplet diameters. The results showed that the $D_{max}$, SMD and spray angle were decreased with increasing the bio-diesel blending rate and BD30 (30% bio-diesel blending rate) could be found to be the maximum blending rate for using without any modification of the gun type burner of the homesize kerosene fuel boiler.

• 한국분무공학회지
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• 제11권1호
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• pp.24-29
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• 2006

Spray characteristics produced by conventional and electrostatic pressure-swirl nozzles for an oil burner have been studied, using kerosine as a test liquid. The charge injection mechanism is used to design the electrostatic nozzle, where specific charge density, breakup length, spray angle and mean diameter are measured and analyzed. Three nozzles with orifice diameters of 0.256, 0.308 and 0.333mm at injection pressures of 0.7, 0.9, 1.1 and 1.3 MPa are used in the study. In case of the electrostatic nozzle, voltages ranging from -5 to -12kV are applied. Comparison of the spray characteristics is made between the conventional and electrostatic nozzles. The results showed that, the electrostatic nozzle is superior to the conventional nozzle. This is due the effect of voltage on the liquid surface tension.

• 한국분무공학회지
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• 제9권4호
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• pp.31-37
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• 2004

This paper presents spray and combustion characteristics of hydrocarbon fuel injected from pressure-swirl nozzles. Three commercial nozzles with orifice diameters of 0.256, 0.308 and 0.333mm and injection pressures ranging from 0.7 to 1.3 MPa were selected f9r the experiments. Spray characteristics such as breakup length. spray angle and drop size (SMD) were analyzed using photo image analyses and Malvern Panicle Size Analyzer. The drop size was measured with and without a blower at the same measuring locations. The flame length and width were measured using photo image analyses. The temperature distribution along the axial distance and the gas emission such as CO, $CO_2\;and\;NO_x$ were studied. The breakup length decreased with an increase in injection pressure for each nozzle but increased with an increase in nozzle orifice diameter. The spray angle increased and SMD decreased with an increase in injection pressure. The flame with an increased linearly with an increase in injection pressure and in nozzle orifice diameter. The flame temperature increased with an increase in injection pressure but decreased along the axial distance. The maximum temperatures occurred closer to the burner exit and flame at axial distance of 242mm from the diffuser tip. The experimental results showed that the level of CO decreased while that of $CO_2\;and\;NO_x$ increased with an increase in injection pressure and nozzle orifice diameter.

• Journal of Biosystems Engineering
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• 제31권3호
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• pp.153-160
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• 2006

This study was performed to evaluate some geometrical characteristics of disc type swirl nozzles and to develop nozzles having improved spraying performance for knapsack sprayers. Considered geometrical characteristics of the nozzles were disc thickness, orifice diameter, swirl chamber diameter and shape of the swirl chamber (nozzle chamber). 3 types of nozzle cores were compared. Main results of this study were as follows. 1. Spraying angle (A) was increased with decreasing disc thickness (x), and with increasing orifice diameter (y) or spraying pressure (z). The equation was as a follow. $$A=3.95\frac{1}{x}+73.50\sqrt{y}+18.97\sqrt{z}-60.16$$ 2. Spraying flow rate (F) was increased with decreasing disc thickness (x), and with increasing orifice diameter (y) or spraying pressure (z). The equation was as a follow. $$F=-89.95x+611.09y+620.49\sqrt{z}-868.20$$ 3. Mean spraying droplet size (V) was decreased with decreasing disc thickness (x), with increasing orifice diameter (y) in low spraying pressure, with decreasing orifice diameter (y) in high spraying pressure, and with increasing spraying pressure (z). $$V=148.77x^4-746.85x^3+1311.76x^2-917.31x$$ 4. The spray pattern was compared using CV values. The CV value of the nozzle core type 1 was 26.7% in spraying pressure $3\;kgf/cm^2$, the CV value of the core type 2 was 23.6% in spraying pressure $2\;kgf/cm^2$, the CV value of the core type 3 was 20.6% in spraying pressure $1\;kgf/cm^2$. 5. Minimum spraying pressure was improved from $1.5\;kgf/cm^2\;to\;1.0\;kgf/cm^2$ by changes of nozzle core shape.