Macro-scale simulation of fibrous liquid aerosol filters

J. Niessner*, A. Baumann, D. Hoch, Heilbronn University of Applied Sciences, Germany

Today, liquid aerosols are produced in many industrial processes like machining, manufacturing of catalysts or in pneumatic compressors. While the harmfulness of fine dust aerosols is well known the equally dangerous liquid aerosols (mist) receive less attention. In order to be prepared for future legal regulations we develop efficient mist filters with less energy consumption.

In our research, we couple micro-scale simulations of two-phase flow in a fibrous porous medium with macro-scale simulations to develop efficient filters for a stationary (oil mist separator) and a mobile (pneumatic truck compressor system) application. Because the computational effort to simulate mist deposition in a whole filter on the micro-scale would be much too high, on the macro-scale, the information of the micro-scale is adopted and the whole filter is considered as porous continuum. In other words, the output of the micro-scale becomes the input of the macro-scale. Specifically, parameters like porosity, intrinsic permeability as well as relative permeability - and capillary pressure – saturation relationship determined from micro-scale simulations are used as input to the macro-scale to simulate the filtration process on the domain of the whole filter. Furthermore, a source term of the liquid (oil) phase is derived from micro-scale simulations which may depend on parameters such as velocity and initial saturation. Thanks to this multi-scale coupling, it is possible to predict the pressure drop and the separation efficiency of a filter and figure out the factors to optimize these two properties.

Furthermore, different parameterizations of the capillary pressure – and the relative permeability - saturationships (e.g. Brooks & Corey and Van Genuchten) are compared. We also present the validation of our simulations by comparing both pressure drop and separation efficiency to measurement results....

Session: G9 - Short Oral Presentations
Day: 23 October 2019
Time: 14:45 - 16:00 h

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