Almost without exception literature data and modeling effort are understandably devoted to water as the sprayed liquid since it constitutes the most common liquid used in spray drying applications. In selected applications, however, the liquid making up the solution or suspension may not be water. The objective of this work is to examine the differences in flow patterns, thermal behavior and drying rates caused by different liquids having different thermo-physical properties spray into a spray dryer using a computational fluid dynamic model.Numerical experiments were carried out for water (base case), ethyl alcohol and isopropyl alcohol-the latter two as model non-aqueous liquids. The chamber geometry was cylinder type with a co-current axial pressure nozzle and also an axial central exit so that the configuration is two dimensional and axi-symmetric. It is shown that the liquid properties can have major influence on the thermal field, droplet trajectories, residence times and overall evaporation capacity when all parameters of the problem are held fixed. Deviations from the single phase turbulent airflow in the same chamber without spray are different for the three liquids examined.
Spray Evaporation of Different Liquids in a Drying Chamber--Effect on Flow, Heat and Mass Transfer Performances
Huang Lixin、Kurichi Kumar、A.S.Mujumdar
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Mechanical Engineering Department, National University of Singapore, 10 Kent Ridge Crescent, Singapore,119260
CFD Division, Institute of High Performance Computing, 1 Science Park road, # 01-01 the Capricorn, Singapore Science Park Ⅱ, Singapore,117528
atomization computational fluid dynamics residence time spray drying turbulence model two phase flow