Search / Korean Journal of Chemical Engineering
HWAHAK KONGHAK,
Vol.31, No.5, 563-568, 1993
역 유동층의 동역학적 특성 연구
Hydrodynamic Characteristics in Inverse Fluidized Bed
Draft tube를 사용한 역 유동층에서 gas의 유입에 따른 gas holdup의 변화와 액체 평균 순환 속도 및 물보다 밀도가 낮은 polystyrene 입자의 유동 특성을 관찰하였다. 기체속도와 gas holdup의 관계는 εgr=0.056Ugr로 나타났으며, 그 관계는 Chisti의 결과와 유사하였다. 액체 평균 순환 속도는 직접 유량 측정 장치를 이용하였으며 초기 수위의 변화에 따른 그 변화를 관찰하였다. Polystyrene 입자와 유체의 물리적 값인 Archimedes number, Ar과 최소 유동화 속도에서의 minimum fluidization Reynolds number, Remf는 Remf=0.0018Ar+18.76의 관계를 가져, 유체와 입자의 물성만으로 최소 유동화 속도를 예측할 수 있었다.
The variation of gas holdup, the liquid circulation velocity and fluidization characteristics of poly-styrene particles in inverse fluidized bed were observed by varying the gas flow rate. The relationship between the superficial gas velocity and the gas holdup was found as εgr=0.056Ugrwhich showed similar to the Chisti model. The liquid circulation velocity was measured directly and gave good relationship with those physical properties of particle and circulating fluid. Since Archimedes number, Ar, and Reynolds number at the mini-mum fluidization velocity could be predicted with the informations of physical properties of particle and fluid invol-ved in the bed.
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