확장테이퍼분공 GDI 노즐의 미립화 향상 및 출구적심 저감 성능에 대한 고찰

문석수 ( Jin Wang ),( Takanori Kito ),( Hitoshi Shibata ) 한국액체미립화학회 2018 한국액체미립화학회 학술강연회 논문집 Vol.2018 No.-

The concept of the diverging-tapered-hole nozzle has been introduced recently for the combustion improvement and PM/PN reduction in GDI engines. Its superior atomization performance and potential of injector-tip-wetting suppression have been reported in a previous study based on the experimental observations of macroscopic and microscopic spray characteristics. However, detailed mechanisms associated with these performances have not been clarified so far, which is essential to extract the best performance from this nozzle concept. In this study, the internal and near-nozzle flow characteristics of the diverging-taperedhole GDI nozzle are investigated using X-ray phase-contrast and absorption imaging techniques. Based on the results, the mechanisms related to the above performances are thoroughly discussed. The results show that the diverging-tapered-hole nozzle generates the three-dimensionally expanding crescent-moon-like flow structure which can increase the fuel-air contact area and also possess the additional tearing force assisting in the liquid flow breakup. This crescent-moon-like flow structure is normally confined within the lower half circle of the hole cross-section which helps the low-velocity flow region does not leak through the upper half circle so that the fuel leak during the injection can be minimized. Also, the expanding hole space in the diverging-taperedhole nozzle helps the dribbling fuel after the needle close can be better released rather than sticking into the nozzle tip. These three-dimensionally expanding crescent-moon-like flow, confined flow area, and the expanding hole space are discussed to be the key mechanisms related to performances of the divergingtapered- hole nozzle.

Numerical Study on Flame Jet and Exhaust Emissions Formation Mechanism of Diverging-tapered-hole Pre-chamber for Pre-Chamber Combustion Engine Fueled by Natural Gas

Soo-Jin Jeong(정수진),Seong-Joon Moon(문성준),Seokpan Seo(서석판),Dong-Il Seol(설동일) 한국자동차공학회 2022 한국자동차공학회 학술대회 및 전시회 Vol.2022 No.11

차량 주행특성을 고려한 감속 완화곡선 설계방법 개발

이점호 한국도로학회 2008 한국도로학회논문집 Vol.10 No.3

I study for design criteria and research about Interchange diverging area of express highway and freeway. the most recent, at interchange diversion of express highway and freeway, design criteria and researches are focus on safety guarantee a point of view movement dynamics of vehicle and road geometric as to transition section, deceleration section, curve radius, nose section, outflow angle etc. that is, design criteria and research of Interchange diverging area have not consider a point of view movement dynamics of vehicle and road geometric and driver. so that I will be focus characteristic of runing speed on trasion curve. and I will consider vehicle running speed characteristics and study problem of Interchange diverging area design criteria. For this study, First, analysis meaning about theory of now design criteria, Second, look at vehicle running speed and traffic accident characteristics of Interchange diverging area , Third, propose new deceleration transition curve design method get along vehicle running speed characteristics of Interchange diverging area. new deceleration transition curve design method put out new outcoums. that is, I definite cause to safety new deceleration transition curve design method better than pressently, used design criteria of Interchange diverging area. especially, deceleration transition curve design criteria produced good result in the running speed 50km/h,40km/h, that is inertia better than inertia of present used design criteria. and deceleration transition curve is extended better than present transition curve criteria. so that new deceleration transition curve design method safety is good better than the past method safety. I study for design criteria and research about Interchange diverging area of express highway and freeway. the most recent, at interchange diversion of express highway and freeway, design criteria and researches are focus on safety guarantee a point of view movement dynamics of vehicle and road geometric as to transition section, deceleration section, curve radius, nose section, outflow angle etc. that is, design criteria and research of Interchange diverging area have not consider a point of view movement dynamics of vehicle and road geometric and driver. so that I will be focus characteristic of runing speed on trasion curve. and I will consider vehicle running speed characteristics and study problem of Interchange diverging area design criteria. For this study, First, analysis meaning about theory of now design criteria, Second, look at vehicle running speed and traffic accident characteristics of Interchange diverging area , Third, propose new deceleration transition curve design method get along vehicle running speed characteristics of Interchange diverging area. new deceleration transition curve design method put out new outcoums. that is, I definite cause to safety new deceleration transition curve design method better than pressently, used design criteria of Interchange diverging area. especially, deceleration transition curve design criteria produced good result in the running speed 50km/h,40km/h, that is inertia better than inertia of present used design criteria. and deceleration transition curve is extended better than present transition curve criteria. so that new deceleration transition curve design method safety is good better than the past method safety.

합·분류부에서 야간 노면표시 휘도의 일관성 평가

박유섭,오흥운 한국도로학회 2022 한국도로학회논문집 Vol.24 No.5

PURPOSES : Aiming to evaluate the consistency of road markings at night, the luminance values of road markings at night were compared for merging and diverging areas. METHODS : To evaluate the consistency of road marking at nighttime in merging and diverging areas, the highway geometric structures and luminance of the road markings were collected and analyzed together at the merging and diverging areas. "Luminance" in this study referred to the overall luminance of the road markings as reflected together from surrounding lights, such as moonlight or artificial lights. The luminance of the road markings 90 m ahead of the driver were used. The measured luminance values were analyzed based on the difference ratios and an analysis of variance. RESULTS : Based on a grouping of three categories (interchanges (ICs), merging, and diverging areas), it was found that the difference ratios and analysis of variance values from the ICs and merging and diverging areas were not consistently acceptable. CONCLUSIONS : After evaluating the consistency of road markings at night in the merging and diverging areas, it can be concluded that there is a need for more consistency in the luminance on merging and diverging areas on highways. To enhance consistency, more dedicated lighting guidance for merging and diverging areas on highway areas may be necessary.

고속도로 분기부에서의 감속차로 길이에 관한 연구

김동녕(Kim Dong Nyong) 대한토목학회 2009 대한토목학회논문집 D Vol.29 No.2D

현재 고속도로 분류부의 감속차로길이 설계는 본선 및 연결로의 설계속도를 고려하여 감속에 요구되는 길이인 감속구간을 고려하고 있다. 이는 유출 차량이 분류부 이전에 노견측차로에 진입하여 변이구간을 통해 감속구간에서 감속을 진행한다는 전제가 필요하다. 그러나 진출하려는 연결로 교통량이 많아지면 동시에 여러 대가 감속차로로 진입하는 상황이 발생한다. 이것은 본선교통류의 흐름을 방해하거나 뒤늦게 감속차로에 진입하여 충분한 감속구간을 확보하지 못하게 하는 원인이 될 수 있다. 이에 본 연구에서는 유출교통량의 크기를 고려하여 분류부에서의 동시진입 상황시 본선의 주행성을 확보하면서 진출차량이 감속차로로 안전한 차로변경을 하기 위한 감속구간 확장길이와 이에 대한 방법론을 제시하는데 목적이 있다. 본 연구의 결과를 FRESIM을 통해 효과분석을 한 결과 분류부의 본선 및 감속차로에서의 차량당 지체의 감소와 평균속도의 증가 그리고 차로별 속도편차의 감소효과를 확인할 수 있었다. At present, the length of deceleration lane at freeway diverging areas are designed based on the design speed of main lines and ramps. This is possible on assumption that diverging vehicles decelerate at deceleration section after moving to shoulder lane in advance. But with high diverging volume, several vehicles will try to change to exit lane at the same time. This will cause the distribution of main lane flows or some vehicles may encounter short deceleration length because they miss the proper time to change the lane. The purpose of this study is to establish a design guideline of the length of deceleration section considering the volume of diverging traffic. Also, the results of analysis by the FRESIM simulation model shows that some improvements in respect of delays, speeds and speed deviations of mainline and deceleration lane.

고속도로 분류부 설계기법 개선 연구

박재범,이승준,강정규,김일환 대한교통학회 2007 大韓交通學會誌 Vol.25 No.1

Freeway diverging areas are very vulnerable to traffic accidents due to abrupt vehicle speed changes and geometric changes. Therefore, in designing diverging areas, much attention should be paid to safety. The present design criteria about freeway diverging areas regulate transition sections for lane changes, deceleration lanes, transition curves for direction changes, and other similar items. However, the design criteria were often violated in implementation because of ambiguities in the criteria. This study aims at clarifying and improving the present design criteria for freeway diverging areas. For this, field survey data and traffic accident data for diverging areas were analyzed. 고속도로 분류부는 고속에서 저속으로의 급격한 감속, 양호한 기하구조에서 취약한 기하구조로의 급격한 선형변화가 발생하는 구간으로, 고속도로 구성요소 중 사고위험이 매우 높은 구간에 해당된다. 따라서 분류부 설계시는 안전하고 원활한 교통흐름이 이루어지도록 세심한 주의를 기울여야 함은 물론 이의 달성을 위한 설계기준이 수립되어야 한다. 이에 따라 현 도로설계기준에서는 차로변경을 위한 변이구간, 감속을 위한 감속구간 그리고 무한 곡선반경에서 유한곡선반경으로의 원활한 차량주행궤적 변경을 위한 완화곡선 등 이를 위한 설계기준을 제시하고 있으나, 실제 그 적용에 있어서는 설계기준상의 각 구간별 구성에 대한 정의가 명확하지 않아 분류부의 각 구성요소가 중첩되어 설계되고 있다. 이러한 설계기준상의 문제로 인한 각 구성요소간 혼재는 현 설계기준에서 의도하고 있는 분류부에서의 역할을 충분히 발휘하지 못하게 하는 결과를 초래하고 있으며, 일관된 선형을 기대하는 운전자에게 혼동을 야기시키는 등 많은 고속도로 분류부 현장에서 안전상 문제점으로 작용하고 있다. 따라서 본 연구에서는 고속도로 분류부에서의 실측 현장조사 데이터를 바탕으로 분류부 차량주행행태 특성 분석 및 사고예측모형의 개발을 통해 다양한 교통조건 및 기하구조 조건을 고려한 분류부 설계기준 개선안을 제시하였다.

불완전 분류식 하수처리구역의 강우에 의한 하수도시설의 침입수/유입수 영향 분석

신정섭,강선홍,한상원,육준수,이춘구 대한상하수도학회 2019 상하수도학회지 Vol.33 No.3

The purpose of this study was to analyze the effects of sewerage facilities through I/I analysis by rainfall by selecting areas where storm overflow diverging chamber is remained due to the non-maintenance drainage equipment when the sewerage system was reconstructed as a separate sewer system. Research has shown that wet weather flow(WWF) increased from 106.2% to 154.8% compared to dry weather flow(DWF) in intercepting sewers, and that the WWF increased from 122.4% to 257.6% in comparison to DWF in storm overflow diverging chamber. As a result, owing to storm overflow diverging chamber of partially separate sewer system with untreated tributary of sewage treatment plant, rainfall-derived infiltration/inflow(RDII) has been analyzed 2.7 times higher than the areas without storm overflow diverging chamber. Meanwhile, infiltration quantity of this study area was relatively higher than that of other study areas. Therefore, it is necessary to reduce infiltration quantity through sewer pipe maintenance nearby river. Drainage equipment maintenance should be performed not to operate storm overflow diverging chamber in order to handle the appropriate sewage treatment plant capacity for rainfall because it is also expected that RDII due to rain will occur after maintenance. In conclusion, it is necessary to recognize aRDII(allowance of rainfall-derived infiltration/inflow) and to be reflected it on sewage treatment plant capacity because aRDII can occur even after maintenance to the complete separate sewer system.

Experimental Research on Self-repairing of Diverging Stepped Magnetic Fluid Seals with Single Magnetic Source

Xiaolong Yang,Yuting Liu,Ruibo Zhang,Shanghan Gao 한국자기학회 2021 Journal of Magnetics Vol.26 No.4

To improve the self-repairing capability of common magnetic fluid seal structures after rupture due to excessive differential pressure in small clearance conditions and to verify the superiority of diverging stepped magnetic fluid seals, a diverging stepped magnetic fluid seal device with single magnetic source was tested. The effect of injection volume, clearance and numbers of teeth on the self-repairing performance of a diverging stepped magnetic fluid seals was investigated experimentally and compared with a common magnetic fluid seal. The experimental results indicate that the self-repairing performance of one stepped magnetic fluid seal device is better. The repair rate of a diverging stepped magnetic fluid seal structure decreases first and then increases with the increase of injection volume, and a minimum value is reached near the saturation value. The smaller the sealing gap and the fewer the number of bore teeth, the higher the repair rate of this structure.

혁신적인 인터체인지 도입 사례 연구

염춘호(Chunho Yeom) 한국혁신학회 2018 한국혁신학회지 Vol.13 No.3

본 연구는 최근 미국에서 그 수가 폭발적으로 증가하고 있는 특이형태 교차로의 하나인 엇갈림 다이아몬드 교차로에 대해 다루었다. 교차로의 기본 특성 및 차량통행 방법을 소개하였고, 교차로의 장단점과 그 수가 기하급수적으로 늘고 있는 사유에 대해 고찰해 봤다. 또한 미국 내 92개의 운영 중이거나 건설 중인 엇갈림 다이아몬드 교차로의 설치위치에 대해서도 분석하였다. 설치위치 분석을 위해 엇갈림 다이아몬드 교차로가 위치하거나 인접한 도시의 인구규모와 도시 중심부까지의 거리를 검토하였다. 다음으로 엇갈림 다이아몬드 교차로의 교통안전 측면도 분석하였다. 특히 7개 교차로에서 수집한 교통상충과 오조작에 대한 카이스퀘어 검정을 통해 발생빈도의 독립성 여부를 확인하였다. 본 연구는 향후 우리나라에서 엇갈림 다이아몬드 교차로 설치를 고려 시 도움이 될 것으로 기대한다. The study ranged over an unconventional interchange, a diverging diamond interchange, which showed an explosive growth recently. The research introduced a fundamental characteristic of the diverging diamond interchange including how to maneuver, and it also looked at pros and cons of the interchange with reasons of the growth. The study also analyzed the place of 92 diverging diamond interchanges that were either being operated or constructed. The population and the distance from the center of the city to the location of each diverging diamond interchange were analyzed. In addition, a chi-square test was conducted to confirm whether traffic conflicts or erratic maneuver were identical or not in the diverging diamond interchanges. The research should be helpful when the same type of an interchange is implemented in Korea in the future.

소형 감마카메라에서 확산형 조준기의 구멍 형태 및 배열에 따른 성능평가

한동희,원종훈,백철하 한국물리학회 2020 New Physics: Sae Mulli Vol.70 No.10

For overcoming the drawbacks of pinhole collimators, which are used to detect a wide field of view, compact diverging collimators using metal-based precision machining have recently been drawing attention in the 3D printer field. Thus, we evaluated the performances of diverging collimators among the square, circular and hexagonal holes, as well as the arrangements of the GAGG crystals. The GATE code and the STL file were used, as was a 99mTc point source. The total area and the height of the collimator were set at 25.8 × 25.8 mm2 and 15 mm respectively. While the spatial resolution for all holes was relatively constant within a low error, the sensitivity for the square holes was 37.3% better than that for circular boles and 52.2% better than that for hexagonal holes, Similar results were obtained when the source was moved to the X-axis. Also, if the arrangement of crystals matched the type of the holes in the collimator, the spatial resolution was slightly better, confirming that the higher the degree of matching the hole, the better the performance. 최근 3D 프린터에서 금속 재질의 정밀 가공기술을 이용한 소형 확산형 조준기에 대한 연구가 활발히진행되고 있다. 이에 본 연구에서는 확산형 조준기의 구멍 형태가 사각형, 원형, 육각형일 때와 섬광체의배열 형태에 따른 민감도와 공간분해능의 차이를 평가하고자 하였다. 이를 위해 몬테카를로 시뮬레이션도구인 GATE와 STL 파일을 이용하였고, 점선원 99mTc(140 keV)과 조준기의 전체 면적, 높이는 각각25.8 × 25.8 mm2, 15 mm로 동일하게 설계하였다. 모든 구멍에서 공간분해능은 작은 오차 내 범위로비교적 일정했던 반면 민감도는 사각형이 원형 대비 37.3%, 육각형 대비 52.2% 우수했으며, 이는 선원이가장자리로 이동했을 때도 유사하였다. 또한, 섬광체의 배열이 조준기의 구멍 형태와 일치했을 경우 공간분해능은 개선되었고, 이를 통해 조준기의 구멍과 일치되는 정도가 높을수록 성능이 개선됨을 확인하였다.