• Title/Summary/Keyword: Volumetric Hydraulic Diameter

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Presumption of Slipper-pad Fault Condition for Hydraulic Rotary Actuator (마멸입자 해석을 통한 유압로터용 Slipper - Pad의 손상상태 추정)

  • 전성재;조연상;서영백;박흥식
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2000.06a
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    • pp.62-67
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    • 2000
  • This paper was undertaken to do morphological analysis of wear debris for slipper-Pad of hydraulic rotary acuator. The lubricating wear test was performed under different experimental conditions using the wear test device and wear specimens of the pin on disk type was rubbed in paraffinic base oil by three kinds of lubricating materials, varying applied load, sliding distance. The four shape parameters(50% volumetric diameter, aspect, roundness and reflectivity) are used for morphological analysis of wear debris. The results showed that the four shape parameters of wear debris depend on a kind of the lubricating condition. It was capable of presuming wear volume for slipper-pad of hydraulic rotary acuator on driving time.

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Morphological Analysis of Wear Particles for Sliding Members of Hydraulic Rotary Actuator (유압피스톤 모터용 습동재료의 마멸분 형태특징 해석)

  • 김성희;조연상;서영백;박흥식;전태옥
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 1999.05a
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    • pp.87-92
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    • 1999
  • This paper was undertaken to do morphological analysis of wear particles for sliding members hydraulic rotary actuator. The lubricating wear test was performed under different experimental conditions using the wear test device and wear specimens of the pin on disk type was rubbed in paraffinic base oil by three kinds of lubricating materials, varying applied load, sliding distance. The four-shape parameters (50% volumetric diameter, aspect, roundness and reflectivity) are used for morphological analysis of wear particles. The results showed that the four shape parameters of wear particles depend on a kind of the lubricating materials. It was capable of presuming wear volume for three kinds of materials on driving time.

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Condition Monitoring of Hydraulic Piston Motor using Morphological Analysis of Wear Particles (마멸입자 형태해석에 의한 유압피스톤용 모터의 상태감시)

  • 문병주;조연상;박흥식;전태옥
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.9 no.6
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    • pp.127-132
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    • 2000
  • Morphological analysis of wear particles is one of useful methods for machine condition monitoring because it is well reflected in machine driving state. This paper was undertaken to apply to the condition monitoring of hydraulic piston motor. The lubricating wear test was performed under different experimental conditions using the wear test device and wear specimens of the pin on disk type was rubbed in paraffinic base oil by three kinds of lubricating materials, varying applied load, sliding distance. The four shape parameters(50% volumetric diameter, aspect, roundness and reflectivity) are used for morphological analysis of wear particles. The results showed that the four shape parameters of wear particles depend on a kind of the lubricating materials. It was capable of calculating presumed wear volume for three kinds of materials on driving time to foresee as damage condition of lubricating materials.

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A Study on the Characteristics of the Hydrostatic Bearing by the Variation of the Orifice in Hydraulic Piston Motor (유압 피스톤 모터의 오리피스 변화에 따른 정압베어링의 특성에 관한 연구)

  • Kim, K.M.;Lee, Y.B.;Kim, T.S.
    • Transactions of The Korea Fluid Power Systems Society
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    • v.7 no.3
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    • pp.7-12
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    • 2010
  • In the case of hydraulic piston motor, hydrostatic bearing is designed to be adapted the hydrostatic bearing for the relative lubrication in the structural design. It's available to make it highly efficient and that's why it's widely used. The thing which largely influence the high pressure, the high efficiency, and the life is the hydrostatic bearing between a shoe and a swash plate. In this study, with the most general "hydrostatic bearing shoe" that has one recess as the subject of this research, I designed and made the 4 kind of piston shoe that have different orifice diameter each other, and studied the features of the hydrostatic bearing by observing the change of the leakage flow rate, the torque and the volumetric efficiency through experiments on the changes of the pressure & the speed of the revolution. As a result, the bigger diameter of the orifice, the less torque. And with an increase of the orifice diameter under the high pressure, the leakage flow rate decreased remarkably. Also it was observed the leakage flow rate increased linearly according to the increase of the supply pressure.

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Analysis of Wear Characteristics for Sliding Members of Hydraulic Rotary Actuator (유압피스톤 습동재료의 마멸특성 해석)

  • 김성희;김동호;이광영;박흥식;전태옥
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1999.06a
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    • pp.101-108
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    • 1999
  • This paper was undertaken to do morphological analysis of wear particles for sliding members hydrauric rotary acuator. The lubricating wear test was performed under different experimental conditions using the wear test device and wear specimens of the pin on disk type was rubbed in paraffinic base oil by three kinds of lubricating materials, varying applied load, sliding distance. The four shape parameters (50% volumetric diameter, aspect, roundness and reflectivity) are used for morphological analysis of wear particles. The results showed that the four shape parameters of wear particles depend on a kind of the lubricating materials. It was capable of presuming wear volume for three kinds of materials on driving time.

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A Study on Friction Coefficient Prediction of Hydraulic Driving Members by Neural Network (신경회로망에 의한 유압구동 부재의 마찰계수 추정 에 관한 연구)

  • 김동호
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.12 no.5
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    • pp.53-58
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    • 2003
  • Wear debris can be collected from the lubricants of operating machinery and its morphology is directly related to the fiction condition of the interacting materials from which the wear particles originated in lubricated machinery. But in order to predict and estimate working conditions, it is need to analyze the shape characteristics of wear debris and to identify. Therefore, if the shape characteristics of wear debris is identified by computer image analysis and the neural network, The four parameter (50% volumetric diameter, aspect, roundness and reflectivity) of wear debris are used as inputs to the network and learned the friction. It is shown that identification results depend on the ranges of these shape parameters learned. The three kinds of the wear debris had a different pattern characteristic and recognized the friction condition and materials very well by neural network. We resented how the neural network recognize wear debris on driving condition.

Characteristics of Heat Transfer and Pressure Drop for Spirally Indented Tubes with Wire Coil Inserts (와이어 코일이 삽입된 나선형 내면가공관의 열전달 및 압력강하 특성)

  • Choi, In-Su;Park, Byung-Duck;Nam, Sang-Chul
    • Journal of the Korean Society of Industry Convergence
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    • v.4 no.4
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    • pp.395-401
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    • 2001
  • The characteristics of heat transfer and pressure drop through tubes has been investigated experimentally for a compound heat transfer enhancement. The test tubes were spirally indented tubes with wire coil inserts which had a various combinations of pitch and helix angles. Pure water was used as working fluids for the experiments, Heat transfer coefficients and friction factors of the test tubes were evaluated from the values of measured temperatures, flow rates and pressure drops. An performance evaluation was performed to find an optimal combination of spirally indented tubes with wire coil inserts. When the helix angle of wire coil insert are $71^{\circ}-72^{\circ}$, the best heat transfer enhancement was shown. The friction factor was 9 - 13 times higher than those in smooth tubes, and the heat transfer was enhanced a maximum of 500%.

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Performance of Evaporation Heat Transfer Enhancement and Pressure Drop for Liquid Nitrogen (액체질소에 대한 증발 열전달 촉진 및 압력강하 성능)

  • Nam, Sang-Chul;Lee, Sang-Chun;Park, Byung-Duck
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.3
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    • pp.363-372
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    • 2000
  • An experiment was carried out to evaluate the heat transfer enhancement and the pressure drop characteristics for liquid nitrogen using wire-coil-insert technique under horizontal two-phase conditions. The tube inner diameters were 8 mm and 15 mm, respectively and the tube length was 4.7 m. The helix angle of the wire coil insert was $50^{\circ}$ and its length was 4.7 m. Heat transfer coefficients for both the plain and the enhanced test tubes were calculated from the measurements of temperatures, flow rates and pressure drops. A correlation in a power-law relationship of the Nusselt number, Reynolds number and Prandtl number for the heat transfer was proposed which can be available for design of cryogenic heat exchangers. The correlation showed that heat transfer coefficients for the wire-coil inserts were much higher than those for plain tubes, increased by more than $1.8{\sim}2.0$ times depending upon the range of the equivalent Reynolds number. The correlation was compared with other various correlations in the turbulent flow conditions.

Analysis of characteristics of sediment transport in sewers by densimetric Froude number (밀도프루드수에 의한 하수관로 침전물 이송 특성 분석)

  • Park, Kyoohong;Lee, Taehoon;Yu, Soonyu;Kang, Byongjun;Hyun, Kirim
    • Journal of Korean Society of Water and Wastewater
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    • v.34 no.1
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    • pp.45-52
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    • 2020
  • Even though sewers have been conventionally designed to prevent from sediment deposition using a specified minimum velocity or shear stress at a particular depth of flow or with a particular frequency of occurrence, it was appreciated that these methods do not consider the characteristics and concentration of the sediment and the specific hydraulic conditions of the sewer with sediment. In this study, a densimetric Froude number formula was suggested considering particle diameter and volumetric concentration of the sediment as well as flow depth and flowrate, based on several domestic field inspections, which was compared with other formulas proposed by previous investigators. When the sediment concentration was not considered, the calibration coefficient of 0.125-1.5 to the densimetric Froude numbers of this study was needed to obtain the similar ones with previous investigators'. For the densimetric Froude number formula obtained with consideration of sediment concentration, the exponent value of term Cv was almost the same as that of previous results and that of d50/Rh was similar for Fr < 2.2.

Modeling the effects of excess water on soybean growth in converted paddy field in Japan 1. Predicting groundwater level and soil moisture condition - The case of Biwa lake reclamation area

  • Kato, Chihiro;Nakano, Satoshi;Endo, Akira;Sasaki, Choichi;Shiraiwa, Tatsuhiko
    • Proceedings of the Korean Society of Crop Science Conference
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    • 2017.06a
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    • pp.315-315
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    • 2017
  • In Japan, more than 80 % of soybean growing area is converted fields and excess water is one of the major problems in soybean production. For example, recent study (Yoshifuji et al., 2016) suggested that in the fields of shallow groundwater level (GWL) (< 1m depth), rising GWL even in a short period (e.g. 1 day) causes inhibition of soybean growth. Thus it becomes more and more important to predict GWL and soil moisture in detail. In addition to conventional surface drainage and underdrain, FOEAS (Farm Oriented Enhancing Aquatic System), which is expected to control GWL in fields adequately, has been developed recently. In this study we attempted to predict GWL and soil moisture condition at the converted field with FOEAS in Biwa lake reclamation area, Shiga prefecture, near the center of the main island of Japan. Two dimensional HYDRUS model (Simuinek et al., 1999) based on common Richards' equation, was used for the calculation of soil water movement. The calculation domain was considered to be 10 and 5 meter in horizontal and vertical direction, respectively, with two layers, i.e. 20cm-thick of plowed layer and underlying subsoil layer. The center of main underdrain (10 cm in diameter) was assumed to be 5 meter from the both ends of the domain and 10-60cm depth from the surface in accordance with the field experiment. The hydraulic parameters of the soil was estimated with the digital soil map in "Soil information web viewer" and Agricultural soil-profile physical properties database, Japan (SolphyJ) (Kato and Nishimura, 2016). Hourly rainfall depth and daily potential evapo-transpiration rate data were given as the upper boundary condition (B.C.). For the bottom B.C., constant upward flux, which meant the inflow flux to the field from outside, was given. Seepage face condition was employed for the surrounding of the underdrain. Initial condition was employed as GWL=60cm. Then we compared the simulated and observed results of volumetric water content at depth of 15cm and GWL. While the model described the variation of GWL well, it tended to overestimate the soil moisture through the growing period. Judging from the field condition, and observed data of soil moisture and GWL, consideration of soil structure (e.g. cracks and clods) in determination of soil hydraulic parameters at the plowed layer may improve the simulation results of soil moisture.

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