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Author: Subject: Detonation Modeling
MineMan
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[*] posted on 11-3-2019 at 12:35
Detonation Modeling


I would like to model detonations and gurney velocities with different percentage and size Metal powders...

Does anyone know of any open source code...?? I am guessing it would be thermochemistry similar to JAGUAR and CHEETAH

https://apps.dtic.mil/dtic/tr/fulltext/u2/a528198.pdf

Here’s how they do it in the military, but I don’t have CHEETAH. Any help would be fantastic, I am willing to work with an university.

Are thier platforms built for this... for example for shape charges you can enter equations and use Autodyn... I think

Thank you all.
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Dornier 335A
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[*] posted on 14-3-2019 at 15:06


Calculating detonation velocity of explosive mixtures with aluminium is not too difficult. Assuming inert aluminium powder gives good agreement with experimental results.
This might not work if the particle size is small enough to react before the CJ point though...

Predicting gurney velocities is on another level since the metal will have time to react, but you need to know when it reacts during the expansion. Drawing a straight line from the unreactive
CJ-state to the reactive isentrope seems to work fairly well according to "Eigenvalue Detonation of Combined Effects Aluminized Explosives".
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MineMan
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[*] posted on 14-3-2019 at 22:39


Quote: Originally posted by Dornier 335A  
Calculating detonation velocity of explosive mixtures with aluminium is not too difficult. Assuming inert aluminium powder gives good agreement with experimental results.
This might not work if the particle size is small enough to react before the CJ point though...

Predicting gurney velocities is on another level since the metal will have time to react, but you need to know when it reacts during the expansion. Drawing a straight line from the unreactive
CJ-state to the reactive isentrope seems to work fairly well according to "Eigenvalue Detonation of Combined Effects Aluminized Explosives".


Dornier. Thank you for the reply, always look forward to your answers!

I should have been more specific. I am not interested in modeling VOD, rather how long it takes for different metal powders to combust at different sizes. For example, they found that 15micron aluminum reacts by 7 volume expansions in a 1” cylinder with RDX and a binder.

I want to do the same but for larger diameters under more confinement (Mining). For example how many milliseconds and volume expansions before the aluminum combust 90 percent in a 100mm dia hole, 200mm dia hole and etc. this becomes trickery because aluminum’s melting tempature changes with pressure. And we know with a explosive dia of 200mm the aluminum will be under that pressure longer then the 25mm cylinder.

How would I go about this? The next step would be for me to model different particle sizes with different explosive diameters.
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