• 수산해양기술연구
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• 제12권1호
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• pp.1-6
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• 1976

To investigate the relation of $NO_x$ emission and consumption rate in a direct injection diesel engine with a multihole nozzle under same fuel consumption and rpm, a naphthyl ethylenediaming method on NO, emission and Tektronix oscilloscop on the indicator diagrams have been used. Comparisons of the $NO_x$ emission and fuel consumption rate made on various conditions have led to the fllowing results. 1. The higher the injection pressure in the later injection time the lower $NO_x$ emission and the fuel consumption rate have been attained. 2. By the change of nozzle hole diameter under the same injection pressure, the $NO_x$ emission was much more lowered in the small diameter than large one, but fuel consumption rate was in inverse proption to the $NO_x$ emission. 3. The effect of injection spray angle, $\frac{1_n}{d_n}$ on $NO_x$ emission, fuel consumption rate under same injection time and injection pressure was neglectable.

• 자원리싸이클링
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• 제11권3호
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• pp.17-24
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• 2002

There has been an increasing demand over the years for steels with lower[s] content. For the purpose of improving the efficiency of desulphrization in the powder injection process of ladle, experimental studies were carried out by using cold model to optimize the lance configuration, gas flow rate, immersion depth of lance nozzle, position of lance nozzle relative to the ladle and the effect with slag, etc. As the results of this study, it was made clear that 2-hole nozzle lance (C, E type) placed in an asymmetric position gives the shortest mixing times.

• 대한기계학회논문집B
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• 제30권6호
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• pp.553-559
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• 2006

Most diesel injector, which is currently used in high-pressure common rail fuel injection system of diesel engine, is driven by the solenoid coil energy for its needle movement. The main disadvantage of this solenoid-driven injector is a high power consumption, high power loss through solenoid coil and relatively fixed needle response's problem. In this study, a prototype piezo-driven injector, as a new injector mechanism driven by piezoelectric energy based on the concept of inverse piezo-electric effect, has been designed and fabricated to know the effect of piezo-driven injection processes on the diesel spray structure and internal nozzle flow. Firstly we investigated the spray characteristics in a constant volume chamber pressurized by nitrogen gas using the back diffusion light illumination method for high-speed temporal photography and also analyzed the inside nozzle flow by a fully transient simulation with cavitation model using VOF(volume of fraction) method. The numerical calculation has been performed to simulate the cavitating flow of 3-dimensional real size single hole nozzle along the injection duration. Results were compared between a conventional solenoid-driven injector and piezo-driven injector, both equipped with the same micro-sac multi-hole injection nozzle. The experimental results show that the piezo-driven injector has short injection delay and a faster spray development and produces higher injection velocity than the solenoid-driven injector. And the predicted simulation results with the degree of cavitation's generation inside nozzle for faster needle response In a piezo-driven injector were reflected to spray development in agreement with the experimental spray images.

• 한국자동차공학회논문집
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• 제12권5호
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• pp.19-24
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• 2004

Entrainment of ambient gas into a transient diesel spray is a crucial factor affecting the following preparation of combustible mixture. In this study, the entrainment characteristics of ambient gas for a non-evaporating transient diesel were investigated using a common-rail injection system. The effects of ambient gas density and nozzle hole geometry were assessed with entrainment coefficient. Laser Doppler Velocimetry (LDV) technique was introduced to measure the entrainment speed of ambient gas into a spray. There appeared a region where the entrainment coefficients remained almost constant while injection rates were still changing. The effect of common-rail pressure, which altered the slope of injection rate curve, was hardly noticed at this region. Entrainment coefficient increased with ambient gas density, that is, the effect of ambient gas density was greater than that of turbulent jet whose entrainment coefficient remained constant. The non-dimensional distance was defined to reflect the effect of nozzle hole diameter and ambient gas density together. The mean value of entrainment coefficient was found to increase with non-dimensional distance from the nozzle tip, which would be suggested as the guideline for the nozzle design.

• 한국분무공학회지
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• 제14권4호
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• pp.147-152
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• 2009

Since a liquid-phase LPG injection system allows accurate control of fuel injection and increase in volumetric efficiency, it has advantages in achieving higher engine power and lower emissions compared to the mixer type LPG supplying system. However, this system also leads to an unexpected event called icing phenomenon which occurs when moisture in the air near the injector freezes and becomes frost around the nozzle hole due to extraction of heat from surrounding caused by instant fuel vaporization. As a result, it becomes difficult to control air/fuel ratio in engine operation, inducing exacerbation of engine performance and HC emission. One effort to mitigate icing phenomenon is to attach anti-icing injection tip in the end of nozzle. Therefore, in this study, the effect of engine operation parameters as well as surrounding conditions on icing phenomenon was investigated in a bench test rig with commercially-used anti-icing injection tips. The test results show that considerable ice was deposited on the surface near the nozzle hole of the anti-icing tip in low rpm and low load operating conditions in ambient air condition. This is because acceleration of detachment of deposited ice from the tip surface was induced in high load, high rpm conditions, resulting in decrease in frost accumulation. The results of the bench testing also demonstrate that little or no ice was formed at surrounding temperature below a freezing point since the absolute amount of moisture contained in the intake air is too small in such a low temperature.

• 폴리머
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• 제33권5호
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• pp.407-412
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• 2009

유기발광소자(OLED)에서 정공 수송층(hole injection layer, HIL)으로 사용되는 N,N'-di-1-naphthyl-N,N'-diphenyl-1,1'-biphenyl-4,4'-diamine (NPD)가 정공 주입층(hole injection layer HIL)으로 사용된 PEDOT-PSS 층 위로 진공 증착되었다. PEDOT-PSS 층은 ITO 유리 위에 스핀 코팅되어 제조되었다. 또한, NPD와 $C_{60}$의 공증착에 의해 $C_{60}$이 약 10 wt% 도핑된 NPD-$C_{60}$ 층을 제조하였으며, AFM과 XRD를 이용하여 NPD-$C_{60}$ 박막의 모폴로지 특성을 관찰하였다. 다층 소자를 제조하여 J-Y, L-V 및 전류 효율 특성이 고찰되었다. $C_{60}$박막은 국부적인 결정성 구조를 가지고 있으나, NPD-$C_{60}$ 박막에서는 $C_{60}$ 분자가 균일하게 분산되어 $C_{60}$의 결정성 구조가 확인되지 않았다. 또한, $C_{60}$의 도핑에 의해서 박막의 표면이 균일해지는 것을 확인하였으며, 박막 내의 전류 밀도가 증가됨을 확인하였다. NPD-$C_{60}$ 박막을 이용하여 ITO/PEDOT-PSS/NPD-$C_{60}/Alq_3$/LiF/Al 다층 소자를 제조하였을 때, 소자의 휘도 측면에서 약 80% 향상 효과가 있었으며, 소자 효율 측면에서도 약 25%의 향상을 기대할 수 있었다.

• 오토저널
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• 제15권1호
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• pp.37-44
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• 1993

Fuel injection system is an important tool in the exhaust emission and performance of a diesel engine. Effects of the fuel injection system in diesel combustion was investigated experimentally by measuring the performance and analyzing the combustion phenomena in a D.I. diesel engine. The selected injection parameters were nozzle opening pressure, nozzle projection length, and nozzle spray angle. From the measured results, it is shown that the fuel injection pipe diameter is an effective means to improve engine performance in a middle and high speed range and the 2 stage spring nozzle holder has the advantage of increasing the engine performance due to the initial injection pressure in a low speed range. It has been also shown that increasing nozzle opening pressure resulted in decrease in smoke, but increase in NO$_{x}$ from the engine.e.

• 대한기계학회논문집
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• 제6권3호
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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.

• 한국자동차공학회논문집
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• 제9권2호
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• pp.11-18
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• 2001

To clarify the influence of SAC shape of hole-type diesel nozzle on injection characteristics and spray patterns, the injection rate of three nozzle types(standard SAC nozzle, Needle-cut VCO nozzle and VCO nozzle) were measured by Zeuch's method and pictures of the sprays were taken by CCD camera. As the pump speed became higher, the injection characteristics of the three nozzles were different. Injection rate and perssure curves at the high pressure pipe in Needle-cut VCO nozzle were much more similar to the VCO nozzle than those of the SAC nozzle. When the needle was at pre-lift period for all speeds, the spray of the Needle-cut VCO nozzle showed almost the same shape as the SAC type nozzle. There was no differense in spray pattern at the needle full-lift periods.

• 지질공학
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• 제28권2호
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• pp.193-206
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• 2018

본 연구는 "포항분지 해상 소규모 $CO_2$ 주입실증 프로젝트"의 일환으로 경상북도 포항시 영일만에 설치된 해상 플랫폼에서 $CO_2$ 주입 실증을 위한 주입정 시추 및 완결(well drilling and completion)을 수행하였다. 주입정 시추(well drilling)는 포항분지 해상지역 퇴적지층에 설치한 해상플랫폼의 상부부터 해저면까지 케이싱 설치를 시작으로 단계별로 굴진 공경을 축소하면서 케이싱 설치 및 시멘트 그라우팅(cement grouting)을 시행하며 진행하였다. 최종심도 816.5 m 까지 공경 4 7/8 inch (${\Phi}124mm$) 규격으로 굴진하여 심도 746.5~816.5 m 구간에 유공 케이싱을 설치하여 주입구간을 형성하였다. $CO_2$ 주입을 위한 주입공 완결(well completion)을 위하여 주입관, 패커(packer), 주입탑(christmas tree)을 설치하였다. 주입공을 완결하고 주입 플랜트 설비를 설치하여 $CO_2$ 시험 주입을 성공적으로 수행하였다. 현재의 주입설비는 100톤 규모의 소규모 주입 실증을 위한 설비로서 향후 주입설비 격상을 통하여 총 1만톤의 중규모 실증 주입설비로 추가적인 연구개발을 진행하고 있다.