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Taylor-Couette Flow를 위한 PIV 시스템 구축 및 예비 결과
안성빈(Seongbin Ahn),송시몬(Simon Song) 대한기계학회 2021 대한기계학회 춘추학술대회 Vol.2021 No.11
Taylor-Coueete flow is the flow of fluid between two concentric cylinders. In this study, we developed a Taylor-Couette flow apparatus and PIV system that maintain accuracy over a wide range of Reynolds number flows, and performed frictional drag measurement and flow visualization under various flow conditions. Transparent PMMA was used for the material in contact with the fluid, so that PIV was possible. 6-micrometer fluorescent particles were used as tracer particles. A high-speed camera and a continuous wave laser were used as the camera and light source. When the fluid is DI-water and the Reynolds number is between 3,000 and 20,000, the error with the empirical formula of the previous study was less than 5%. The velocity field using PIV was measured and validated, and the possibility of drag reduction research using PIV was confirmed in the future.
SeongBin Ahn(안성빈),JaeJin Kim(김재진),DongMin Seo(서동민),ChungSeok Kim(김정석) 한국기계가공학회 2018 한국기계가공학회지 Vol.17 No.6
Nondestructive evaluation for mechanical degradation of ultrasuper-critical (USC) heat-resistance steel, which is attractive to the next generation of power plants is studied by magnetic reversible permeability. The interrelationship between reversible permeability and high-temperature mechanical degradation has been investigated by precise measurement of permeability nondestructively. Also, the effects of microstructural variation on reversible permeability are discussed. Isothermal aging was observed to coarsen the tempered carbides (Cr23C6), generated the intermetallic phases (Fe₂W), and grow rapidly during aging. The dislocation density also decreases steeply within lath interior. The peak to peak interval (PPI) of reversible permeability profile decreased drastically during the initial 500 h aging period, and was thereafter observed to decrease only slightly. The variation in PPI is closely related to the decrease in the number of pinning sites and the degradation in tensile strength.
상수도관 내 소수력 발전을 위한 터빈 블레이드 형상설계
안성빈(Seongbin Ahn),강승민(Seungmin Kang),송시몬(Simon Song) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11
Recently, small hydro power generation has received attention as effective renewable energy. This study explored and described factors involved in the water pipe generation, one of the small hydro power generations. Savonius turbine was chosen to develop our studies. Design parameters consist of four types of parameter: curvature radius, thickness, overlap ratio, and tip clearance. In our research, ANSYS FLUENT 14.0 was used in order to calculate 2D and 3D turbulence models. Since this study is focused only on analyzing tendency of moments, static approach is considered as a research method. Our research confirmed that moments are increasing as curvature radius, thickness, and tip clearance are decreasing. In addition, the maximum value of moment was observed when the overlap ratio is between 0.5 and 0.6. As a result, it is confirmed that the tip clearance and the overlap ratio are the most influencing design parameters.