• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 춘계 학술논문 발표대회
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• pp.201-203
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• 2012

The establishment of the technology for evaluating friction resistance and pipe pressure and the relation of the fluid characteristics and pumpability of concrete is essential for the evaluation of concrete pumping performance for high speed construction of super-tall building. So, this study focuses on quantitative evaluation of concrete fluid characteristics and surface friction resistance under the change of concrete mix proportion and pumping condition. In this study, we measured the rheology of concrete and pipe pressure and surface friction characteristics when pumping. And, relations between the rheology characteristics of concrete and pumping performance was investigated by experiment. As the result of the experiment, high regression between the surface friction and pressure gradient was confirmed. And, prediction model to evaluate the friction resistance coefficient and pipe pressure reduction coefficient was suggested.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2001년도 유체기계 연구개발 발표회 논문집
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• pp.191-196
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• 2001

In the systems with largely pipe head loss, variable speed pumps are generally used because substantial energy saving can be expected from such systems by controlling pump speed and also they offer simpler maintenance and operational ease even in conditions where abrupt changes In flow rate and head can occur. The invertor or the fluid coupling system are mainly adopted to control the rotating speed. In this paper, operating conditions at Migum pressing pump station(5 stage), where the fluid coupling system was the first installed for KOWACO, are investigated and analysed so that information thus gained can be usefully employed in the efficient operation of variable speed pump in new installations of in-line booster pumping station.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2010년도 제39회 하계학술대회 초록집
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• pp.18-18
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• 2010

Methods of the characteristics evaluation of turbo-molecular pumps (TMP) are well-defined in the international measurement standards such as ISO, PNEUROP, DIN, JIS, and AVS. The Vacuum Center in the Korea Research Institute of Standards and Science has recently designed, constructed, and established the integrated characteristics evaluation system of TMPs based on the international documents by continuously pursuing and acquiring the reliable international credibility through measurement perfection. The measurement of TMP pumping speed is normally performed with the throughput and orifice methods dependent on the mass flow regions. However, in the UHV range of the molecular flow region, the high uncertainties of the gauges, mass flow rates, and conductance are too critical to precisely accumulate reliable data. With UHV gauges of uncertainties less than 15% and a calculated conductance of the orifice, about 35% of pumping speed uncertainties are experimentally derived in the pressure range of less than $10^{-6}$ mbar. In order to solve the uncertainty problems of pumping speeds in the UHV range, we introduced an SRG with 1% accuracy and a constant volume flow meter (CVFM) to measure the finite mass flow rates down to $10^{-3}$ mbar-L/s with 3% uncertainty for the throughput method. In this way we have performed the measurement of pumping speed down to less than $10^{-6}$ mbar with an uncertainty of 6% for a 1000 L/s TMP. In this article we suggest that the CVFM has an ability to measure the conductance of the orifice experimentally with flowing the known mass through the orifice chambers, so that we may overcome the discontinuity problem encountering during introducing two measurement methods in one pumping speed evaluation sequence.

• 설비공학논문집
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• 제15권1호
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• pp.50-58
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• 2003

An analytical study was carried out to investigate the performance of an oil pumping system of a variable speed compressor using a commercial CFD program. The simulations for the oil supplying system with the oil and air mixture were performed by varying compressor speed from 40 Hz to 90 Hz. Comparing the predicted with the measured data on the modified scroll compressor validated the simulation model. The predicted results were consistent with the test data with a maximum deviation of 12.8%. The oil flow rate significantly increased with a rise of compressor speed due to a higher oil flow rate from the swing pump and a greater centrifugal force on oil gallery.

• 한국진공학회지
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• 제12권2호
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• pp.79-85
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• 2003

다단 원판형 드래그펌프의 배기특성을 출구측 압력변화에 따른 입구측의 압력을 측정함으로써 파악하였다. 압력측정범위는 유량이 없을 때 출구측에서 0.13∼533 Pa로 하였다. 펌프 로터의 회전 속도는 24,000rpm이며, 질소가스를 사용하여 유량에 대한 성능실험을 수행하였다. 본 연구에서는 원판의 단의 수에 따른 원판형 드래그 펌프의 성능을 측정하였다. 3단, 2단, 단단형으로 원판형 드래그펌프를 구성하여 성능 실험하였으며, 최대도달진공도, 최대압축비, 배기속도등을 각각 측정하여 상호 성능을 비교·고찰하였다.

• 한국건축시공학회지
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• 제15권4호
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• pp.375-381
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• 2015

본 연구에서는 초고층 구조물 시공시, 적용되는 규격별 고성능 콘크리트의 특성을 평가하고 60MPa의 고성능 콘크리트를 대상으로 높이가 500m부터 575m인 지점까지 압송계측 결과를 근거로 하여 압송성능과 고성능 콘크리트의 유동특성의 상관관계를 분석하였다. 분석 결과, 각 규격별 굳지 않은 콘크리트의 물성과 재령 12시간의 초기강도 및 기준 재령에서의 압축강도 및 탄성계수는 모두 품질기준을 만족함이 확인되었다. 또한, 높이별 최대 압송압력은 약 5% 정도씩 증가하였으며, 시간당 토출량도 최소 $25m^3$를 만족하는 것으로 나타났다. 펌프압송 후 콘크리트의 온도증가와 압송전의 콘크리트 소성점도의 크기에 따라 슬럼프 플로우의 손실이 증가됨을 확인할 수 있었다.

• 한국농공학회논문집
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• 제48권3호
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• pp.73-82
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• 2006

Wind energy is one of the promising renewable energies that could provide electricity and other mechanical power. Wind energy market is dramatically growing in many European countries, but wind power is only 0.2% of the total renewable energy uses that is only about 2% of the primary energy consumption in Korea. It is widely accepted that wind resources fur power generation are only limited in some areas including coastal regions and mountainous areas in Gangwon province in Korea, particularly in terms of large scale wind power developments. In this study, wind velocity data were analyzed with respect to the potential utilization. The data provided from National Weather Service were used for the analysis. In addition, field wind data were also collected and analyzed for the comparison between the national data. The comparison showed that there were significant differences between the experimental station and the national station that are about 5km away. Annual average wind speed at the experimental station was less than 2 m/s, which is not enough fur wind power generation. It seemed that the topographic condition resulted in a significant difference in wind speed. When 600 W and 2.5 kW wind turbines were used, annual power productions were only 186 kWh and 598 kWh, respectively. When the average wind speed is lower, wind pumping is an alternative use of wind. At the experimental station, the average pumping rate of $3m^3/h$ at the head of 3 m was expected at a 2.5 m rotor under the conditions that efficiencies of the rotor and the pump were 40% and 80%, respectively. It did not seem that the wind pumping was not applicable at the station either. A higher wind speed was required to install the wind machines. Meanwhile, wind pumping would be applicable in conditions with lower pumping heads. Other applications were introduced far further wind energy utilization, including wind powered ventilation and friction heat generation in greenhouses.

• 한국진공학회지
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• 제20권6호
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• pp.387-394
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• 2011

진공펌프의 운전성능을 나타내는 가장 중요한 지표 중의 하나인 배기속도 측정에 관해서는 많은 연구를 통해 정립된 이론에 따라 표준장치와 측정절차에 대한 규격이 만들어지고 널리 활용되고 있다. 그러나 실제 펌프 배기속도 측정 시 이상적인 조건에 비해 변형이 불가피할 때가 있고 그 영향을 간과하면 큰 측정오차를 유발할 수 있다. 본 논문에서는 배기속도를 측정하기 위한 이상적인 또는 실용적인 다양한 방안들이 가지는 물리적 특징과 구조적 오차에 대해 분석하고 보정 식들을 제시했다.

• 한국진공학회지
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• 제13권2호
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• pp.47-53
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• 2004

국내 진공기술 기반을 구축하는 국가사업의 일환으로 게터펌프 성능평가장치를 개발하고 있다. 본격적으로 장치를 구성하기 전에 평가절차의 개발, 장치 설계요건 및 사양을 확정하기 위해 예비실험장치를 만들었다. 이 장치를 이용하여 밀봉형 기기에 들어가는 비교적 활성화 온도가 낮은 게터 소자들의 특성평가 절차를 만들고 이를 적용하여 수소, 일산화탄소, 질소 등에 대해 배기속도와 배기용량을 측정해 보았다. 주로 고순도 기체 공급장치용으로 국내에서 개발된 게터 소자와 램프용으로 널리 쓰이는 외국제품의 배기성능을 비교해 보았다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2004년도 춘계학술대회
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• pp.1703-1708
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• 2004

In this study, we are investigated experimentally the pumping characteristics about the pumping channel shapes of disk-type drag pump (DTDP). We are experimented the pumping performance about the rotors which have channel or do not exist. The channel disk-type rotor has spiral channels both upper and lower part, and stator is planar. The planar disk-type rotor hasn't channel and stator has spiral channels both upper and lower part. The flow-meter method is adopted to calculate the pumping speed. Compression ratio and pumping speeds for the nitrogen gas are measured under the inlet pressure range of 0.001 ${\sim}$ 4 Torr. The maximum of compression ratio was about 3300 for three-stage DTDP (channel disk-type rotor), 1000 for four-stage (planar disk-type rotor) and two-stage DTDP (channel disk-type rotor) at zero throughput. The ultimate pressure was $1.6{\times}10^{-6}$ Torr for three-stage DTDP (channel disk-type rotor), $2.5{\times}10^{-6}$ Torr for four-stage DTDP (planar disk-type rotor).