Needs in Dust Explosion Testing.
Kauffman-CW; Srinath-SR; Tai-CS
Proceedings of the International Symposium on the Explosion Hazard Classification of Vapors, Gases, and Dusts, National Materials Advisory Board, Publication NMAB-447 1987:41-64
Dust explosion testing was discussed in terms of the need for information of a fundamental nature, and hazards which current testing procedures may not accurately evaluate. Problems associated with determining the combustion parameters of dusts were described. The measured values of ignition sensitivity and explosion severity on which explosibility hazard assessments are based depend on the apparatus in which the measurements are made. Existing testing procedures do not offer a reliable way to determine the minimum dust layer thickness required to support the combustion process for a secondary explosion. In order to be able to evaluate the explosion hazards of dusts more accurately more reliable data on the uniformity and extent of turbulence of the dispersed dust/air mixture must be obtained. When these quantities are known, the effect on the power and energy necessary to ignite the mixture and on the burning velocity can be accurately determined. A new technique for measuring burning velocity of dust clouds was described. It is based on using a jet stirred reactor, known as the premixed turbulent combustion bomb (PTCB), to measure the turbulent burning velocity of a dust/air mixture. The PTCB has made it possible to create a homogeneous dust/air mixture and measure quantitatively the effects of turbulence on ignition sensitivity, explosion severity, and laminar and turbulent burning velocity. Secondary explosion measurements have been made in a flame acceleration tube (FAT), consisting of a 3000 pounds per square inch working pressure steel tube 120 feet long with a 1 foot diameter. The FAT has made it possible to reproduce accurately conditions under which secondary dust explosions can occur.
Laboratory-testing; Dust-explosions; Industrial-safety; Explosive-atmospheres; Air-flow; Testing-equipment; Physical-properties;
Proceedings of the International Symposium on the Explosion Hazard Classification of Vapors, Gases, and Dusts, National Materials Advisory Board, Publication NMAB-447