Nitrogen is an essential element for all living organisms, existing abundantly in nature primarily as inert atmospheric N₂. However, its direct utilization is limited by chemical stability, requiring conversion into reactive forms such as nitrogen oxides. Currently, the conventional Haber-Bosch process dominates large-scale nitrogen fixation but operates under harsh conditions of 650-750 K and 50-200 bar. This process consumes approximately 1-2% of the world's fossil energy annually and emits nearly 300 million tons of CO₂, placing significant burden on global energy resources and the environment.
Plasma-based methods offer promising alternatives. Non-thermal plasma technology enables N₂ activation under ambient conditions through electron impact excitation, ionization, and dissociation. Gliding arc plasmas provide advantages including atmospheric-pressure operation, high energy efficiency, and simple device architecture. The rotating gliding arc, a three-dimensional evolution, expands the reaction zone and achieves more uniform distribution of reactive species. Introducing a magnetic field further enhances arc rotation and improves energy utilization.
In this study, researchers from Xi'an Jiaotong University developed a flow-magnetic field synergistically driven rotating gliding arc discharge system. Through experimental analysis and flow field simulations using COMSOL Multiphysics, the effects of inlet configurations on discharge characteristics and nitrogen fixation performance were systematically explored.
Results demonstrated that inlet configuration significantly affects reactor performance, with nitrogen fixation efficiency following the trend: uniform tangential > single tangential > vertical inlet. At 7 L·min⁻¹, the uniform tangential inlet achieved the lowest energy consumption of 3.06 MJ·mol⁻¹, approximately 30% lower than vertical inlet. The uniform tangential configuration maintained arc elongation even at high flow rates, while single tangential inlets caused reverse breakdown that reduced average voltage.
Optical emission spectroscopy revealed that plasma under uniform inlet exhibits a higher degree of non-equilibrium, with more electron energy directed toward nitrogen excitation rather than gas heating. Under uniform inlet, rotational temperature was 1850 K and vibrational temperature was 3100 K, compared to 2100 K and 3000 K under tangential inlet. This larger temperature gap indicates more energy allocated to vibrational excitation, facilitating formation of reactive species including N₂(v), N₂⁺, and N that lower reaction energy barriers.
Increasing magnetic field strength reduced energy consumption, with optimal performance at 200 mT where NOₓ concentration reached 7427.9 ppm. Analysis further revealed that 40% oxygen concentration produced the highest density of excited N₂ species, aligning with nitrogen fixation trends. At this oxygen content, energy consumption dropped to 4.52 MJ·mol⁻¹.
These findings provide theoretical basis and practical guidance for industrial applications, demonstrating that uniform tangential inlet combined with optimized magnetic field and gas composition significantly enhances nitrogen fixation efficiency and stability. This configuration offers a promising strategy for plasma-assisted nitrogen fixation and gas treatment processes.

DOI
10.1007/s11705-026-2628-8