i also have a book that talks ALOTt about detonating flash,with and without blasting caps...IM HUMBLY ASKING THE SAME THING?
Posted 16 March 2021 - 08:19 AM
Posted 14 June 2021 - 06:27 PM
Different decomposition pathways. There are several common examples that will burn if lit with a flame. Some compositions however are capable of a DDT, which despite a common misconception, is not shorthand for detonation. It stands for deflagration detonation transition. The materials that are capable of a sustained stable deflagration need to be initiated with a shockwave. This starts off a chain reaction of a different pathway that usually will release more energy, and be self-sustaining. This is just postulation, but I suspect some of the reactions needed to induce a detonation are pressure dependent.
I believe your last sentence is right on the money. For example, detonable smokeless powder is "burned" in small arms ammunition, among others, WITHOUT detonation, which CAN occur, and does cause devastating results. Typical burn rate vs pressure curves for smokeless show a peak pressure following which pressure begins to drop. This illustrates it's use as a propellant for projectiles (bullets). Such curves are based on increasing volume behind the projectile and increasing velocity of it, thus halting burn rate increase,in order to illustrate the PEAK pressure reached as it applies to the particular application.
In the event the burning commences in a rigidly confined volume, the burning rate will increase exponentially very quickly, possibly until "something gives". Thus the use of smokeless powder as propellant depends on the burning rate never reaching that "point of no return" pressure. If it does, ruptured barrels, damaged gun mechanisms, and possible injury result.
It may be said then that smokeless powder MAY detonate under certain conditions whereas black powder will not.
Edited by tenneyguy, 14 June 2021 - 06:29 PM.
Posted 14 June 2021 - 06:36 PM
From a quick look round on the web, there appears to be a lot of disagreement and confusion about what constitutes detonation. The guy who wrote the Wikipedia entries seems to be particularly confused. For me, it's only detonation if it propagates by the shock wave first, with the chemical reaction following. Any reaction that propagates only chemically is deflagration. Flash powder self-confines, but it doesn't detonate. It propagates chemically, by fire. It does go pretty fast, though, something in the order of 2000 ft/sec. That's less than any true high explosive, but it's comparable. I think TNT goes around 6000 ft/sec.
TNT detonation rate = 23,000 feet per second, very fast. 10 times the speed of a common rifle bullet.
Posted 12 September 2021 - 12:39 PM
I'm far from an expert but it's been my understanding that a detonation happens when a shockwave travels thru the material at sufficient speed/energy that molecular bonds are broken releasing a tremendous amount of energy almost simultaneously. And no heat, flame, or oxygen is required as with burning, and many times there are no visible flames. This is why Tannerite detonates because the bullet is traveling fast enough to impart enough energy to start the bond breaking. When it burns there is heat/flame and oxygen and the material/fuel heats and destructively oxidizes like a normal fire which lacks the necessary energy to break the molecular bonds that releases the explosive energy.
In something like flash powder the particles are very small with lots of surface area so burns fast like a small piece of tissue paper vs a log. And it also has its own oxygen supply and isn't slowed down by having to use what's in the air which is consumed and takes time for more to move in and replace the supply. Without the limits a very fast burn results, releasing lots of energy in a small instant. Metals also burn hot and higher temperatures result in higher pressure which increases how fast it burns which is also why containment can be important to allow greater pressure. And in some cases the chemicals involved can burn fast and hot enough to release enough energy to start breaking those energetic molecular bonds which adds more energy and it turns into a detonation thru the rest of the material, which is the deflagration detonation transition (DDT - where deflagration means burns really really fast).
At least this is my layman understanding of it all...
Posted 14 September 2021 - 10:27 AM
That is exactly the way I take it also.
I can say without doubt, you can take almost all of the above and detonate it with the right package and cap.. Double base "like Bullseye" is extremely impressive with a good cap. Kidd you not!
0 user(s) are reading this topic
0 members, 0 guests, 0 anonymous users