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HWAHAK KONGHAK,
Vol.32, No.4, 614-621, 1994
Vol.32, No.4, 614-621, 1994
2차 공기가 주입되는 상온 유동층에서 고체입자의 비산에 관한 모델
Model on Particle Entrainment in a Cold Model Fluidized Bed with Secondary Air Injection
2차 공기가 주입되는 상온 유동층에서 입자비산속도에 관한 간략화된 모델을 고찰하였다. 프리보드에서 비산되는 입자의 상방향 운동방정식, 층표면에서 입자의 비산속도 및 상승속도가 고려되었다. 모래를 층물질로 사용하고 공기 분배기로부터 0.2m 높이에 2차 공기가 공급되는 상온 유동층(직경0.1m, 높이2.4m)에서 측정된 입자비산속도와 모델의 계산값을 비교 고찰하였다. 총괄 비산속도에 있어서 모델의 예측은 2차 공기분율의 영향을 잘 나타낼 수 있었다. 그러나 입도별 비산속도에 있어서 모델의 예측은 굵은 입자의 경우에는 측정값보다 컸고, 작은 입장의 경우에는 그 반대현상을 보였다. 모델의 개선을 위해서 층표면의 입도분리현상에 관한 고려가 더 개선되어야 할 것으로 사료되었다.
A simplified model on particle entrainment was discussed in a cold model fluidized bed with a secondary air injection. The model considered the one-dimensional equation of motion for the entrained particles in the freeboard, the entrainment rate at the bed surface, and the rising velocity of the particles at the bed surface. The model was compared with the measured particle entrainment rate in a cold model fluidized bed(0.1m-ID, 2.4m-height) of sand as a bed material and a secondary air injection at 0.2m above the distributor plate. For the total entrainment rate, the model described the effect of the secondary air fraction well. However, the model predicted the lower entrainment rate than the measured value for the small particles and vice versa for the large particles. It was thought that the model should consider the particle segregation additionally for the better prediction.
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