• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1629-1633
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• 2004

Liquid is commonly introduced as transversal jets in venturi scrubber which is one of the gas cleaning equipments. The jet dynamics such as penetration and breakup is of fundamental importance to the dust-collection efficiency. We have developed a model that can numerically simulate the breakup of the liquid jet in crossflow. This simulation consists of models on liquid column, jet surface breakup, column fracture and secondary droplet breakup. These models have been embedded in the KIVA3-V code. We have calculated such parameters as the jet penetration, jet trajectory, droplet size, velocity field and the volume flux distribution. The results are compared with the experimental data in this paper.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.11a
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• pp.83-88
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• 2007

The spray characteristics and liquid column penetration of steady and pulsed injection measurements have been experimentally studied using high speed camera in liquid jets injected into subsonic crossflow. The objectives of this research are to comparison the spray characteristics of steady injection with pulsed injection. Moreover. the effects of frequency are also studied. As the result, This research has been showed that pulsed injection has different penetration compared with steady injection.

• Journal of ILASS-Korea
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• v.15 no.4
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• pp.170-176
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• 2010

This paper describes the grid-size dependency of the conventional Eulerian-Lagrangian method to spray characteristics such as spray penetration and SMD in modeling DME sprays. In addition, the reduction of the grid-size dependency of the present Gas-jet model was investigated. The calculations were performed using the KIVA code and the calculated results were compared to those of experimental result. The results showed that the conventional Eulerian-Laglangian model predicts shorter spray penetration for large cell because of inaccurate calculation of momentum exchange between liquid and gas phase. However, it was shown that the gas-jet model reduced grid-size dependency to spray penetration by calculating relative velocity between liquid and ambient gas based on gas jet velocity.

• Journal of ILASS-Korea
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• v.6 no.3
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• pp.17-22
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• 2001

Recently LPG engine is developed to fulfill such new requirements as improved fuel efficiency in additional to further reduced exhaust emission. This experimental study is conducted to analyze spray characteristics for pintle type injector used in a LPLi (Liquid Phase LPG injection) engine. Since spray parameters including penetration length and spray angle make a role to design injector and engine intake system, spray visualization experiment is performed under atmosphere ambient and charging condition using Mie scattering method. From the experimental result under various LPG formation, the increased propane component decreases penetration length because boiling point of propane is lower than butane. To simulate intake charging condition in MPI engine, spray visualization is performed under high pressure condition. As a result, as ambient pressure is increased from atmosphere to 3.0 bar, penetration length is decreased. However, as ambient pressure is increased from atmosphere to 3.0 bar, spray angle is increased.

• Korean Journal of Materials Research
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• v.18 no.3
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• pp.128-136
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• 2008

Evaluation of the solid surface properties by an analysis of the liquid penetration rate into powder beds is very important in applications of powder products. The penetration rate is related the surface property in powder beds. In order to analyze the surface property of powders, the contact angle values of several powders were obtained using the Washbun equation and the Wicking method. The surface free energy value ${\gamma}S$ was divided into a polar component ${\gamma}S^p$ and a dispersion component ${\gamma}S^d$. Inorganic powders such as calcite were used as test samples. The effects of the particle size and the type of experimental liquid on the penetration rate were measured. It was confirmed that the surface free energy of the grinding sample is smaller than that of the classification sample.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.34 no.3
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• pp.25-31
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• 2002

The purpose of this study was to analyze how the fiber properties and mixing ratio of softwood and hardwood pulp affect on roundness of printed image. Softwood pulp and hardwood pulp were refined to 400 and 600ml CSF by Valley beater and handsheets of 70 g/$m^2$ basis weight were made at different mixing ratios of hardwood and softwood pulp. The roundness, dot area, and shape of the printed dot were measured by Image Analyzer. The depths and shapes of the acridine orange penetration into paper were measured by CLSM. With higher mixing ratio of hardwood pulp, the paper showed higher air-permeability and better formation, especially at lower freeness. The roundness of the printed image became better and the dot size became smaller when the amount of hardwood pulp increased. Penetration depth of acridine orange by CLSM became greater and roundness increased to real circle when the amount of hardwood pulp increased. It was thought that higher mixing ratio of hardwood fibers resulted in efficient penetration by better formation with uniform micro-pore distribution and it increased roundness. It was thought that fiber properties and mixing ratio affected the structure of paper and the shape of the printed dot. This study showed that the measurement of depth of the liquid penetration into paper without destruction and contact was feasible. Moreover, this method showed that the shape of the liquid penetration was measurable.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.6
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• pp.727-736
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• 2016

Numerical simulations of n-heptane spray characteristics in a constant volume combustion chamber under diesel engine like conditions with increasing ambient gas density ($14.8-142kg/m^3$) and ambient temperature (800-1000 K) respectively were performed to understand the non-vaporizing and vaporizing spray behavior. The effect of fuel temperature (ranging 273-313 K) on spray characteristics was also simulated. In this simulation, spray modeling was implemented into ANSYS FORTE where the initial spray conditions at the nozzle exit and droplet breakups were determined through nozzle flow model and Kelvin-Helmholtz/Rayleigh-Taylor (KH-RT) model. Simulation results were compared with experimentally obtained spray tip penetration result to examine the accuracy. In case of non-vaporizing condition, simulation results show that with an increment of the magnitude of ambient gas density and pressure, the vapor penetration length, liquid penetration length and droplet mass decreases. On the other hand vapor penetration, liquid penetration and droplet mass increases with the increase of ambient temperature at the vaporizing condition. In case of lower injection pressure, vapor tip penetration and droplet mass are increased with a reduction in fuel temperature under the low ambient temperature and pressure.

• Journal of ILASS-Korea
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• v.19 no.4
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• pp.155-166
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• 2014

This review will be concentrated on the spray characteristics of bioethanol and its derived fuels such as ethanol-diesel, ethanol-biodiesel in compression ignition (CI) engines. The difficulty in meeting the severe limitations on NOx and PM emissions in CI engines has brought about many methods for the application of ethanol because ethanol diffusion flames in engine produce virtually no soot. The most popular method for the application of ethanol as a fuel in CI engines is the blending of ethanol with diesel. The physical properties of ethanol and its derivatives related to spray characteristics such as viscosity, density and surface tension are discussed. Viscosity and density of e-diesel and e-biodiesel generally are decreased with increase in ethanol content and temperature. More than 22% and 30% of ethanol addition would not satisfied the requirement of viscosity and density in EN 590, respectively. Investigation of neat ethanol sprays in CI engines was conducted by very few researchers. The effect of ambient temperature on liquid phase penetration is a controversial topic due to the opposite result between two studies. More researches are required for the spray characteristics of neat ethanol in CI engines. The ethanol blended fuels in CI engines can be classified into ethanol-diesel blend (e-diesel) and ethanol-biodiesel (e-biodiesel) blend. Even though dodecanol and n-butanol are rarely used, the addition of biodiesel as blend stabilizer is the prevailing method because it has the advantage of increasing the biofuel concentration in diesel fuel. Spray penetration and SMD of e-diesel and e-biodiesel decrease with increase in ethanol concentration, and in ambient pressure. However, spray angle is increased with increase in the ethanol percentage in e-diesel. As the ambient pressure increases, liquid phase penetration was decreased, but spray angle was increased in e-diesel. The increase in ambient temperature showed the slight effect on liquid phase penetration, but spray angle was decreased. A numerical study of micro-explosion concluded that the optimum composition of e-diesel binary mixture for micro-explosion was approximately E50D50, while that of e-biodiesel binary mixture was E30B70 due to the lower volatility of biodiesel. Adding less volatile biodiesel into the ternary mixture of ethanol-biodiesel-diesel can remarkably enhance micro-explosion. Addition of ethanol up to 20% in e-biodiesel showed no effect on spray penetration. However, increase of nozzle orifice diameter results in increase of spray penetration. The more study on liquid phase penetration and SMD in e-diesel and e-biodiesel is required.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.99-102
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• 2009

LES(Large eddy simulation) of breakup and atomization of a liquid jet into cross turbulent flow was performed. Two phase flow between a gas phase and a liquid phase was modeled by a mixed numerical scheme of both Eulerian and Lagrangian methods for gas and liquid phases respectively. The first and second breakup of liquid column was observed. The penetration depth in cross flow was comparable with experimental data for several variant of a liquid-gas momentum flux ratio by varying liquid injection velocities. SMD(Sauter Mean Diameter) distribution downstream of jet was analyzed.

• Journal of ILASS-Korea
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• v.14 no.2
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• pp.59-64
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• 2009

These experiments are close examination of spray characteristics that are continuous liquid jet and modulated liquid jet. The experiments were conducted using water, over a range of crossflow velocities from $42{\sim}l36\;m/s$, with modulation frequencies of $35.7{\sim}166.2\;Hz$. Between continuous crossflow jet and modulated cross-flow jet of penetration, breakup point, spray angle and macro spray shape are experimentally investigated with image analysis. In cross-flow field, main parameter of liquid jet for breakup was cross-flow stream rather than modulation effect. As oscillation of the periodic pressure that could make liquid jet moved up and down, the mixing efficiency was increased. Also, a bulk of liquid jet puff was detected at upper field of liquid surface. So, this phenomenon has a good advantage of mixing spray from concentration of center area to outer area. Because of modulation frequency, SMD inclination of the structured layer was evanescent. Cross-sectional characteristics of SMD at downstream area were non-structured distributions. Then cross-sectional characteristics of SMD size were about same tendency over a range that is effect of spray mixing. The tendency of volume flux value for various modulation frequency was same distribution. And volume flux was decreased when the modulation frequency increase.