Powdery Explosive Charges

The discussion given by ZeTdovich Kompaneets (Ref 6), based on investigations by Apin and Bobolev (sometimes spelled Bobylev) (Ref 1-4), may be summarized as follows  

Apin Bobolev (Refs 1-4) developed the concepts of the deton of powders in detail by the device of expl burning or granular combustion. Gas jets penetrate the pores between separate particles of the expl substance and ignite them. 

Each particle as it burns is surrounded by expln products where the combustion rate depends on the pressure of the surrounding gas. 

The deton vel of powders is a smooth function of the granular density or of the pressing density and for a large chge diam it does not depend on the dimensions of the expl particles. It is precisely from the dependence of D on p for powders that one can establish the equation of state of the products. Thus, it would not be correct to state that in expl combstn the deton vel is equal to the vel of the gas jets which penetrate the powd. In actuality, upon detonation by the mechanism of explosive combustion, the deton vel is detd by the equation of state. That is, by the pressure of the expln products according to hydro-dynamic theory, while the vel of the gas streams in this case is automatically established equal to the deton vel 

For powders, such as Lead Azide (LA), the limiting diam is small and it is possible to have conditions such that each particle of the powder taken separately is able to detonate. In this case the deton wave being propagated represents an aggregate of deton waves being propagated in separate crysts and which are transmitted from one cryst to the next 

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