• Proceedings of the KSME Conference
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• 2002.08a
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• pp.393-396
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• 2002

Submerged gas-injected system can be applied to various industrial field such as metallurgical and chemical processes, So this study aims at presenting the relevant relationship between gas phase and liquid phase in a gas-injected bath. In a cylinderical bath, local gas volume fraction and bubble frequency were measured by electroconductivity probe and oscilloscope. The temperature of each phase was measured using thermocouple and data acquisition system. In vertical gas injection system, gas-liquid two phase plume was formed, being symmetry to the axial direction of injection nozzle and in a shape of con. Lacal gas-liquid flow becomes irregular around the injection nozzle due to kinetic energy of gas and the flow variables show radical change at the vicinity of gas(air) injection nozzle As most of the kinetic energy of gas was transferred to liquid in this region, liquid started to circulate. In this reason, this region was defined as 'developing flow region' The Bubble was taking a form of churn flow at the vicinity of nozzle. Sometimes smaller bubbles formed by the collapse of bubbles were observed. The gas injected into liquid bath lost its kinetic energy and then was governed by the effect of buoyancy. In this region the bubbles which lost their kinetic energy move upward with relatively uniform velocity and separate. Near the gas nozzle, gas concentration was the highest. But it started to decrease as the axial distance increased, showing a Gaussian distribution.

• Journal of Mechanical Science and Technology
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• v.14 no.12
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• pp.1365-1375
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• 2000

Two phase flows have been numerically calculated to analyze plume characteristics and liquid circulation in gas injection through a porous plug. The Eulerian approach has been for formulation of both the continuous and dispersed phases. The turbulence in the liquid phase has been modeled using the standard $textsc{k}$-$\varepsilon$ turbulence model. The interphase friction coefficient has been calculated using correlations available in the literature. The turbulent dispersion of the phase has been modeled by the "dispersion Prand시 number". The predicted mean flows is compared well with the experimental data. The plume region area and the axial velocities are increased with the gas flow rate and with the decrease in the inlet area. The turbulent intensity also shows the same trend. Also, the space-averaged turbulent kinetic energy for various gas flow rates and inlet areas has been obtained. The results are of interest in the design and operation of a wide variety of materials and chemical processing operations.

• Transactions of the Korean Society of Automotive Engineers
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• v.9 no.6
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• pp.1-7
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• 2001

Recently, several LPG engines for heavy-duty vehicles have been developed, which can replace some diesel engines that are one of a main source for air pollution in urban area. As a preliminary study on the liquid phase LPG injection (hereafter LPLI) system applicable to a heavy duty LPG engine, the engine output and combustion performance were investigated with various combustion chambers and fuel compositions using a single cylinder engine equipped. Experimental results revealed that ellipse, double ellipse and nebula type combustion chamber made a more advantage in breaking swirl flow into small turbulence scale than bathtub type. Especially, performance of nebula type showed most highest efficiency and engine output under lean mixture conditions. An investigation fur various LPG fuel compositions was also carried out, and revealed that the case with 40% propane and 60% butane shows the lowest efficiency at stoichiometry, however, as the mixture became leaner its efficiency increased and became even higher for 100% propane case.

• Journal of ILASS-Korea
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• v.6 no.3
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• pp.32-37
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• 2001

The characteristics of engine performance with fuel injection system in D.I. diesel engine were studied in this paper. A fuel injection system has an important role in the performance and emission gas in a diesel engine. In this paper, an experimental study has been performed to verify the effect of the performance and the emission gas with the factors such as diameters of an injection nozzle hole, diameters of an injection pipe and injection timing in the fuel injection system. The authors have obtained the results that optimizing the factors of fuel injection system is significant to enhance the performance of the engine system and consumption ratio of fuel, smoke, and NOx.

• Transactions of the Korean Society of Automotive Engineers
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• v.10 no.4
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• pp.23-32
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• 2002

Combustion and flame propagation characteristics of the liquid phase LPG injection (LPLI) engine were investigated in a single cylinder optical engine. Lean bum operation is needed to reduce thermal stress of exhaust manifold and engine knock in a heavy duty LPG engine. An LPLI system has advantages on lean operation. Optimized engine design parameters such as swirl, injection timing and piston geometry can improve lean bum performance with LPLI system. In this study, the effects of piston geometry along with injection timing and swirl ratio on flame propagation characteristics were investigated. A series of bottom-view flame images were taken from direct visualization using an W intensified high-speed CCD camera. Concepts of flame area speed, In addition to flame propagation patterns and thermodynamic heat release analysis, was introduced to analyze the flame propagation characteristics. The results show the correlation between the flame propagation characteristics, which is related to engine performance of lean region, and engine design parameters such as swirl ratio, piston geometry and injection timing. Stronger swirl resulted in foster flame propagation under open valve injection. The flame speed was significantly affected by injection timing under open valve injection conditions; supposedly due to the charge stratification. Piston geometry affected flame propagation through squish effects.

• Journal of ILASS-Korea
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• v.8 no.1
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• pp.9-15
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• 2003

The liquid phase LPG injection (LPLI) system is considered as one of the next generation fuel supply systems for LPG, vehicles, since it can accomplish the higher power, higher efficiency, and lower emission characteristics than the existing mixer type fuel supply system. However, during the injection of liquid LPG fuel into the inlet duct of an engine, a large quantity of heat is extracted due to evaporation of fuel. A problem is that the moisture in the air freezes around the outlet of a nozzle, which is called icing Phenomenon. It may cause damage to the outlet nozzle of an injector. The frozen ice deposit detached from the nozzle also may cause a considerable damage to the inlet valve or valve seat. In this work, the experimental investigation of the icing phenomenon was carried out. The results showed that the icing phenomenon and process were mainly affected by humidity of inlet air instead of the air temperature in the inlet duct. Also, it was observed that the icing occurs first in the inlet of a nozzle, and grows considerably at the upper part of the nozzle inlet and the opposite side of the nozzle entrance. An LPG fuel, mainly consisting of butane, has lower latent heat of vaporization than that of propane, which is an advantage in controlling the icing phenomenon.

• 유체기계공업학회:학술대회논문집
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• 2005.12a
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• pp.273-277
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• 2005

The large particles of suspended matter in raw water can be removed by allowing them to settle out in a presedimentation basin. But there are smaller particles in almost all surface water and some groundwater that will not settle out within a reasonable time without some help to accelerate the process, In the coagulation and flocculation processes, nonsettleable solids are converted into large and heavier settleable solids by physical-chemical changes broght about by adding and mixing coagulant chemicals into the raw water. The object of this research was to improve corrective injection method for low dissolution liquid in the water treatment plant. A sort of chemical feed equipment are diaphram pump, flow control in combined magnetic flowmeter md control valve, roto dipper wheel system and tube pump. Particularly low dissolution liquid (Calcium Hydroxide) put in a bit by feed equipment, tube pump is very useful method for corrective injection method in the water treatment plant.

• Transactions of the Korean Society of Mechanical Engineers
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• v.6 no.3
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• pp.256-260
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• 1982

This paper presents the characteristics of fuel spray in a diesel engine. In this paper, in order to obtain spray droplet size in a diesel engine, water was injected into the cylinder at room temperature and pressure by injection system. Spray droplet size was measured by liquid immersion technique with a lubricant used as an immersion liquid for spray water from injection nozzle. In this experiment, single hole type throttle nozzle are used at same operating conditions, which included opening pressure of nozzle, fuel delivery, and injection speed. Sauter mean diameter decrease with the increase of injection pressure and decrease in injection nozzle diameter. The rate of spray penetration increased with increasing injection pressure and diameter of injection nozzle at the constant spray conditions.

• 한국전산유체공학회:학술대회논문집
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• 1997.10a
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• pp.113-119
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• 1997

This paper addresses to the injection pressure effect on the diesel spray. The injection pressure is varied from 10MPa, in general system, upto 200MPa, in high pressured system in order to understand the effect. The gas phase is modelled in terms of the Eulerian continuum conservation equations of mass, momentum, energy and fuel vapour fraction. The liquid phase is modelled following the discrete droplet model approach in Lagrangian form. The droplet distributions, vapor fractions and gas flows are analyzed in various injection pressure cases.

• Journal of ILASS-Korea
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• v.6 no.1
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• pp.1-8
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• 2001

Fuel injection system is very important in diesel combustion. Recently electronic control of fuel injection system and common rail systems are introduced to reduce the emission and to increase the energy efficiency from diesel engine by control of the injection timing and duration. In this study, evaluation possibility of the system for electronic control by spool valve, one of the accumulator type injection systems with spool valve using solenoid was composed and the operating characteristics were investigated to evaluate the effects of spring coefficient, initial spring force, solenoid driving time, fuel supply pressure on the injection timing and duration. We could confirm the capability that diesel injection was electronically controlled by spool valve.