摘要
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.
Almost without exception literature data and modeling effort areunderstandably devoted to water as the sprayed liquid since it constitutes the most common liquidused in spray drying applications. In selected applications, however, the liquid making up thesolution or suspension may not be water. The objective of this work is to examine the differences inflow patterns, thermal behavior and drying rates caused by different liquids having differentthermo-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 isopropylalcohol-the latter two as model non-aqueous liquids. The chamber geometry was cylinder type with aco-current axial pressure nozzle and also an axial central exit so that the configuration is twodimensional and axi-symmetric. It is shown that the liquid properties can have major influence onthe thermal field, droplet trajectories, residence times and overall evaporation capacity when allparameters of the problem are held fixed. Deviations from the single phase turbulent airflow in thesame chamber without spray are different for the three liquids examined.
