Eur. Phys. J. D (2015) 69: 100
https://doi.org/10.1140/epjd/e2015-50331-6

Regular Article

Generation of dc pin-hole discharges in liquids: comparison of discharge breakdown in diaphragm and capillary configuration

Faculty of Chemistry, Brno University of Technology, Purkyňova 118, 61200 Brno, Czech Republic

^a e-mail: kozakova@fch.vutbr.cz

Received: 27 April 2014
Received in final form: 6 December 2014
Published online: 7 April 2015

Abstract

Electrical discharges in liquids can be generated in several electrode configurations; one of them is called as a pin-hole. The discharge is created inside a small orifice in the dielectric barrier connecting two chambers filled by any conductive solution. Each chamber contains one electrode. Based on the orifice length/diameter ratio, the discharge is called as a capillary or diaphragm discharge. The present paper gives the first detailed observation of the dependence of discharge creation on the orifice shape for selected NaCl solution conductivities (250−1000 μS cm^-1). As a dielectric barrier, ceramic discs with thickness varying from 0.3 to 1.5 mm were used. Diameter of one central pin-hole was in the range of 0.25−1.00 mm. The non-pulsing dc high voltage up to 2 kV with power up to 500 W was used for the presented study. The bubble theory of the discharge generation was confirmed at the set conditions.