The acoustic resonator combined with electrical discharges

Environmental applications, such as pollution control, utilize different chemical reactions. Their efficiency can be improved by the application of a power acoustic field. Many reactions can be enhanced by ionization of the reactant medium, which is most frequently performed by electrical discharges. One way to meet these requirements utilizes the combination of an acoustic resonator with non-thermal electrical discharges. The important factors in industrial applications are discharge power and volume. In order to increase the discharge volume and to prevent a discharge transition into sparks, we designed a discharge stabilization of multi-needle to axial-wire electrode system, which is situated in the pressure node of the acoustic resonator. Factors which contribute to the stabilization are: first, the gas particles that are swung on the pressure node plane; and second, the acoustic pressure gradient, which strongly influences breakdown conditions. With the reduction of acoustic pressure, the reduced electric field is increased, and suitable conditions for discharge streamer tracing are established. The streamers are easily swung into place over the estimated maximal amplitude of sound displacement and discharges are strongly spread. The discharges are stabilized at all needles even if they are connected to the same potential. The needle tips are effectively cooled by the acoustic wave. Several multi-needle electrodes can be placed around the resonator diameter centered at the node plane so that the considerable resonator node volume is filled with the discharges. The stabilization may be applied to different regimes of discharges; e.g. corona, glow and streamer.