Influence of impurities on electroconvection in insulating liquids

The concentration of impurities in nonpolar liquids in the test liquids was varied either by removing naturally existing impurities by filtration, or by adding conducting particles of carbon, copper, or iron or insulating particles of alumina to filtered test liquids. It is shown that the measured currents in filtered liquids are influenced by the net change in the concentration of charge carriers due to removal of suspended impurities and charge separation. It is established that small conducting particles (diameters, of 0.07 to 1.4 μm) have a greater influence on electrohydrodynamic motion than larger particles. Copper particles can reduce the breakdown strength of liquid to a greater extent than from iron particles. Alumina particles did not have any influence on induced liquid motion; however, the dominance of dwell time over transit time, for these particles produced a thin insulating coating on the electrode surface that reduced the current slightly