• 한국기계가공학회지
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• 제18권11호
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• pp.109-114
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• 2019

Hydraulic pumps are widely used in fields such as machinery manufacturing, engineering and construction. Although the research on hydraulic engineering is mature, it is still necessary to examine various performance aspects in detail for specific applications. This paper will focus on the hydraulic pump used in special construction machinery that needs high temperature and high pressure resistance. It will analyze the theoretical design, structure and thermal characteristics of the pump system using the Fundamentals of Engineering (FE) method, and will measure the key tolerance parameters of the hydraulic pump to ensure the accuracy of the machining. Through this research, a good design method for the linear reciprocating type of hydraulic pump can be summarized.

• 한국기계가공학회지
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• 제10권2호
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• pp.61-66
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• 2011

The purpose of this paper is to design a hydraulic actuator to operate under high pressure conditions. The flow characteristics under design conditions of hydraulic actuator were numerically conducted by commercial fluid dynamic code(ANSYS CFX V11). The numerical analysis was performed by transient technique according to the variation of stroke times, which was changed from 0 to 1 second by interval of 0.01. Turbulence model, $k-\omega$ SST was selected to secure more accurate prediction of hydraulic oil flow. The ICEM-CFD 11 and CFXMesher, reliable grid generation software was also adapted to secure high quality grid necessary for the reliable analysis. According to the simulation results, the flow rate which was supplied to the hydraulic actuator was 30.4l/min. These results are in good agreement with design results within 3.5% error.

• International Journal of Fluid Machinery and Systems
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• 제10권1호
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• pp.1-8
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• 2017

Bifurcation refers to wye division of penstock to divide the flow symmetrically or unsymmetrically into two units of turbine for maintaining economical, technical and geological substrates. Particularly, water shows irrelevant behavior when there is a sudden change in flow direction, which results into the transition of the static and dynamic behavior of the flow. Hence, special care and design considerations are required both hydraulically and structurally. The transition induced losses and extra stresses are major features to be examined. The research on design and analysis of bifurcation is one of the oldest topics related to R&D of hydro-mechanical components for hydropower plants. As far as the earlier approaches are concerned, the hydraulic designs were performed based on graphical data sheet, head loss considerations and the mechanical analysis through simplified beam approach. In this paper, the multi prospect approach for design of Bifurcation, incorporating the modern day's tools and technology is identified. The hydraulic design of bifurcation is a major function of dynamic characteristics of the flow, which is performed with CFD analysis for minimum losses and better hydraulic performances. Additionally, for the mechanical design, a simplified conventional design method as pre-estimation and Finite Element Method for a relevant result projections were used.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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• pp.408-416
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• 2002

Hydraulic performance of the pump with an inducer was predicted by 3-D Navier-stokes calculation. The evaluated pump was the single-stage centrifugal pump with a separated inducer to pressurize fuel (LCH4) in Turbo-pump system with a specific speed (Ns) of approximately 0.3[rad/s, m3/s, J/kg] and a suction specific speed(s) of 15[rad/s, m3/s, J/kg]. That conventional pump was designed with the combination of 1-D theory and empirical correlation. In this study, preliminary design to select key parameters such as inlet flow coefficient was reviewed by investigating sets of the known design methods to achieve appropriate suction performance, and the performance of newly designed inducer and impeller was compared with the old one, using CFD method. The numerical results showed that the hydraulic efficiency of the new pump was predicted $5.5\%$ higher than that of the conventional one, through design parameter re-selection, configuration improvement and blade loading control

• Tribology and Lubricants
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• 제29권3호
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• pp.171-179
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• 2013

In this study, hydraulic systems of the rope brake system of an elevator are modeled to evaluate design parameters that consider friction characteristics such as cylinder pressure, piston displacement, and flow rate. Hydraulic systems of the rope brake system are analyzed using the commercial program AMESim. Analysis modeling data are compared with data obtained from experiments, and the analysis modeling results are found to be reliable. The analysis results will be used to design hydraulic systems of the rope brake system of elevators.

• 유공압시스템학회논문집
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• 제2권4호
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• pp.7-13
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• 2005

This paper presents modeling and ostimator/controller design for the hydraulic system in Vehicle Stability Control(VSC) system. A nonlinear mathematical model of the VSC hydraulic system is proposed and its accuracy is experimentally verified. A brake pressure estimator is then designed based on the derived mathematical model of VSC hydraulic system. And a disturbance observer, which compensates the estimation error between the brake pressure and the computed brake pressure is also designed to enhance the accuracy of the estimator. The proposed controller has the form of a feedback controller and determines explicitly the on/off ratio of valves' driving PWM signals by means of making use of the simplified mathematical model in the VSC hydraulic system. The performance of the designed controller whose feedback signal is generated by the brake pressure estimator is validated through experimental results.

• 한국산학기술학회논문지
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• 제13권4호
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• pp.1447-1452
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• 2012

산업현장에서 사용되고 있는 기존의 밸브 수압측정기는 압력조절을 수동으로 제어함으로서 정확한 압력측정을 할 수 없는 불편함이 있었다. 이를 개선하기 위하여 기존의 밸브 수압측정기에 대하여 자동설계 프로그램인 CATIA를 활용하여 설계하고 3차원 유한요소 해석코드인 ANSYS를 활용하여 설계된 밸브 수압측정기에 대하여 구조해석을 수행하고 내부압력에 따른 내부누수, 응력, 변형률, 총변형량 등을 구하였다. 이러한 결과는 새로운 밸브 수압측정기를 개발하기 위한 기초자료로 활용할 계획이다.

• 전기학회논문지
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• 제62권12호
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• pp.1809-1812
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• 2013

The bogie of monorail vehicles applies rubber wheel system not steel wheel system. In addition, The structure of the bogie is very complicated because vehicle operates on the elevated road and vehicle drives with wrapping the guide way. When the monorail vehicle applies air brake system, lower device of vehicle may be complex and some devices may be limited. On the other hand, hydraulic brake equipment is compact and not weighing. Braking force is also outstanding compared with air brake so the hydraulic brake equipment is suitable for monorail vehicle. Also urban transit system such as monorail, applies mixed system both friction brake and electric brake in order to save electric energy. But application case of hydraulic brake in the country is very rare because hydraulic brake have difficulty in satisfaction of control requirement and maintenance. Therefore, this study suggests ways to design hydraulic brake system with blending brake for monorail vehicle and applies the ways to future monorail.

• 한국산학기술학회논문지
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• 제13권5호
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• pp.1963-1968
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• 2012

본 논문은 현장에서 사용하고 있는 밸브 수압측정기를 3차원 자동설계 프로그램인 CATiA를 활용하여 설계하였다. 또한 유한요소 해석코드인 ANSYS를 활용하여 설계된 밸브 수압측정기에 대하여 유동해석을 수행하여 내부압력에 따른 유체의 흐름을 구하였다. 이러한 해석결과는 새로운 밸브 수압측정기를 개발하는데 기초자료로 활용될 계획이며 개발예정인 밸브 수압측정기는 밸브 점검 시 시간을 단축하고, 사고를 방지하여 안전성을 향상시킨다.

• 한국수자원학회논문집
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• 제36권5호
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• pp.811-821
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• 2003

본 연구에서는 수리모형실험을 실시하여 방류관의 흐름특성을 분석 방류관 설계의 적정성을 검토하는데 있다. 수리모형실험 결과 기본계획의 방류관 통수능은 과소설계 되었고, 이를 토대로 설계 변경한 기본설계의 방류관 통수능 설계치는 실험치와 거의 일치하여 적절하게 설계되었음을 알 수 있었다. 또한 방류관 부압발생 여부 및 종단형상의 적정성을 검토한 결과 허용치 이내 값이 발생되어 적절한 것으로 판명되었다. 이러한 과정을 토대로 기본설계의 방류관 규모 및 위치가 적절하였음이 검토되었다.