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다중나선모듈로 이루어진 마그네틱 로봇의 좁고 굽은 관 환경에서의 구동 특성에 관한 연구
이용훈(Y. H. Lee),이학준(H. J. Lee),이청(C. Lee),이종희(J. H. Lee),전승문(S. M. Jeon) Korean Society for Precision Engineering 2021 한국정밀공학회 학술발표대회 논문집 Vol.2021 No.11월
본 연구에서는 다중나선모듈로 이루어진 마그네틱 로봇(MHMM)의 좁고 굽은 관 환경에서의 구동 특성을 소개한다. MHMM 은 기존의 심혈관 치료를 위해 사용되던 유선 카테터 기반 관상동맥성형술의 의료적 한계를 극복하기 위해 연구되는 자기장으로 무선 구동이 가능한 초소형나선로봇이다. MHMM 은 다수의 나선모듈이 유니버셜 조인트로 직렬 연결된 구조로서 기존의 단일 모듈로 구성된 로봇에 비해 공간적 제약이 적어 각종 기능성 모듈 탑재가 가능하여 다양한 기능을 구현할 수 있는 장점이 있다. 본 연구에서는 인체의 혈관과 같이 좁고 굽은 관 환경에서 MHMM의 모듈 수에 따른 구동 특성 변화에 대한 연구결과를 제시한다. MHMM은 전체 길이 대비 모듈 수가 증가할 수록 곡선에 가까운 자세를 취할 수 있으므로 더 좁고 굽은 관에서도 이동이 가능하다. 또한, MHMM의 각 모듈은 유니버셜 조인트를 통해 회전 동력이 비선형적으로 전달되는데, 모듈 수가 증가할수록 이러한 비선형성이 감소하여 MHMM의 회전 진동이 감소되므로 구동 특성이 향상된다. 본 연구에서는 이러한 특성을 기하학적 모델을 이용하여 이론적으로 예측하였고, 각종 MHMM 시제품과 유사 혈관 환경을 제작하여 실험적으로도 검증하였다. 본 연구는 관환경에서 다양한 기능을 수행할 수 있는 다기능 초소형로봇시스템 개발에 기여할 수 있을 것으로 기대된다.
이용훈(Y. H. Lee),박기태(G. T. Park),이경환(G. H. Lee),김필환(P. H. Kim),정효민(H. M. Jeong),정한식(H. S. Chung) 한국동력기계공학회 2007 한국동력기계공학회 학술대회 논문집 Vol.- No.-
Liquefied gas vaporizer means machine to vaporize the liquefied gas as liquid nitrogen(LN₂), liquefied natural gas(LNG), liquid oxygen(LO₂) etc. In the air type vaporizer, the frozen dew is also created by temperature drop (below 273 K) on vaporizer surface. This problem increases as the time progresses and humidity increases. In addition, the frozen dew gradually becomes frost deposit consequently, heat transfer through vaporizer decreases because frost deposit form adiabatic sheet. Because of this reason, recent vaporizer system is installed as parallel type, this vaporizer system needs more expensive installation costs and more space. This study carried out structure analysis on the material of vaporizer along the working fluid flow direction using liquefied super low temperature gas. The experimental study was investigated the heat transfer characteristics and performance on the tube length 4000 ㎜, 6000 ㎜ and 8000 ㎜ of three vaporizer models and was analyzed for evaluating the optimum efficiency on the vaporizer.
계절별 조건에 따른 초저온 액화가스 기화기의 실험적 연구
이용훈(Y. H. Lee),Eldwin Djajadiwinata,정효민(H. M. Jeong),정한식(H. S. Chung) 한국동력기계공학회 2006 한국동력기계공학회 학술대회 논문집 Vol.- No.-
This paper was studied for optimum design of the used vaporizer at a satellite station. Generally, the frozen air is created by temperature drop on the vaporizer surface. In addition, the frost creates ice deposit layer, therefore, heat transfer on vaporizer decreases into the adiabatic condition. By this reason, recent vaporizer system is installed as parallel type, and it takes tree times of vaporizer capacity. But this vaporizer system requires much installation costs and restricted by some space. It is very important to solve this problem. This study paper is regarding air vaporizer where the utilization increases recently. There are three variable conditions which are used in this study research. To contribute in developing an efficient air-heating vaporizer, we did experiment on finless and 4fin801e and 8fin551e type air-heating vaporizer. The experiment was conducted by varying the ambient condition and the length of the vaporizer. The ambient air was managed so that it has the same condition with air condition in each season. In this experiment, the main aspect in analyzing the performance of air heating vaporizer is the inlet and outlet temperature compare to the length of the vaporizer at different season.
자동차용 공기청정기의 성능 평가 및 설치 조건 도출을 위한 수치해석적 연구
이용훈(Y.H. Lee),서진원(J.W. Seo),박재홍(J.H. Park),최윤호(Y.H. Choi) 한국전산유체공학회 2010 한국전산유체공학회 학술대회논문집 Vol.2010 No.5
In this study, an air cleaner is considered to improve comfort, safety, and health of automobile passengers. The performance and installation conditions of the air cleaner have been studied to investigate their effects on the air quality in the cabin room using numerical analysis. A five-passenger sedan and a seven-passenger minivan that have comparatively large indoor volume have been considered. The distributions of the local mean age and the volume averaged age of indoor air are calculated according to the variation of the placement and the air flow of the air cleaner. In addition, a decrease of contamination concentration, especially VOCs(volatile organic compounds), by the air cleaner is numerically analyzed with time-accurate unsteady calculation to quantify the effect of the air cleaner on the indoor air quality. As a result, the effective installation and operation conditions of the air cleaner for the automobile cabin room could be suggested.
액화가스를 이용한 여러 가지 형상 기화기의 기화특성에 관한 실험적 연구
이용훈(Y. H. Lee),이상철(S. C. Lee),지명국(M. K. Ji),정효민(H. M. Jeong),정한식(H. S. Chung) 한국동력기계공학회 2006 한국동력기계공학회 학술대회 논문집 Vol.- No.-
This paper was studied for optimum design of the used vaporizer at a satellite station. Generally, the frozen air is created by temperature drop on the vaporizer surface. In addition, the frost creates ice deposit layer, therefore, heat transfer on vaporizer decreases into the adiabatic condition. By this reason, recent vaporizer system is installed as parallel type, and it takes tree times of vaporizer capacity. But this vaporizer system requires much installation costs and restricted by some space. It is very important to solve this problem. This study paper is regarding air vaporizer where the utilization increases recently. There are three variable conditions which are used in this study research. First, fin lengths of 4000㎜, 6000㎜, 8000㎜ and 0, 4, 8 fin types were applied on each vaporizer. Second, we applied four season condition which consist of humidity, temperature and air velocity to the experimental environment. Finally, pressure was applied to get flow rate during experiment. This paper objective is to propose vaporizer type and length data for best performance of vaporizer through experiment.