http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
시뮬레이션 기반 PEM 수전해 시스템 고장 진단 모델 개발
구태형,고락길,노현우,서영민,하동우,현대일,한재영 한국수소및신에너지학회 2023 한국수소 및 신에너지학회논문집 Vol.34 No.5
In this study, fault diagnosis and detection methods developed to ensure the reliability of polymer electrolyte membrane (PEM) hydrogen electrolysis systems have been proposed. The proposed method consists of model development and data generation of the PEM hydrogen electrolysis system, and data- driven fault diagnosis learning model development. The developed fault diagnosis learning model describes how to detect and classify faults in the sensors and components of the system.
극저온 냉동기를 활용한 기체수소 예냉 시스템의 검증에 관한 연구 Part I: 실험적 연구 및 이론적 분석
하동우,노현우,서영민,구태형,고락길 한국수소및신에너지학회 2023 한국수소 및 신에너지학회논문집 Vol.34 No.4
In this study, the experimental investigation and theoretical analysis were conducted to verify the cooling capacity of the cryocooler used for pre-cooling of hydrogen gas. The effect of the flow rate on a copper pipe attached to the bottom of the cryocooler, which has a coil shape in a hydrogen line, was investigated. Temperature sensors were strategically placed at various positions on the cryocooler to analyze the temperature variations with respect to the flow rate. In this study, the thermal properties of hydrogen for the pressure and temperature were utilized using REFPROP to analyze the cooling capacity of the cryocooler. Based on the experimental results derived from this study, the cooling capacity of the cryocooler for pre-cooling hydrogen gas was considered by calculating the cooling temperature according to the flow rate through theoretical analysis.
응축형 수소 액화 시스템에 대한 LabVIEW 기반 데이터 저장 및 모니터링 프로그램 개발
하동우,노현우,서영민,구태형,고락길 한국수소및신에너지학회 2023 한국수소 및 신에너지학회논문집 Vol.34 No.5
In this study, a compact hydrogen liquefaction system was constructed with the aim of creating a data storage and monitoring program for liquid hydrogen production. This program was designed to receive and record signals from diverse control equipment through the LabVIEW software. A range of measurement instruments were devised to collect data, encompassing variables such as flow rate, pressure, temperature, and liquid level. As a result, it was possible to directly check the production of liquid hydrogen by obtaining various data of condensed liquid hydrogen. In addition, it was confirmed that long-term storage of liquid hydrogen is possible by developing automatic ON/OFF through the LabVIEW program.
극저온 냉동기를 활용한 기체 수소 예냉 시스템 검증에 관한 연구 Part II: CFD 시뮬레이션
서영민,노현우,하동우,구태형,고락길 한국수소및신에너지학회 2023 한국수소 및 신에너지학회논문집 Vol.34 No.5
In this study, the computational fluid dynamics (CFD) simulations were conducted to verify the cooling capacity of the cryocooler used for pre-cooling of hydrogen gas. Based on the experimental results, the effect of the flow rate on a copper pipe attached to the bottom of the cryocooler was investigated. In this study, the temperature data was calculated through the change of boundary condition for heat flux in the copper pipe. In addition, the cooling capacity of the cryocooler for pre-cooling hydrogen gas was considered by calculating the cooling temperature according to the flow rate in the certified operating range. Consequently the pre-cooing system for hydrogen gas was validated with a reasonable accuracy through CFD simulations.
냉각 실린더의 수평 거리가 저장 용기 내부의 기체 수소 자연대류 현상에 미치는 영향
서영민,노현우,하동우,구태형,고락길 한국수소및신에너지학회 2023 한국수소 및 신에너지학회논문집 Vol.34 No.3
This study conducted direct numerical simulations of the natural convection phenomena of gaseous hydrogen in a physical storage container containing four circular cylinders. Rayleigh numbers (Ra) in the range of 10 4 ≤Ra ≤10 6 and a Prandtl number (Pr)=0.69 (gaseous hydrogen) were considered. The main parameter is a horizontal distance of four circular cylinders and the values of εh=0.1, 0.2, 0.3, 0.4, and 0.5 are considered. The flow and thermal structures and corresponding heat transfer characteristics are investigated with respect to the transition of the flow regime. The time- and surface-averaged Nusselt number on the cylinder surface and the wall of physical storage container increased by about 57% and 69% according to the Ra and εh, respectively. Thus, the horizontal distance has an influence on the heat transfer characteristics on natural convection of gaseous hydrogen.
액체수소 저장 탱크의 중력 방향 및 수소 충전율이 BOG에 미치는 영향에 관한 수치적 연구
서영민,노현우,하동우,구태형,고락길 한국수소및신에너지학회 2023 한국수소 및 신에너지학회논문집 Vol.34 No.4
In this study, a numerical simulations were conducted to analyze the phase change behavior of a liquid hydrogen storage container. The effects of gravity direction and hydrogen filling rate on boil-off gas (BOG) in the storage container were investigated. The study employed the volume of fluid, which is the phase change analysis model provided by ANSYS Fluent (ANSYS, Canonsburg, PA, USA), to investigate the sloshing phenomenon inside the liquefied hydrogen fuel tank. Considering the transient analysis time, two-dimensional simulation were carried out to examine the characteristics of the flow and thermal fields. The results indicated that the thermal flow characteristics and BOG phenomena inside the two-dimensional liquefied hydrogen storage container were significantly influenced by changes in gravity direction and hydrogen filling rate.