Propellant flame propagation

Prevention of Propellant Flame Propagation through Conveyors Using the Primac/Telemac Sprinkler System... 

During flame propagation, a constantly increasing amount of propellant combustion products is added to the igniter products, thereby producing a constantly increasing mass velocity of total gas. As a first approximation to the real situation, the following expression has been used in the theoretical analysis to account for this effect ... 

Application of these data to CASBL show that most water and/ or solvent-wet propellant and propellant ingredients will not sustain a burning reaction for the conditions which will exist in CASBL (Figure 2). These tests demonstrated that the existing conveyor sprinkler system is more than adequate to prevent between bays flame propagation in most CASBL locations. 

Seven confirmatory tests were conducted using the modified test setup shown in Figure 8. These tests were conducted to assure that additional propellant within a conveyor feed hopper would not result in a more severe burning condition than previously tested. Three nozzles with 90 psig water pressure were used for these tests since there were at least three nozzles on actual CASBL conveyors. One-hundred ten pounds of MISP propellant was used for each test. Initial tests used two IR detectors in the upper conveyor. Table IV shows that two of four tests stopped flame propagation. 

For most dry MISP propellant (one-inch bed depth) and other wet and dry in-process propellant states, a single water nozzle spraying 17 gpm of water at 55 psig pressure is sufficient to prevent flame propagation in conveyors. 

The propellant build-up condition presents more severe burning. Therefore, two water nozzles spaced six feet apart and spraying 21 gpm (each) of water at 90 psig pressure are required to prevent flame propagation in conveyors. 

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