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고경남,강문종,허종철,Ko, Kyung-Nam,Kang, Mun-Jong,Huh, Jong-Chul 한국태양에너지학회 2007 한국태양에너지학회 논문집 Vol.27 No.1
This paper reveals both the operational situation and the cause of the error occurred in wind turbine generator system of Hangwon wind farm in Jeju island. The four wind turbines were selected for this work, and the monitored period was for six months. Wind resource in the wind farm was analyzed, and the estimated energy production was compared with the actual energy production. As a result, with a decrease of system error, the estimated energy production was in good agreement with the actual energy production. The errors occurring in components such as gearbox and hydraulic motor affected the Availability of the wind turbine. Also, poor external conditions such as a strong wind, lightning and gust caused a standstill of wind turbines.
권기린(Ki-Rin. Kwon),허종철(Jong-Chul Huh) 한국해양공학회 1996 韓國海洋工學會誌 Vol.10 No.3
Many studies of heat transfer on the swirling flow or unswirled flow in a abrupt pipe expansion are widely carried out. The mechanism is not fully found evidently due to the instabilities of flow in a sudden change of the shape and appearance of turbulent shear layers in a recirculation region and secondary vortex near the corner.<br/> The purpose of this study is to obtain data through an experimental study of the swirling flow and heat transfer downstream of an abrupt expansion in a circular pipe with uniform heat flux.<br/> Experiments were carried out for the turbulent flow and heat transfer downstream of an abrupt circular pipe expansion. The uniform heat flux condition was imposed to the downstream of the abrupt expansion by using an electrically heated pipe. Experimental data are presented for local heat transfer rates and local axial velocities in the tube downstream of an abrupt 3:1 & 2:1 expansion.<br/> Air was used as the working fluid. In the upstream tube, the Reynolds number was varied from 60,000 to 120,000 and the swirl number range (based on the swirl chamber geometry, i.e. L/d ratio) in which the experiments were conducted were L/d=0, 8 and 16.<br/> Axial velocity increased rapidly at r/R=0.35 in the abrupt concentric expansion turbulent flow through the test tube in unswirled flow. It showed that with increasing axial distance the highest axial velocities move toward the tube wall in the case of the swirling flow abrupt expansion.<br/> A uniform wall heat flux boundary condition was employed, which resulted in wall-to-bulk temperatures ranging from 24℃ to 71℃. In swirling flow, the wall temperature showed a greater increase at L/d=16 than any other L/d. The bulk temperature showed a minimum value at the pipe inlet, it also exhibited a linear increase with axial distance along the pipe.<br/> As swirl intensity increased, the location of peak Nu numbers was observed to shift from 4 to 1 step heights downstream of the expansion.<br/> This upstream movement of the maximum Nusselt number was accompanied by an increase in its magnitude from 2.2 to 8.8 times larger than fully developed tube flow values.
혼류형 팬의 설계변수가 성능에 미치는 영향에 대한 실험적 연구
박진욱(Jin-Wook Park),허종철(Jong-Chul Huh),이철형(Chul-Hyung Lee),박완순(Wan-Soon Park) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.11
This study aims to analyze the effects of design parameters of mixed-flow fans. The eight kinds of mixed impellers with backward curved blades, which have four different back swept angles of hub plate, were selected. The impellers having exit blade angle of 45˚ and the range of 6 to 12 for number of blades were designed. The three kinds of casing having different guide vane angles were selected and organized with impellers to evaluate the performance of mixed-flow fans.