• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1081-1086
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• 2007

It is strongly requested to reduce fuel consumption because of high oil price and exhaust gases of road vehicles for environmental preservation. To solve these problems, several types of hybrid vehicles have been developed. Among them, flywheel hybrid vehicle using variable displacement pump/motor was already proposed as one of the feasible hybrid systems in place of hybrid vehicle by the conventional storage battery. The proposed flywheel hybrid vehicle is to keep constant pressure of high pressure line by the control of swash plate angle of flywheel pump/motor as pressure compensator. The efficiency of the overall system depends severely on the efficiency of hydraulic pump/motor in the energy saving hydraulic control system by simulation. According to the control methods of swash plate angle of piston pump/motor, there remain several problems to be solved. In this paper, experimental setup for energy saving is fabricated and the efficiency of energy saving is investigated by experiments with respect to various experimental conditions.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2005년도 제25회 추계학술대회논문집
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• pp.220-223
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• 2005

본 연구에서는 러시아, 미국, 유럽, 일본의 가스발생기 사이클 엔진 시스템 설계인자를 조사하여 비교 검토하였다. 연소기의 특성속도, 연소기 분사기 차압, 터보펌프 토출압, 펌프효율, 터빈의 비출력 등의 설계인자를 비교한 결과 연소기의 특성속도는 1700-1770 m/s, 분사기차압은 4-10bar, 터보 펌프 토출압은 연소기 압력의 120-230%, 펌프효율은 60-80%, 터빈의 비출력은 $0.28-0.58MW{\cdot}s/kg$의 범위에 있다. 터빈 입구의 가스온도는 터빈의 비출력과 밀접한 관련이 있으며 터빈재질로 인한 한계를 고려하여 결정되어야 한다.

• Journal of Advanced Marine Engineering and Technology
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• 제40권4호
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• pp.295-300
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• 2016

P사의 실린더 당 210 kW 급 중속디젤엔진의 연료분사펌프를 대상으로 연료 송출 압력파에 대해서 Ansys Fluent R15.0을 사용하여 수치 해석하였다. 연료 송출 압력파의 실험 결과와 수치 해석 결과가 유사하게 나타났으며, 전산유체역학을 이용한 연료분사펌프의 연료 송출 압력파에 대한 수치 해석의 신뢰성을 확인하였다.

• 한국정밀공학회지
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• 제24권5호
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• pp.68-76
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• 2007

It is strongly requested to reduce fuel consumption because of high oil price and exhaust gases of road vehicles for environmental preservation. To solve these problems, several types of hybrid vehicles have been developed. Among them, flywheel hybrid vehicle using variable displacement pump/motor was already proposed as one of the feasible hybrid systems in place of hybrid vehicle by the conventional storage battery. The proposed flywheel hybrid vehicle is to keep constant pressure of high pressure line by the control of swash plate angle of flywheel pump/motor as pressure compensator. The efficiency of the overall system depends severely on the efficiency of hydraulic pump/motor in the energy saving hydraulic control system by simulation. According to the control methods of swash plate angle of piston pump/motor, there remain several problems to be solved. In this paper, experimental setup for energy saving is fabricated and the efficiency of energy saving is investigated by experiments with respect to various experimental conditions.

• 설비공학논문집
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• 제21권6호
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• pp.333-339
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• 2009

The objective of this study is to predict optimal intermediate pressure of a 2-stage compression heat pump system using river water. To determine the maximum performance of the 2-stage compression heat pump system, the experimental evaluations on the 2-stage compression cycle were carried out under various operating conditions. Electronic expansion valves were applied to control intermediate pressure and superheat. Based on the experimental data, an empirical correlation for predicting optimal intermediate pressure which considering cycle operating parameters was developed. The present correlation was verified by comparing the predicted data with the measured data. The predictions showed a good agreement with the measured data within a relative deviation of ${\pm}4%$ at various operating conditions.

• International Journal of Naval Architecture and Ocean Engineering
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• 제13권1호
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• pp.794-803
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• 2021

The instantaneous acceleration affects the performance of the water-jet pump obviously. Here, based on the user-defined function, the method to simulate the inner flow in water-jet pumps under acceleration conditions was established. The effects of two different acceleration modes (linear acceleration and exponential acceleration) and three kinds of different acceleration time (0.5s, 1s and 2s) on the performance of the water-jet pump were analyzed. The results show that the thrust and the pressure pulsation under exponential acceleration are lower than that under linear acceleration at the same time; the vapor volume fraction in the impeller under linear acceleration is 27.3% higher than that under exponential acceleration. As the acceleration time increases, the thrust gradually increases and the pressure pulsation amplitude at the impeller inlet and outlet gradually decreases, while the law of pressure pulsation is the opposite at the diffuser outlet. The main frequency of pressure pulsation at the impeller outlet is different under different acceleration time. The research results can provide some reference for the optimal design of water-jet pumps.

• 한국가시화정보학회지
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• 제9권4호
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• pp.69-73
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• 2011

Butterflies have been known to suck viscous liquids through a long, cylindrical proboscis using the large pressure difference formulated by the cyclic expansion and contraction of a muscular pump located inside their head. However, there are few studies on the liquid-feeding phenomena in a live butterfly, because it is hard to observe the internal morphological structures under in vivo condition. In this study, the dynamic motion of the pump system in a butterfly was in vivo visualized using synchrotron X-ray micro-imaging technique to analyze the liquid-feeding mechanism. The period of the liquid-feeding process is about 0.3sec. The expansion stage is about two times larger than the contraction stage in one cycle. The cyclic variation of pump volume generate large negative suction pressure and the pressure difference inside the long proboscis of a butterfly is estimated to be larger than 1atm.

• International Journal of Fluid Machinery and Systems
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• 제4권4호
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• pp.375-386
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• 2011

The turbo-type blood pump studied in this paper has an impeller that is magnetically suspended in a double volute casing. The impeller rotates with minimal fluctuations caused by fluid and magnetic forces. In order to improve stability of the rotating impeller and to facilitate long-term use, a careful investigation of the pressure fluctuations and of the fluid force acting on the impeller is necessary. For this purpose, two models of the pump with different volute cross-sectional area are designed and studied with computational fluid dynamics software. The results show that the fluid force varies with the flow rate and shape of the volute, that the fluctuations of fluid force decrease with increasing flow rate and that the vibratory movement of the impeller is more efficiently suppressed in a narrow volute.

• 한국자동차공학회논문집
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• 제8권6호
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• pp.70-78
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• 2000

A balanced vane pump for the use of automotive power steering systems generates a flow ripple which is imposed upon the mean flow rate. The flow ripple interacts with the characteristics of the connected pipes, valves and steering gear in a complex manner to produce a pressure ripple, also known as fluid-borne noise. In order to reduce vibration level and produce quieter and more reliable power steering systems, it is important to measure the flow ripple produced by a pump with high accuracy and fast response. In this paper, the flow ripple generated by a vane pump in automotive power steering systems is measured by the remote instantaneous flow rate measurement method (RIFM) using hydraulic pipeline dynamics. In experiment, flow and pressure ripple wave forms are measured under various operating conditions. Also, the parameters affected upon the flow and pressure ripple are investigated by the frequency analysis.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2010년 춘계학술대회논문집
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• pp.83-85
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• 2010

A hydraulic gear pump is widely used in many industrial applications to provide both high pressure and high flow rate by physical displacement of finite volume of fluid with each revolution. In this study, two dimensional fluid-structure interaction simulation of gear pump flow was carried out to examine detailed complex flow patterns and structural stress distribution on rotors by using a commercial software ADINA. The effect of rotor clearance size on the flow characteristics, specially the temporal variation of velocity and pressure field, which is a main source of flow noise, also was investigated.