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이지근,유경원,노병준,강신재,Lee, Ji-Geun,Yu, Gyeong-Won,No, Byeong-Jun,Gang, Sin-Jae 대한기계학회 1997 大韓機械學會論文集B Vol.21 No.6
This experimental study was mainly investigated on the swirl flow characteristics in the cylinder generated by a helical intake port. LDA system was used for the measurement of in-cylinder velocity fields. Tangential and axial velocity profiles, with varying valve lifts, valve eccentricity ratios and axial distance, were measured. When the intake valve was set in the cylinder center, we could find that in-cylinder swirl flow fields were composed of a forced vortex motion and a free vortex motion in the vicinity of the cylinder center and the cylinder wall respectively. In case of valve eccentricity ratio, N$_{y}$ = 0.45, the vortex flow which rotates to the opposite direction of a main rotating flow in the cylinder was found. And the reverse flow toward the cylinder head surface was also found in axial velocity profile and it showed the tendency of the linear decrease in the region of 0.leq.Y/B.leq.1.2.2.
4밸브 디젤기관의 흡기포트 편심과 두 흡기포트 사이의 격막이 실린더 내 선회 특성에 미치는 영향에 관한 연구
이지근,강신재,노병준,Lee, Ji-Geun,Gang, Sin-Jae,No, Byeong-Jun 대한기계학회 1997 大韓機械學會論文集B Vol.21 No.7
The effects of intake port eccentricity and a partition between the two intake ports on the incylinder swirl characteristics in a 4 valve diesel engine having the two intake ports, one is a helical intake port and the other is a tangential intake port, were investigated by using the impulse swirl meter(ISM) in a steady flow test rig. Mean flow coefficient ( $C_{f(mean)}$, swirl ratio ( $R_{s}$) and the mass flowrate through the two intake ports with and without intake port partition were measured. The results showed that the characteristics of in-cylinder swirl ratio formed by a 4-valve cylinder head were largely affected by valve eccentricity ratio ( $N_{y}$) and the existence of an intake port partition between the two intake ports. Mean flow coefficient ( $C_{f(mean)}$) increases and swirl ratio ( $R_{s}$) decreases in case of being the partition between the two intake ports. And also the mass flowrate through the tangential intake port is 19.0% and 7.7% more than that of the helical intake port in case of the two intake ports with and without partition respectively.ively.
흡기포트 형상에 따른 선회비 분포특성에 관한 실험적 연구
이지근,주봉철,노병준,강신재,Lee, Ji-Geun,Ju, Bong-Cheol,No, Byeong-Jun,Gang, Sin-Jae 대한기계학회 1997 大韓機械學會論文集B Vol.21 No.6
The effect of helical intake port geometry on in-cylinder swirl flow characteristics was studied. Two helical intake ports were selected to change swirl ratio, mean flow coefficient with the variation of valve lifts, valve eccentricity ratios and axial distance. The measurements were made by using an impulse swirl meter. The port B modified to increase the swirl ratio( $R_{s}$) had the tendency of the increased non-dimensional rig swirl ( $N_{r}$) distribution in comparison with that of the port A. And the $N_{r}$ distribution was remarkably improved at low valve lifts. The modification of the geometry to increase the swirl ratio ( $R_{s}$) in helical intake port resulted in the decrease of the mean flow coefficient ( $C_{f(mean)}$) regardless of valve eccentricity ratio ( $N_{y}$). And also non-dimensional rig swirl ( $N_{r}$) in the high valve lift affected the calculation of swirl ratio considerably.onsiderably.
조병진 ( Cho Byung Jin ),이지근 ( Lee Ji Geun ),안기원 ( Ahn Kee Won ) 한국농공학회 1999 한국농공학회 학술대회초록집 Vol.1999 No.-
The purpose of this study is to investigate on tideland reclamation projects as a part of situation on farm land improvement measures in north korea. By using satellite image data beyond the national boundaries, it makes possible to analyze tideland reclamation projects, and owing to the developed software and procedure we can analyze data regardless of difference in data acquisition date. Satellite image data LANDSA T TM and JERS-l data are mainly used, and analysing software ER Mapper, ERDAS, IDRISI are used. Reclamation survey result made by the ministry of unification in 1994 were examined by means of remote sensing using satellite image data. The results are ; Completed and/or partly completed project are 24,596ha and planned are about 142,223ha, 166,819ha in total. However, they already reported about 300 thousand ha would be reclaimed from the sea in early 1980.
벼 재배 시 농업용 드론의 분무 노즐에 따른 방제 성능 및 효과 분석
강영호 ( Yeong-ho Kang ),이덕렬 ( Deok-ryeol Lee ),김효진 ( Hyo-jin Kim ),조대호 ( Dae-ho Jo ),이지근 ( Ji-geun Lee ),유성현 ( Seong-hyeon Yu ),유승화 ( Seung-hwa Yu ),김주 ( Ju Kim ) 한국농업기계학회 2021 한국농업기계학회 학술발표논문집 Vol.26 No.2
벼 재배 시 노동력 및 노동시간 등을 절감할 수 있는 농업용드론을 활용한 항공방제의 수요가 꾸준하게 증가하고 있는 추세이다. 그러나 드론의 분무 노즐 등 분무시스템에 따른 최적화된 방제작업을 위한 피복도 및 방제가 등을 고려한 방제 성능 및 효과에 대한 현장실증 데이터가 매우 부족한 실정이다. 이에 본 연구에서는 농업현장에서 효율적인 농업용드론을 활용한 항공방제가 이루어질 수 있도록 AI 및 XR 계열의 분무 노즐을 드론에 각각 장착하여 항공방제를 실시하였다. 이후 분무 노즐에 따른 방제 성능 및 효과를 조사하였다. 본 방제시험은 김제평야의 약 4,000㎡ 면적의 신동진벼 재배 포장에서 수행하였다. 농업용드론은 8엽기(21inch)에 노즐이 2개 부착된 기체를 활용하였다. 항공살포조건은 작물체 기준(canopy) 2m 고도에서 2m/s의 전진속도와 40psi(2.76bar) 분무압으로 진행하였다. 약제의 피복도를 조사하기 위해서 약제 처리전 포장 안에 작물의 상단과 하단에 감수지를 설치하고 약제 살포 후 수거하였다. 병해충 방제는 무인항공용 방제약제로 등록된 농약을 활용하여 벼 출수기 전후로 총 3회 실시하였다. 감수지를 통한 약제 피복도 분석결과 AI계열의 노즐이 XR계열의 노즐 대비 작물의 상부에서 평균 약 1.4배, 하부에서 2.0배 정도의 피복도로 높게 나타났다. 또한 병해충 발병률 조사결과 AI계열의 노즐이 XR계열의 노즐에 비하여 잎집무늬마름병, 목도열병, 이화명충에 대하여 각각 약 6, 9, 40% 이상의 결과로 방제효과가 향상된 것으로 조사되었다. 따라서 AI계열의 분무노즐이 XR계열의 분무노즐에 비하여 방제 성능 및 효과가 높다고 판단된다. 이를 토대로 연차간 실험과 기종 및 노즐 등 시험요인을 추가한 강화된 현장검증으로 영농현장의 최적화된 드론 항공방제를 위한 기술 보급이 필요할 것으로 판단된다.