• 대한기계학회논문집B
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• 제20권10호
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• pp.3272-3281
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• 1996

The flow analysis method which had been developed for the numerical calculation of 3-dimensional, incompressible and turbulent flow within an axial compressor was extended to the flow field within centrifugal impeller. In this method based on the SIMPLE(Semi Implicit Method Pressure Linked Equations) algorithm, the coordinate transformation was adopted and the standard k-.epsilon. model using wall function was used for turbulent flow analysis. The calculated flow fields have agreed very well with measurement results. Especially, 3-dimensional and viscous flow characteristics including secondary flows, jet-wake flow and decreased pressure rise along impeller passage, which can't be predicted by inviscid Q3D calculation were predicted very reasonably.

• 대한기계학회논문집B
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• 제25권10호
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• pp.1293-1302
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• 2001

It is generally known that radial vane blowers with vaneless diffuser may generate mostly only a rotating stall but backward curved vane blowers may do both an impeller and a diffuser rotating stalls. In this study, it was found from the numerical and experimental results that the diffuser rotating stall does not appear in a radial vane because of the suppression for the diffuser stall appearance by occurring of impeller rotating stall in a large flow rate coefficient. The diffuser rotating stalls occurring when the width of diffuser is broaden fur a backward curved vane blower are classified definitely by the diffuser flow rate coefficient defined by adopting the varying diffuser width.

• 대한기계학회논문집B
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• 제20권10호
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• pp.3262-3271
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• 1996

Flow patterns were measured in a shrouded centrifugal impeller. The flow rate in measurements was fixed at the value corresponding to a nearly zero incidence at the blade inlet. By using a single slanted hot-wire probe and a Kiel probe mounted on the impeller hub disk, the 3-D relative velocities and the rotary stagnation pressures were measured in seven circumferential planes from the inlet to the outlet of impeller rotating at 700 rpm, and the static pressure distribution along flow passage and the slip factor at impeller outlet were calculated from the measured values. From these measured data, the primary and secondary flows, the wake production and the static pressure rise in the impeller passage were investigated. Furthermore, the secondary flow patterns and the wake's location in this impeller passage were compared with those of the unshrouded impeller.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 춘계학술대회 논문요약집
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• pp.135-135
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• 2004

21세기 정보화시대에 미디어의 발전은 고저장밀도를 요구하는 정보저장 장치의 개발을 필요로 하게 되었고, 현재 정보저장 장치의 주류를 이루는 magnetic recording 방식에 의한 HDD는 향후 5년 이내에 초자성한계 (super paramagnetic limit)라는 물리적 현상에 직면하여 더 이상 발전이 어려울 깃이다 따라서 이러한 한계를 극복하기 위한 여러 기술 증 Scanning Probe Microscope (SPM)을 이용한 차세대 탐침형 정보저장 기술은 미세한 끝단 반경을 가지는 탐침과 표면의 상호작용을 이용하여 정보를 기록/재생하는 기술로써 수십 nm 크기의 bit를 형성하여 Tbit/in$^2$ 이상의 높은 저장밀도를 가질 수 있으므로 현재 가장 상용화될 가능성이 높다.(중략)