• Proceedings of the Korea Water Resources Association Conference
• /
• 2017.05a
• /
• pp.309-309
• /
• 2017

EPANET은 U.S. EPA(U.S. Environmental Protection Agency, 미 환경청)에서 개발한 상수관망 시스템의 수리해석 모의 프로그램으로서, 다양한 상수관망의 설계 및 운영을 모의하기 위해 세계적으로 활발히 활용되고 있다. EPANET 프로그램은 사용자 친화적인 GUI(Graphic User Interface) 환경으로 개발되었으며, 직관적인 네트워크 요소와 폭 넓은 모의 옵션을 제공한다는 장점이 있다. 특히, 상수관망의 실무 및 연구 분야에서는 공학용 분석프로그램과 프로그래밍 언어의 활용이 활발해짐에 따라, 이를 EPANET 프로그램과 연계시킬 수 있는 EPANET Toolkit이 개발되면서 그 활용도는 계속해서 확장될 전망이다. 그러나 지속적인 보완에도 불구하고, 기존의 EPANET Toolkit에서 제공하고 있는 기능은 EPANET 프로그램을 전부 반영하지 못하고 있어 실용성 있는 프로그램의 개발이 제한되고 있는 실정이다. 기존 연구에서는 EPANET Toolkit의 미비한 기능에 대해, "프로그램 수행 - 결과 확인 - EPANET 네트워크 수정"을 반복 수행하여 문제를 해결하였으며, 따라서 복잡하고 세밀한 상수관망 모의 연구에 많은 제약이 존재하였다. 본 연구에서는 EPANET Toolkit의 내부를 수정, 보완하여 기존에 고려하지 못하였던 다양한 기능을 추가하여 관련 연구에 활용할 수 있도록 하였다. 구체적으로는 Pump Curve를 변경 및 입력하여 Pump 교체를 위한 최적 펌프용량을 결정하거나, Energy Pattern을 입력하여 손쉽게 전력비용을 산정하는 등의 기능이 개선되었다. 그밖에도 EPANET Toolkit의 활용성을 향상시키기 위한 다양한 함수들을 추가적으로 구성하였으며, 이는 펌프 용량 및 효율 곡선과 배수지 설계 등 상수관망 구성요소의 설계에도 폭 넓게 활용할 수 있을 것으로 기대된다.

• Journal of the Korean Institute of Gas
• /
• v.26 no.5
• /
• pp.1-9
• /
• 2022

Selection of a suitable artificial lift is important in terms of efficient operation and economics for oil production. In general, process of well design includes the selection of artificial lift, but the oil recovery could be enhanced by use of hybrid system combined with two types of artificial lift method according to reservoir condition for oil production. Electric submersible pump (ESP), as a presentative artificial lift method, is a manner for supplying the pressure in the lower part of oil well by using of a multi-stage centrifugal pump with an electric energy. However, there is a disadvantage that has a limit to the application period because of mechanical defection on ESP. Accordingly, it is possible to reduce the shutdown time of production well by applying the ESP/Gas lift hybrid system, which is to switch to a gas lift when an ESP is defective. This study describes the effect of ESP/gas lift hybrid system compared with ESP method for a onshore horizontal well locating in the of Permian basin, USA. As a result of study, ESP/gas lift hybrid system could make more effective productivity than ESP method. Also, we quantitatively predicted how much economic benefit would be obtained when the hybrid system was applied in the production well.

• Journal of Advanced Marine Engineering and Technology
• /
• v.34 no.1
• /
• pp.195-201
• /
• 2010

In this paper, a cooling system of high-power propulsion motor with Energy Saving System(ESS) is described. Normally, the cooling system for ship consists of fresh water pump, sea water pump, 3-way valve and cooler. In the cooling system, F.W(Fresh Water) and S.W(Sea Water) pump is operated on rated rpm, and the 3-way valve is controlled for preventing over-cooling. So, the consumption power of pump's motor is changed according to a sea water temperature. In the proposed cooling system, F.W. pump and S.W pump is controlled by inverter, and it is can be reduced the consumption power. Also, it is proved with simulation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2010.05a
• /
• pp.34-37
• /
• 2010

One dimensional transient analysis was studied for turbopump-fed liquid propellant rocket engine(LRE) system in starting using AMESim. The effects of timing of gas generator fuel valve opening and gas generator ignition to start-up stability were researched for open cycle type system using LOX/RP-1 to propellants. Result show that the parameters and sequence on start-up should be considered to design optimized turbopump-fed LRE system.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2016.05a
• /
• pp.4-4
• /
• 2016

기후변화에 따른 강우패턴의 변화로 인하여 도시홍수에 의한 인명 및 재산피해가 증가하여 대응 방안의 마련이 필요한 상황이다. 도시홍수 피해원인을 조사한 기존의 연구결과(심우배, 2008)를 살펴보면, 도시유역에서의 침수피해는 배수능력부족, 하수관거 용량부족 등의 치수시설물의 성능부족이 주원인으로 나타나고 있다. 이와 같은 문제를 해결하기 위해서는 시설물의 설계기술을 향상시켜 치수능력의 증대를 기대할 수 있는 연구성과가 필요하다. 본 연구에서는 내수배제시설의 성능강화를 위하여 내수배제시설 계획수립 기준, 내수배제시설의 성능개선을 위한 정량적 설계지침 개발, 배수시스템의 개선 기법 개발을 수행하였다. 내수배제시설의 계획수립 및 기준 개발을 위하여 침수위험지역 특성에 따른 내배수시설 도입 기준과 내배수시설 설치에 침수위험 저감 효과 분석기법 및 내배수시설 최적 조합을 통한 내수배제능력 평가기법을 개발하였다. 내수배제시설의 성능개선을 위해서는 빗물펌프장 성능 평가 기법과 유입 유출부 및 흡수조 개선 기술, 유출부 주변 부속시설 안정성 향상 기술 개발을 주요 연구내용으로 설정하였다. 마지막으로, 배수시스템의 개선 기법 개발을 위해서는 도시하천 설계빈도 상향에 따른 우수관거 구조개선 기술을 개발하고, 우수관거 시스템 저류능력 평가 기술 및 우수관거 연계 저류시스템 설계 기술개발을 수행하였다. 본 연구에서는 내수배제시설에 대한 정량적 설계기법을 개발하여 도시침수에 대한 구조적인 대응방안을 수립하였다. 시설물 계획단계에서 고려하여야하는 문제점을 연구내용에 반영하여 내수배제시설 설계실무에 실용적으로 적용할 수 있는 성과를 도출하였다. 향후 내수배제시설 설계실무자의 의견을 반영하여 연구성과를 고도화한다면 실무에 적용가능한 성과가 도출될 것으로 기대된다.

• Journal of Korea Water Resources Association
• /
• v.42 no.9
• /
• pp.759-771
• /
• 2009

The electricity cost of pumping system accounts for a large part of the total operating cost for long distance water supply networks. This study presents a method based on dynamic programming for establishing an joint optimal operation of pumps and storages system on a hourly basis. Analysis is taken of the relative efficiencies of the available pumps, the structure of the electricity tariff, the consumer-demand pattern, and the storage characteristics and operational constraints of the pipe. The possible system objectives and constraints are described. An application of the method to the existing Yangju Water Supply System consisted of two pump station and 5 storage pools under the condition of expanding pumping facility in the part of the Capital Area Water Supply System is presented, showing that considerable electricity cost savings are remarkable. The approach was found to be implementable in real system operation and large-scale water supply system design in respect of minimizing life-cycle total cost.

• Journal of Energy Engineering
• /
• v.20 no.3
• /
• pp.224-230
• /
• 2011

For developing high performance fuel cell, peripheral devices and key components have to be studied in priority. In this study, centrifugal pump was studied for heat recovery. For PEM fuel cell system, a four-impeller centrifugal pump was designed, tested and compared with result of commercial product (IWAKI). In addition, effects of number of impeller were analyzed by CFD. The experiment and analysis were progressed in the same conditions. The results showed the quantitative difference under 30% between the numerical and the experimental pressure difference and mass flow rate.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.38 no.5
• /
• pp.567-573
• /
• 2014

Since the development of microelectromechanical systems (MEMS) technology for the medical field, various micro-fluid transfer systems have been studied. This paper proposes a micro-piezoelectric pump that imitates a stomach's peristalsis by using two separate piezoelectric elements, in contrast to existing micro-pumps. This piezoelectric pump is operated by using the valve-less traveling wave of peristalsis movement. If the piezoelectric plates at the two separated plates are actuated at the input voltage, a traveling wave occurs between the two plates. Then, the fluid migrates by the pressure difference generated by the traveling wave. Finite element analysis was performed to understand the mechanics of the combined system with piezoelectric elements, elastic structures, and fluids. The effects of design variables such as the chamber height and number of ceramics on the flow rate of the fluid were examined.

• Journal of Biomedical Engineering Research
• /
• v.10 no.2
• /
• pp.139-150
• /
• 1989

A new motor-driven blood pump for artificial heart was developed. In this blood pump, a small size, high torque brushless DC motor was used as an energy converter and the motor rolls back and forth on a circular track. This movement of the "rolling-cyliner" causes blood ejection by alternately pushing left or right polyurethane blood sacs. This moving-actuator mechanism could be eliminate two potential problems of other motor-driven artificial hearts such as large size and poor anastomosis for the implantation. Theoretical analyses on the pump efficiency, the temperature rise, and the inflow mechanism were also performed. In a series of mock circulation tests, the theoretical analyses were compared to the measured hemodynamic and mechanical values. The pump system was shown to have sufficient cardiac output (upto 9 L/min), sensitivity to preload, and mechanical stability to be tested as an implantable total artificial heart.ial heart.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2008.05a
• /
• pp.495-499
• /
• 2008

This study developed a determination method for a rainwater retention-pumping combination system for roof runoff control. The outflow and stored water volume in the rainwater system was simulated using a water balance equation. Its result is presented in the TPP (Tank capcity-Peak outflow-Pumping rate) curves for rainfall return periods. In a case study on reduction of the peak flow rate of 100-year return period to 5-year in Seoul, The range of pumping rate for $100m^2$ roof area is determined as $0{\sim}25{\ell}$/min. Additionally, retention volume of $8.5{\sim}10m^3$ can be combined with the pumping rate range. That is to say an effective combination of a retention-pumping system capacity can be determined from a system of $8.5m^3$ tank with $25{\ell}$/min to $10m^3$ tank without pump. Using the TPP curves, engineers can determine the effective combination range of retention & pumping system capacity. Furthermore, that can be helpful to decide a detail system capacity for field condition.