액체-액체-고체 유동층(직경 0.102m × 높이 2.5m)에서 층공극률과 열전달 특성에 대해 고찰하였으며, 분산액상과 연속액상의 유속 그리고 유동입자의 크기가 층공극률과 열전달계수에 미치는 영향을 검토하였다. 물과 석유를 각각 연속 액상과 분산액상으로 사용하였으며 직경이 1.0, 2.1, 3.0 그리고 6.0mm인 유리구슬을 고체 입자로 사용하였다. 열전달계수와 층공극률은 유동입자의 크기가 비교적 큰 범위(dp≥3.0mm)에서는 분산액상의 유속이 증가함에 따라 증가하였으나, 유동입자의 크기가 비교적 작은 범위(dp≤2.1 mm)에서는 분산액상의 유속증가에 따라 국부적인 최소값을 나타낸 후 완만하게 증가하는 경향을 나타내었다. 열전달계수는 유동입자의 크기가 증가함에 따라 증가하였으나 연속액상의 유속과 층공극률이 증가함에 따라 국소적인 최대값을 나타내었다. 열전달계수를 나타내는 무차원군인 넛셀수는 등방난류 모델에 의해 미소 소용돌이의 무차원 속도와 크기의 함수인 상관식으로 나타낼 수 있었다.

Bed porosity and heat transfer characteristics have been investigated in a liquid-liquid-solid fluidized bed(0.102 I.D.×2.5m in height). Effect of velocities of dispersed and continuous liquid phases and particle size on the bed porosity and heat transfer coefficient in the bed have been determined. Water and kerosene have been used as a continuous and a dispersed liquid phase, respectively. Glass beads whose diameter are either 1.0, 2.1, 3.0 or 6.0 mm have been used as a fluidized solid phase. It has been found that the heat transfer coefficient and bed porosity have increased in the beds of relatively large particles(dp≥3.0 mm), but they have attained their local minima in the beds of relatively small particles(dp≤2.1 mm), with increasing the dispersed liquid velocity. The heat transfer coefficient has increased with increasing the particle size, however, it has exhibited the local maximum with increases in the continuous liquid velocity and bed porosity. The heat transfer coefficient has been well correlated in terms of Nusselt number and dimensionless velocity and scale of micro-eddy based on the isotropic turbulence theory.

Heat Transfer Bed Porosity Liquid-Liquid-Solid Fluidized Bed

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