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수직이착륙 무인항공기용 엇회전식 덕티드팬의 팁간극 영향에 대한 연구
민준호,류민형,조이상,조진수 한국항공우주학회 2013 한국항공우주학회 학술발표회 논문집 Vol.2013 No.4
수직이착륙 무인항공기용 엇회전식 덕티드팬에 대하여 로터의 팁간극 변화가 추력특성에 미치는 영향을 전산 해석하였다. 한양대학교 소형 아음속 풍동에서 정지비행과 축방향 비행상태에 대한 추력을 측정하였고, CFX를 이용한 전산해석을 통해 팁간극 변화에 대한 추력특성 변화를 분석하였다. 전방로터의 팁간극이 증가할 수록 추력특성을 저감시키는 것을 알 수 있었다. 정지비행 상태에서 덕티드팬 반경에 대한 전방 로터의 팁간극이 1.33%으로 고정되었을 때 후방 로터의 팁간극 증가는 오히려 추력특성을 향상시켰다. 전방 로터의 팁간극이 1.33%이고, 후방 로터의 팁간극이 4.00%일 때 가장 높은 추력임을 확인하였다. The thrust characteristics of the tip clearance effect for the counter-rotating ducted fan of VTOL UAV changes were analyzed by Ansys CFX. The thrust for the hovering and forward flight was measured on the subsonic wind tunnel of Hanyang University. Computational studies of the ducted fan showed that increasing tip clearance decreased the thrust obtained in hover condition. When the tip clearances are 1.33% for front rotor and 4.00% for rear rotor, the best thrust in hover condition was observed.
양 말단에 MPTMS-아크릴아미드로 치환된 폴리이미드의 합성
민준호,박찬영,민성기,Min, Jun Ho,Park, Chan Young,Min, Seong Kee 한국재료학회 2016 한국재료학회지 Vol.26 No.9
An amide group was introduced to restrain the cohesion of silica nano-particles and copolymerized with polyamic acid. Amide block copolymers were prepared using silica and (3-mercaptopropyl) trimethoxysilane (MPTMS) with a siloxane group, using 2, 6-Lutidine as a catalyst. Amide block polymers and copolymers were synthesized via ATRP after brominating pyromellitic dianhydride (PMDA) and polyamic acid of methylene diphenyl diamine (MDA) using ${\alpha}$-bromo isobutyryl bromide. Characteristic peaks of copolymer with amide and imide groups and patterns of amorphous polymers were studied using FT-IR and XRD analyses; an analysis of the surface characteristic groups was conducted via XPS. Changes in the thermal properties were examined through DSC and TGA; solubility for solvents was also studied.
徐成燮,閔焌皓 弘益大學校 科學技術硏究所 1996 科學技術硏究論文集 Vol.7 No.1
The breakthrough curves of mole fraction and gas velocity were examined under the condition of bulk gas and were compared with the trace system. In the bulk gas system, the breakthrough time obtained from the mass transfer model was faster than that from the local equilibrium(LEQ) model, approaching to the LEQ model as mass transfer coefficient and cell number increased. On the contrary, the center value of the breakthrough curve in the trace system was in accordance with the breakthrough time by LEQ model. For bulk gas mixture, breakthrough of gas velocity was slower than that of concentration. The more distinct this phenomenon was, the higher the adsorbate concentration was. However, in the trace system, the breakthrough curve of gas velocity corresponded with the breakthrough curve of adsorbate concentration. In the LEQ model and cell model, gas velocities before breakthrough occurred at the outlet were in agreement with each other.
수직이착륙 무인항공기용 엇회전식 덕티드팬의 팁간극 영향에 대한 연구
민준호(Junho Min),류민형(Minhyoung Ryu),이세욱(Seawook Lee),조진수(Jinsoo Cho) 한국항공우주학회 2013 韓國航空宇宙學會誌 Vol.41 No.7
제자리 비행하는 수직이착륙 무인항공기용 엇회전식 덕티드팬의 전ㆍ후방동익 팁간극이 덕티드팬에 미치는 영향을 파악하기 위해 전산해석을 수행하였다. κ-ω SST 난류 모델을 사용하여 엇회전식 덕티드팬의 전산해석을 수행하였으며, 기준형상에 대해 제자리 및 전진 비행 상태의 공력특성을 풍동시험을 통해 계측하여 전산해석 기법을 검증하였다. 엇회전식 덕티드팬에서 특정 동익의 팁간극이 증가하면 그 동익과 덕트의 추력계수는 감소하고, 다른 동익의 추력계수는 증가하는 경향을 확인하였다. 후방동익의 팁간극이 증가하면 덕티드팬 출구면의 평균 전압을 상승시켜 덕티드팬의 추력을 증가시켰다. The tip clearance effect on counter-rotating ducted fan of VTOL UAV in hovering condition, was investigate using computational analysis. The κ-ωSST turbulence model is employed in this study. The numerical results of baseline model are validated by wind tunnel test in hovering and forward conditions. It is observed that if tip clearance of one rotor in the counter-rotating ducted fan increase then the thrust coefficient of another rotor increases. In Addition to this, when the tip clearance of the rear rotor increases, the thrust of the ducted fan is improved due to increasing of average total pressure at exit plane.
민준호(Jun-Ho Min),이창헌(Chang-Hun Lee),유재광(Jae-Kwang Ryu),김효산(Hyo-San Kim) 한국철도학회 2011 한국철도학회 학술발표대회논문집 Vol.2011 No.10
This research increases efficiency of track-maintenance repair and cuts maintenance cost with relocating Continuous Welded Rail how to set up install criteria by comprehension analysis through an on-the-spot survey and track measurement about installing place at expansion joint of Continuous Welded Rail. This scope of this research is 427 places installed at Line No.1~4 Seoulmetro. We take a field study and select two spots. So we survey wheel-load cross-load and railbed cross-resistance and suggest install criteria of expansion joint of Continuous Welded Rail through investigation and analysis of track facilities about neighboring section of expansion joint.