Suppression of dust explosions by means of an active superfast explosion-suppression system of five liter volume

This research was aimed at the development and testing of a superfast explosion-suppression system of 5 dm3 volume, using smokeless powder or pyrotechnic material as an explosive charge, and sodium bicarbonate or water as suppressing materials. The experiments were carried out on a prototype device-a steel container with capacity of 5 L, closed by means of an aluminum membrane. Below the membrane, there was an exhaust connector pipe ending with a dispersing head. Inside the container, ∼ 1.75 kg of extinguishing powder was located. The membrane was ruptured by the explosion of a specially developed explosive charge located inside a perforated steel combustion chamber and mounted over the suppressing powder surface. There was no overpressure inside the container during the period of observation. The system was triggered by a signal sent by a pressure detector or by a photodiode reacting to a flame developing in a protected volume. Investigations of the efficiency of the developed active explosion suppression system were carried out in a 1.25 m 3 explosion chamber, which in our experiments plays the role of a protected volume. The explosion was initiated in the cornstarch-air mixture of 0.2 kg/m3 concentration. The cornstarch dust was dispersed pneumatically inside the chamber. The dust explosion-suppression process occurred as a result of activity of the extinguishing powder blown out from the extinguisher, after membrane perforation by means of the compressed combustion products. Finally, the process of dust explosion suppression by means of an extinguishing powder was modeled, and numerical simulations were carried out. © 2010 by Begell House, Inc.