Investigation of discharge phenomena in porous materials

This paper deals with investigations of discharge phenomena in porous materials. Experimental investigations with high-resistivity dust have been performed in a laboratory scale electrostatic precipitator. High dust resistivities in combination with a high electric field are responsible for the occurrence of discharges inside the dust layer, so called back corona. The local occurrence strongly depends on dust layer thickness and porosity which is strongly influenced by forces of the electrohydrodynamic field. The corresponding increase of the electric current density was monitored and compared for different geometric parameters and electric operation settings. This paper verifies a correlation between the electric current density, the quality of the porous material and the discharge phenomena. Furthermore a model based on percolation theory describing the initial electrical process in correlation with the porous material is presented.