Burning unstable

The burning rates of AN pyrolants are of the order of 1-3 mm s" at 10 MPa, which is very slow compared with AP pyrolants. Decomposition catalysts for AN powder, such as chromium trioxide (Cr203) and ammonium dichro-mate((NH4)2Cr207), need to be incorporated into AN pyrolants to aid their successive burning. Very unstable burning occurs without these catalysts. 

Fig. 13.16 Stable, oscillatory, and unstable burning zones for a lead-catalyzed double-base propellant.

E.W. Price, "Catastrophic Changes in Burning Rates of Solid Propellants During Combustion Instability , ARS J 30, 707(1960) C) R. Denison E. Baum, "A Simplified Model for Unstable Burning in Solid Propellants ,... 

J.F. Bird, "Scaling Problems Associated With Unstable Burning in Solid Propellant Rockets , Ibid, 993-1004 M4) M.D. Horton... 

Motor applications of PVC plastisol propellants have been notably free of unstable burning problems. 

The average burning rate for the proplnt during these oscillations is always higher than expected. This phenomenon of unstable burning is known as resonance burning [See under Burning, Unstable (in Rocket Motors)]... 

Another term used in conjunction with unstable burning of solid rocket proplnts is chuffing. This usually refers to an unstable condition in burning when the chamber pressure drops below minimum value necessary to sustain the burning processes(Ref l6,p 88)... 

In regard to liquid rocket proplnts, the earliest theory of unstable burning was that of Summerfield(Ref 4). This was followed by theories of Crocco(Ref 5), Crocco Cheng(Ref 6) and Ross Datner(Ref 8Xsee also Ref l4,p 105)... 

Crawford (Ref 17) found that unstable burning in double-base proplnts can be overcome by incorporating in the powder opaque C black or, as Hickman (Ref 24) found,lampblack for preventing self-ignition by radiation. See also Cannonite... 

HYDROXYNITROBENZENE (88-75-5) Combustible solid (flash point 215°F/102°C). Dust or powders form explosive mixture with air. A strong oxidizer. Thermally unstable burns even in absence of air, causing fast rise in pressure closed containers may explode. Violent reaction with reducing agents. Reacts with combustible, organic, and other easily ox-idizable materials. Forms shock-sensitive explosive mixtures with chlorine trifluoride. Incompatible with strong acids, caustics, aliphatic amines, amides, diethyl amine, potassium hydroxide. 

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