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미터링 노치의 형상에 따른 유압 스푸울 밸브의 유동특성 해석
장명준(M. J. Jang),이준오(J. O. Lee),박태조(T. J. Park) 유공압건설기계학회 2012 유공압건설기계학회 학술대회논문집 Vol.2012 No.6
Hydraulic spool valves are widely used in many applications. In particular, detailed knowledge of the internal flow field between spool and valve chamber is required for their design optimization. This paper presents the flow characteristics of hydraulic spool valve with two different metering notches using a commercial computational fluid dynamics (CFD) code FLUENT. To simulate the flow features, three-dimensional spool-housing CFD model is fabricated. Streamlines, velocity fields, discharge coefficient and flow force with amount of valve openings and notch shape are analyzed, and the results of notched spool are compared with those of un-notched spool. The flow characteristics are highly dependent on the metering notches and amount of valve openings.
Micro-texturing한 Slider-bearing의 윤활특성
이준오(J. O. Lee),정요한(Y. H. Jeong),장명준(M. J. Jang),박태조(T. J. Park) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.5-3
Surface texturing methods are widely applied recently to reduce friction and improve reliability of machine components such as parallel thrust bearings, mechanical face seals and piston rings, etc. In this paper, numberical analysis is carried out to investigate the effect of uniformly spaced hemispherical dimples on the lubrication characteristics of slider bearing using a commerical computational fluid dynamics (CFD) code, FLUENT. The pressure distributions, load capacity, leakage flowrate and friction force are highly affected by dimple diameter and their numbers. Especially load capacity and friction force decrease linearly with dimple density whereas leakage increase. The results can be use in design of optimum characteristics to improve lubrication performances of slider bearing and further researches are required.