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Effect of unstable density gradients on back‐mixing in a reciprocating plate column
Author(s) -
Aravamudan Kannan,
Baird Malcolm H. I.
Publication year - 1996
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690420805
Subject(s) - dissipation , reciprocating motion , mixing (physics) , chemistry , dispersion (optics) , mechanics , phase (matter) , density gradient , thermodynamics , kerosene , physics , optics , organic chemistry , quantum mechanics , gas compressor
Axial dispersion coefficients were measured in the continuous phase in a 5‐cm‐dia. Karr column, operated cocurrently with the system kerosene(d)‐water(c). The effect of unstable density gradient in the continuous phase was studied by injecting a steady stream of sodium chloride solution as a tracer near the top of the column. The effects of energy dissipation due to unstable density gradient, mechanical agitation, and the flow of the dispersed phase were investigated as the three principal variables, and two plate spacings (2.55 and 5.10 cm) were also employed. The axial dispersion results were correlated in terms of a weighted power‐law model based on Kolmogoroff's mixing length concept and incorporating contributions due to each of the three modes of energy dissipation. Axial mixing was significantly increased in the presence of unstable density gradients even though these contributed very little (typically less than 1 mW/kg) to the total specific energy dissipation rate.