Propagation of detonation

Frobese, D. H. and Forster, H. 1992. Propagation of Detonations Through Pipework Junctions. Proe. 7th Inti. Symposium on Loss Prevention and Safety Promotion in the Process Industries, Taormina, Italy, May 4-8, 1992. 

Examining the conditions for the formation and propagation of detonation waves is relevant to special applications of detonations to propulsion as well as safety. 

In the early studies [22,24,39] on propagation of detonation in very rough tubes, the steady propagation velocities as low as 50% of the normal CJ value have been observed. Such low-velocity detonations have been referred to as quasi-detonations [4]. 

Explosives must be transported through the factory between the buildings and can assist the propagation of detonation from one building to another. 

Summarizing the experience with BG, Taylor (Ref 1, p 163) stated that a non-aerated expl tended to fail in propagation of deton when initiated by weak detonators well-aerated "creamy mixes with extremely fine bubbles tended to detonate at, or pick up to high vel, and gelatins of intermediate aeration tended to exhibit the low-vel regime. 

Air Gap Sensitiveness to Detonation (and Explosion). It is a term which has been applied to the maximum distance of the consistent propagation of detonation by influence from a primer charge across an air gap to a receptor charge. The air-gap test for sensitiveness has been used for many years as a control test for dynamites and other commercial expls. 

The propagation of detonation wave in the explosive was observed by means of flash-radiography. It was possible also to compare, in some cases, the pressure exerted on the confining Perspex walls as a function of the priming of the chge by photographing the shock wave in a Perspex block (Ref 7)... 

A)Ya.B. Zel dovich, "Teoriya Goreniya i Detonatsii v Gazakh (Theory of Combustion and Detonation in Gases), TipogrAkadNauk, Moscow (1944) B) G.N. Abramovich L.A. Vulis, DoklAkadN 55, 111 (1947) (On the mechanics of propagation of detonation and combustion) C) Ya.B. Zel dovich K.S. Zarembo, ZhFizKhimii 22, 427(1948) (Investigation of a structure of a Bunsen flame)... 

Studies of Propagation of Detonation Between Small Confined Explosive Charges", NOLM 10577(1950) 4) W.E. Dimmock, "A Small... 

Some relations characteristic of the unidimensional steady propagation of deton and normal burning are given with special ref to the physical proof of the Chapman rule of the minimum vel in the deton wave... 

C.G. Dunkle, in his Syllabus (Addnl Ref E) describes Propagation of Detonation in Air Blasts (pp 313-15), Mach Waves (pp 315-17) and Blast Effects in Water and Earth (pp 317-18). In his private communication (Ref G), he suggests including the following ... 

Extent of Propagation of Detonation (and Explosion). See Ability to Propagate Detonation in Vol 1, p VII... 

Horvat E.J. Murray, "Propagation of Detonation in Long Narrow Cylinders of Explosives at Ambient Temperature and at -65°F , PicArsn SFAL TechRept 2389 (Jan 1957 ) 5) J.E. Bubser, "Investiga-... 

W.A. Gey M.A. Cook (Ref 4). Their experiments in propagation of deton thru steel glass plates showed that thin plates of inert material invariably interrupt the deton wave completely, requiring the deton to re-form if it continues to propagate beyond the interrupter. A remarkable "new phenomenon, called flash-across, was observed when a bluish-white hot spot on one frame and another hot spot that developed between adjacent frames on the opposite SPHF plate had both flashed across the chge and met at the collision interface... 

SS 16, 9-10, 25-7 35-7(1921) (Detonations-iibertragung brisanter Sprengstoffe) 4) Anon, Army Ordn 3, 180-82(1922) (Sympathetic deton tests of HE shells) 5) C.G. Storm, ArmyOrdn 3, 256-60(1923) (Sympathetic detons) 6) G. St. Perrott D.B. Gawthrop, JFrankllnst 203, 103 8t 387-406 (1927) (Propagation of deton betw two cart-... 

CA 27, 5979(1933) (A detonating cap was placed in a lead cylinder and axially under this, and at definite distance, a 2nd cap was fixed. When the 1st cap exploded the deton wave traveled thru the air to the 2nd cap whose expln made an impression in the Pb cylinder. By changing the distance betw the caps, a value for the sensitiveness to propagation of deton was obtd) 9) D.B. Gawthrop, JFrankllnst 214, 647(1932) (Deton by influence) 10) R.L. Clark, IEC 25, 663-67(1933) (Deton by influence)... 

Propagation of deton was indicated by the initiation of the expl pellet placed below the non-expl substance. Tests reported as non-propagating indicate that the lower expl pellet was not completely reacted as shown by a powder residue after deton]... 

M.A. Cook et al, JApplPhys 30, 1579-84(1959) (Instrumented Card-Gap or SPHF-Plate Test) 23) Baum, Stanyukovich Shekhter (1959). 754-71 (Deton by influence thru air) 771-78 (Deton by influence thru condensed media) 778-81 (Safe distances for propagation of deton betw some expl chges used in Rus coal mines) 23a) Liquid Propellants Info Agency, Applied Physics Lab, Johns Hopkins Univ, "Liquid Propellants Test Methods, Test No 1, Card-Gap Test for Shock Sensitivity of Liquid Monopropellants (March i960)... 

Refs 1) W.A. Taylor A. Weale, PrRoySoc 138A, 92-116(1932) (Mechanism of initiation and propagation of detonation in solid explosives) la) E. Burlot, CR 197, 1223-25 (1933) CA 28, 2538 (]934) (Ignition of explosives in vacuo) lb) A.F. Belyaev, DoklAkadN 18, 267 (1938) (Origination of detonation in explosives under the action of a thermal impulse) 2) A.F. Belyaev et al, KhimReferatZh 1940, No 10-11 CA 37, 1270(1943) (Investigation of initiation of small quantities of expls by heat with an impulse lasting for 10 3-10 secs, showed that the more volatile the expl, the harder... 

SocJ 30, 151-58(1960) (Recent advances in condensed media detonation) 37b) Dunkle s Syllabus (1960-1961), pp 4a 4b (Initiation of shock waves) lOa-lOg (Initiation of deflgrn and deton) p 12a (Frank-Kamenet-skii formulation) p 13b (Initiation by electric discharge) p 13f (Thermal Decomposition and Initiation of Explosives, as discussed by B. Reitzner) pp 17a to 17e (Mechanism of initiation and propagation of detonation in solid explosives) pp 17e 17f [Marlow Skidmore (Ref 31) concluded from their investigations that the problem of shock initiation is somehow related to the temperature distribution in the shock pulse and its effect on the chemical reaction rate. They used an Arrhenius type relationship for the rate increase in the frac-... 

CA 50, 10409(1956) (Investigations of relation between propagation of deton of mining expls and the diameter of the cartridge)... 

E) S.J. Lowell, "Propagation of Detonation in Long and Narrow Columns of Explosives, PATR 2138(1955) (Conf) (Not used as a source of info)... 

Expansion of the expln products in the forward direction in a cylinder is accompanied by compression of new layers previously undisturbed in the xplosion and this causes some loss of energy, which is considered, however, not as a loss, but as a normal part of the detonation process. Expansion of the expln products in the rearward direction proceeds more slowly as the path traversed by the wave in the explosive becomes greater, i.e., the thicker the layer of compressed expln products behind the wave becomes, the more slowly the expansion proceeds. Thus for a large chge diam, the more powerful is the initiator causing the initial wave, the smaller are the losses at the origin of propagation of detonation. 

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