Wire/cylinder device with space charge distortion: ozone production

Ozone cannot be stored and must therefore be generated at the point of use. Conventionally this involves generating an AC corona discharge in a geometry consisting of two metal electrodes with one or more solid dielectric barriers between them. The efficiency of this generation process is extremely low with most of the energy input being lost as unwanted heat. An alternative approach which promises higher efficiency is to dispense with the dielectric barrier and to use a highly nonuniform field geometry such as a point/plane or wire/cylinder arrangement. When this is done using continuous AC or DC application, obviously the voltage must be kept below the breakdown voltage for the device and, in general this implies a very weak corona discharge in which little ozone is generated. If the voltage is applied as an individual pulse or a train of pulses, however, voltages considerably greater than the DC breakdown voltage can be applied if the pulse duration is sufficiently short. The required pulse duration for any given voltage is controlled by the rate of expansion of the corona region and this contribution presents some preliminary results of a computational method aimed at exploring the evolution with time of the corona discharge around a wire held centrally within a cylinder