Interactions Among Jets in an Atmospheric Pressure Plasma Jet Array in Argon

Abstract

In this paper a linear jet array consisting of three jets is generated in Ar and is employed to investigate the interactions among its plasma plumes. The characteristics of the array are studied by optical, electrical and Schlieren diagnosis, and they are compared to those of a single jet. The uniformity of the array is characterized and studied by deviation angles of plasma plumes from the optical and gas channel from Schlieren images, and the electrical interactions are investigated by estimating the actions of Coulomb forces and Lorentz force, with the influence of the applied voltage and gas flow rate on these effects being studied. Results show that both hydrodynamic and electrical interactions exist among the jets in the array. The measured current and dissipated power of the jet array are not three times as large as those of a single jet, and deviations of the side jets are observed both in the flow field and lighting images. The difference between two deflection angles in optical and Schlieren images indicates the j oint effort of hydrodynamic and electrical interactions which determinates the shape of plasma plumes in the array. The hydrodynamic interaction is considered to be caused by the gas heating and the pressure fluctuation, and the electrical interaction is caused by the accumulation of impulsive Coulomb force between the adjacent streamer channels of the plasma plume. Increasing the gas flow rate and limiting the applied voltage can restrain the interactions and thus contribute to a uniform jet array.