Premium
Theory of competition between breakup and coalescence of droplets in flowing polymer blends
Author(s) -
Fortelný Ivan,
Živný Antonín
Publication year - 1995
Publication title -
polymer engineering and science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.503
H-Index - 111
eISSN - 1548-2634
pISSN - 0032-3888
DOI - 10.1002/pen.760352306
Subject(s) - breakup , coalescence (physics) , materials science , scaling , polymer , smoluchowski coagulation equation , polymer blend , shear flow , weber number , drop (telecommunication) , chemical physics , thermodynamics , mechanics , statistical physics , composite material , physics , turbulence , reynolds number , copolymer , astrobiology , telecommunications , geometry , mathematics , computer science
Abstract The Smoluchowski equation for the breakup and coalescence of dispersed droplets has been solved for flowing polymer blends. A scaling form for the distribution of droplet sized derived and published for a system of clusters with fragmentation and coagualation was used in our dervation. Equations are developed here for the average droplet size and for the characteristic time of transition to steady state flow of blends with a high content of the dispersed phase. Expressions reasonably describing the average size of droplets for all concentrations were obtained by a theory modification. Measured dependences of droplet size on the blend composition can be matched only if simultaneous collisions of three and more droplets are considered. The results of the theory indicate that the mechanism of droplet breakup (formation of pieces with the same or different volumes) has only a small effect on their average size in concentrated systems. The dependence of droplet size on the shear rate in flow is determined by properties of the blend components, and is generally nonmonotonic.