• 한국기계가공학회지
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• 제21권6호
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• pp.1-7
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• 2022

This work investigated the performance improvement of a medium-pressure fixed-displacement-type SPUR gear pump, which is mainly used in the machine tool industry. The 3D CFX analysis and IS technique were applied using ANSYS (commercial FEM code) and compared with experimental results to ensure the reliability of the analysis. In addition, the performance improvement of the pump was obtained using the theoretical volumetric displacement equation, and the gear tooth width was changed. The pressure flow performance curves were compared, and the results were analyzed according to the width of the gear teeth. This is a factor that can cause irregular flow, vibration, and noise inside the gear pump owing to friction between the housing and gear pump.

• 드라이브 ㆍ 컨트롤
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• 제21권2호
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• pp.15-22
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• 2024

The objective of this study was to examine whether a gerotor pump used in a transmission could be converted into an electric vehicle thermal management system pump using a virtual design environment. To achieve this objective, we first built an environment that could analyze the performance of a gerotor pump in heat transfer fluid. Flow rate, pressure, and volumetric efficiency were then analyzed when using heat transfer fluid in a gerotor pump. Finally, how large the displacement volume of the pump should be designed when using a heat transfer fluid other than oil was determined. Based on results of this study, it is expected that gerotor pumps will be applied to new business fields such as electric vehicle cooling systems.

• 한국가시화정보학회지
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• 제9권4호
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• pp.28-34
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• 2011

A volumetric gear pump is often used in extensive industrial applications to provide both high pressure and sufficiently high flow rate by physical displacement of finite volume of fluid with each revolution. Template mesh function in commercial CFD software, PumpLinx, by which 3-D meshes in the complex region between rotor and housing can be readily generated was employed for 3-D flow simulations. For cavitation analysis full cavitation model was included in 3-D simulations. The results showed high pulsation in pressure and flowrate which is implicated in pump vibration and noise. A model test for cavitation visualization was conducted and the results showed good qualitative agreement with numerical prediction.

• 한국유체기계학회 논문집
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• 제13권5호
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• pp.17-21
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• 2010

A volumetric gear pump is often used in extensive industrial applications to provide both high pressure and sufficiently high flow rate by physical displacement of finite volume of fluid with each revolution. To better understand the unsteady flow characteristics within the pump, numerical simulations were conducted by using moving dynamic meshing (MDM) techniques in commercially available CFD software, FLUENT. The effects of rotor clearance size and rotational speed of rotor on the flow characteristics, specially the temporal variation of velocity and pressure field, which is a main source of flow noise, was investigated. The results showed that significant reverse flow is developed in the rotor clearance and that its size is one of the most important factors affecting flow characteristics and pressure pulsation.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1997년도 제25회 춘계학술대회
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• pp.204-209
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• 1997

This paper reports on the theoretical study of the vane motions in a positive displacement vane pump. Vane detachment cause the pressure fluctuation, noise, wear in cam ring, and decrease the volumetric efficiency. Dynamic equation of vane motion and flow continuity equation have been modeled and solved simultaneously using 4th order Runge-Kutta method. As results of analysis, vane detachment occurs due to pressure overshoot by excess compression in the pumping chamber. Amount of vane detachment has been reduced by decreasing the pressure overshoot.

• 한국지반환경공학회 논문집
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• 제19권9호
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• pp.29-36
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• 2018

국내 외에서는 사면붕괴를 사전에 예방할 수 있는 모니터링 및 자동계측기에 관한 다수의 연구가 수행되어져 오고 있으나, 이러한 연구들은 다소 복잡한 구조로 이루어져 있고, 계측시스템의 대부분은 사면표층에 설치되어 있으며, 사면파괴 전 붕괴징후를 사전에 감지하고 경보를 울려주는 계측시스템에 관한 연구는 미진한 실정이다. 본 연구에서는 강우 조건에서의 사면 붕괴 메카니즘을 파악하기 위하여 사면 붕괴 실험을 수행하고 지중 변위와 체적 함수비 계측을 통해 사면 모델의 붕괴 초기에 발생되는 함수비와 변위 거동 특성을 분석하였다. 본 연구를 통해 고찰된 내용은 지방자치단체에서 집중호우로 인해 급경사지 붕괴위험지역 등 사면붕괴나 산사태가 예측될 때 사전에 주민을 대피시키는 사면붕괴 예 경보시스템 구축 시 기초자료로 활용될 수 있을 것으로 기대된다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 춘계학술대회 논문집
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• pp.895-896
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• 2010

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2008년도 하계학술발표대회 논문집
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• pp.171-176
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• 2008

As one way of design optimization of two-stage two-cylinder rotary compressor used for R410A heat pump application, displacement volume ratio, being defined by the ratio of the second stage cylinder volume to that of the first stage, has been varied and its effect on the compressor performance has been investigated by a computer simulation program. For simplicity, only the cylinder height of the second stage was varied to change the volume ratio. With increasing the volume ratio in the range of VR=$0.55{\sim}0.9$, volumetric efficiency increased monotonically, but adiabatic efficiency showed a maximum at around VR=0.6. Mechanical efficiency was little influenced by the volumetric ratio. As a consequence, maximum improvement of the compressor performance was found at around VR=0.7. Compared to a one-stage two-cylinder rotary compressor with about the same cooling capacity, COP improvement was about 6.96%.

• 드라이브 ㆍ 컨트롤
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• 제16권2호
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• pp.15-21
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• 2019

In this study, the maximum system efficiency of the electro-hydrostatic actuators was experimentally investigated, where small size external gear pumps with volumetric displacement under 1.3 cc/rev were combined with a 400W servomotor as the prime mover. Since the efficiency data of the servomotor, gear pumps and hydraulic cylinder were not provided by the suppliers, experimental apparatuses for their efficiency measurement were extra built up. When a gear pump with a volumetric displacement of 1.27cc/rev was used on an electro-hydrostatic actuator system, the maximum system efficiency was not higher than 70%. This was because the most effective operation ranges of the motor and pump did not coincide each other. In order to match their operation ranges as one of the most crucial design factors, a speed reduction mechanism can be used, such as a timing belt. It was shown in the study that the maximum system efficiency could be increased from 70% to 76% in that way.

• 한국윤활학회:학술대회논문집
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• 한국윤활학회 1998년도 제28회 추계학술대회
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• pp.190-195
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• 1998

This paper reports on the theoretical and expetimental study of the vane and cam ring motions in a variable displacement vane pump which is already used widely in various industrial and automotive applications. Dynamic equations of vane and cam ring motion and flow continuity equations are derived and then solved simultaneously using the numerical method. Vane detachment cause the pressure tipples, noise, wear in cam ring, and decrease the volumetric efficiency. Consequently, Vane detachment occurs due to excess compression in the pumping chamber, and it can be reduced by adjustment of design parmeters.