Recent results and persisting problems in modeling flow induced coalescence

0428566 - ÚMCH 2015 RIV US eng C - Conference Paper (international conference)
Fortelný, Ivan - Jůza, Josef
Recent results and persisting problems in modeling flow induced coalescence.
AIP Conference Proceedings. Melville: American Institute of Physics, 2014, Roč. 1593, s. 646-649. ISSN 0094-243X.
[International Conference of the Polymer Processing Society /29./ - PPS-29. Nuremberg (DE), 15.07.2013-19.07.2013]
R&D Projects: GA ČR GAP106/11/1069
Institutional support: RVO:61389013
Keywords : flow induced coalescence * polymer blends * viscoelasticity
Subject RIV: BK - Fluid Dynamics

The contribution summarizes recent results of description of the flow induced coalescence in immiscible polymer blends and addresses problems that call for which solving. The theory of coalescence based on the switch between equations for matrix drainage between spherical or deformed droplets provides a good agreement with more complicated modeling and available experimental data for probability, Pc, that the collision of droplets will be followed by their fusion. A new equation for description of the matrix drainage between deformed droplets, applicable to the whole range of viscosity ratios, p, of the droplets and matrixes, is proposed. The theory facilitates to consider the effect of the matrix elasticity on coalescence. Pc decreases with the matrix relaxation time but this decrease is not pronounced for relaxation times typical of most commercial polymers. Modeling of the flow induced coalescence in concentrated systems is needed for prediction of the dependence of coalescence rate on volume fraction of droplets. The effect of the droplet anisometry on Pc should be studied for better understanding the coalescence in flow field with high and moderate deformation rates. A reliable description of coalescence in mixing and processing devices requires proper modeling of complex flow fields.
Permanent Link: http://hdl.handle.net/11104/0236994