Revisiting gas temperature in dielectric barrier discharge (DBD): an unsolved problem of plasma catalysis

Abstract Gas temperature is an essential parameter in terms of thermodynamics and kinetics of a plasma chemical reaction, but the gas temperature in dielectric barrier discharge (DBD) plasma is difficult to measure and often misunderstood as near room temperature. In this work, the axial distributions of center ( T c ) and wall ( T w ) temperatures in bare, water-cooled, heat-insulated and furnace-heated DBD reactors are measured. It is found that T c is significantly higher than T w and has an asymmetric bow-like profile of axial distribution, which indicates axial and radial nonuniformity of gas temperature in DBD plasma. Based upon the radial distribution of the gas temperature in the DBD plasma by simulation, a radial-averaged gas temperature ( T g RA ) is obtained, which confirms that the T c is a reliable representative of gas temperature in DBD plasma. Finally, the effects of flow rate, discharge power, specific energy input, alternating-current frequency and pulse modulation on the gas temperature are investigated.