• Title/Summary/Keyword: Pump system

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A Study on the Simulation of Chemical Heat Pump System Based on 2-Propanol /Acetone/Hydrogen System (2-Propanol/Acetone/Hydrogen 반응계로 구성된 화학적 열펌프 시스템의 모사 연구)

  • 김범재;여영구;정연수;송형근
    • Journal of the Korea Society for Simulation
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    • v.5 no.1
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    • pp.43-50
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    • 1996
  • 2-propanol/acetone/hydrogen 반응계로 구성된 화학적 열펌프 시스템은 낮은 온도(82.5~$90^{\circ}C$)에서의 2-propanol의 탈수소화 반응과 높은 온도(약 $200^{\circ}C$ 부근)에서의 acetone의 수소화반응을 이용하여 열을 고품위화 시키는 장치이다. 본 연구에서는 이 시스템의 해석 및 설계를 목적으로 이 시스템에 대한 수치적인 모델들을 세우고 Sequential modular approach를 이용하여 시스템의 모사를 수행하였다. 또한 에너지 효율을 최대화하기 위하여 열펌프 시스템에서의 환류비의 영향을 규명하였다. 모사결과 이 시스템의 scale up을 위한 정량적인 정상상태 운전조건들을 구할수 있었으며 두 반응의 반응 전화율이 다르더라도 반응물의 유량의 차이를 통하여 두 반응열이 거의 같아지는 것을 알수 있었다. 아울러 주어진 운전조건에서 증류의 환류비는 최소환류비 근처의 최적값이 존재함을 알수 있었다.

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The Experimental Study of Ice Thermal Storage for Falling Film Type - Sprint Coil Type - (스파이럴형 냉동코일을 사용한 유하액막식 빙축열조에서 열전달현상에 관한 실험적연구)

  • Lee, C.M.;Kim, D.H.;Cho, N.C.;Kim, I.G.;Park, S.R.;Choi, K.K.;Yim, C.S.
    • Solar Energy
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    • v.19 no.2
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    • pp.1-8
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    • 1999
  • The heat transfer characteristics of ice storage system of falling film type using sprial coil is investigated. The experimental facilities consisted of a water tank, spiral coils located above the tank, an upper water distributor, and a circulating water pump. Water is distributed uniformally over the spiral coils and it forms falling thin films. In the process of freezing, ice is formed on outside of the spiral coils through recirculation of tank water. In the process of melting, ice is melted with return water from the heat load, while the water is chilled again and drops into the tank. The results of falling film type of ice thermal storage system are as follows. The highly efficient shower flowrates for icing is near $3{\ell}/min$. Icing rates on spiral coils is rosed while brine flowrates is increased. Lower brine temperature is not only increased freezing rates but. also become higher total icing weight and overall heat transfer coefficient. Smaller shower flowrates is obtained lower water temperature on outlet for a long time. The amounts of quantity can be detected more accurately by measuring storage tank weight.

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A Study of Spray Characteristic with Orifice Diameter for Single Column Rotating Fuel Nozzle (단열식 회전연료 노즐의 오리피스 직경에 따른 분무특성 연구)

  • Jang, Seong-Ho;Choi, Seong-Man
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2009.05a
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    • pp.253-256
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    • 2009
  • In the micro turbojet engine less than 350kw power class, it is not easy to find out the good atomization fuel injector with good spray quality. However conceptually, rotating fuel injection system can give high atomization quality by only the centrifugal force of a high speed rotating shaft of the engine without high-pressure fuel pump. With this motivation, we manufactured very small rotating fuel injector of 40 mm diameter and performed under a variety of injection orifices. We measured droplet size, velocity and spray distribution by the PDPA(Phase Doppler Particle Analyzer) system. Also spray was visualized by using high speed camera. From the test results, we could understand that the length of liquid column from the injection orifice is mainly controlled by the rotational speeds. Furthermore, droplet size(SMD) is decreased with the rotational speeds and is influenced by the diameter of the injection orifice and liquid film thickness.

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Resistivity Monitoring of Saturated Rock Cores at Room Temperature (수포화 암석코어의 상온 전기비저항 모니터링)

  • Lee, Sang Kyu;Lee, Tae Jong;Yi, Myeong-Jong
    • Geophysics and Geophysical Exploration
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    • v.18 no.3
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    • pp.105-114
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    • 2015
  • A long-term resistivity monitoring system has been developed for saturated cores in room temperature and humidity condition. A 3-channel water-pump continuously drops the water onto the top of saturated core sample surrounded by shrinkable tube as well as on the paper filters of the electrodes at both sides of the core sample, by which one can monitor the resistivity changes with maintaining full saturation of the rock core for a week or longer. Monitoring the resistivity changes has been performed with 3 kinds of rock samples including biotite gneiss, andesitic tuff, and shale for 9 days using the system. Consequently, it is proposed two hypothesis that conversion speed of temperature coefficient has close relation to the thermal properties of the rock sample and that the ratio of resistance between dry and saturated conditions for a rock sample can be related to the effective porosity of the sample. The ratio between dry and saturated resistance for the three rock types are 48, 705, and 2, while effective porosity was 3.7%, 3.3%, and 13.0%, respectively.

Numerical Investigation of Cooling Performance of Liquid-cooled Battery in Electric Vehicles (하이브리드/전기 자동차용 수냉식 배터리 셀의 냉각성능에 관한 수치 해석적 연구)

  • Kwon, Hwabhin;Park, Heesung
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.40 no.6
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    • pp.403-408
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    • 2016
  • Lithium-ion batteries are commonly employed in hybrid electric vehicles (HEVs), and achieving high energy density in the battery has been one of the most critical issues in the automotive industry. Because liquid cooling containing antifreeze is important in automotive batteries to enable cold starts, an effective geometric configuration for high-cooling performance should be carefully investigated. Battery cooling with antifreeze has also been considered to realize successful cold starts. In this article, we theoretically investigate a specific property of an antifreeze cooling battery system, and we perform numerical modeling to satisfy the required thermal specifications. Because a typical battery system in HEVs consists of multiple stacked battery cells, the cooling performance is determined mainly by the special properties of antifreeze in the coolant passage, which dissipates heat generated from the battery cells. We propose that the required cooling performance can be realized by performing numerical simulations of different geometric configurations for battery cooling. Furthermore, we perform a theoretical analysis as a design guideline to optimize the cooling performance with minimum power consumption by the cooling pump.

Micro-scale Solar Energy Harvesting System with a New MPPT control (새로운 MPPT 제어기능을 갖는 마이크로 빛에너지 하베스팅 회로)

  • Yoon, Eun-Jung;Yoon, Il-Young;Choi, Sun-Myung;Park, Youn-Soo;Yu, Chong-Gun
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.17 no.11
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    • pp.2627-2635
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    • 2013
  • In this paper micro-scale solar energy harvesting system with a new MPPT control are proposed. In conventional solar energy harvesting systems, continuous perturbation techniques of the clock frequency or duty cycle of a power converter have been used to implement MPPT(Maximum Power Point Tracking) control. In this paper, we propose a new MPPT technique to control the duty cycle of a power switch powering a power converter. The proposed circuit is designed in $0.35{\mu}m$ CMOS process, and the designed chip area including pads is $770{\mu}m{\times}800{\mu}m$.

A Study on Oriental Medicine Hybrid Multi-cup Electric Cupping Contents using Vacuum Pressure (진공압을 이용한 한방 하이브리드 멀티 전동 부항 콘텐츠에 관한 연구)

  • Kim, Jong-Chan;Wei, Tung-Shuen;Ko, Jae-Sub;Choi, Heung-Kook;Tak, Myung-Ja;Kim, Cheeyong
    • Journal of Korea Multimedia Society
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    • v.17 no.11
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    • pp.1363-1373
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    • 2014
  • In this study, a hybrid multi-cup electric cupping system (HMECS) was proposed, based on the ancient cupping method. HMECS consisted of several cups that could be used simultaneously to treat different areas of the patient's body. Each cup was equipped with its own pump and pressure-monitoring system. Moreover, the vacuum pressure of the cups was controlled using fuzzy logic. Through automated control of the vacuum pressure, long-term relief of muscle tightness was achieved. To develop a scientific foundation for this alternative treatment, we compared the VAS(Visual Analog Scale) and ODI(Oswestry Disability Index) scores from conventional basic cupping to the VAS and ODI scores for our proposed HMECS. The improvement rate in the VAS and ODI scores using HMECS after three treatments was higher than that achieved by basic cupping. These results, combined with the convenience offered by enhanced IT capabilities, should increase the popularity of this device among an aging society, and facilitate the opportunity to further explore the potential of Oriental medical practices.

침지형 분리막을 사용한 오수처리

  • 최광호
    • Proceedings of the Membrane Society of Korea Conference
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    • 1998.06a
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    • pp.113-133
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    • 1998
  • In activated sludge process, sludge settling condition is affected by organic loading rate or operation condition, and if settling condition is getting worse, it is common that overall process fails due to wash-out of biomass causing low concentration in the aeration tank. Also activated sludge process has such several problems as requiring large area, consuming a lot of power and producing large volume of sludge. Increased public concern over health and the environment combined with a strong desire to reduce capital, operating and maintenance costs, have created a need for innovative technologies for building new high quality effluents which vail meet 21st century crkeria. MBR(Membrane Bioreactor) process consists of a biological reactor and ultrafiltration(UF) membrane system that replaces the conventional clarifier of an activated sludge process. The main operating advantages of this system are that the quality of the effluent is independent of the settleability of the mixed liquor and that the effluent is free of suspended solids in any operating condition. It is possible to eliminate clarifier and to reduce the volume of aeration tank because it can afford to accumulate high biomass concentration in the bioreactor(20, 000~30, 000mg/L), which would not be possible in a conventional activated sludge process. Therefore, this process reduces overall treatment plant area. In addition to those advantages, Longer SRT condition enables higher sludge digestion in MBR process so the sludge volume produced is 50 to 70% lower than that of conventional activated sludge process There are two kinds of MBR process according to the allocations of membrane. One is cross flow type MBR of which module is located outside of the bioreactor and mixed liquor is driven into the membrane module. The other is submerged type MBR process of which module is submerged in the bioreactor and mixed liquor is generally sucked from the lumen side. addition to that the cake layer is often removed by the uplifting flow of bubbling air. A submerged MBR process is superior to a crossflow MBR in regard to the power consumption because suction pressure of a submerged MBR is generally lower than that of a crossflow MBR which has recirculation pump. A submerged MBR, therefore, has the potential to be applied to small wastewater treatment plants that need low cost treatment systems.

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Waterhammer for the In-Line Intake Pumping Station with Air Chamber (에어챔버가 설치된 인라인 취수펌프장에서 수격현상)

  • Kim, Kyung-Yup;Ahn, Cheoul-Hong;Kim, Bum-Jun
    • The KSFM Journal of Fluid Machinery
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    • v.15 no.6
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    • pp.70-76
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    • 2012
  • Recently, because people are taking a great interest in the water supply system and the related facilities are getting larger, the surge suppression is very important problem. The waterhammer occurs when the pumps are started or stoped for operation or tripped due to the power failure. As the waterhammer problems as a result of the pump power failure were very serious, these situations were carefully investigated. Accordingly, we carried out both numerical simulations and field tests to confirm the safety of Juam intake pumping station in which had the in-line pumps. In this paper, it was reviewed that the water supply system has the reliability on the pressure surge, in case the air chambers were installed at both the inlet and the oulet of the in-line pumping station. From the numerical simulations, we found that negative pressure occurred at the inlet disappeared and high pressure occurred at the outlet reduced due to the air chambers. And these results of numerical simulations verified by the field tests. The field tests carried out in case of normal start, normal stop, one and two of pumps emergency stop. By results of simulations and field tests, we are sure that Juam intake pumping station in which have the air chambers is safe for the waterhammer. In addition, we suggested the operation methods of facilities for safe maintenance of the pumping station.

Performance Prediction of a Turbopump System (유동해석을 이용한 터보펌프 성능 예측)

  • Choe, Chang-Ho;Hong, Sun-Sam;Kim, Jin-Han;No, Jun-Gu;Kim, Dae-Jin
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.34 no.4
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    • pp.70-75
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    • 2006
  • The performance of a turbopump system composed of an inducer, an impeller, a volute and seals has been computationally analyzed. To save the computational time, only one flow passage of the inducer and impeller is considered for the computations. A steady mixing-plane method is used on the impeller/volute interface for simulating the unsteady interaction phenomena. The axial thrust is predicted from the turbopump calculation in its entirety, which is necessary for such estimation. Moreover, the effects of each component on the pump performance are investigated at a design condition through the analysis of flow structures. The predicted performance is in good agreement with experimental data in terms of head rise, efficiency and volute wall pressure distributions despite of highly complex flow structures being present. The computational results also show that the axial and radial thrusts are within the design limit although corresponding experimental measurements were not taken.