Numerical Analysis for Liquid Droplet and Thin Liquid Film Behavior in a Zig-Zag Drift Eliminator
Kai Han, Adrian Mistreanu and Brian D’Entremont
A series of numerical analyses are conducted to trace liquid droplets and thin liquid film in a zig-zag drift eliminator with the assistance of computational fluid dynamics (CFD). The effects of turbulent models, turbulent dispersion models, and liquid droplet drag models are investigated. The standard κ-ε, the Re-Normalization Group (RNG) κ-ε, the Realizable κ-ε, Reynolds Stress Model turbulence models are evaluated. Regarding turbulent dispersion models, the particle cloud tracking model better predicts than the discrete random walk model (DRW) in terms of liquid droplet tracing with more computing time. DRW performance can be improved with the modification of liquid droplet drag laws. Several liquid droplet drag laws like spherical, non-spherical, and Stokes-Cunningham models are tested with available experimental data. A modified Cunningham correction factor prediction equation is presented for the considered experimental data for the DRW model. The effect of rotational lift force is not detected in this simulation settings. For the convenient and reliable liquid droplet escape estimation, a one-way coupling method to model the discrete phase is adopted. The Eulerian Wall Film model is used to depict the thin liquid water film behavior on the drift eliminator to estimate the liquid entrapment by the high air velocity.
Keywords: Drift eliminator, CFD, discrete phase model, Eulerian Wall Film Model, liquid droplet recovery, liquid entrapment