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View Full Version : Suppressors and Computational Fluid Dynamics... HELP!



Reagans Rascals
03-25-12, 03:36
I've just finished modeling a Form 1 suppressor in SolidWorks 2012 and am ready to use Flow Analysis to work out the kinks and gauge how well I can expect it to perform, basically get the most performance I can get out of it before I even begin to machine it.

In the model the Suppressor is mated to a 10.3" barrel, with all dimensions true (chamber, bore, rifling, gas port, gas tube)

I believe using the max pressure of 55,000 psi can work but I'd like to be a little more precise, so I need the starting temperature and velocity of the expanding gasses within the chamber during firing.

From what I've found online its going to be difficult to be completely precise because, as the powder burns the pressure increases to max at about .5 milliseconds after firing and then begins to fall off until exiting the barrel...

at this point in time my settings are 55,000 PSI of pressure , and around 3300 degrees Fahrenheit for temperature at the chamber.

http://www.frfrogspad.com/intballi.htm


"According to The World s Great Rifles, by Roger Ford (1998, Brown Packaging Books, Ltd., London) it is estimated that just one-fifth of one percent of the energy produced when a cartridge is fired goes to rotating the bullet, while friction in the barrel accounts for another three percent, 20 to 30 percent goes to propelling the bullet, 30 percent goes in heat to the barrel, and 40 percent goes in muzzle blast"

Basically trying to mitigate the last 40%

so if any of you have done this type of suppressor or barrel design and have any advice I'm all ears...

MistWolf
03-25-12, 04:23
Until the bullet uncorks the muzzle, the velocity of the gas is the same speed as the bullet. If I recall, the velocity of the gases at the muzzle when the bullet finally uncorks is about 4750 fps.

There is a thread with a link to an article you might find useful
Thread- http://m4carbine.net/showthread.php?p=1247534#post1247534
Article- http://sadefensejournal.com/wp/?p=1093

308sako
03-25-12, 12:00
Beyond the shear velocity of the gases is the direction, or redirection in which they flow. I am a total amatuer and certainly no engineer, but to anyone who has used a suppressor it is instantly obvious that heat energy or the creation of it is a major aspect of sound suppression.

Thanks for bringing this intriguing thread to light.

ginarik
03-29-12, 16:48
Have you tried asking the same question in the silencertalk forums? I know there's a couple people in the forum that use SolidWorks/Inventor when they created their suppressor.

Hopefully this helps.

semtex41
04-02-12, 00:21
Reagans Rascals, I have been studying solidworks for this same purpose, mostly for my own education. I found some great info and help here:http://www.varmintal.com/aengr.htm

Are you using SW Simulation for the computations?