Stabilizing Effect and Diffusion Control on Diffusion Flames by Magnetic Field

Diffusion control and stabilizing effect on diffusion flame of propane gas were found in a magnetic field. Magnetic field strength was changed at 0.11.38xl05A/m at the center of the field. Experiment of diffusion control was carried out with a nozzle of 8-mm diam. Experiments of stabilizing effect were carried out with a nozzle of 2-mm diam. These nozzles were set at the center position of the uniform magnetic field and propane gas was run through with these nozzles at a constant flow rate. Property of propane gas and flame are diamagnetism, on the other hand air and oxygen gas are paramagnetism. Particularly volumetric susceptibility of oxygen gas is very large value. The magnetic pressure on flames was attributed to paramagnetic (air) and diamagnetic (flame) properties. As magnetic field was applied, the flame changed from an oscillating flame to a stable flame with a low frequency and small oscillating amplitude. The stabilizing effect was examined by temperature and luminosity measurement by observation with the schlieren method and high-speed photographs. The width of the outer swelled combustion gas region became narrower and keeps a constant width when the magnetic field was applied. In the condition that magnetic field was not applied, when oxygen gas was injected coaxially in the outer nozzle as secondary flow of gas, the length of the diffusion flame changed extremely short. Under this condition when magnetic field was applied, the flame length increased with increasing in magnetic field. This means that the diffusivity of oxygen gas can be controlled by magnetic field. In this study, flow control of fuel and stabilizing effect to oscillating flame are proved by using magnetic field. These effects were expressed by pressure acting on the flame by magnetic force.