• Title/Summary/Keyword: 펌프 제어

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Implementation of a Small Size Electric Automatic Lubrication System for Heavy Commercial Vehicle (대형상용차량을 위한 소형전기식 윤활유 자동 공급시스템 구현)

  • Kim, Man Ho;Lee, Sang Hyeop;Lee, Suk;Lee, Kyung Chang
    • Journal of the Korean Society for Precision Engineering
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    • v.30 no.10
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    • pp.1041-1049
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    • 2013
  • One of the causes of malfunction of commercial vehicle is corrosion or wear. In order to prevent corrosion and wear, lubricants have to be supplied periodically. However, the period of lubrication usually depends on operator's judgment. If the period is too short, excess lubricant will cause pollution and unnecessary expenses, where as long periodic supply of lubricant might cause wear, damage and eventual breakdown. Therefore, an automatic lubrication system with predetermined interval will reduce the excessive supply of lubricating oil and prevent wear and damage. This thesis presents an automatic lubrication system which consists of a lubricant pump and an embedded controller. An automatic lubrication operating algorithm is used to operate the lubricant pump and feedback the pressure status of the system using pressure sensors. The developed system shows an efficient periodic supply of lubricant.

Control of Heat Pump for Low Emission Diesel Engine (저공해 중소형 디젤차량 히트펌프 제어)

  • Park, Byung-Duck;Lee, Won-Suk;Won, Jong-Phil;Kwon, Sun-Ik
    • Journal of the Korean Society of Industry Convergence
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    • v.5 no.4
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    • pp.379-384
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    • 2002
  • As automotive diesel engines adopt the direct injection method for a lower level of the exhaust emission and a higher fuel efficiency, the maximum temperature of engine coolant decreases. Consequently, the total available heat source from the engine coolant decreases over 35%. However, the heating source of air-conditioning system in automobiles depends on the hot engine coolant completely, so that it is nearly impossible to control air conditioning in heating season. Therefore, the present study has been carried out to develop the air conditioning system for the high efficient heat pump type using the HFC-134a. Especially, the air conditioning system of heating has been developed at a beginning stage, when it has low heat source from small and medium sized diesel recreation vehicles. To develop a control logic system for air conditioning system which is a heat pump type with a heat recovery exchanger, its cycle characteristics has been investigated according to the opening of LEV at a bench system.

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Control of Subsurface Vortex on Cylindrical Sump Wall (원통형 펌프 흡입정 벽면에서 발생하는 수중 보텍스 제어)

  • Park, Young Kyu;Jeon, Joon Ho;Lee, Yoen Won
    • Journal of the Korean Society of Visualization
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    • v.17 no.2
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    • pp.73-82
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    • 2019
  • The subsurface vortex - which occurs inside the cylindrical sump - was visualized through Computational Fluid Dynamics (CFD) and experiment. The analysis of subsurface vortex inside the cylindrical sump was already carried out using CFD techniques by the first author. To understand the subsurface vortex more clearly, an experimental analysis was carried out with a 1/5th scale model; and the flow rate was calculated according to the similarity law. The experimental results of vortex visualization matches well with the CFD results. The surface roughness model and Anti Vortex Device (AVD) model have been investigated to control the subsurface vortex. For the case of average surface roughness of 1mm and 5mm, the subsurface vortex appears and the vorticity is higher when compared to that of a smooth surface condition. However, for the AVD model, the subsurface vortex is completely removed and the internal flow is stabilized.

A Study on the Localization of 1500lb High-Pressure Drop Control Valve for Boiler Feedwater Pump (보일러 급수펌프용 1500lb 고차압 제어밸브 국산화 개발에 관한 연구)

  • Lee, Kwon-Il;Jang, Hoon;Lee, Chi-Woo
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.21 no.8
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    • pp.19-24
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    • 2022
  • We developed a prototype from the design of a trim, which is the most important in the localization development of a 1500 Ib high-differential pressure-control valve used for boiler feedwater, and measured the flow coefficient, the most basic design data for valves. The following conclusions were drawn. The comparison of the design values of the flow coefficients for the existing X-trim and the multicore trim designed for localization development showed that they were almost identical, and the X-trim value was slightly lower. The comparison of the X-trim and multicore trim based on the valve flow coefficient test showed that they were generally similar, indicating no problem with the design. In the future, we plan to compare and analyze the flow paths for the X-trim and multicore trim via flow analysis.

A Study on the Flow Coefficient Test and Numerical Analysis about 1500lb High-Pressure Drop Control Valve for Boiler Feedwater Pump (보일러 급수펌프용 1500lb 고차압 제어밸브 유량시험 및 수치해석에 관한 연구)

  • Lee, Kwon-Il;Jang, Hoon;Lee, Chi-Woo
    • Journal of the Korean Society of Industry Convergence
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    • v.25 no.4_2
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    • pp.541-547
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    • 2022
  • Before making a prototype, we predicted the inlet/outlet differential pressure and flow coefficient, which are the most basic design data for the valve through the design and numerical analysis of the trim, which is the most important in the localization development of the 1500Ib high differential pressure control valve used for boiler feed water. As a result, the design value and the analysis value were found to be about 98% similar. The flow field within the fluid velocity of 23m/s to prevent cavitation was also found. The result of the numerical analysis on thermal stress due to the characteristics of valves exposed to high temperatures showed that it was found to be about 18% less than the allowable stress of the bolt fixing the trim. When all loads such as pressure, self-weight, and vibration are applied, however, it is judged to go beyond the currently calculated thermal stress, exceeding the allowable stress.

Reinforcement learning model for water distribution system design (상수도관망 설계에의 강화학습 적용방안 연구)

  • Jaehyun Kim;Donghwi Jung
    • Proceedings of the Korea Water Resources Association Conference
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    • 2023.05a
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    • pp.229-229
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    • 2023
  • 강화학습은 에이전트(agent)가 주어진 환경(environment)과의 상호작용을 통해서 상태(state)를 변화시켜가며 최대의 보상(reward)을 얻을 수 있도록 최적의 행동(action)을 학습하는 기계학습법을 의미한다. 최근 알파고와 같은 게임뿐만 아니라 자율주행 자동차, 로봇 제어 등 다양한 분야에서 널리 사용되고 있다. 상수도관망 분야의 경우에도 펌프 운영, 밸브 운영, 센서 최적 위치 선정 등 여러 문제에 적용되었으나, 설계에 강화학습을 적용한 연구는 없었다. 설계의 경우, 관망의 크기가 커짐에 따라 알고리즘의 탐색 공간의 크기가 증가하여 기존의 최적화 알고리즘을 이용하는 것에는 한계가 존재한다. 따라서 본 연구는 강화학습을 이용하여 상수도관망의 구성요소와 환경요인 간의 복잡한 상호작용을 고려하는 설계 방법론을 제안한다. 모델의 에이전트를 딥 강화학습(Deep Reinforcement Learning)으로 구성하여, 상태 및 행동 공간이 커 발생하는 고차원성 문제를 해결하였다. 또한, 해당 모델의 상태 및 보상으로 절점에서의 압력 및 수요량과 설계비용을 고려하여 적절한 수량과 수압의 용수 공급이 가능한 경제적인 관망을 설계하도록 하였다. 모델의 행동은 실제로 공학자가 설계하듯이 절점마다 하나씩 차례대로 다른 절점과의 연결 여부를 결정하는 것으로, 이를 통해 관망의 레이아웃(layout)과 관경을 결정한다. 본 연구에서 제안한 방법론을 규모가 큰 그리드 네트워크에 적용하여 모델을 검증하였으며, 고려해야 할 변수의 개수가 많음에도 불구하고 목적에 부합하는 관망을 설계할 수 있었다. 모델 학습과정 동안 에피소드의 평균 길이와 보상의 크기 등의 변화를 비교하여, 제안한 모델의 학습 능력을 평가 및 보완하였다. 향후 강화학습 모델을 통해 신뢰성(reliability) 또는 탄력성(resilience)과 같은 시스템의 성능까지 고려한 설계가 가능할 것으로 기대한다.

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Design of the Condenser and Automation of a Solar Powered Water Pump (태양열 물펌프의 운전 자동화 설계)

  • Kim Y. B.;Son J. G.;Lee S. K.;Kim S. T.;Lee Y. K.
    • Journal of Animal Environmental Science
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    • v.10 no.3
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    • pp.141-154
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    • 2004
  • The solar powered water pump is very ideal equipment because solar power is more intensive when the water is more needed in summer and it is very helpful in the rural area, in which the electrical power is not available. The average so]ar radiation energy is 3.488 kWh/(m2day) in Korea. In this study, the automatic control logic and system of the water pump driven by the radiation energy were studied, designed, assembled, tested and analyzed for realizing the solar powered water pump. The experimental system was operated automatically and the cycle was continued. The average quantity of the water pumped per cycle was about 5,320 cc. The cycle time was about 4.9 minutes. The thermal efficiency of the system was about 0.030%. The pressure level of the n-pentane vapour in flash tank was 150%450 hPa(gauge) which was set by the computer program for the control of the vapour supply. The pressure in the condenser and air tank during cycles was maintained as about 600 hPa and 1,200 hPa respectively. The water could be pumped by the amount of 128kg/(m2day) with the efficiency of 0.1% and the pumping head of 10 m for the average solar energy in Korea.

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Construction and Tests of the Vacuum Pumping System for KSTAR Current Feeder System (KSTAR 전류전송계통 진공배기계 구축 및 시운전)

  • Woo, I.S.;Song, N.H.;Lee, Y.J.;Kwag, S.W.;Bang, E.N.;Lee, K.S.;Kim, J.S.;Jang, Y.B.;Park, H.T.;Hong, Jae-Sik;Park, Y.M.;Kim, Y.S.;Choi, C.H.
    • Journal of the Korean Vacuum Society
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    • v.16 no.6
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    • pp.483-488
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    • 2007
  • Current feeder system (CFS) for Korea superconducting tokamak advanced research(KSTAR) project plays a role to interconnect magnet power supply (MPS) and superconducting (SC) magnets through the normal bus-bar at the room temperature(300 K) environment and the SC bus-line at the low temperature (4.5 K) environment. It is divided by two systems, i.e., toroidal field system which operates at 35 kA DC currents and poloidal field system wherein 2026 kA pulsed currents are applied during 350 s transient time. Aside from the vacuum system of main cryostat, an independent vacuum system was constructed for the CFS in which a roughing system is consisted by a rotary and a mechanical booster pump and a high vacuum system is developed by four cryo-pumps with one dry pump as a backing pump. A self interlock and its control system, and a supervisory interlock and its control system are also established for the operational reliability as well. The entire CFS was completely tested including the reliability of local/supervisory control/interlock, helium gas leakage, vacuum pressure, and so on.

A Study on the Air Vent Valve of the Hydraulic Servo Actuator for Steam Control of Power Plants (발전소의 스팀제어용 유압서보 액추에이터의 공기배출 밸브에 관한 연구)

  • Lee, Yong Bum;Lee, Jong Jik
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.40 no.6
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    • pp.397-402
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    • 2016
  • To produce adequate electricity in nuclear and thermal power plants, an optimal amount of steam should be supplied to a generator connected to high- and low-pressure steam turbines. A turbine output control device, which is a special steam valve employed to supply or interrupt the steam to the turbine, is operated using a hydraulic servo actuator. In power plants, the performance of servo actuators is degraded by the air generated from the hydraulic system, or causes frequent failures owing to an increase in the wear of the seal. This is due to the seal being burnt as generated heat using the produced compressed air. Some power plants have exhausted air using a fixed orifice, and thus they encounter power loss due to mass flow exhaust. Failures are generated in hydraulic pumps, electric motors, and valves, which are frequently operated. In this study, we perform modeling and analysis of the load-sensing air-exhaust valves, which can be passed through very fine flow under normal use conditions, and exhaust mass flow air at the beginning stage as with existing fixed orifices. Then, we propose a method to prevent failures due to the compressed air, and to ensure the control accuracy of hydraulic servo actuators.

A System Simulation Model of Proton Exchange Membrane Fuel Cell for Residential Power Generation for Thermal Management Study (가정용 연료전지 시스템의 열관리 해석을 위한 시스템 운전 모델 개발)

  • Yu, Sang-Seok;Lee, Young-Duk;Ahn, Kook-Young
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.34 no.1
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    • pp.19-26
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    • 2010
  • A PEMFC(proton exchange membrane fuel cell) is a good candidate for residential power generation to be coped with the shortage of fossil fuel and green house gas emission. The attractive benefit of the PEMFC is to produce electric power as well as hot water for home usage. The thermal management of PEMFC for RPG is to utilize the heat of PEMFC so that the PEMFC can be operated at its optimal efficiency. In this study, thermal management system of PEMFC stack is modeled to understand the dynamic response during load change. The thermal management system of PEMFC for RPGFC is composed of two cooling circuits, one for controling the fuel cell temperature and the other for heating up the water for home usage. The different operating strategy is applied for each cooling circuit considering the duty of those two circuits. Even though the capacity of PEMFC system (1kW) is enough to supply hot domestic water for residence, heat-up of reservior takes some hours. Therefore, in this study, time schedule of the simulation reflects the heat-up process. Dynamic responses and operating strategies of the PEMFC system are investigated during load changes.