Electrostatic phenomena are pervasive in powder handling processes. In this study, contact electrification and electrostatic interactions during powder handling processes are explored using the discrete element method coupled with computational fluid dynamics (DEM-CFD), in which contact electrification and electrostatic interaction models are developed and implemented. The effects of particle shape on contact electrification are also investigated, for which multi-sphere methods are adapted and implemented into the DEM-CFD. The electrostatic and dynamic behaviours in various powder handling processes are analyzed, which include contact electrification of spherical particles during fluidization; electrostatic interactions during deposition of mono-charged and bi-charged particles; contact electrification and electrostatic interactions of spherical particles during fluidization; contact electrification of elongated particles in a vibrating container and particles of arbitrary shapes in a rotating drum. It is found that charge accumulation and distribution of particles are caused by contact electrification and dispersion of mono-charged particles and agglomeration of bi-charged particles are induced by electrostatic interactions. The combined effects of contact electrification and electrostatic interactions can alter the dynamic behaviours of particles and the performance of powder handling processes. Non-uniform charge distributions can be induced on particles of irregular shapes and the charge accumulation is also affected by particle shapes.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:600285 |
| Date | January 2014 |
| Creators | Pei, Chunlei |
| Publisher | University of Birmingham |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://etheses.bham.ac.uk//id/eprint/4871/ |
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