The Potential of Simple, Low-Cost Permanent Magnets for Flame Manipulation in Flow Fields

The effect of electric fields on combustion is well established [1]. However, few studies have been conducted about the effect of magnetic fields on combustion, though the fact that magnetic fields can influence combustion was first realized over one hundred and fifty years ago. As early as 1846, Faraday applied a magnetic field to a flame on a wax taper and observed its tendency to form an equatorial disc [2]. Para magnetism is the situation where certain materials are attracted by an externally applied magnetic field, and form internal, induced magnetic fields in the direction of the applied magnetic field. Oxygen, an element essential for combustion is considered a paramagnetic substance because the oxygen molecule has two unpaired electrons that spin in the same direction as each other, increasing the magnetic field effect. The products of combustion, in contrast are diamagnetic materials. They are repelled by magnetic fields and form induced magnetic fields in the direction opposite to that of the applied magnetic field. Ueno [3] also examined the ability of the magnetic field to quench flames. A candle flame between two columnar electromagnets, hollowed out, to enclose the flame was exposed to a field of 1.5 T in an air gap of 5-10 mm. The flame was quenched soon after the application of the magnetic field. Mizutani et al. [4] studied the effect of a uniform magnetic field on premixed laminar flames. The structure of the flame was observed using a schlieren system. It was observed that the presence or absence of a magnetic field had no perceptable influence on the flame structure. They inferred that the magnetic field, even ones as high as 5 T had no effect on the burning velocity as it was dominated by high-speed chemical reactions.