THE CHARACTERISTICS OF IONIC WIND AND ITS EFFECT ON ELECTROSTATIC PRECIPITATORS

The ionic wind and turbulent flow field formed in a nonconservative electric force field have long been recognized to have a significant effect on an electrostatic precipitator (ESP). To simulate the flow field in an ESP, one should include the electric force term in the momentum equation. We considered the flow field in an ESP to be a turbulent flow and applied two- and three-dimensional models of k-epsilon-A and k-epsilon-E to close turbulence. The SIMPLE-C numerical scheme was applied to investigate the characteristics of the ionic wind and its influence on an ESP. The collecting efficiency of an ESP for a particle diameter of each grade was calculated to understand how the ionic wind interferes with the collecting efficiency. The results indicate that under normal operating conditions the effect of ionic wind is not pronounced. However, as the flow velocity becomes smaller, especially when the flow velocity is < 0.6 m/s, the ionic wind becomes pronounced and has a significant influence on the flow field and the collecting efficiency. The collecting efficiency is substantially diminished and the turbulent intensity is enlarged. When the main flow velocity is < 0.23 m/s, the collection efficiency may decrease about 12% owing to the ionic wind effect.