Effect of boric acid on the severity of vapor explosions in pure water and surfactant solutions

Abstract

Four different dilute aqueous solutions of boric acid and surfactant/boric acid were tested to determine the impact of these coolant additives on the severity of vapor explosions in small-scale experiments with molten tin. Twelve grams of molten tin at 800°C were dropped into 6 l of coolant solution at room temperature; for each solution, the experiment was repeated 20 times. The coolants examined were pure water, 500 wppm boric acid solution, 2000 wppm boric acid solution, 5 wppm of a non-ionic surfactant (nonylphenol polyethylene glycol ether) in a 500 wppm boric acid solution, and 5 wppm of an ionic surfactant (dodecylbenzene sulfonate sodium salt) in a 500 wppm boric acid solution. Pressure and impulse data suggest that the presence of boric acid up to 2000 wppm concentration did not significantly affect the severity of the interactions. Particle size analysis, however, indicates that enhanced fragmentation took place at the higher concentration (2000 wppm). The data indicate that the presence of boric acid negates the potentially mitigating effects of the surfactant additives previously reported in experiments where the surfactants were added to pure water.