Radicals' Emissions and Butane Diffusion Flames Exposed to Upward-Decreasing Magnetic Fields

A diffusion flame of nonpremixed butane gas was exposed to upward-decreasing magnetic fields. Increases in emission intensities of OH * , CH * and C 2 * radicals' transitions, an increase in the flame temperature, a decrease in the flame dimension, and a bluing tendency of the flame occurred. The magnetic gradient field affected C 2 * the most, CH * somewhat less, and OH * the least. The emission intensity of a continuous spectrum decreased drastically with increasing magnetic gradient field. This means that the reaction liberating carbons decreased. The Lorentz force had no significant effect on flame shape changes. Magnetic forces originating from the magnetic gradients accelerated, stretched and squeezed the flame, resulting in a change in the flame shape. An attempt is made to explain the combustion changes by a simplified diffusion model based on changes in a mixing condition and a diffusion coefficient.