• 대한기계학회논문집B
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• 제27권9호
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• pp.1256-1261
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• 2003

Since the viscous effect increases as the size of device decreases, viscous-driven micropump is a promising mechanism in microscale applications. In the present study, a dual-rotor type pump which contains two counter-rotating cylinders for improving performance characteristics is proposed. First, for flows in the single-rotor type pump, the present unstructured grid simulation method is validated by comparing its results to the previous results. Next, the performance of the dual-rotor type pump is evaluated by the parametric studies and is compared to that of the previous single-rotor type pump. The flow characteristics are qualitatively similar to those of single-rotor type pump. However, the performance of the micropump with tandem rotors is still better than that of previous pumping type, e.g. much larger flow rate, smaller driving region, higher efficiency, and wider operation range.

• 대한기계학회논문집B
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• 제30권9호
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• pp.858-865
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• 2006

SMART Pilot is a multipurpose small capacity integral type reactor. Main coolant pump (MCP) of SMART Pilot is a canned-motor-type axial pump to circulate the primary coolant between nuclear fuel and steam generator in the primary system. The reactor is designed to operate under condition of $310^{\circ}C$ and 14.7MPa. Thus MCP has to be tested under same operating condition as reactor design condition to verify its performance and safety. In present wort a test apparatus to simulate real operating situations of the reactor has been designed and constructed to test MCP. And then functional tests, performance tests, and endurance tests have been carried out upon a prototype MCP. Canned motor characteristics, homologous head/torque curves, coast-down curves, NPSH curves and lift-time performance variations were obtained from the qualification test as well as hydraulic performance characteristics of MCP.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2003년도 학술대회지
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• pp.329-334
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• 2003

Design of pre-compression region(trapping region) of the valve plate is an important element to minimize the pressure fluctuation in a cylinder and in discharge process, and pump noise. In this study, we tried to prove what the characteristics of the oil hydraulic pump would be according to the angle of the trapping region. Three kinds of asymmetrical valve plates were used. As a result, we found that by designing the trapping region, the slope of the pressure rise in the cylinder port from low-pressure suction region to high-pressure discharge region is relaxed and the pressure fluctuation width and the discharge pressure pulsation are reduced. Therefore, because the pump gets smooth pressure fluctuation and low fluid Impact, the pump noise is reduce.

• 설비공학논문집
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• 제13권9호
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• pp.878-887
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• 2001

Experimental investigation has been carried out to examine the operating characteristics of a bubble pump for diffusion absorption refrigerator. The effects of heat input and delivery height on generation rate of refrigerant vapor and circulation rate of solution have been investigated. as a result heat input and delivery height increase, circulation rate of solution increases. And the smaller the tube diameter, the larger the circulation rate of solution. Pumping ratio increases to a critical point and then decrease with the increase of heat input, and it increases with the increase in delivery height. In this paper, Marcus's analytical theory was also examined. It was found that the Marcus\`s analytical theory of a bubble pump was not appropriate for a bubble pump using ammonia aqueous solution as a working fluid.

• 한국지열·수열에너지학회논문집
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• 제8권2호
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• pp.9-15
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• 2012

The objective of this study is to investigate the influence on the heating performance for a water-to-water 10RT ground source heat pump by using the water switching and refrigerant switching method. The test of water-to-water ground source heat pump was measured by varying the compressor speed, load side inlet temperature, and ground heat source side temperature. The heating capacity and COP of the heat pump increased with increasing ground heat source temperature. As a result, compared to a refrigerant switching method, the water switching method with counter flow improves the heating capacity and COP by approximately 5% in average, respectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.83-86
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• 2005

This paper proposed a hydraulic pump system which uses a variable SR drive and constant capacity pump. The base and maximum speed, torque are determined from displacement capacity of the pump and maximum pressure. The drive system is set to have a minimum power consumption having hydraulic preset pressure, which is operated within a maximum capacity and maximum preset pressure. This is achieved by controlling motor speed and power with feedback signal of pressure of the hydraulic pump. A 2.2kw, 12/8-pole SR motor and DSP based digital controller are designed and prototype drive system is manufactured. The proposed variable speed SR drive system is simulated and tested with experimental set-up. The test results show that the system has some good features such as high efficiency and high response characteristics.

• 조명전기설비학회논문지
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• 제19권5호
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• pp.68-73
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• 2005

본 논문은 선형유도전동기를 이용한 전자기펌프의 특성해석에 대하여 연구한 것이다. 전자기 펌프는 선형유도전 동기의 추진력에 의하여 용융 금속을 이송할 수 있다. 추진력을 높이기 위해 유전 알고리즘을 사용하여 최대 추력을 가지는 선형유도전동기를 설계 하고, 선형유도전동기를 이용한 전자기 펌프의 특성해석을 유동해석에 의하여 분석하였다.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 2001년도 제33회 춘계학술대회 개최
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• pp.340-345
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• 2001

Surface hardness is one of the major sources on wear in the oil hydraulic axial piston pump. To increase the performance of the oil hydraulic axial piston pump, it is need to know the surface layer characteristics in the sliding contact parts of them. This paper reports an experimental study on surface treatment characteristics in the piston of the oil hydraulic axial piston pump. We investigated surface wear with not only surface hardness and surface roughness but also material of the piston. We obviously observed that the surface hardness of piston in the oil hydraulic axial piston pump plays an important role to high power density and remain long life.

• 드라이브 ㆍ 컨트롤
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• 제11권2호
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• pp.1-8
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• 2014

In this study, the authors carried out experiments and numerical simulations in order to clarify the pressure pulsation characteristics in multiple-delivery rotating-cam and stationary-cylinder type radial piston pumps. Also, a tee filter was applied to the pump in order to mitigate the pressure pulsation. Through the experiments and simulations, it was known that pressure pulsation with a magnitude higher than 40% of the mean load pressure could occur in the pump used in the experiments. Moreover, it was confirmed that a tee filter designed in this study could effectively mitigate the pressure pulsation.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년 영문 학술대회
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• pp.751-755
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• 2008

During the rapid startup transient of a centrifugal pump, in order to investigate its transient characteristics, the torque equations are deduced. Based on these equations, numerical simulation is carried out with the Large Eddy Simulation(LES) method and UDFs(User Defined Functions) are applied during the simulation. Comparison between simulation and experiment results of pump heads and rotational speed shows that they are in good agreement, indicating that the dynamic characteristics of this pump can be predicted accurate comparatively through simulation with LES method during its startup process.