(32d) Multiscale Process Simulation By Combining CFD and Subgrid Modeling

Many real-world processes are multiscale processes, which mean that they have important features at different scales in time and/or space. Typically not all features can be resolved, so that for simulations of such processes certain assumptions or simplifications have to be made and so-called subgrid models are used to capture the effects of one scale onto the other. The benefit of combining different scales was previously shown e.g. for a wet granulation process [1].

In this contribution we show a new automated coupling method between the CFD-tool STAR-CCM+ by Siemens PLM and gPROMS by PSE, where STAR-CCM+ solves for all flow properties and gPROMS evaluates the fine scales based on the solution provided by STAR-CCM+. The coupling between both codes is done in an automatic way. This includes the domain decomposition, the calculation of and the transfer of all relevant variables.

The details of the coupling as well as the advantage of this approach is demonstrated based on a liquid-liquid emulsion for PVC production in a full scale slim vessel. The numerical results are compared against experimental results [2] and the effect of different ways of decomposing the domain is discussed.

[1] Barosso, D. et al.: A multi-scale, mechanistic model of a wet granulation process using a novel bi-directional PBM–DEM coupling algorithm, Chem. Eng. Sci. 2015, 123, 500–513

[2] Maass, S. et al.: Flow Field Analysis of Stirred Liquid-Liquid Systems in Slim Reactors, Chem. Eng. Technol. 2011, 34, No. 8, 1215–1227