Injection rate, injection quantity and injection timing of fuel are controlled precisely by electric control in CRDI system.Particularly, injection rate being influenced with injection pressure affects to spray characteristics and fuel-air ratio, so it is a very important factor in diesel combustion. In this study, injection rates in accordance with injection pressure at a constant ambient pressure were measured with Zeuch's method. Under the same condition, non-evaporating spray images were taken with a high speed camera and analyzed carefully with Adobe Photoshop CS3. Macroscopic spray characteristics and breakup processes in the spray could be found from the examined and analyzed data. Injection start time and injection period were practically affected with injection pressure. Also, initial injection rate, spray penetration, spray angle and breakup of high density droplets region in the spray were affected with injection pressure. The results and techniques of spray visualization and injection rate measurement in this study would be practically effective to study a high pressure diesel spray for common rail direct injection system.

Our environment is faced with serious problems related to the air pollution from automobiles in these days. In particular, the exhaust emissions from the diesel engines are recognized main cause which influenced environment strong. In this study, the potential of biodiesel fuel and oxygenated fuel (ethylene glycol mono-n-butyl ether; EGBE) was investigated as an effective method of decreasing the smoke emission. The smoke emission of blending fuel (EGBE 0~20 vol-%) was reduced in comparison with diesel fuel and it was reduced approximately 64% at 2000 rpm, full load in the 20% of blending rate. But torque and brake specific energy consumption (BSEC) didn't have no large differences. But, NOx emissions from biodiesel fuel and EGBE blended fuel were increased compared with diesel fuel.

PURPOSES: This study aims to establish the priority of introducing anti-icing spray system for regions of the National Highways in South Korea. Using this study, a logical plan for instituting such an anti-icing spray system can be established for the National Highways METHODS : The Analytical Hierarchy Process (AHP) was employed to prioritize the implementation of an anti-icing spray system on Korean highways. For this purpose, an existing scoring table developed by the Ministry of Land, Infrastructure Transport Affair was slightly modified in order to reflect recent trends in winter maintenance. A survey was conducted to gather the preferences regarding the developed hierarchy of road experts and agencies. Finally, the final score was produced by integrating the scoring results with estimated weights for each evaluation criterion. RESULTS: In general, Honam and the metropolitan areas have relatively high priority while other areas such as Chungcheong, Young Nam, and Gang Won appear to be uniform in importance in terms of establishing an anti-icing spray system. This result may indicate that historical weather data and traffic volumes are significant factors in deciding in winter maintenance polices CONCLUSIONS : In this study, useful insights are suggested regarding winter maintenance by simultaneously performing rapid snow removal and proactive treatment. Issues of resource allocation may be potential research items in the field transportation engineering.

This study involved the shape of water jet nozzle to promote blasting ability and an increase of projection distance when cleaning VLBC cargo hold. Furthermore, I researched the effect of pressure, length of reducer, nozzle caliber size and nozzle shape on the nozzle through CFD simulation. Simulation of water jet projection process inside VLBC cargo hold was done in both 2D and 3D environment. Simulation results show installing suitable nozzle can increase the cleaning effect of cargo hold.

High temperature plasma coating technology has been applied to recover damaged aluminum dies from wear by spraying pure aluminum and alumina powder. However, the coated mixed powder layer composed of aluminum and alumina often undergoes a detachment from the substrate, making the coated substrate die unable to maintain its expected life span. In this study, in order to increase the bonding strength between the substrate and the coating layer, a pure aluminum layer was applied as an intermediate bond layer. In order to prepare the specimen with variable bond coating conditions, the bond coat layers with a various gun speed from 10 cm/sec to 30 cm/sec were prepared with coating cycle variations ranging from three to nine cycles. The specimen with a bond coat layer coated with a gun speed of 20 cm/sec and three coating cycles exhibited ~13MPa of adhesion strength, while the specimen without a bond coat layer showed ~6 MPa of adhesion strength. The adhesion strength with a variation of bond coat layer thickness is discussed in terms of coating parameters.

Diesel vehicle is regulated EURO 5 and will be apply to EURO 6 in 2014. Thus, researches have been performed to meet the strict emission regulations. We have obtained that the results of engine performance operated by lard biodiesel at various engine load and speed was slightly decreased, but brake specific energy consumption (BSEC) at using animal biodiesel below 15% was better than diesel fuels. When the mixing ratio of biodiesel increased, NOx was a slight increase. But PM and CO was a significantly reduced. Therefore, that the biodiesel of animal fats is available for eco-friendly fuel of diesel engine was confirmed.

일반적으로 선박용 디젤엔진의 아산화질소(N₂O)배출률은 이산화황(SO₂)배출률과 밀접한 상관성을 갖고 있고, 선박에서 사용되는 연료의 다양성은 N₂O배출특성에 영향을 미친다고 받아들여져 왔다. 최근의 연구보고에 의하면 연료 연소에서 발생한 충분한 일산화질소(NO)가 존재할 경우, 배기의 SO₂배출률이 N₂O생성에 미치는 영향은 NO의 영향보다 막대하게 크다. 그러므로 SO₂성분으로부터 기인하는 N₂O생성은 NOx저감을 위한 배기가스 재순환(EGR) 시스템에서 중요한 인자로 작용한다. 본 실험적인 연구의 목적은 SO₂유량 증가를 갖는 디젤엔진의 흡기가 배기의 N₂O배출률에 미치는 영향에 대하여 조사하는 것이다. 실험에 사용된 테스트 엔진은 2600rpm에서 12kW의 출력을 갖는 4행정 직접분사식 디젤엔진이고, 운전조건은 75% 부하에서 실시되었다. 0.499%(m3/m3)의 SO₂표준가스는 흡기의 SO₂농도를 변화시키기 위해 사용되었다. 결과적으로 황 성분을 포함하지 않는 연료는 SO₂를 배출시키지 않았고, 흡기 중에 SO₂표준가스의 증가에 따른 배기의 SO₂배출률은 SO₂흡입률과 비교하여 거의 같은 비율이었다. 또한, 흡기의 SO₂유량 상승은 N₂O배출률을 상승시켜 배기 중의 N₂O는 흡기의 SO₂혼합기에 의해 생성되었다. 결국 황 성분을 함유한 연료는 연소 중에 SO₂를 형성하고 배기 중의 N₂O는 연소실에 존재하는 NO와 SO₂의 반응에 의해 발생된다고 할 수 있다.

LNG 선박에서 발생하는 슬로싱 충격하중은 다상유동 및 기체의 압축효과에 따라 CCS에서 발생하는 압력과 구조응답에 큰 영향을 미칠 수 있다. 본 연구에서는 슬로싱 운동 시 LNG의 유동에 의해 발생하는 슬로싱 충격을 시뮬레이션하기 위해서 다상유동을 적용한 수치해석 모델을 제시하였으며, 그 결과를 실험과 비교하여 타당성을 검토하였다. 또한 효율적인 구조응답 계산을 위해 분사모델을 이용한 유체구조 연성해석 방법에 대해서 검토하고 멤브레인형 Mark III 화물창의 강도평가에 적용하여 LNG 화물창의 강도평가를 위한 가능성을 검토하였다.

Within aging rotary painting system for plastic wheel cover, sprayed paint particles caused the quality problem as attached to back surface of the wheel cover by the cyclone vortex in the booth. The purpose of this study is to select the spray conditions to ensure a stable quality of the rotary painting system. For this, simulation for flow characteristics of each spray nozzle have been carried out using ANSYS program, and tested to find the optimum spray condition, such as spray distance, spray pressure and rotation speed by manufactured test apparatus of paint spray. Finally, satisfactory results were obtained by testing with a actual painting system in developed spray conditions.

The purpose of this study is to develop the flowmeter of high viscosity paint spraying system. In this study, the numerical flow analysis of the flowmeter was performed. The velocity and the pressure distributions were obtained using the turbulent SST(Shear Stress Transport) model. The ICEM-CFD13 and CFXMesher, reliable grid generation software was also adapted to secure high quality grid necessary for the reliable analysis. According to the simulation results, the flow rate of flowmeter is 6.49l/min in case of Δp=45bar. This result was in good agreement with design result and could be applied to the actual design of the high viscosity paint spraying system

주변 환경이 작물의 엽온에 미치는 영향을 규명하고, 포그분사 및 공기유동에 의한 엽온조절의 효과를 검토하기 위하여 이류체 포그시스템 및 공기유동 장치를 설치한 토마토 재배온실에서 다양한 실험조건하에 작물의 엽온과 실내외 온습도, 일사량, 풍속 등의 환경을 계측하여 분석하였다. 처리조건별 엽온 및 실내외 기온의 변화를 분석한 결과, 무처리와 차광조건에서는 실내기온과 엽온 모두 외기온보다 상당히 높았으나, 포그분사 조건 에서는 실내온도가 외기온보다 낮거나 약간 높은 정도를 유지하는 것으로 나타났고, 포그분사와 공기유동 조건에서는 엽온을 실내온도와 비슷하거나 더 낮게 유지할 수 있는 것으로 나타났다. 일사량, 풍속 및 포차에 따른 엽 기온차의 변화를 분석하였으며, 주변 환경요인과 엽온과의 관계를 도출하기 위하여 다중회귀분석을 실시하였다. 엽기온차에 대한 최적의 회귀방정식은 일사량, 풍속, 포차를 모두 고려한 것으로써 RMS 오차는 0.8oC였다. 본 회귀방적식을 이용하여 온실의 온습도, 일사량, 풍속을 측정하면 엽온을 추정할 수 있으며, 토마토 재배온실의 고온기 작물 스트레스 경감을 위한 환경조절에 활용할 수 있을 것으로 판단된다. 처리조건별 광합성 속도는 포그분사와 공기유동의 병행 처리에서 가장 컸고, 포그분 사, 공기유동, 무처리 순으로 나타났다. 포그분사에 공기 유동까지 병행하면 체온조절 효과가 증대하여 작물의 고온 스트레스를 경감할 수 있으며 결국 광합성을 증대시킬 수 있는 것으로 판단된다. 이상을 종합해보면 엽온과 기온의 차이는 주변 환경에 큰 영향을 받는 것으로 나타났으며, 주변 환경을 계측함으로써 엽온을 추정할 수 있고, 그것을 고온 스트레스 경감을 위한 환경조절에 활용할 수 있을 것으로 판단된다. 또한, 포그분사 및 공기 유동을 통해 엽기온차를 줄이고 광합성 속도를 증가시켜 작물생장에 유리한 환경을 조성할 수 있으며, 고온 스트레스를 경감시키는데 효과적일 것으로 판단된다.

Vacuum kinetic spray(VKS) is a relatively advanced process for fabricating thin/thick and dense ceramic coatings via submicron-sized particle impact at room temperature. However, unfortunately, the particle velocity, which is an important value for investigating the deposition mechanism, has not been clarified yet. Thus, in this research, VKS average particle velocities were derived by numerical analysis method(CFD: computational fluid dynamics) connected with an experimental approach(SCM: slit cell method). When the process gas or powder particles are accelerated by a compressive force generated by gas pressure in kinetic spraying, a tensile force generated by the vacuum in the VKS system accelerates the process gas. As a result, the gas is able to reach supersonic speed even though only 0.6MPa gas pressure is used in VKS. In addition, small size powders can be accelerated up to supersonic velocity by means of the drag-force of the low pressure process gas flow. Furthermore, in this process, the increase of gas flow makes the drag-force stronger and gas distribution more homogenized in the pipe, by which the total particle average velocity becomes higher and the difference between max. and min. particle velocity decreases. Consequently, the control of particle size and gas flow rate are important factors in making the velocity of particles high enough for successful deposition in the VKS system.

The performance of spray vale using three nozzles has been investigated experimentally. Experimental apparatus is composed of the steam line and water line. Capacity 20kW electric heaters were used to produce the 1l0oC steam. The 300C water was produced using a water bath. Water outlet temperature is measured for each model to evaluate the performance of the nozzle.

Fe-based amorphous coatings were fabricated on a soda-lime glass substrate by the vacuum kinetic spray method. The effect of the gas flow rate, which determines particle velocity, on the deposition behavior of the particle and microstructure of the resultant films was investigated. The as-fabricated microstructure of the film was studied by field emission scanning electron microscopy (FE-SEM) and high resolution transmission electron microscopy (HR-TEM). Although the activation energy for transformation from the amorphous phase to crystalline phase was lowered by severe plastic deformation and particle fracturing under a high strain rate, the crystalline phases could not be found in the coating layer. Incompletely fractured and small fragments 100~300 nm in size, which are smaller than initial feedstock material, were found on the coating surface and inside of the coating. Also, some pores and voids occurred between particle-particle interfaces. In the case of brittle Fe-based amorphous alloy, particles fail in fragmentation fracture mode through initiation and propagation of the numerous small cracks rather than shear fracture mode under compressive stress. It could be deduced that amorphous alloy underwent particle fracturing in a vacuum kinetic spray process. Also, it is considered that surface energy caused by the formation of new surfaces and friction energy contributed to the bonding of fragments.

Injection rate characteristics of biodesel fuels according to the blending ratio was described in this work. The injection rate measuring system based on the Bosch's method was utilized to measure and compare the fuel injection rate characteristics. Three different types of biodiesel which were derived from seed, unpolished-rice, and soybean were blended with the diesel fuel in 20% and 40% of volumetric ratio. The fuel properties, injection mass, and injection rate characteristics were obtained and compared in various injection conditions. It is expected that this observations provide important insights into the effect of fuel properties on the biodiesel fuel injection rate performance in a CI engine