Electrostatic filter efficiency improvement based on velocity and pressure field numerical simulation

Abstract

This paper deals with the numerical simulation of exhaust gas flow through the electrostatic filter (EF) in block IV of the Šoštanj thermal power plant. Four different variants of the geometry were analysed. The exhaust gas flow was modelled as a turbulent incompressible viscous fluid flow. The commercial computational fluid dynamics package CFX-4.4 from ANSYS was used for flow analysis. The discrete models were very complex due to the internal objects such as guide vane rows, perforated screens, and electrodes. The turbulence model was the standard k—ɛ model with wall functions. Perforated screens were considered by an additional source term in momentum conservation equations. Velocity boundary conditions were obtained by interpolating the measured values on the discrete model nodes. The results of numerical simulation show that the most efficient is the variant where an additional screen is inserted between the second and the third EF volume. The maximum velocity is decreased and the distribution of velocity over the cross-section is more uniform. The increase in pressure drop was acceptable. The measurements of the velocity field after EF modification confirmed the prediction of the numerical simulation.