• 제목/요약/키워드: Uniformity of Spray

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노즐 홀 직경에 따른 단공 GDI 인젝터의 분무 특성 연구 - (2) 분무 균일도 및 미립화 특성 비교 (Study on Spray Characteristics of Single-Hole GDI Injector according to Nozzle Hole Diameter - (2) Comparison of Spray Uniformity and Atomization Characteristics)

  • 박정현;노승천;상몽소;박수한
    • 한국분무공학회지
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    • 제25권4호
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    • pp.154-161
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    • 2020
  • A single spray plume is the basic unit of the entire spray plume and is an important factor in understanding the spray characteristics. However, since the multi-hole GDI injector has a narrow spray angle, the superposition of the spray plumes occurs severely. Therefore, the spray uniformity and the spray atomization characteristics of a single spray plume were analyzed in this study using a single-hole GDI injector. Five single-hole GDI injectors with different nozzle hole diameters were used in the experiment. The uniformity of the spray was evaluated through the analysis of the spray pattern images. In addition, the atomization characteristics were compared using the diameter distribution of the spray droplets obtained using PDPA. As a result, the larger diameter of the nozzle hole, the less uniformity of the spray, and the injection pressure did not have a significant effect on the spray uniformity. It is judged that the surface roughness of the injector has a greater effect on spray uniformity than the diameter of the nozzle hole. Also, the size of the spray droplets increased sharply when the diameter of the nozzle hole was 230 ㎛.

건설기계용 Urea-SCR 시스템의 촉매전단에서 암모니아 균질도 해석 및 DeNOx 성능에 관한 연구 (Study on Ammonia Uniformity and DeNOx Analysis in the Urea-SCR System for Construction Machinery)

  • 김동환;박준규;강정호;문성준;박성욱
    • 한국분무공학회지
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    • 제24권2호
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    • pp.51-57
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    • 2019
  • In this study, the spray atomization characteristics of urea injector used in SCR system for construction machinery was analyzed, and the uniformity index at the front of mixer and NOx conversion efficiency were evaluated through numerical analysis. Spray visualization and droplet size/velocity measurement were performed and the measured results were used to verify the spray analysis model to calculate the uniformity index in the exhaust gas after-treatment system. For the flow analysis, STAR-CCM, a three-dimensional CFD, was used and the uniformity index of the SCR system at the front of the mixer was calculated using the droplet dissociation model and the wall collision model. Finally, the DeNOx performance for the average condition of the NRTC driving mode was calculated to understand the NOx conversion efficiency reflecting the exhaust gas temperature. The simulation results show that the uniformity index at the front of mixer was calculated as 0.862 and DeNOx efficiency was 75.9%.

요소수 분무특성이 SCR시스템 내 분무균일도에 미치는 영향 (Effect of NH3 Uniformity Index on SCR System According to Urea Spray Characteristics)

  • 김세훈;고진석;고재유;조영준;이동률
    • 한국분무공학회지
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    • 제24권4호
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    • pp.178-184
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    • 2019
  • Diesel engines have the advantages of higher thermal efficiency and lower CO2 emissions than gasoline engines, but have the disadvantages that particulate matter (PM) and nitrogen oxides (NOx) emissions are greater than those of gasoline engines. In particular, nitrogen oxides (NOx) emitted from diesel engines generates secondary ultrafine dust (PM2.5) through photochemical reactions in the atmosphere, which is fatal to humans. In order to reduce nitrogen oxides (NOx), pre-treatment systems such as EGR, post-treatment systems such as LNT and Urea SCR have been actively studied. The Urea SCR consists of an injection device injecting urea agent and a catalytic device for reducing nitrogen oxides (NOx). The nitrogen oxide (NOx) reduction performance varies greatly depending on the urea uniformity in the exhaust pipe. In this study, spray characteristics according to the spray hole structure were confirmed, and the influence of spray uniformity on spray characteristics was studied through engine evaluation.

두 개의 셔터 구멍이 적용된 원심식 비료 살포기의 살포패턴 분석 (Spray Pattern Analysis for a Centrifugal Fertilizer Distributor with Two Shutter Holes)

  • 황석준;박정현;이주연;김기덕;신범수;남주석
    • 한국기계가공학회지
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    • 제18권10호
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    • pp.8-19
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    • 2019
  • In this study, the spray pattern of a centrifugal fertilizer distributor with two shutter holes was analyzed and an effective driving width that satisfies proper spray uniformity was derived. The centrifugal fertilizer distributor was mounted on a tractor with a rated power of 23.7 kW and static and dynamic spray pattern tests were performed according to the standard procedure proposed by the American Society of Agricultural and Biological Engineers Standard ASAE S341.5. The height of the fertilizer distributor was 80 cm from the ground and the PTO (power take-off) shaft speed of the tractor was fixed at 540 rpm. The fertilizer scattered in space was collected using 275 evenly spaced collectors at shutter opening ratios of 25%, 50%, 75%, and 100%. The spray pattern was analyzed via the amount of sprayed fertilizer at each collector location and the coefficient of variation was used as an indicator of spray uniformity. Using the analyzed spray pattern, the effective driving width that satisfied less than 15% of the coefficient of variation was derived for different tractor driving patterns (race track mode, back and forth mode). From the results, spray uniformity increased as the shutter opening ratio decreased. The largest effective driving width was 8 m at a shutter opening ratio of 25% for both driving patterns.

트랙터 부착 붐 방제기 노즐 분무특성 (Characteristic of Tractor Attachment Boom Sprayer Nozzle)

  • 강태경;김성우;김영근;이상희;최용;전현종;최일수;김형곤
    • 한국분무공학회지
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    • 제21권4호
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    • pp.195-199
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    • 2016
  • Spraying of nozzles and design of tractor-attached boom sprayers have been studied for analysis of liquid spraying features. The following conclusions have been drawn. At all pressures, twin flat spray tips was finer than flat spray tips. A fine spray with VMD of 101 to 200 appeared at 1.5MPa. So, it was selected as the boom sprayer nozzle. In spraying uniformity analysis, Type B was proven to have more uniformity than Type A and Type C at 52.0 cm attached distance. Type A and Type C were proven to have more uniformity than Type B at 58.5 cm attached distance. It is concluded that these results reflect atomizing characteristics of nozzles during pest control with tractor-attached boom sprayer. Therefore, optimum setting will be putting Type C with 58.5 cm distance.

수도(水稻) 기부(基部) 방제용(防除用) 붐-형(型) 주간(株間) 살포(撒布) 장치(裝置) 개발(開發)에 관(關)한 연구(硏究) (Development of A Boom Sprayer for Effective Pest-and-Disease Control on Densed Paddy Stems)

  • 정창주;장영창
    • Journal of Biosystems Engineering
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    • 제10권1호
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    • pp.13-23
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    • 1985
  • Spraying method from the paddy-field levee is known to give insufficient penetration of the spray droplets to the rice stem of the densely grown plants, which is generally encountered at the last stage of rice growth. This study was intended to investigate the spraying system to solve this existing problem. As an approach, it was attempted to develop the boom-with-nozzle, between-the-row application system. Several types of nozzles and their different arrangements in the boom were tested in the field to measure the penetration-reaching distance and the uniformity of spray droplet distribution. The results of the study are summarized as follows: 1. Field experiments by the spraying method from the paddy-field levee showed to have practically no penetration of the spray droplets to the portion of the plant stem with the normal flow volume generally applied and thus need for improving present spraying method. 2. It was found that, considering both the uniformity of the spray droplet distribution and performance rate, the most efficient type of nozzle in the between-the-row boom-type spraying system was one that has core-insert hollow-cone with some clearance between the cone and tip. 3. When tested by applying the spraying method of between-the-row, the nozzle pressure did not affect the uniformity of spray droplet distribution. However, the nozzle pressure had a positive effect on the penetrating-reaching distance of the facing side of the rice stem and did not affect much on that of the opposite face of the stem. It was also found that the maximum pressure to affect the penetration-reaching distance was about $10kg/cm^2$. 4. The uniformity of the spray droplet distribution in the between-the-row system was greatly affected by the height and orientation of the nozzles in the boom. Based on experimental work for the different type of the boom-with-nozzle arrangements, it is recommended that the position of nozzle is set at about 0.45 m above the ground and two nozzles in the boom are oriented to be faced with each other with some angle such that the droplet stream from the nozzle would not directly face with each other.

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SECFR 시스템의 차량적용을 위한 분무균일도향상에 관한 연구 (A Study for Improving Spray Uniformity of the SECFR System for Vehicle Applications)

  • 손정욱;우승철;김수겸;이기형
    • 한국분무공학회지
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    • 제20권2호
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    • pp.95-100
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    • 2015
  • Lower recirculated gas temperature at EGR system reduces NOx and PM emissions. However, EGR Cooler can be polluted by PM generated from recirculated EGR gas, and it reduces cooling efficiency and the amount of EGR gas simultaneously. The SECFR(Steam EGR Cooler Fouling Remover) system which uses the evaporated washer fluid steam caused by high temperature of EGR gas was manufactured for removing fouling generated on the cooler surface. Since an injection pressure of wind shield washer fluid in the vehicle is approximately 0.5 bar, it is not enough to atomize the injected washer fluid. Thus, it is necessary to apply a method to atomize the washer fluid. In this study, the impinging plate was used to promote the atomization of spray washer fluid for the purpose of apply SECFR system to vehicles and measured the DAR(Droplet Area Ratio) and DUI(Droplet Uniformity Index) through the spray visualization.

에칭공정에서의 Panel-Scale Etching Uniformity 향상을 위한 에칭노즐 궤적예측에 관한 연구 (The Prediction of Nozzle Trajectory on Substrate for the Improvement of Panel-Scale Etching Uniformity)

  • 정기호
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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    • pp.160-160
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    • 2008
  • In practical etching process, etch ant is sprayed on the metal-deposited panel through nozzles collectively connected to the manifold and that panel is usually composed of many PCB(printed circuit board)'s. The etching uniformity, the difference between individual PCB's on the same panel, has become one of most important features of etching process. In this paper, the prediction of nozzle trajectory has been performed by the combination of algebraic formula and numerical simulation. With the pre-determined geometrical factors of nozzle distribution, the trajectories of individual nozzles were predicted with the change of process operational factors such as panel speed, nozzle swing frequency and so on. As results, two dimensional distribution of impulsive force of etchant spray which could be considered as a key factor determining the etching performance have been successfully obtained. Though only qualitative prediction of etching uniformity have been predicted by the process developed in this study, the expansion to the quantitative prediction of etching uniformity is expected to be apparent by this study.

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Lead-Frame 에칭공정에서 분무특성을 이용한 에칭특성의 예측 (The Prediction of Etching Characteristics Using Spray Characteristics in Etching Process of Lead-Frame)

  • 정흥철;최경민;김덕줄
    • 대한기계학회논문집B
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    • 제30권4호
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    • pp.381-388
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    • 2006
  • The objective of this study is to predict the etching characteristics using spray characteristics for the optimization on the etching process of Lead-Frame. The etching characteristics such as etching factor, uniformity were investigated on the actual operating conditions. The correlation between the etching characteristics and the spray ones obtained by measurement were analyzed to simulate the etching characteristics according to actual conditions of lead-frame etching process. These conditions of lead-frame process were spray pressure, distance from nozzle tip to substrate, pipe pitch, and nozzle pitch. To improve the etching characteristics in the lead-frame process, effects of the various operating conditions should be understood in detail. The spray characteristics obtained by experiment using PDA system were simulated by the Monte-Carlo method. The etching process model was coded by Java language. It was found that simulation results generally agreed well with the measured results of etching characteristics in lead-frame etching process. The optimal operating parameters were successfully found under variable conditions.

무인항공 변량방제 시스템의 살포 균일도 분석 (Uniformity Analysis of Unmanned Aerial Application with Variable Rate Spray System)

  • 구영모;배영환
    • 농업생명과학연구
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    • 제52권6호
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    • pp.111-125
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    • 2018
  • 본 연구에서는 변량방제기술을 적용한 농용 회전익기를 이용하여 살포한 입자의 구간비행 상태에서의 거리별 살포 패턴을 측정함으로써 무인 항공방제의 농약 부착률과 입자경의 분포 균일도를 평가하였다. 비행을 등속으로 유지하는 안내비행과 자동비행 모드에서 유효살포폭 3.6m로 인접비행 구간과 살포폭이 일부 중첩된 피복률에 대한 가로방향 분포의 변이계수는 30% 정도를 보였고, 비행방향 진로위치에 대한 피복률의 변이계수는 10% 미만으로 매우 균등한 것으로 평가되었다. 따라서 살포작업시 기체의 지면속도(ground speed)의 변이를 보상하는 변량살포기술은 균일도 측면에서 우수한 것으로 판명되었으며, 또한 입자경의 분포에 있어서 체적중위직경(VMD)과 개체중위직경(NMD) 모두 항공방제에 적절한 크기와 균일한 분포를 보였다. 따라서 농용 회전익기를 이용하여 소필지의 항공방제작업을 무인화 하는데 있어, 변량방제장치를 적용함으로써 소규모 필지의 균일 정밀방제를 도모하고자 하였다.