Hydrodynamic Recirculation Induced by Nanosecond Discharges: A Strategy to Mitigate Cumulative Heating
Résumé
This work studies the impact on flames of the toroidal hydrodynamic regime induced by Nanosecond Repetitively Pulsed discharges. Thanks to OH Planar Laser-Induced Fluorescence, experimental images of toroidal recirculation cells are observed for the first time in a plasma-assisted combustion experiment. In addition, the gas temperature between the electrodes is measured by optical emission spectroscopy of the (0,2) and (1,3) vibrational bands of N2(C 3 Pi_u-B 3 Pi_g). The temperature in the inter-electrode gap is below 2500 K in the experimental conditions for which recirculation cells are observed. This level of cumulative heating by the repetitive discharges is far below previous experimental and numerical literature results reporting values around 3500 K for the same pulsing frequency and energy per pulse. The lower temperature is beneficial for NOX emissions as it reduces the production of NOX via the thermal Zeldovich reactions. The total NOX emissions due to the thermal and chemical effects induced by the plasma increase slower with the pulse energy than the traditionally observed linear dependence. This work shows that exploiting the hydrodynamic recirculation effects induced by nanosecond spark discharges is an effective way to deposit more plasma power, increasing the reactivity, with lower NOX emissions.
| Origine | Fichiers produits par l'(les) auteur(s) |
|---|---|
| Licence |
