300 blk design help

[Angus46]

http://youtu.be/lXzXek8qsfc

Here is a CFD video of my new design for a 300blk suppressor. I have not built one before and am a new member of this forum so trying to learn as much as I can before I submit my form and start building.

I have a few designs I'm working on for a 300 BLK with a 10.5 inch barrel. What the video is of is a reflexed design that has a reflexed area of about 4 inches, a muzzle brake/blast chamber area to take most of the high pressure gasses then a combination of baffles, and ports that will hopefully direct most of the remaining gases away from the bore axis and dissipate them in the design.

The video is only of the traces at the absolute center of the bore since from my analysis these gases seem to be the hardest to divert. Please let me know your thoughts and if you think I'm on the right track with my design.

BT

[L1A1Rocker]

Do you plan on mostly sub-sonic, or mostly supers?

[gunny50]

http://youtu.be/lXzXek8qsfc

Here is a CFD video of my new design for a 300blk suppressor. I have not built one before and am a new member of this forum so trying to learn as much as I can before I submit my form and start building.

I have a few designs I'm working on for a 300 BLK with a 10.5 inch barrel. What the video is of is a reflexed design that has a reflexed area of about 4 inches, a muzzle brake/blast chamber area to take most of the high pressure gasses then a combination of baffles, and ports that will hopefully direct most of the remaining gases away from the bore axis and dissipate them in the design.

The video is only of the traces at the absolute center of the bore since from my analysis these gases seem to be the hardest to divert. Please let me know your thoughts and if you think I'm on the right track with my design.

BT

What CFD program did you use?

Keep in mind that you would need expanding gasses, and a moving projectile to see this work better that it did now.

Place a projectile in the line of flight on several locations and run it again, you will see that gas wil react different then.

Gunny

[Angus46]

Thanks for the feedback so far.

I plan on a mix of super and subsonic. The video is of pressures in the supersonic range.

The program is an auto desk product called CFD. I know the settingings are pretty far from reality. Though the pressures I used should be close. I was able to get the volume of the design and then calculate the resultant pressures pretty close. However, the solution is a steady state solution which is very, very far from the reality of what happens. However, I was hopeful that this design/software would allow me to see how the design and the resultant changes in velocity of the gas can be impacted.

I would love to place a bullet into the design, and use a dynamic simulation, however I can't figure out how to do that. Is it possible with this program?

I have looked at many different solutions at varying pressure rangges though.

[Angus46]

Just thought of what I think you may have been saying. Actually put a projectile into the design and run the solution to see how it would effect the gases at that point. I can do that, that is a great idea! I can then run several solutions with the bullet in several different chambers basically as an obstruction to the gas flow.

[Fulmen]

I don't there is much to gain from a steady-state run with a stationary bullet. I've tried running dynamic sims using Dassaults CFD, but it was way to complex for me. I've switched to Autodesk since then, but haven't tried the CFD so I don't know it's capabilities.

But a steady state sim is not useless by any means, if you get good turbulent flow in steady state it should work well in real life as well. Just compare it to a SS of a simple washer-design and you'll see the difference. These work OK as long as the volume is large, allowing gas to expand into the chambers due to pressure difference. But with a small volume the chambers tend to "fill up", after that the gas flows through the bore like it was a straight pipe.

[Angus46]

Here is a video with the bullet located just at the end of the muzzle brake. Since it's still a steady state solution with a pressure differential the trace/velocity vectors are going all the way to the bore and I don't see them beating the bullet out of the barrel. I realize there will be some expansion around the bullet since the uncontained expanding gases will expand at a rate faster than the bullet can travel. However, because they will have to move a further distance even though they are going faster. I have read between 4k and 8k FPS the bullet will still beat most of them out of the bore.

https://youtu.be/CoIeVD-Xumk


I will do a few more and see what I can determine/analyze as I place the bullet in different spots in the design. The down side it just takes a long time. My computer has to run for several hours solving the solutions. In addition, I'll see if I can learn more how to use the CFD program and solve the solution in a dynamic state and determine if I can set it up to more closely resemble actually what happens when the gun is fired.

Thanks for all the help so far

BT

[gunny50]

Here is a video with the bullet located just at the end of the muzzle brake. Since it's still a steady state solution with a pressure differential the trace/velocity vectors are going all the way to the bore and I don't see them beating the bullet out of the barrel. I realize there will be some expansion around the bullet since the uncontained expanding gases will expand at a rate faster than the bullet can travel. However, because they will have to move a further distance even though they are going faster. I have read between 4k and 8k FPS the bullet will still beat most of them out of the bore.

https://youtu.be/CoIeVD-Xumk


I will do a few more and see what I can determine/analyze as I place the bullet in different spots in the design. The down side it just takes a long time. My computer has to run for several hours solving the solutions. In addition, I'll see if I can learn more how to use the CFD program and solve the solution in a dynamic state and determine if I can set it up to more closely resemble actually what happens when the gun is fired.

Thanks for all the help so far

BT

Glad to be of any help.

I know that there is a CFD program Fluent and some Russian software that can even have a moving projectile but is is way over my R&D Budget.

link to: Projectile Moving Inside a Barrel - http://cfd-offline.com/projectile-movin ... e-a-barrel

Video of CFD by Ansys. https://www.youtube.com/watch?v=VuGSVLNtzFU#t=74

https://encrypted-tbn1.gstatic.com/imag ... bcn2aoXNSQ

Below also link to a nice article.
http://scialert.net/fulltext/?doi=itj.2 ... 180&org=11

Gunny

[Angus46]

https://youtu.be/ZELJ7iLvnvA

Here is a side view of about 80 thousands of a second for the gases coming out of the barrel. This is a transient state solution, still working on the iterations, but this is getting me close to what I think will happen. Unfortunately, It takes about an hour to complete each one, so it's taken quite a while to get here.

If you all would give me some feedback on your thoughts if this solution looks like it's working correctly for how the gases are responding I'd appreciate it. I know that the bullet path is a little off, while I did figure out how to place it into the simulation, not sure why it's not reacting correctly with the gases. So I'm working on that still. However, at this point I'm really looking more at how the K baffle is reacting to the gas and pushing the jet downward. That is why I have the cone with the outer ring around it to capture some of those gases and then redirect them.

Based upon what I see here the changes I'm considering is shortening up the outer area to be similar in length to the cones, then adding in an additional cone assembly in front of the first k baffle. It seems that these chambers don't need to be as large as they are in this simulation, and then hopefully it will modify the way the gases are reacting on the first baffle set to then get a similar result as is seen in the second.

BT

[gunny50]

https://youtu.be/ZELJ7iLvnvA

Here is a side view of about 80 thousands of a second for the gases coming out of the barrel. This is a transient state solution, still working on the iterations, but this is getting me close to what I think will happen. Unfortunately, It takes about an hour to complete each one, so it's taken quite a while to get here.

If you all would give me some feedback on your thoughts if this solution looks like it's working correctly for how the gases are responding I'd appreciate it. I know that the bullet path is a little off, while I did figure out how to place it into the simulation, not sure why it's not reacting correctly with the gases. So I'm working on that still. However, at this point I'm really looking more at how the K baffle is reacting to the gas and pushing the jet downward. That is why I have the cone with the outer ring around it to capture some of those gases and then redirect them.

Based upon what I see here the changes I'm considering is shortening up the outer area to be similar in length to the cones, then adding in an additional cone assembly in front of the first k baffle. It seems that these chambers don't need to be as large as they are in this simulation, and then hopefully it will modify the way the gases are reacting on the first baffle set to then get a similar result as is seen in the second.

BT

I would at least make the distance between front of the muzzle-brake and blast baffle bigger 3/4 to 1"

Gunny

[Angus46]

Thanks So much for the feedback.

By shortening up the baffles I gained back exactly 3/4 of an inch. Which is the lenght of the cone baffle assembly. Do you think it would be better to put it in there or just open space?