Response mechanism of methane non-premixed diffusion flame under the influence of an applied magnetic field

• DOI: 10.1016/j.csite.2025.105944
• Publication Date: 2025-02-24T17:12:43Z
• Authors: Yaqing Li; Haochen Li; Jun Deng; Yutao Zhang; Chi-Min Shu; Qiang Guo; Bo Che
• Keywords: Magnetic induction distribution; Diffusion flame; Combustion characteristics; Applied magnetic field; TA1-2040; Ionic current; Engineering (General). Civil engineering (General)

To explore the influence of an applied magnetic field on non-premixed diffusion flames, a methane non-premixed diffusion flame combustion system was constructed. MATLAB was utilized for processing flame split-frame images, while DPIV technology was employed to analyze the two-dimensional instantaneous flow field of the flame. A custom-built Langmuir ion probe was used to monitor the variation in flame ionic current concentration. The study reveals that under constant excitation voltage, magnetic intensity along the flame axis decreases linearly with nozzle distance, exceeding a 60 % reduction. In a negative gradient field, the flame elongates, with height increasing and width narrowing as the magnetic field gradient intensifies. The applied magnetic field raised the average flame temperature significantly, peaking at a 379.4 °C increase for a 20 mm nozzle at 100 V, while jet exit temperature decreased with higher flow rates. Ionic current along the flame axis increased with nozzle distance, improving combustion efficiency. At a flow rate of 0.60 slpm, ionic current dropped sharply at the jet exit due to charged particle accumulation near the flame tip. The ionic current rose from sub-microamp to microamp levels under the magnetic field, providing valuable insights for flame combustion regulation.