Description of aerosol release associated with sodium burning

Incipient temperatures of sodium oxidation, sodium oxide aerosol release and sodium ignition were observed in relation with oxygen concentration in supplying gas by a thermobalance method. On this results, a burning rate and an aerosol release fraction were determined by burning about 0.5 g of sodium samples on a crucible in a burn tube under conditions ranging 400 to 6000C in sodium temperature, 0.1 to 1.0 Nl/min in the supplying gas flow rate and 2.5 to 20v/0 in the oxygen concentration. Particle sizes of sodium aerosols released from the samples made a log-normal distribution, of which mass median diameter ranged from 0.6 to 2.0 μm. The burning rate increased with the increases of the sodium temperature, of the gas flow rate and of the oxygen concentration, and the aerosol release fraction also increased in proportion to the burning rate at fixed oxygen concentrations. It was found that the aerosol release rate defined as a product of the burning rate and the aerosol release fraction describes fairly well not only the present experimental data but also reported ones. (auth.)