• 제목/요약/키워드: Vertical axis

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Hydraulic Performance Characteristics of Vertical-Axis Propeller Turbine Model (일체형 입축 프로펠러수차 모형의 수력학적 성능특성)

  • Park, Wan-Soon;Lee, Chul-Hyung
    • 한국신재생에너지학회:학술대회논문집
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    • 2008.10a
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    • pp.379-382
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    • 2008
  • The propeller type hydro turbine model with vertical axis has been tested and analized. The blade angle of runner of turbine model were designed to be varied according to the condition of head and flowrate. When the changes in head and output were comparatively large, the efficiency drop were small, so the efficiency characteristics and stability of the entire operating condition were maintained in good condition. These results showed that the developed model in this study will be suitable for small hydro power stations with large changes in head and load such as sewage treatment plants and agricultural reservoirs.

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A Basic Study on the Desist of Vertical Axis Darrieus Turbine for Wind-Power Generating System (수직축 Darrieus 풍력발전 시스템의 설계에 관한 기초연구)

  • Seo, Young-Taek;Kim, Gi-Seung;Oh, Chul-Soo
    • Proceedings of the KIEE Conference
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    • 1994.07a
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    • pp.82-84
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    • 1994
  • This paper presents a design of vertical axis Darrieus wind turbine for wind-power generating system. The wind turbine consists of two troposkien blades, diameter is 10m approximately, and chord length 380mm, tip ratio speed 4. The design of turbine is laid for the main data of rated wind speed 10m/s, turbine speed 78rpm, the generating power is estimated to 25kW, and this is contorted to commercial power line by means of three phase synchronous generator-inverter system.

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A Study on the Analytical Methods for the Aerodynamic Characteristics of Vertical-Axis Darrieus Wind Turbine (수직축(垂直軸) Darrieus 풍력(風力) 터어빈의 공기역학적특성(空氣力學的特性) 해석(解析)에 관한 연구(硏究))

  • Kim, Keon-Hoon;Lee, Chul-Hyung;Lee, Kyu-Hyun
    • Solar Energy
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    • v.7 no.2
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    • pp.74-85
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    • 1987
  • Performances of 3 different aerodynamic analytical models, single multiple and double multiple stream tube, for vertical axis Darrieus turbine were analyzed comparatively. From the study it has been found that the models derived from stream tube assumptions can be useful for simple prediction of basic design characteristics of Darrieus turbine. But, for a large tip speed and solidity ratios, the models has shown a certain limit in its applicability according to the formulation scheme applied. The results have shown that for the case having large tip speed and solidity ratios the consideration due to stream conditions, such as trailing vortices or wakes, should be included for accurate prediction of the aerodynamic performances of Darrieus turbine.

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A MEMS Z-axis Microaccelerometer for Vertical Motion Sensing of Mobile Robot (이동 로봇의 수직 운동 감지를 위한 초소형 MEMS Z축 가속도계)

  • Lee, Sang-Min;Cho, Dong-Il Dan
    • The Journal of Korea Robotics Society
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    • v.2 no.3
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    • pp.249-254
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    • 2007
  • 본 논문에서는 웨이퍼 레벨 밀봉 실장된 수직 운동 가속도 신호를 감지할 수 있는 초소형 Z축 가속도 센싱 엘리먼트를 제작하였다. 초소형 Z축 가속도 센싱 엘리먼트는 수직 방향의 정전용량 변화를 필요로 하기 때문에 단일 기판상에 수직 단차의 형성을 가능케 하는 확장된 희생 몸체 미세 가공 기술 (Extended Sacrificial Bulk Micromachining, ESBM) 을 이용하여 제작되었다. 확장된 희생 몸체 미세 가공 기술을 이용하면 정렬오차가 없이 상하부 양쪽에 수직 단차를 갖는 실리콘 구조물의 제작이 가능하다. 또한, MEMS 센싱 엘리먼트의 부유된 실리콘 구조물을 보호하기 위하여 웨이퍼 레벨 밀봉 실장 기술이 적용하여 고신뢰성, 고수율, 고성능의 Z축 가속도 센서를 제작하였다. 신호 처리 회로와 가속도 센서를 결합하여 Z축 가속도 센싱 시스템을 제작하였고 운동가속도 범위 10 g 이상, 정지 드리프트 17.3 mg 그리고 대역폭 60 Hz 이상의 성능을 나타내었다.

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Evaluation of Seismic Force Effects on Skew Bridges (사교에 작용하는 지진하중의 영향 평가)

  • 박형기
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 1998.10a
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    • pp.113-119
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    • 1998
  • This study is focused on evaluation of the structural behavior of skewed bridge during earthquake. The variation of natural frequencies and the lateral forces at pier shoes by the skewness and the rotational effect about vertical axis of skewed bridge due to seismic activity are analytically evaluated and identified through case studies. For this purpose, the composite steel girder highway bridges are selected as case study models. The seismic analyses by response spectrum method and time history method are performed for the selected models. It has been recognized that the frequency of longitudinal model increased as the skew angle decreased, while the lateral mode frequency showed the opposite trends. When the skew angle decreased, longitudina seismic forces of the bridge at the pier were increased but decreased in transverse direction. And it also has been found that the skewed bridges of the case study models showed the rotational behavior about vertical axis due to motion of San Fernando earthquake at Pacoima Dam.

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Influence of guide vane shape on the performance and internal flow of a cross flow wind turbine

  • Son, Sung-Woo;Singh, Patrick Mark;Choi, Young-Do
    • Journal of Advanced Marine Engineering and Technology
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    • v.37 no.2
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    • pp.163-169
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    • 2013
  • In order to make the vertical-axis cross flow wind turbine commercially feasible, a guide vane is adopted and the effect of the guide vane shape is examined in order to improve the wind turbine performance. CFD analysis on the performance and internal flow of the turbine is carried out for the wind turbine model. The result shows that when the guide nozzle is installed, almost over two times of power coefficient are achieved in comparison with the case of no guide nozzle installation. The guide nozzle acts as a role of suppressing the flow resistance at the blade passage, which is found when the guide nozzle is installed. Moreover, in this study, two kinds of the guide vane with a straight type and a curved type are adopted and compared. The curved guide vane nozzle produces higher power coefficient in comparison with that of straight guide vane nozzle.

Hydraulic Performance of Vertical Axis Propeller Type Hydro Turbine for Small Hydropower Plants (수소력발전용 입축 프로펠러 수차의 수력학적 성능특성 분석)

  • Lee, Chul-Hyung;Park, Wan-Soon
    • Journal of Hydrogen and New Energy
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    • v.14 no.2
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    • pp.171-176
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    • 2003
  • The propeller type hydro turbine model with vertical axis has been tested and analyzed. The blade angle of turbine model were designed to be varied according to the condition of head and flowrate. When the changes in head and output were comparatively large, the efficiency drop were small, so the efficiency characteristics and stability of the entire operating condition were maintained in good condition. These results showed that the developed model in this study will be suitable for small hydro power stations with large changes in head and load such as sewage treatment plants and agricultural reservoirs.

Bond Characteristics of Glass Fiber Reinforced Polymer Rebar according to the Bar Location (GFRP 보강근의 단면 위치에 따른 부착특성)

  • Park, Ji-Sun;Park, Young-Hwan;You, Young-Jun;Hwang, Geum-Sic;Kim, Keung-Hwan
    • Proceedings of the Korea Concrete Institute Conference
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    • 2006.11a
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    • pp.197-200
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    • 2006
  • The bond characteristics of three different types of glass fiber reinforced polymer(GFRP) reinforcing bars with different surface deformations were studied experimentally. Each specimen consisted of a concrete prism, 150 by 150 mm on each edge, with the longer axis in the vertical direction. Two rebars were embedded in each specimen, perpendicular to the longer axis and parallel to and equidistant from the sides of the prism. In vertical direction, one rebar was located at 75 mm from the bottom of the prism, and the other 225 mm from the bottom. All testing procedures including specimens preparation, set-up of test equipments and measuring devices were made according to the recommendations of CSA Standard S806-02.It was found that the bottom reinforcements showed higher bond stress than that of the top rebars.

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Optimization of a four-bar mechanism cyclic pitch control for a vertical axis wind turbine

  • Montenegro-Montero, Mariana;Richmond-Navarro, Gustavo;Casanova-Treto, Pedro
    • Wind and Structures
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    • v.35 no.2
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    • pp.121-130
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    • 2022
  • In this paper, the issue of pitch control in a vertical axis wind turbine was tackled. Programming the Actuator Cylinder model in MATLAB, a theoretical optimum pitch solution was found and then a classic four-bar mechanism was adapted to that theoretical solution to achieve a simple and elegant control of the pitch in the turbine. A simulation using the mechanism worked to find the optimum pitch cycles, where it was found that the mechanism would, in fact, increase the efficiency of the VAWT, by at least 11% and in the best case, over 35%. Another aspect that is studied is the possibility of self-start of the turbine by only changing the pitch on the blades. This analysis, however, proved that a further individual pitch control must be used to surpass the cogging torque. All analyses conducted were done for a specific wind turbine that is 2 m2 in the swept area.

Development of the Pointing Device using EOG (EOG를 이용한 포인팅 디바이스의 개발)

  • Park, Hyoung-Joon;Park, Jong-Hwan;Chun, Woo-Young
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.48 no.10
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    • pp.1356-1363
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    • 1999
  • In this paper, a new method for controlling the pointing device using EOG(electrooculogram) signal generated from eye movement was suggested. The basic idea of the method is to control the direction of pointer, as using the results of measuring each component of the horizontal EOG and the vertical EOG by angle of eye-gaze. As a practical example, pointing device controlling the personal computer's pointer is manufactured. The designed pointing device consists of pre-amplifier, A/D converter, serial transmission device and PC program. That is, first, the EOG is amplified by pre-amplifier. Secondly, the amplified EOG is digitized and transmitted to personal computer by PIC16C74A. Finally, the software for controlling the pointer on personal computer is programed. As the result, the measured horizontal EOG and vertical EOG by eye-gaze angle had high linearity; the correlation coefficients of the regression line were 0.998 and 0.996 respectively. And the developed pointing device is able to control the personal computer's pointer, and the average of the errors between the objective value and the observed value had 3.77% for horizontal axis and 5.85% for vertical axis. The pointing device developed in this study is able to control personal computer's pointer by subject's eye movement, that is, the user's intention. Furthermore, the algorithm of this study is applicable for many field, such as a new method remote control, a new wheelchair control and so forth.

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