Two-dimensional imaging of NO density profiles by LIF technique in a pipe with nozzles electrode during NO treatment

Two-dimensional NO concentration distribution was studied by a planar laser-induced fluorescence (PLIF) technique in nonthermal plasma during NO treatment. A pipe with a nozzles-to-plate electrode system, having an electrode gap of 50 mm, was used. A stable DC streamer corona discharge was generated in an NO/air mixture at atmospheric pressure. Laser pulses in the form of a sheet were shot between the electrodes during the discharge. LIF signal emitted at 90° to the laser sheet was imaged onto a gated-ICCD camera and two-dimensional distributions of NO concentration in the reactor were measured as a function of time during NO treatment. NO concentration was also monitored at the reactor outlet. The images of NO concentration covering almost the whole length of the reactor show that the density of NO molecule decreased not only in the plasma region formed by corona streamers but also in the upstream region of the reactor. This information is important for modeling and optimizing the plasma processes and designing the nonthermal plasma reactors.