Abstract
In previous studies, J. B. Wijffels and K. Rietema developed and verified a theoretical model for a tall circulating spray column. This model underlies the proposition that in order to reduce the axial mixing in a spray column the overall circulation must be suppressed. An analogy is raised between the occurrence of circulating flows in dispersed two-phase flow systems and the phenomenon of convective instabilities in fluid layers and columns when heated from below. For this reason the influence of an applied negative density gradient, realized as a positive temperature gradient, upon the axial mixing has been investigated in several tall spray columns. A gradient of 10 degree C m** minus **1 can reduce the axial mixing to half the isothermal amount. The favorable effect upon column performance is also shown: the efficiency increases by more than 10%. The influence of slip velocity and of quality of heat exchange upon the attainable reduction of mixing is discussed.
Original language | English |
---|---|
Pages (from-to) | 84-93 |
Number of pages | 10 |
Journal | Trans Inst Chem Eng |
Volume | 57 |
Issue number | 2 |
Publication status | Published - 1979 |