Hydrogen Enrichment Effect on Heat Flux from Plasma-Assisted Flames

The European industries are transitioning from natural gas usage to renewable gases to enhance climate neutrality and energy security—therefore, hydrogen and ammonia gases could be great alternatives to natural gas. Hydrogen can be produced via electrolysis powered by renewable energy or from natural gas with carbon capture. Moreover, ammonia, composed of hydrogen and nitrogen, could also act as an energy carrier and storage medium. This study investigates the combustion process and efficiency of the hydrogen-enriched NH3 and CH4 blends using nonthermal plasma assistance. The experiments were performed with a gas burner with a thermal power of 1.30 kW using fully premixed gas blends. The nonthermal plasma was created with a high-voltage and high-frequency generator at 120 kHz and 8.33 kV. Time-resolved chemiluminescence data for OH* and NH2* were captured using an ICCD camera, an MIR emission spectrometer and a thermal irradiance flux meter. The results indicated that nonthermal plasma enhances the flame stability and increases the infrared radiation intensity. The MIR spectroscopy showed an intensity increase of 13% for ammonia-hydrogen blends under plasma assistance and heat flux measurements showed a 15% increase for the 70% ammonia and 20% hydrogen mixture. These results demonstrate that plasma-assisted combustion can enhance the efficiency and stability of low-carbon fuel blends, facilitating their integration into current infrastructure while reducing greenhouse gas emissions.