Experimental study of nanosecond surface dielectric barrier discharge for plasma-assisted ammonia combustion: Effects of pulse number and pulse interval

Plasma-Assisted Ammonia Combustion (PAAC) addresses several challenges of using Ammonia (NH 3 ) as a carbon-free fuel. Nanosecond Surface Dielectric Barrier Discharge (nSDBD) is an effective strategy with improved ignition and combustion efficiencies for PAAC. The effectiveness of nSDBD depends on both discharge device and parameters. However, there is a lack of experimental investigations into discharge parameters of PAAC ignited by nSDBD. This research experimentally examined two significant discharge parameters: pulse number (PN) and pulse interval (PI). Stoichiometric NH 3 /air mixture was placed into a Constant Volume Chamber (CVC) at the initial pressure of 1 bar and the initial temperature of 90 ∘ C. Nanosecond pulses at the voltage of 15 kV were generated by a self-designed power source and applied to an nSDBD device. The results show that increasing PN enhances ignition success, flame kernel growth, and combustion performance, up to an optimal point at PN = 180. Shorter PI improves the supplied energy to the nSDBD per pulse, accelerating flame kernel expansion and ignition. However, excessively short PI (e.g., 50 μ s ) leads to gas disturbances and potential radical quenching, while intermediate PI (e.g., 80 μ s ) introduces anisotropic spatial distribution and poor combustion repeatability. The optimal discharge setting was found to be PN = 180 and PI = 60 μ s at the initial pressure of 1.0 bar and the initial temperature of 90 ∘ C , achieving the fastest combustion and highest heat release. This study fills the current experimental gap and provides practical guidelines for the design of efficient PAAC systems. • Nanosecond-scale high-frequency nSDBD was applied in NH 3 /air mixtures for ignition. • Effects of pulse number and pulse interval of nSDBD discharge on NH 3 ignition. • Pulse number of 180 and pulse interval of 60 μ s achieved optimal combustion at the initial pressure of 1.0 bar and the initial temperature of 90 ∘ C. • Excessive pulse numbers or overly short pulse intervals lead to deteriorated combustion performance.