Improved Control for Media-Scale Multipass Simulations.

Dr. Stefan Rief, Dr. Jürgen Becker, Dr. Andreas Wiegmann
Fraunhofer ITWM, Kaiserslautern, Germany


Abstract  

Current media-scale multipass simulations in GeoDict / FilterDict work with a fixed 
amount of test dust per iteration. This is to ensure that for each step collected 
particles do not overlap. But this does not make use of the transition from depth 
filtration to cake filtration. During depth filtration, the amount of test dust may be 
larger because a three-dimensional volume is available for deposition. When the surface 
filtration regime is entered, only a two-dimensional surface is available for deposition. 
With a fixed amount of test dust per iteration, either the simulation is inefficient 
because the amount is chosen appropriately for the surface filtration, and many more 
flow fields are computed than necessary during the depth filtration, or the simulation 
has to be stopped after the depth filtration because too high particle concentrations 
would yield unrealistic overlapping particles and too high pressure drop in the cake filtration regime. 
The current work concerns the automatic detection of the transition from depth filtration 
to cake filtration in multipass filtration simulations and the automatic control of the 
simulation to account for this in terms of numbers of particles / amount of test dust 
deposited in a single iteration of the multipass filter life time simulations. The old 
and new methodology are compared with experiments performed on a multipass test stand.