http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
Flow Analysis of Ultra-high Pressure Needle Valve for Hydrogen Charging Station
J. A. Choi(최지아),J. H. Kim(김주현),M. G. Park(박민규),J. H. Yun(윤진호),Y. J. Cho(조영진),J. S. Jang(장지성) 유공압건설기계학회 2021 유공압건설기계학회 학술대회논문집 Vol.2021 No.11
Hydrogen energy is the clean energy of the future. While research to safely use such hydrogen gas is being actively conducted, hydrogen charging stations have been installed and used as vehicle fuel. Ultra-high pressure hydrogen is used at hydrogen refueling stations, and parts are being developed accordingly. On the other hand, the ultra-high pressure valve, which is one of the parts, is dependent on foreign countries, and the level of domestic research on this is about 10% of that of overseas advanced technologies. In this study, the flow characteristics inside the needle valve using ultra-high pressure hydrogen gas were analyzed using three-dimensional numerical analysis. The flow characteristics according to the displacement of the needle were analyzed, and the SST (Shear Stress Transport) model is used for the turbulence analysis model. The flow coefficient was calculated according to ISA 753.02.01 for valve capacity test using the numerical analysis results. Finally, the flow coefficient according to the displacement of the needle was presented as a graph.
부하감응 시스템 MCV 제어용 EPPR 밸브 개발 및 센서리스 고장진단에 관한 연구
윤진호(J. H. Yun),장달식(D. S. Jang),구준태(J. T. Koo),신상우(S. W. Shin),차상봉(S. B. Cha),이준엽(J. Y. Lee),유승진(S. J. Yoo) 유공압건설기계학회 2023 유공압건설기계학회 학술대회논문집 Vol.2023 No.5
Over the years, the number of agricultural workers as a percentage of the total population has been declining. As a result, the agricultural market is faced with the challenge of meeting the same food demand as before with fewer people. As a solution to these problems, automation of agricultural machinery is emerging. In this study, we develop Electric Proportional Pressure Reducing(EPPR) valve, which is a key part of agricultural machinery automation. The EPPR valve is a component that can vary the discharge pressure by using the suction force generated according to the signal input to the coil. It can be used for various purposes in agricultural machinery, and it used here is to control the Main Control Valve(MCV) spool of the Load Sensing system. The Load Sensing system is a circuit that reduces wasted energy by varying the pump according to the work load. The reliability of the EPPR valve is secured through the sensorless fault diagnosis system. After obtaining the Magnetic Flux Linkage Diagram using the current and voltage input to the coil, various failure analyzes can be performed by comparing it with a normal product. We check hysteresis and repeatability to evaluate EPPR valve performance. A total of 6 failure types are selected: Coil Failure, Spring Failure, Part Omission, Electromagnetic Top Pollution, Sliding Part Adhesion and Excessive Sliding Friction. In addition, machine learning techniques are used to ensure higher reliability as the test is repeated.