Articles & Issues

Conflict of Interest: In relation to this article, we declare that there is no conflict of interest.

This is an Open-Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/bync/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

All issues

삼성유동층에서 유동입장의 비정상상태 거동 및 요동

Unsteady State Behavior and Fluctuations of Fluidized Particles in Three Phase Fluidized Beds

강용 우광재 고명한 김상돈

Kang Y Woo KJ Ko MH Kim SD

HWAHAK KONGHAK, October 1995, 33(5), 633-639(7), NONE

Download PDF

Abstract

삼성유동층(직경0.152m, 높이2.5m)에서 유동입자의 비정상상태 거동 및 요동특성을 통계적 방법을 사용하여 고찰하였다. 기체로는 공기를, 액체로는 물을, 그리고 고체 유동입자로는 밀도가 2500kg/㎤이고, 직경이 1.0-6.0X10^-3m의 유리구슬을 사용하였으며, 비정상상태 거동의 해석으로부터 유동입자의 일정 시험영역에서의 평균분율, 유출속도, 평균체류시간 및 요동빈도수등을 구하였다. 삼상유동층이 비정상상태에서 균일팽창을 하는 동안 유동입장의 일정 시험영역에서의 유출속도는 시간에 따라 지수적으로 감소하였으며, 평균체류시간은 기체의 유속이 증가함에 따라 감소하였다. 유동입자의 요동빈도수는 기체의 유속과 유동입장의 크기가 증가함에 따라 증기하였으나 액체의 유속과 층공극률이 증가함에 따라서는 최대값을 나타내었다. 삼성유동층에서 유동입장의 요동빈도수는 등방난류 이론에 의한 무차원 유동입자의 크기와 무차원 유체속동의 상관식으로 나타낼 수 있었다.

Characteristics of unsteady state behavior and fluctuations of fluidized particles have been investigated by adopting the stochastic method in a three-phase fluidized bed of 0.152m ID and 2.5m in height. Air, water and glass beads whose density is 2500kg/㎥ and diameter is in the range of 1.0-6.0X10-3m have been used as gas, liquid and solid phase, respectively. The mean fraction, mean residence time and fluctuating frequency of fluidized particles in the test section, and the exiting rate of the particles from the test section have been obtained. The exiting rate of the particles has decreased exponentially with time lay during the relaxation of the bed, and the mean residence time of the particles in the test section has decreased with an increment of the gas velocity. The fluctuating frequency of particles has increased with an increment of the gas velocity and particle size, but it has attained its maximum value with an increment an increment of the gas velocity and particle size, but it has attained its maximum value with an increment of the liquid velocity and bed porosity. The particle fluctuating frequency has been well correlated in terms of dimensionless particle size and dimensionless fluid velocity based on the isotropic turbulence theory.

Keywords

References

Fan LS, Gas-Liquid-Solid Fluidization Engineering, Butterworths Publish, Stoneham, MA (1989)
Epstein N, Handbook of Fluids in Motion, Cheremisimiff, N.P. and Gupta, R. ed., Ann Arbor Science (1983)
Kang Y, Suh IS, Kim SD, Chem. Eng. Commun., 34, 1 (1985)
Schumpe A, Deckwer WD, Nigam KDP, Can. J. Chem. Eng., 67, 873 (1989)
Kim SD, Kang Y, Encyclopedia of Fluid Mechanics, Cheremisimiff, N.P. ed. Gulf Pub. Co. (in print) (1995)
Morooka S, Uchida K, Kato Y, J. Chem. Eng. Jpn., 15, 29 (1982)
Kang Y, Kim SD, Chem. Ind. Technol., 13(1), 27 (1995)
Kwon HW, Kang Y, Kim SD, Yashima M, Fan LT, Ind. Eng. Chem. Res., 33(7), 1852 (1994)
Fan LT, Nieogi D, Yashima M, Nassar R, AIChE J., 36, 1529 (1990)
Kikuchi R, Tsutsumi A, Yoshida K, Proc. 4th Asian Conf. on Fluidized Beds and Three Phase Reactors, 289 (1994)
Yashima M, Nassar R, Fan LT, Kang Y, AIChE J., 38, 629 (1992)
Fan LS, Yamashita T, Jean RH, Chem. Eng. Sci., 42, 17 (1987)
Kang Y, Kim SD, Part. Sci. Technol., 6, 133 (1988)
Yutani N, Ototake N, Too JR, Fan LT, Chem. Eng. Sci., 37, 1079 (1982)
Kang Y, Nah JB, Min BT, Kim SD, Chem. Eng. Commun., 97, 197 (1990)
Fan LT, Kang Y, Nieogi D, Yashima M, AIChE J., 39, 513 (1993)
Kim SD, Kim CH, J. Chem. Eng. Jpn., 16, 172 (1983)
Sanger P, Deckwer WD, Chem. Eng. J., 22, 179 (1981)