A computational study on the energy efficiency of species production by single-pulse streamers in air

TL;DR

This study uses a 2D fluid model to analyze how different parameters affect the energy efficiency of species production in streamer discharges in air, revealing key factors that influence efficiency and potential improvements.

Contribution

It provides a detailed computational analysis of energy efficiency variations in streamer discharges, highlighting the impact of electric field and energy deposition on species production.

Findings

G-values vary by 30-55% depending on streamer parameters

Energy efficiency is higher in positive streamers compared to negative ones

Reducing Joule heating and increasing electric field can improve efficiency

Abstract

We study the energy efficiency of species production by streamer discharges with a single voltage pulse in atmospheric dry air, using a 2D axisymmetric fluid model. Sixty different positive streamers are simulated by varying the electrode length, the pulse duration and the applied voltage. Between these cases, the streamer radius and velocity vary by about an order of magnitude, but the variation in the maximal electric field is significantly smaller, about 30%. We find that G-values for the production of N(4S), O(3P), NO and N2O, which have relatively high activation energies, vary by about 30% to 55%. This variation is mainly caused by two factors: differences in the fraction of energy deposited in the streamer head region, and differences in the maximal electric field at the streamer head. When accounting for both factors, our computed G-values are in good agreement with an analytic estimate proposed by Naidis (2012 Plasma Sources Sci. Technol. 21 042001). We also simulate negative streamers and find that their production of N(4S), O(3P) and NO is less energy efficient. The results suggest that energy efficiency can be increased by reducing Joule heating in the streamer channel and by increasing the maximal electric field at the streamer head, for example by using short voltage pulses with a high applied voltage.