• 제목/요약/키워드: Pumping power

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The natural frequency measurement for a suction pile about the intrusion depth (관입깊이에 따른 석션파일 고유진동수 측정 및 분석)

  • Lee, Jong-Hwa;Kim, Min-Su;Seo, Yoon-Ho;Kim, Bong-Ki;Lee, Ju-Shin;Yu, Mu-Sung;Kwak, Dae-Jin
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2014.10a
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    • pp.495-496
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    • 2014
  • The suction method is the substructure installation using the water pressure difference generated by discharging water inside the pile by the pumping operation, after the intrusion by the self-weights of a large hollow steel pipe or a concrete structure. It is known as the low-noise and low-vibration method against the general pile driven method and eco-friendly, also. Most current design and safety assessment of the support structure and considering only the static load, however, the importance of dynamic behavior becomes magnified as the size of wind power generator increases. This study measures the natural frequency of the suction pile prototype about the penetration depth as a part of basic research and analyzed the interaction between the soil and the structure.

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Development of Solar Powered Water Pump - Energy conversion test and performance analysis - (태양열을 동력원으로 한 물펌프 연구개발 - 에너지변환실험과 성능해석 -)

  • 김영복;이양근;이승규;김성태;나우정;정병섭
    • Journal of Biosystems Engineering
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    • v.27 no.4
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    • pp.327-334
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    • 2002
  • In this study, energy conversion from thermal energy to mechanical power by using n-pentane was tested and exergy variation, cycle number, water quantity pumped and thermal efficiency were analyzed. The energy conversion was done and the water head could be ten meters on the experimental conditions. The operating temperature range of cycle was recommended to be around the liquid-vapour saturation temperature of the working fluid on the viewpoint of the maximum work. The cycle diagram was analyzed by the exergy analysis. For the constant water head, the cycle number was decreased and the water quantity per day was increased and thermal efficiency become higher when the water quantity per cycle become increasing. For the constant pumping water quantity per cycle, cycle number and the water quantity per day was decreased and the thermal efficiency become higher because the saturation temperature become higher when the water head become higher.

Analysis of Cylinder Compression Pressure & Valve Timing by Motoring Current & Crank Signal during Cranking (모터링시 전류 파형과 크랭크각 센서를 이용한 기관의 압축압력 및 밸브 타이밍 분석)

  • Kim, In-Tae;Park, Kyoung-Suk;Shim, Beom-Joo
    • Transactions of the Korean Society of Automotive Engineers
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    • v.19 no.5
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    • pp.45-50
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    • 2011
  • Compression pressure of individual cylinder and valve timing have big influence on combustion pressure, indicated mean effective pressure (IMEP), emission, vibration, combustion noise and many other combustion parameters. Conventional method, however, to check compression pressure uniformity is done by mechanical pressure gage and valve timing is checked manually. This conventional method causes inaccuracy of cylinder pressure measurement because of different cranking speed results from battery status and temperature. Also to check valve timing, related FEAD parts should be disassembled and timing mark should be checked. This study describes and suggests new methodology to measure compression pressure by analysis of start motor current and to check valve timing by cylinder pressure with high accuracy. Results, it is found that detection of bulky as well as small leaky cylinder is possible by cranking motor current analysis and wrong valve timing can be detected by cylinder pressure analysis and cam and crank sensor signal.

Development and Optimization of the Hybrid Engine System Model to Improve the Fuel Economy (연비향상을 위한 하이브리드 엔진 시스템 모델 개발과 최적화에 관한 연구)

  • Lee, Dong-Eun;Hwang, In-Goo;Jeon, Dae-Il;Park, Sim-Soo
    • Transactions of the Korean Society of Automotive Engineers
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    • v.16 no.6
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    • pp.65-73
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    • 2008
  • The purpose of this study is development of universal engine model for integrated Hybrid Electric Vehicle (HEV) simulator and a optimization of engine model. The engine model of this study is based on the MATLAB Simulink for universal and include engine fuel economy technologies for HEV. Various engine fuel economy technologies for HEV is estimated by commercial engine 1-D simulation program - WAVE. And, the 1-D simulation model of base version is compared with engine experiment result. The analyzed engine technologies with 1-D simulation are Dual-CVVT, Atkinson-Cycle and Cylinder-Deactivation System. There are improvement of fuel economy and power performance with Dual-CVVT model at part load and full load, pumping loss reduction with Cylinder-Deactivation System at idle and regeneration. Each estimated technologies are analyzed by 1-D simulation on all operation region for base data to converse simulink. The simulink based engine model maintains a signal with ECU for determination of engine operation point.

A Study on the Improvement of the Water System in Domestic Boiler (가정용 보일러의 급탕시설 개선방안에 관한 연구)

  • Han, Gyu-Il;Park, Jong-Un
    • Journal of the Korean Society of Fisheries and Ocean Technology
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    • v.34 no.2
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    • pp.200-211
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    • 1998
  • Heat transfer performance improvement by fin and groovs is studied for condensation of R-11 on integral-fin tubes. Eight tubes with trapczodially shaped integral-fins having fin density from 748 to 1654fpm(fin per meter) and 10, 30 grooves are tested. A plain tube having the same diameter as the finned tubes is also used for comparison. R-11 condensates at saturation state of 32 $^{\circ}C$ on the outside tube surface coded by inside water flow. All of test data are taken at steady state. The heat transfer loop is used for testing singe long tubes and cooling is pumped from a storage tank through filters and folwmeters to the horizontal test section where it is heated by steam condensing on the outside of the tubes. The pressure drop across the test section is measured by menas pressure gauge and manometer. The results obtained in this study is as follows : 1. Based on inside diameter and nominal inside area, overall heat transfer coefficients of finned tube are enhanced up to 1.6 ~ 3.7 times that of a plain tube at a constant Reynolds number. 2. Friction factors are up to 1.6 ~ 2.1 times those of plain tubes. 3. The constant pumping power ratio for the low integral-fin tubes increase directly with the effective area to the nominal area ratio, and with the effective area diameter ratio. 4. A tube having a fin density of 1299fpm and 30 grooves has the best heat transfer performance.

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Effects of Temperature and Pressure on the Breakdown Characteristics of Liquid Nitrogen

  • Baek, Seung-Myeong;Joung, Jong-Man;Kim, Sang-Hyun
    • KIEE International Transactions on Electrophysics and Applications
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    • v.3C no.5
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    • pp.171-176
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    • 2003
  • For practical electrical insulation design of high temperature superconducting (HTS) power apparatuses, knowledge of the dielectric behavior of both liquid nitrogen (L$N_2$) and subcooled liquid nitrogen (SL$N_2$) are essential. To achieve SL$N_2$ at atmospheric pressure, cryostat was designed and constructed. By pumping up the L$N_2$ in the outer dewar, the temperature of L$N_2$ in the inner dewar at atmospheric pressure can be controlled. The breakdown characteristics of L$N_2$ in quasi-uniform and non-uniform electrical fields for temperatures ranging from 77 K to 65 K at atmospheric pressure and pressure ranging from 0.1 to 0.5 MPa were investigated experimentally. The experimental data suggested that the breakdown voltage (BDV) of L$N_2$ is both highly temperature and pressure dependent. We also carried out statistical analysis of the experimental results using the Weibull distribution. The Weibull shape parameter m for the sphere-to-plane electrodes in SL$N_2$ was estimated to be 11 to 18.

A Study on the Drag Reduction by an Additives in Cylindrical Vertical Tube (수직원형관에서 첨가제에 따른 마찰저항 감소에 관한 연구)

  • Cha, K.O.;Kim, J.G.
    • Solar Energy
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    • v.20 no.2
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    • pp.85-96
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    • 2000
  • When the liquid with the additive of ppm unit of a polymer flows, the pressure drop can be manifestly decreased compared to that of pure liquid: that's the drag reduction. This method is that a small amount of a polymer which doesn't make the transformation of the properties of the working fluid is dissolved into the working fluid, the links of chains of the polymer do a buffer action to the molecules of the working fluid which come out between near the wall of the pipe and the interface, so that the pressure drop is dramatically decreased. When we transport the fluid, therefore, we can save a lot of pumping power, or we can increase the transportation capacity with using the same transportation equipment. But when a polymer solution is also flowing in the fluid transportation system, the degradation which have a very close relation with the phenomena of the drag reduction occurs necessarily. When adding polymer to reduce the drag in two phase flow system, It is impossible to find some studies. This study is focussing on a searching examination for the experimental study considering the mechanical degradation in the closed tow phase system to find out the conditions which could improve the pump capacity.

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Experimental Study on the Drag Reduction & Heat Transfer Ratio in the Circular Pipe with Swirl Generater (난류발생기를 가지는 원형 파이프내에서의 마찰저감 및 열전달율에 관한 실험적 연구)

  • Kim, Seong-Su;Cho, Sung-Hwan;Yoon, Seok-Mann
    • Proceedings of the SAREK Conference
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    • 2008.06a
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    • pp.430-435
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    • 2008
  • Total lengths of domestic pipe network for district heating system are above about 2,500Km. A lots of pumping power for heat transportation through long pipe are required by the flow friction of pipe surface. Until now there have been considered about various methods to reduce the flow friction for district heating system such as using surfactants and turbulence promoters by swirl flow and baffles etc. At this study, swirl flow generator was tested about the possibility to increase the heat transfer ratio at the heat exchanger in the case which the suppling water temperature increased from $50^{\circ}C$ until $120^{\circ}C$. Experimental results showed that the heat transfer ratio increased and also pressure increase ratio increased simultaneously in the case which swirl flow generator installed. The amount of the increasing ratio for heat transfer and pressure were reached until 4.33% and 11% at the case of $120^{\circ}C$ suppling temperature which domestic district heating system were using.

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Solar District Heating System (지역난방용 태양열시스템)

  • Baek, Nam-Choon;Lee, Jin-Kook;Yoon, Eung-Sang;Yoon, Suk-Man;Sin, U-Chul
    • Proceedings of the SAREK Conference
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    • 2008.06a
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    • pp.663-668
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    • 2008
  • This study was carried out solar heating system design for district heating and it's the performance analysis by experiment. This experimental system was installed in Bundang district heating area in the end of 2006. The flat plate and vacuum tube solar collector are combined in one system. So district heating water is heated first by flat plate solar collector and than by vacuum tube solar collector. This solar heating system has not a solar buffer tank and is operating with variable flow rate to obtain a setting temperature of $90{\sim}95^{\circ}C$. As a result, the daily solar thermal collection efficiency is about 30 to 40% for the plate type and 50 to 55% for the vacuum tube solar collector. It varied especially depend on the weather condition like as solar radiation and ambient temperature. This variable flow rate system can be also reduced much pumping power more than 50%.

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RESEARCH ON LASER-ACCELERATED PROTON GENERATION AT KAERI

  • PARK SEONG HEE;LEE KITAE;CHA YOUNG HO;JEONG YOUNG UK;BAIK SUNG HOON;YOO BYUNG DUK
    • Nuclear Engineering and Technology
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    • v.37 no.3
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    • pp.279-286
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    • 2005
  • A prototype of a relativistic proton generation system, based on laser-induced plasma interaction, has been designed and fabricated. The system is composed of three major parts: a fs TW laser; a target chamber, including targets and controls; and a diagnostic system for charged particles and lasers. An Offner-type pulse stretcher for chirped pulse amplification (CPA) and eight pass pre-amplifier are installed. The main amplifier will be integrated with a new pumping laser. The design values of the laser at the first stage are 1 TW in power and 50 fs in pulse duration. We expect to generate protons with their maximum energy of approximately 3 MeV and the flux of at least $10^6$ per pulse using a 10 $\mu$m Al target. A prototype target chamber with eight 8-inch flanges, including target mounts, has been designed and fabricated. For laser diagnostics, an adaptive optics based on the Shack-Hartmann type, beam monitoring, and alignment system are all under development. For a charged particle, CR-39 detectors, a Thomson parabola spectrometer, and Si charged-particle detectors will be used for the density profile and energy spectrum. In this paper, we present the preliminary design for laser-induced proton generation. We also present plans for future work, as well as theoretical simulations.