Idea for blastchamber finned heatsink.

[whiterussian1974]

I've had the idea for years and Historian was kind enough to post a link to a Patent and example in one of his posts.
http://www.freepatentsonline.com/6657862.pdf

This goes great with my current maturing brainchild.

It also mimics OPS's OSS stator screw method of reversing flow direction and adding linear lenght by twisting the airflow.

[Dr.K]

I cut fins in the blast chamber of the first can I machined on my lathe, they filled with gunk pretty quickly, and I don't think they did much. If they were larger maybe, but I've abandoned the idea.

[JFettig]

The cooling effect of the exhaust gasses by a suppressor via convection heat transfer is negligible.

[Grounded]

The cooling effect of the exhaust gasses by a suppressor via convection heat transfer is negligible.

One of our original designs sought to cool through a surging and purging effect. The heat sink will go to hell if internal in short time.

[whiterussian1974]

The cooling effect of the exhaust gasses by a suppressor via convection heat transfer is negligible.

One of our original designs sought to cool through a surging and purging effect. The heat sink will go to hell if internal in short time.

JFettif: DoD studies show a 6dB Improvement using heatsink.
Only 6-12 fins depending upon relative IDvsOD though, otherwise they will fill w junk like DrK said in a previous post.
And I wouldn't use it w a dirt round like .22lr or .300BLK w short barrel. Unburned Powder fouling can be a B.

PS: The OPS OSS uses this spiralled heatsink concept as stators to spin the gas mass. Many Threads have mentioned that added surface area is sometimes more effective than added volume.
Just some thoughts for your beautiful Sunday Morning.

[Bendersquint]

The cooling effect of the exhaust gasses by a suppressor via convection heat transfer is negligible.

One of our original designs sought to cool through a surging and purging effect. The heat sink will go to hell if internal in short time.

JFettif: DoD studies show a 6dB Improvement using heatsink.
Only 6-12 fins depending upon relative IDvsOD though, otherwise they will fill w junk like DrK said in a previous post.
And I wouldn't use it w a dirt round like .22lr or .300BLK w short barrel. Unburned Powder fouling can be a B.

PS: The OPS OSS uses this spiralled heatsink concept as stators to spin the gas mass. Many Threads have mentioned that added surface area is sometimes more effective than added volume.
Just some thoughts for your beautiful Sunday Morning.

Can you please post a link to the DoD study?

[whiterussian1974]

The cooling effect of the exhaust gasses by a suppressor via convection heat transfer is negligible.

One of our original designs sought to cool through a surging and purging effect. The heat sink will go to hell if internal in short time.

JFettif: DoD studies show a 6dB Improvement using heatsink.
Only 6-12 fins depending upon relative IDvsOD though, otherwise they will fill w junk like DrK said in a previous post.
And I wouldn't use it w a dirt round like .22lr or .300BLK w short barrel. Unburned Powder fouling can be a B.

Can you please post a link to the DoD study?

I've already sent you the link 3 seperate times in different threads.
viewtopic.php?f=10&t=123359

[Bendersquint]

Can you please post a link to the DoD study?

I've already sent you the link 3 seperate times in different threads.
viewtopic.php?f=10&t=123359

Thank you for the link, I didn't know THAT was the report you were saying it came from.

[delta9mda]

why do people have to make this harder than it is?

[joe0121]

why do people have to make this harder than it is?

Experimentation is fun though expensive in this game. I have often entertained the idea of getting an 07 SOT license just to try design idea's like this and post up results.

I read on a forum one time from a guy who was well known and respected in the internal ballistics world that Cartridge cases with longer necks and steep shoulder angles tend to have longer barrel life when compared to other cartridges using the same amount of powder and bore diameter. The longer neck carried more heat away from the burning gunpowder thus reducing throat erosion. Not saying I buy it all that much.

So maybe even a small amount of cooling early on can carry away enough energy to make a difference. Problem is the metals that are good heat conductors (other than steel) are generally soft and or expensive.

[whiterussian1974]

why do people have to make this harder than it is?

Experimentation is fun though expensive in this game. I have often entertained the idea of getting an 07 SOT license just to try design idea's like this and post up results.

I read on a forum one time from a guy who was well known and respected in the internal ballistics world that Cartridge cases with longer necks and steep shoulder angles tend to have longer barrel life when compared to other cartridges using the same amount of powder and bore diameter. The longer neck carried more heat away from the burning gunpowder thus reducing throat erosion. Not saying I buy it all that much.

So maybe even a small amount of cooling early on can carry away enough energy to make a difference. Problem is the metals that are good heat conductors (other than steel) are generally soft and or expensive.

For a slowfire bolt action that only fires 20rds per trip to range, the geometry is more important than conductive metal. Smear li grease in the blast chamber, use only a few spiralled fins to retain volume/avoid fouling and the concept has merit.

Or, go for a long linear length in reflexed tube like Ops OSS. both iterations have merit.

My current brainchild has stator disc around barrel, below blast chamber. This avoids majority of fouling, adds a bit of surface area, and causes swirling effect in reflex.

This design has YEARS of maturing before it is born. Just something that I'm kicking around.

Also, the metal could be 304 SS coated w bronze. I'm no metalurgist (nearly all I've learned has been from this forum and Wiki) but perhaps that surface coating would stand up, maybe not. Certainly any carbon fouling would insulate it regardless of material.

Even a poor conducting metal would cause cooling. The main effect is caused by the goemetry and stagnation period.

And Joe0121's comment makes since. Many people neglect that a barrel is a long, thin rocket nozzle.

[Dr.K]

Ive thought about the gas spinning spiraling stuff in the past, and what my research concluded was that the gas does not take that motion easily. It is possible, but you'll never get that motion to propagate past the fins, it just turns toward the exit as soon as it passes.

[whiterussian1974]

Ive thought about the gas spinning spiraling stuff in the past, and what my research concluded was that the gas does not take that motion easily. It is possible, but you'll never get that motion to propagate past the fins, it just turns toward the exit as soon as it passes.

Darn it!
At least sharing your experience has saved me spending 1000$ R+D, though.

[LavaRed]

I've posited for several years now that thermodynamics does a much better job of explaining what happens inside a suppressor than does fluid dynamics. Not to dismiss the importance of baffle geometry or the diversion of gases, but at its core, what a suppressor does is take one form of energy, i.e., sound, and transform it into another, i.e., heat. From a conservation of energy standpoint, it is undeniable that all of that energy from sound and the motion of the gases has to be transformed into another form of energy. It cannot simply disappear. And anyone who has touched a suppressor after firing knows how hot it gets. Therefore, it is impossible to surmise anything save that all that energy is being transformed into heat. From this, any number of cycles and expressions may be explored that result in forms which more efficiently accomplish the aforementioned goal.
Now, having said that, we can deduce that what baffle geometry and diverting the gases away from the bore-stream does is to delay their exit, such that they have a longer time to allow their sound and kinetic energy to be transformed into heat. As to how this transformation occurs, I daresay that baffle geometry plays more of an active role than the heat transfer properties of the materials involved in manufacture, and, therefore, will be responsible for the most significant effects; which, nonetheless, leaves some of the responsibility up to heat transfer.
In general, one could argue that the packing which used to be the mainstay in suppressor designs of the past was more of a heat-transfer device than anything. So, while a heat-sink alone won't a modern suppressor make, its contribution is certainly not to be taken lightly...

[whiterussian1974]

I've posited for several years now that thermodynamics does a much better job of explaining what happens inside a suppressor than does fluid dynamics. Not to dismiss the importance of baffle geometry or the diversion of gases, but at its core, what a suppressor does is take one form of energy, i.e., sound, and transform it into another, i.e., heat.

De accuerdo, mi hermano.

I want noone to think that I am contradicting or correcting LavaRed.
I WOULD like to AMPLIFY a point to avoid confusion.

P,V,T are bound together in Ideal Gas Laws. As V is increased, T*P concurrently drop. So, Temp is best transformed during the earliest possible stage where the gradient is highest.

Many people believe that sound is inherant to propellent discharge. However, accoustic energy is only .25-1.0% of energy just prior to bullet exit. It's the rapid CHANGE in pressure that causes the generation of the sound impulse in atmosphere. This rapid compression results in precursor wave, muzzle blast, etc.

Now, having said that, we can deduce that what baffle geometry and diverting the gases away from the bore-stream does is to delay their exit, such that they have a longer time to allow their sound and kinetic energy to be transformed...

This is called stagnation. This adds a time variable to the equation. (P*V*T)/t=k
So, any increase to t is inversely proportional to delta(k).

Too bad that this site doesn't link the studies in viewtopic.php?f=10&t=123359 to a FAQs section.
A thourough grounding in multi-disciplinary elements is needed to advance "Systems" theories so that increasing value in 1 field, doesn't harm another.

Muchas Gracias por su contribución a cualidad, Amigo.

[LavaRed]

I've posited for several years now that thermodynamics does a much better job of explaining what happens inside a suppressor than does fluid dynamics. Not to dismiss the importance of baffle geometry or the diversion of gases, but at its core, what a suppressor does is take one form of energy, i.e., sound, and transform it into another, i.e., heat.

De accuerdo, mi hermano.

I want noone to think that I am contradicting or correcting LavaRed.
I WOULD like to AMPLIFY a point to avoid confusion.

P,V,T are bound together in Ideal Gas Laws. As V is increased, T*P concurrently drop. So, Temp is best transformed during the earliest possible stage where the gradient is highest.

Many people believe that sound is inherant to propellent discharge. However, accoustic energy is only .25-1.0% of energy just prior to bullet exit. It's the rapid CHANGE in pressure that causes the generation of the sound impulse in atmosphere. This rapid compression results in precursor wave, muzzle blast, etc.

Now, having said that, we can deduce that what baffle geometry and diverting the gases away from the bore-stream does is to delay their exit, such that they have a longer time to allow their sound and kinetic energy to be transformed...

This is called stagnation. This adds a time variable to the equation. (P*V*T)/t=k
So, any increase to t is inversely proportional to delta(k).

Too bad that this site doesn't link the studies in viewtopic.php?f=10&t=123359 to a FAQs section.
A thourough grounding in multi-disciplinary elements is needed to advance "Systems" theories so that increasing value in 1 field, doesn't harm another.

Muchas Gracias por su contribución a cualidad, Amigo.

Es un gusto y un placer poder contribuir!

Also, I thank you as well for having expressed mathematically so succintly and elegantly what I was attempting to describe with words.

[gunny50]

P,V,T are bound together in Ideal Gas Laws. As V is increased, T*P concurrently drop. So, Temp is best transformed during the earliest possible stage where the gradient is highest.
Many people believe that sound is inherant to propellent discharge. However, accoustic energy is only .25-1.0% of energy just prior to bullet exit. It's the rapid CHANGE in pressure that causes the generation of the sound impulse in atmosphere. This rapid compression results in precursor wave, muzzle blast, etc.
Now, having said that, we can deduce that what baffle geometry and diverting the gases away from the bore-stream does is to delay their exit, such that they have a longer time to allow their sound and kinetic energy to be transformed...his is called stagnation.

This adds a time variable to the equation. (P*V*T)/t=k

So, any increase to t is inversely proportional to delta(k).
A thourough grounding in multi-disciplinary elements is needed to advance "Systems" theories so that increasing value in 1 field, doesn't harm another.

Gents,

So if we keep working this we might be able to make calculations related to Caliber - Barrel length / silencer length and weapons type. As so called gas-guns will behave different / silencers will behave different between Gas-guns and bold actions. Due to back pressure increase and ejection port blowout etc eye. Not to forget powder type, burnrate etc
Over barrel designs, when done right will lower back pressure, Some will argue but whats new in ST.
Question is what does the User want, small, quiet? what weapons is used.


All in all I do think that we should be able to make a formula that gives most of the people here a basic guideline in what is safe and what is not.


Gunny

[whiterussian1974]

A thourough grounding in multi-disciplinary elements is needed to advance "Systems" theories so that increasing value in 1 field, doesn't harm another.

So if we keep working this we might be able to make calculations related to Caliber - Barrel length / silencer length and weapons type. As so called gas-guns will behave different / silencers will behave different between Gas-guns and bold actions. Due to back pressure increase and ejection port blowout etc eye. Not to forget powder type, burnrate etc.

Question is what does the User want, small, quiet? what weapons is used.
Gunny

Gunny, Historian asked me a similar ? about my goal in design/performance goals.
He said (to paraphase) his is the quietest possible can, so he was focused on a .22lr w large volume like an example he saw on utube.

I have 3 envelopes w different requirements for each.
1-a LongRange/high vel/high energy rd; ie: .375CheyTac w 30" bbl.
2-a subsonic/high caliber/high retained energy; ie: 1750gr .729x2.5" (12ga from Hell)
3-a subsonic/mid-caliber rd; ie: 200gr .40SW Speer Gold Dot, 250gr 9x39mm

I'm certainly game to collaborate with any others that would would like to pool our imagination/ingenuity/academics/experience.

[Historian]

Whiterussian1974 is to be commended in his search coupled with sound grounding in
technical depth and enhanced with extensive experience and practicality.

A nuance in his design that might be missed is that the main use of the fins
is more than for heat dispersion, though this is useful.

Geometry. The more fractal surface that the gas envelope attains while
still in the can ... the fractal surface as notionally suggested by the Sierpinski cube* ...
the more dispersion, and in turn lower Db out put at the mouth.

The Frankford Arsenal Report contains test results of their try at a sintered
can with surprising low report. But it clogged up in short order.

One might muse over the increase in surface area that the gases sense within
various modern designs and their corresponding sound reduction. Included
in the parameters of analysis is primitive lengthening of a tube ( ad absurdum,
2' long tube with K-Baffles) to the other end a shorty with a fat can with multi-crenulations
[ for the dyspeptic: lots of sharp surfaces ] such as an earth movers diesel
oil filter.

Thus the fins are definitely more than for heat dispersion.

Way to go, W.R.

Edison's observation that genius is 10% inspiration and 90% perspiration.
[For him it was also helpful to steal ideas from Nikola Tesla. ]


* << http://www.google.com/search?q=Sierpins ... 61&bih=987 >>

[Capt. Link.]

Love the conversation but the idea of adsorbing the heat through convection dose not work well in real life.
I'm not a engineer but the surface area required to adsorb heat to lower pressure for the few usec it takes for the gas to escape is enormous.
The best of the WWII through 1960's trials was 24db and most of that was due to turbulence caused by the mesh and increased dwell time of the gases.
Today's cans are champions at retaining gas and releasing it in a regulated fashion allowing the gas to cool and expand lowering pressure.The heat transfer is next to nothing as mass is not available.
If you doubt me do the math and a simple scientific test.Take the can of your choice and place a temperature probe under a layer of insulation next to the can and take one shot.You can figure out the calories adsorbed through convection.Then figure out how much that will lower the SPL of that can, best have a calculator with lots of spaces behind the decimal point.You can do the same test if you have a mesh packed suppressor to prove the dwell time.
My point is convection is impractical unless the gasses are exposed to a huge volume of heat conductive material and you don't mind a huge suppressor.Dwell time will trump it every time or you may end up with Gunny's oil drum.

[Baffled]

But if we pursue the surface area angle to the extreme, we will be back to stuffing out cans with chore-boy scrubbies.

Somewhere in the middle is that optimum blend of volume, geometry, and surface area. I would venture to say that yes surface area absorbs thermal energy, but its primary role is gas flow disruption; slowing of the propellant gases.

[whiterussian1974]

But if we pursue the surface area angle to the extreme, we will be back to stuffing out cans with chore-boy scrubbies.

yes surface area absorbs thermal energy, but its primary role is gas flow disruption; slowing of the propellant gases.

Yes, increasing stagnation, which is my ultimate goal. Unless you've read my 1 way valve thread and others, it's difficult to get inside my head.

Here's a clue into my process:
My initial concept was 8 straight fins parallel to boreline. 4 Long in N,E,S,W and 4 shorts in NW,NE,SE,SW. Then smear each with li grease for use in 5-20 shots from bolt action.

Then I thought, "Curves are both stronger AND offer more surface, while consuming minimal added volume.

Then, my background w highbypass Turbofans came into play. I wanted to use Ventouri Effect to pull cool Atm air to blend w high PTv (Pressure, Temp, velocity) exhaust gas, while only exchanging V (Volume.)
This minimizes the sudden change of P and V during t at can exit. (Would PV/t be the correct equation? something tells me not.)

I wanted to pull air from the far endcap, drawn along the inner surface of the outer tube, mixed w the air in the 1st expansion chamber post blast chamber, then return the mixed air forward through the inner tube. (either within or along boreline.) Something like a thrust reverser w exhaust blown down centerline, rather than external circumference.

However, I lacked the topological geometric background to work through this analysis.

As for Steel wool scrubbers, the below would be preferrable. The thing it lacks is compressability. (This is another member's design and workmanship.)


I have another idea of a series of 7 conch shells with wire cilia of varied thickness, lengths and shapes. This involves a take on Mass Damped Springs.

The air pockets are the Springs. The wires just add turbulence, harmonic and other properties.
(Think macro expressions of Brownian Motion vibration.) The concepts involved are too complex to add to this thread. Perhaps I will start another devoted to that concept. It should have application for the low pressure subsonic envelope which I mentioned.

[whiterussian1974]

Love the conversation but the idea of adsorbing the heat through convection dose not work well in real life.
I'm not a engineer but the surface area required to adsorb heat to lower pressure for the few usec it takes for the gas to escape is enormous.

Sure you're an engineer, just perhaps not by formal training. Don't sell yourself short.

Evaporation of volitile substance was my goal. Added surface enabled quicker transfer in the usec timeframe which we are investigating. (u=micro)
But stagnation is the main goal in my line of thought. Evaporation is a "quick and dirty" fix.

Please read my previous post.

BTW, the math shows that the MAX # of dB that cooling can practically offer is 6dB.
-Vacuuming out the can and barrel offers nearly no help. (1.47psi std atm)
-Injection of compressed gas to create endothermic reaction gives little benefit due to adding PV to system.
-Evaporation/Sublimation offer the best result. A solid has max caloric adsorbtion per volume. A volitile uses quickest conversion rate.

Think of the fins as a surfactant, rather than a heat transfer medium.

Comments welcome.

[57fairlane]

Love the conversation but the idea of adsorbing the heat through convection dose not work well in real life.
I'm not a engineer but the surface area required to adsorb heat to lower pressure for the few usec it takes for the gas to escape is enormous.
The best of the WWII through 1960's trials was 24db and most of that was due to turbulence caused by the mesh and increased dwell time of the gases.
Today's cans are champions at retaining gas and releasing it in a regulated fashion allowing the gas to cool and expand lowering pressure.The heat transfer is next to nothing as mass is not available.
If you doubt me do the math and a simple scientific test.Take the can of your choice and place a temperature probe under a layer of insulation next to the can and take one shot.You can figure out the calories adsorbed through convection.Then figure out how much that will lower the SPL of that can, best have a calculator with lots of spaces behind the decimal point.You can do the same test if you have a mesh packed suppressor to prove the dwell time.
My point is convection is impractical unless the gasses are exposed to a huge volume of heat conductive material and you don't mind a huge suppressor.Dwell time will trump it every time or you may end up with Gunny's oil drum.

I go along with this . . .

I've made and metered a box-type can similar to the osprey that all I did was fill it with steel wool . . . literally only a bore hole.

In 9mm it was in the 142-143db range. Switched the "core" out for some packed in slanted sidewalls and it dropped 10db.

The only area I could see heat transfer working is in a reflex application and then you have to worry about clogging it up since you are allowing the gas to cool in an area that makes buildup almost impossible to get out.

[Historian]

The discussion of slim heat-absorption is correct. The real
import of the folding of the copper surfaces is to increase
the 'fractal' like surface area contact that the percussive wave front meets.

An analog that might help is the amount of surface area of the
alveolar sacs of the human lung. The ever increasing folds give
a surface area that the Science Channel once stated was
nearly that of a tennis court. And that is why smoking is so deadly
as it pops the bubbles creating in the limit eventually one small surface area -
death by emphysema.

Think a room filled with soap bubbles or ping-pong balls. Same volume but if we summed
the surface areas of all the tiny bubbles you would be surprised the orders of magnitude
increase in total surface area. This has a correlation with transition time and corresponding
reduction of the pressure at the barrels front.

Otherwise a straight tube with a snorkel like an old Parker Hale would
give the same Db reduction as Sparrow, etc. or 10" K-baffled can.

Maximize internal surface area for a given
volume.

Heat absorption is a nice third order benefit but not the real impact that using 'fractal' foldings might
give one.