• Title, Summary, Keyword: spray system

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Comparison of Pilot Spray Characteristics of HP Diesel Injectors with Different Driving Method for CRDi System (II) (커먼레일 직접분사(CRDi)용 고압 디젤인젝터의 구동방식별 Pilot Spray 특성비교(II) - 솔레노이드 및 피에조 구동방식 비교분석 -)

  • Lee, Jin-Wook
    • Journal of ILASS-Korea
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    • v.15 no.2
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    • pp.67-73
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    • 2010
  • The capability of pilot injection with small fuel quantity at all engine operating conditions is one of the main feature of the common rail direct injection system. The purpose of the pilot injection is to lower the engine noise and to reduce the NOx emissions. This study describes the pilot spray structure characteristics of the common-rail diesel injectors with different electric driving characteristics, including solenoid-driven and piezo-driven type. Namely three common-rail injectors with different electric current wave were investigated in this study. The pilot spray characteristics such as spray speed, spray tip penetration, and spray angle were obtained by spray images, which is measured by the back diffusion light illumination method with optical system for high-speed temporal photography. As this research results, it was found that pilot injection of common-rail system was effected by rate of injection with different electrical characteristic for injector driving.

Comparison of Pilot Spray Characteristics of HP Diesel Injectors with Different Driving Method for CRDi System (I) (커먼레일 직접분사(CRDi)용 고압 디젤인젝터의 구동방식별 Pilot Spray 특성비교 (I) - 실제 직접분사식 디젤엔진에서의 사전분사 특성 분석 -)

  • Lee, Jin-Wook
    • Journal of ILASS-Korea
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    • v.15 no.1
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    • pp.25-30
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    • 2010
  • The capability of pilot injection with small fuel quantity at all engine operating conditions is one of the main feature of the common rail direct injection system. The purpose of the pilot injection is to lower the engine noise and to reduce the NOx emissions. This study describes the pilot spray structure characteristics of the common-rail diesel injectors with different electric driving characteristics, including solenoid-driven and piezo-driven type. Namely three common-rail injectors with different electric current wave were investigated in this study. The pilot spray characteristics such as spray speed, spray tip penetration, and spray angle were obtained by spray images, which is measured by the back diffusion light illumination method with optical system for high-speed temporal photography. As this research results, it was found that pilot injection of common-rail system was effected by rate of injection with different electrical characteristic for driving the injector.

Development of Digital Particle Holographic System for Measurements of the Characteristics of Spray Droplets (분무 액적 특성 계측을 위한 디지털 입자 홀로그래피 시스템의 개발)

  • Yan, Yang;Kang, Bo-Seon
    • Journal of ILASS-Korea
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    • v.15 no.2
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    • pp.53-60
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    • 2010
  • This study presents development of digital particle holographic system and its application to spray field to measure three-dimensional velocities and sizes of spray droplets. A double exposure hologram recording system with synchronization system for time control was established and digital holograms can be recorded in a short time interval. To process recorded holograms, the correlation coefficient method was used for focal plane determination of particles. To remove noises and improve the quality of holograms and reconstructed images, the Wiener filter was adopted. The two-threshold and image segmentation methods were used in binary image transformation. For particle pairing, the match probability method was adopted. The developed system was applied to spray field and three-dimensional velocities and sizes of spray droplets were measured. The measurement results of digital holographic system were compared with those made by laser instruments, PDPA(Phase Doppler Particle Analyzer), which proved the feasibility of in-line digital particle holographic system as a good measurement tool for spray droplets.

Spray Characteristics of the Rotating Fuel Injection System (회전연료 분사시스템의 분무특성)

  • Lee, D.H.;Park, J.B.;Choi, S.M.
    • Journal of ILASS-Korea
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    • v.11 no.2
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    • pp.81-88
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    • 2006
  • The spray characteristics of the rotating fuel injection system were investigated. The special test rig was devised to get the spatial and momentary droplet information. This experimental apparatus consists of a high-speed motor, a shaft, a rotating fuel nozzle and an acrylic case. Spray droplet size and velocity were measured by PDPA(Phase Doppler Particle Analyzer) and instantaneous velocity field was measured by 1'IV (Particle Image Velocimetry) system. At the same time, spray visualization was performed by using ND-YAG laser-based flash photography. From these two different laser diagnostic techniques, we could get spatial and instantaneous spray information fur rotating fuel injection system. The results presented in this paper indicate that spray characteristics such as droplet size, velocity and spray pattern were strongly influenced by rotational speed.

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An Experimental Study on the Behavior of Twin-Spray with Flow Interaction in a Condensable Environment (주위기체내에서의 두 액체분무간의 유동간섭현상에 대한 정상적 고찰)

  • 이상룡;정태식;한기수
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.10 no.3
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    • pp.326-334
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    • 1986
  • The effects of flow interaction between adjacent sprays in twin-spray system on the spatial distribution of injected liquid (water) and drop size distribution in condensable (steam) environment were carefully observed through experiments. The spatial distribution of injected liquid in twin-spray system appears to be more uniform than the simple superposition of the spatial distributions of liquid obtained from each individual spray. Drop size distribution was obtained by using the immersion sampling technique. It was found that, in the twin-spray, the larger numbers of small drops are collected throughout the spraying region due to the increase of entrainment velocity of ambient steam compared with the case of simple superposition of each individual spray. Moreover, in the overlapped portion of the twin-spray, the drop size distribution was changed also due to the collision between large drops. As a result, the behavior of twin-spray system (and eventually multiple-spray system) can not be predicted precisely by simple superposition of the behaviors of each constituting spray. Hence, for the design of multiple spray system, the effect of flow interaction between sprays should be taken into account seriously.

A Study on the Spray Characteristics with Ultrasonic added Fuel Injection System (초음파 연료분사장치의 분무특성에 관한 연구)

  • Yoon, M.K.;Ryu, J.I.
    • Journal of ILASS-Korea
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    • v.1 no.1
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    • pp.85-91
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    • 1996
  • This experiment was undertaken to investigate spray characteristics of the conventional inject ion system and the ultrasonic energy added inject ion system. Sauter mean diameter was mesured under the variation of inject ion pressure and the spray distance. To measure the droplet size we used the Malvern system 2600C. The spray angle and mass distribution was analyzed to the CCD camera and the patternater. After experiment, it was found that the ultrasonic energy added injection system had smaller sauter men diameter of droplet, wider mass distribution and wider spray angle than the conventional inject ion system had.

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Fan-shaped Spray Characteristics of High Pressure Slit Nozzle in a Gasoline Direct Injection Engine (가솔린 직접분사식 고압 슬릿 노즐의 팬형 분무 특성 고찰)

  • Song, Bhum-Keun;Kim, Chong-Min;Kang, Shin-Jae
    • Proceedings of the KSME Conference
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    • pp.2239-2244
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    • 2003
  • A new stratified charge combustion system has been introduced and developed for GDI engines. Before this new GDI system, the stratified mixture was formed by a high pressure swirl injector. But, the special feature of new system is employed of a thin fan-shaped fuel spray formed by a slit type nozzle. Also, this system has been adopted a shell-shaped piston cavity. We made high pressure gasoline injection system and investigated the fan-shaped spray characteristics such as spray tip penetration, spray angle, SMD and velocities of droplets using PDPA(Phase Doppler Particle Analyzer) system and spray visualization system to obtain the concept of the new design and the fundamental data for the next generation GDI system. The experiment was performed at the injection pressures of 5 and 9MPa under the atmospheric condition.

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Experimental study on the spray density distribution of water spray system in road tunnel (터널 물분무소화설비의 살수밀도분포에 대한 실험연구)

  • So, Soo-Hyun;Park, Kyung-Hwan
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.13 no.1
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    • pp.1-8
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    • 2011
  • Spray density of the water spray system which is installed in long road tunnels and hazardous vehicle tunnels is applied without proper performance assessment process. In this study, the requirements of Spray Density Guidelines at the standard pressure is investigated through spray test set up the nozzle of a water spray system in a simulated road tunnel. The results showed that all the nozzles used in the test area did not meet the requirements of the Guidelines. The absence of performance test codes and inspection process on the nozzle at real scale in tunnels may have caused this practice. Therefore, it is suggested that the performance test regulations of the nozzle on the water spray system is established in order to properly assess the system performance.

Study of Manual Spray Coating Method for Fabricating Flexible Cantilever (유연성 높은 캔틸레버 제작을 위한 스프레이 코팅 방법 연구)

  • Kim, Ji-Kwan
    • Journal of Sensor Science and Technology
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    • v.26 no.5
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    • pp.366-369
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    • 2017
  • This work presents a detailed study of several parameters on the spray coating method for fabricating a flexible cantilever. Conventionally, spin coating method have been widely used in the microelectromechanical system (MEMS) fabrication process. However, the major drawback of this method is the difficulties in protecting various topography with photoresist film, particularly when the device is manufactured in high aspect ratio. It is also a challenging process to form a small pattern in the etched area. On the other hand, the commercial spray coating systems are not advantageous from an economic perspective and the technique is also providing less efficient. In order to solve these issues, we have developed a manual spray coating system which can be efficiently used by combining the accessories available in the laboratory. The developed spray coating system consists of a spin-coater, motorized stage, a spray gun with the capable of controlling centrifugal force, injection amount, injection angle, and spray range. The major advantage of the proposed spray coating system is its reasonable fabrication cost. Secondly, the system can be easily disassembled after finishing the coating experiment. Owing to the mentioned advantages, we sincerely believe that the proposed spray coating system can be effectively used in many related applications.

MACROSCOPIC STRUCTURE AND ATOMIZATION CHARACTERISTICS OF HIGH-SPEED DIESEL SPRAY

  • Park, S.-W.;Lee, C.-S.
    • International Journal of Automotive Technology
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    • v.4 no.4
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    • pp.157-164
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    • 2003
  • An experimental and numerical study was performed to investigate the macroscopic and microscopic atomization characteristics of high-speed diesel spray issued from the common-rail injection system. For the experiments, spray visualization system and a phase Doppler particle analyzer system were utilized to obtain the spray atomization characteristics such as the process of spray development, spray tip penetration, and SMD distribution. In order to analyze the process of spray atomization with KIVA-3 code, the TAB breakup model is changed to the KH-DDB competition model, which assumes the competition between the wave instability and droplet deformation causes the droplet breakup above the breakup length. The calculated results were also compared with the experiments in terms of spray tip penetration and SMD distribution. The results provide the process of spray development, axial and radial distribution of SMD, and calculated overall SMD as a function of time after start of injection.