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Estimation of bed expansions in a freely‐bubbling three‐dimensional gas‐fluidized bed
Author(s) -
Hepbasli A.
Publication year - 1998
Publication title -
international journal of energy research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.808
H-Index - 95
eISSN - 1099-114X
pISSN - 0363-907X
DOI - 10.1002/(sici)1099-114x(199812)22:15<1365::aid-er456>3.0.co;2-z
Subject(s) - fluidization , fluidized bed , superficial velocity , mechanics , materials science , thermodynamics , mathematics , chromatography , chemistry , physics , flow (mathematics)
Abstract Knowledge of bed expansions is important in the design and operation of gas–solid fluidized beds. This paper presents a study on the estimation of expanded bed height in a large three‐dimensional gas‐fluidized bed with a square section of 0·61×0·61 m 2 . All experiments were performed at the freely bubbling mode and the bed expansions were recorded by a video camera. Bed materials were used 593 μm raw perlite and 1233 μm sand falling within the categories of Geldart's Groups B and D, respectively. The bed height at minimum fluidization ranged from 0·0398 to 0·3176 m, while the excess air velocity from 0·034 m s −1 to 0·7453 m s −1 . Equations related to the bed expansion were given using a modified form of two‐phase theory of fluidization. A correlation for the average bed expansion (void fraction) was also presented that has been derived from the principal form found successful in gas–liquid systems as follows: R=0·5482 d −0·129 p (U o −U mf ) 0·111 with an average deviation of less than 1%. The experimental findings were compared with previously reported results and were discussed in the light of available correlations. © 1998 John Wiley & Sons, Ltd.