Experimental study on high-frequency nSDBD assist ignition of ammonia/air mixture

This study investigates the enhancement of ignition and combustion in NH3/air mixtures using a dual-group high-frequency nanosecond discharge pulse strategy. By employing the same nanosecond surface dielectric barrier discharge (nSDBD) electrode for both pre-treatment and ignition, the strategy improves ignition performance. The research, conducted in a constant volume combustion chamber (CVCC), shows that lowering the pulse repetition frequency (PRF) below 12.5 kHz prevents ignition during pre-treatment. Increasing the pre-treatment pulse number (PPN) and PRF intensifies the airflow produced by the discharge, displacing the initial flame kernel outward and enhancing its dissipation. At higher flow intensities, the initial flame kernel is blown toward the CVCC walls and compressed. Active components generated during pre-treatment expand the initial flame kernel area and increase its development rate, reducing the number of ignition pulses needed. However, the effects of gas flow, active particles, and heat from high-frequency nSDBD pre-treatment are opposing, limiting control over the initial combustion rate. Adjusting discharge parameters (PPN and PRF) influences the flame development time (FDT) and flame rise time (FRT), providing insight into the regulation of the combustion phase and combustion rate. This study offers experimental evidence for the use of high-frequency nSDBD in NH3/air combustion enhancement.