Design And Experiment Of An Atmosphere Microwave Plasma Jet Device

One atmospheric microwave plasma has great application prospect due to its unique characteristics, such as low cost, electrode contamination free and suitable for industrial production. The device is currently designed and optimized from three aspects in the major way of the discharge, the electrode structure and the power source. An atmospheric microwave plasma device was developed and simply modified to meet the carbon waste gas treatment after using Ansoft HFSS software to optimize the short circuiting plunger position and the shape and position of nozzle.An atmospheric microwave plasma jet device consists of programmable microwave source, circulator, water load, rectangular antenna cavity and coupling antenna. The 2.45GHz microwave with TE10 mode propagate in BJ26 rectangular waveguide and forms TE103 mode standing wave in the resonant cavity by means of adjusting the position of short circuiting plunger. TE103 mode wave was characterized by only Ey component, Ey sinusoidal distribute along the Z direction and there are three standing waves in a direction, in which the strongest electric field of the middle one is utilized to form plasma jet by breakdowning working gas.Microwave discharge successful occurred via debugging the position of short circuiting plunger and nozzle. Microwave energy meter readings up to the maximum, reflectivity is the smallest and the maximum area of electromagnetic field appears in the cavity center when the distance is 3λg/4 between short flat and coupling hole. In addition, the studies on the shape of the nozzle have shown that the electric field strength around the graded nozzle is more focused and the best position is that the nozzle tip is flush with the flange compared with the mutant nozzle. The treatment experiment of carbon gas was carried on based on studying the generation mechanism of microwave plasma jet under the condition of an atmospheric pressure. The result showed that: Argon plasma jet is more stable and longer than nitrogen plasma jet because of the lower electric field breakdown strength of the argon. The increase of gas flow is conducive to the increase of the plasma jet length. The discharge level increases and the plasma jet is more stable with the increase of microwave power. It was also proved that the discharge of gradient of nozzle is better than mutant nozzle. XRD diffraction analysis showed that the product of carbon gas treatment experiment by water-cooled is graphite.