Investigations on Particle Dynamics in a Plate Type Electrostatic Precipitator Using Double-pulse Holography

The separation of particles from gases within electrostatic precipitators is mainly depending on the flow conditions. The flow field is governed by the mutual interaction of the electric field with the gas ions and the turbulent channel flow. Especially for wire-plate electrostatic precipitators this causes secondary flows, well known as the 'ionic wind'. The influence of the ionic wind on the precipitation of particles has been discussed widely in the past. Double-pulse holography was applied to investigate the particle motion within a laboratory scaled plate-type electrostatic precipitator with round wires as discharge electrodes. This experimental method allows to determine size, location and velocity of all particles within a specified volume at one distinct moment. Subsequently frequency distributions as well as spatial distributions of the particle collective within the precipitation zone are evaluated. A quantitative analysis of the migration velocities in the near-wall region and a comparison with theoretical migration velocities, leads to the conclusion that the ionic wind has an order of magnitude about some 10 cm/s.