Simulation of Temperature Distribution of Pulse Arc Discharge in Argon and Nitrogen

Summary form only given. The reduction of damage by lightning is difficult, even if it is the 21st century. It is important to research the basic lightning characteristics in order to reduce the damage. The lightning is very unstable and momentary arc phenomenon. It is considered as the free arc and pulse arc discharge. Since its measurement is difficult, the experimental elucidation of the phenomenon is difficult. The reports of measurement are quite few. On the other hand, the various methods in theoretical elucidation have been developed recently. However, a two-dimensional model has not been calculated recently. In this paper, a lightning phenomenon is simulated by a two-dimensional pulse arc model. The calculation conditions in a pulse arc are in an LTE condition, above 10,000 K, and with a gas flow rate of 12 slm around the upper electrode. The current peak of pulse arc is 100 A. Its rise time is 1 ms and the half-fall time is 12 ms in milliseconds order. And a DC arc discharge is also simulated for comparison. As a result, the temperature distributions of DC and pulse arc discharge are different in argon and nitrogen. In argon, the temperature distribution of pulse arc spread more than it of the DC arc discharge in axial direction. However, in nitrogen, the spread of temperature distribution is reserved in comparison of that in argon. This result comes from the difference of thermal dynamics and transport properties between argon and nitrogen. Therefore, the nitrogen pulse arc discharge in milliseconds order is more effective for keeping the temperature lower by nitrogen when the temperature is above 10,000 K.