Deflagrations of solids

Refs 1)W.H.Andersen R.F.Chaiken, Detonability of Solid Composite Propellants , Tech Memorandum of Aerojet-General Corp No809 (Jan 1959), Contract NOrd 17012, Task II and NOrd 18487 [A fundamental investigation of the factors involved in the detonation and abnormal (accelerating) deflagration of solid composite propints is described] 2)T.G.O.Berg, "Study of Susceptibility of Solid Composite Propellants to Explosion or Detonation , Aerojet-General Corp, Final Report No 0253-05(01)FP (April 1963) Contract NOrd 18487(FBM/Task 4) (A study of sensitivity to initiation of proplnts and expls by a modified Impact Machine)... 

A discussion with 14 refs on expls and proplnts considering the thermodynamic characteristics of expl substances, the kinetics of combustion of powders and the effects of catalysts, corrosion, and instability on the kinetics, the occurrence of deflagration on detonation, and forms of solid mixts in view of the augmentation of their performance and the extension of conditions used in their mixts. The importance of modern methods of calcn is stressed... 

A considerable amount of research has been conducted on the decomposition and deflagration of ammonium perchlorate with and without additives. The normal thermal decomposition of pure ammonium perchlorate involves, simultaneously, an endothermic dissociative sublimation of the mosaic crystals to gaseous perchloric acid and ammonia and an exothermic solid-phase decomposition of the intermosaic material. Although not much is presently known about the nature of the solid-phase reactions, investigations at subatmospheric and atmospheric pressures have provided some information on possible mechanisms. When ammonium perchlorate is heated, there are three competing reactions which can be defined (1) the low-temperature reaction, (2) the high-temperature reaction, and (3) sublimation (B9). 

Silver acetylide decomposition was studied [679] by X-ray diffraction and microscopic measurements and, although the a—time relationship was not established, comparisons of intensities of diffraction lines enabled the value of E to be estimated (170 kj mole 1). The rate-limiting step is believed to involve electron transfer and explosive properties of this compound are attributed to accumulation of solid products which catalyze the decomposition (rather than to thermal deflagration). 

The deflagration [1] and thermal decomposition [2] of the salt, a component of solid rocket propellants, have been studied. It also explodes on impact [3],... 

Fierz, H., and G. Zwahlen, "Deflagration in Solids—A Special Hazard in Chemical Production, Proceedings of the 6th Loss Prevention and Safety Promotion in the Process Industries Symposium, Oslo, Norway (1989). 

An acoustic emission system was designed for use in a strand burning bomb (Refs 10 15). The signal, presumably created by the thermal fracture or deflagration of the solid oxidizer, reveals anomalies such as side burning, voids and sudden changes in bum rate... 

The latter method typically requires less severe conditions than the former because of the labile nature of the organic anhydride (87,137). Both of these reactions can result in explosions and significant precautions should be taken prior to any attempted synthesis of a peracid (87). For solid peracids the reaction mixture can be neutralized with sodium hydroxide and the resulting filtercake washed with water. In the case of the sulfuric acid mediated reaction the peracid has sodium sulfate incorporated in the cake (135). The water of hydration present in the sodium sulfate is desirable to prevent detonation or deflagration of the solid peracid when isolated in a dry state (87,138,139). 

Early explanations about the effect of mechanical energy on the reactivity of solids are the hot-spot-model [23] and the magma-plasma-model [8]. The generation of hot-spof may be used to explain the initiation of a self-sustained reaction such as explosion, deflagration, or decomposition. Temperatures of over 1000 K on surfaces of about 1 pm2 for KM to 10-3 s can be created. These temperatures can also be found near the tip of a propagating crack [24]. Typically nonequilibrium thermodynamics are used to describe these phenomena. The magma-plasma-model allows for local nonequilibrium states on the solid surface during impact however, due to the very short time scale of 1(H s of these states only statistical thermodynamics can describe the behavior. 

I960) (Deflagration of mining expls) 10a)Blasters Hdb (1958), 49 ll)J.F.Roth, Explosivst 1958, 48-52 (Deflagration and detonation) 12)M.A.Cook et al, PrRoySoc 246A, 281-83 (1958) (Deflagration-to-detonation transition in solid and liquid expls) 13)C. 

The purpose of the test is to determine the detonation or deflagration hazards of solid materials with combustible materials. A mixture of the test sample and a combustible material is put into the steel tube and ignited. The extent of cracking of the steel tube is observed. 

As broad as the coverage of this symposium appears, there is much propellant chemistry which has not been included. The experimental determination of thermodynamic properties such as heats of formation and equilibrium constants as well as the calculations of theoretical performance have been presented at other symposia. The applied chemistry related to modifying polymers, and hence mechanical and burning properties of solids, have other forums. The actual firing of solid motors and determination of thrust and efficiency have been omitted while the research into combustion instability and the transition from deflagration to detonation are only alluded to. 

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