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HWAHAK KONGHAK,
Vol.24, No.4, 277-284, 1986
Vol.24, No.4, 277-284, 1986
액체유동층의 고체입자 흐름형태 변화와 액상 반경방향 혼합
Flow Transition of Solids and Radial Dispersion of Liquid in Liquid-Fluidized Beds
직경 10.2 cm의 액체 유동층에서 고체 유동입자의 흐름형태 변환（transition of flow pattern）과 액상의 반경방향 혼합특성(liquid radial dispersion characteristics)을 고찰하였다. 액상의 유속(4-12 cm/s), 유동층 공극률 및 유동입자의 흐름형태 변환이 액상의 반경방향 혼합계수에 미치는 영향을 검토하였다. 액상의 반경방향 혼합계수는 유동입자의 크기가 증가함에 따라 증가하였으나, 액상의 유속과 유동층 공극률의 증가에 따라서는 최대값을 나타내는 곡선으로 변화하였다. 액상의 반경방향 혼합계수가 최대값을 나타낼 때의 층 공극률(bed porosity)은 유동입자의 연속파동속도(continuity wave velocity)로 예측된 유동입자의 흐름형태가 변환할 때의 층 공극률과 일치하였으며, 이때의 층 공극률은 액체 유동층내에서의 난류강도(turbulent intensity)와 역학적 에너지 소멸속도가 최대값을 나타내는 때의 층 공극률과 일치하였다.
Flow transition of solids and radial dispersion of liquid phase in liquid fluidized beds have been studied in a 10.2 cm-ID plexiglas column.
The effects of liquid velocity and particle size on bed porosity and radial dispersion coefficient have been determined.
The radial dispersion coefficient increased with particle size. Whereas, the coefficient exhibited a maximum value at a liquid velocity or bed porosity.
The bed porosity at which maximum radial dispersion coefficient occured coincide with the bed porosity which was derived from the continuity wave velocity at which the flow transition of solids occured. Also, the porosity value at which the coefficient exhibited a maximum value agreed well with the values at which the turbulent intensity and energy dissipation rate attained its maximum values.
The effects of liquid velocity and particle size on bed porosity and radial dispersion coefficient have been determined.
The radial dispersion coefficient increased with particle size. Whereas, the coefficient exhibited a maximum value at a liquid velocity or bed porosity.
The bed porosity at which maximum radial dispersion coefficient occured coincide with the bed porosity which was derived from the continuity wave velocity at which the flow transition of solids occured. Also, the porosity value at which the coefficient exhibited a maximum value agreed well with the values at which the turbulent intensity and energy dissipation rate attained its maximum values.
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