Spherical CC ?

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Ghrey
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Spherical CC ?

Post by Ghrey » Tue May 13, 2008 9:23 am

Has any one tried this configuration ( see attached .pdf ) ??

I was thinking of a lockwood Pulled through it's self into a coaxial arrangement and added a spherical CC and Hemispherical intake plate.

No dimensions given here my motes ( as usual ) are covered with Matha-gibberations. but I think it called for a .125 gap in the intake, over the central exhaust. All dimensions assuming a 2 inch dia. CC. The tail was calked out as 9x(CC dia) + 3 inches or some such.

Drawing not to scale.

My problems with it are;

1: The CC will likely concentrate detonation dead center. rather than near the tail. Good / Bad ??

2: Heat buildup on the upper exhaust may be excessive. BAD.

3: Cost benefit ratio may be bad.

4: the intake may show many bad and nonfunctional problems due to the close clearances and odd geometry.

Your thoughts?

Brant
Attachments
SphericalCCConcept.cwk (PT).pdf
(5.65 KiB) Downloaded 161 times
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PyroJoe
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Post by PyroJoe » Wed May 14, 2008 3:06 pm

I think you will find the combustion zone doesn't center in the combustion chamber (even if it is a sphere). The best way to find out how she runs is to put it in steel. Keep in mind she will probably be fussy with that intake.

Several stainless steel salad bowls later you may have a real thumper.

GRIM
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spheres

Post by GRIM » Wed May 14, 2008 6:58 pm

I came accross some stainless steel spherical pulsejet combustión chambers today, there is a box of them, some new, some old, all around about 4”diameter,
Everyone else here thinks they are floats for steam traps , they have no idea that they are really pulsejet parts , oh well their loss my gain :twisted:
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stainless spheres 2.jpg
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Ghrey
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Awesome!!

Post by Ghrey » Thu May 15, 2008 11:28 pm

Thats absolutely awesome!

It's amazing what you can see when you have a mind toward combustion...

The new stainless steel door knobs we just put in have a spherical shell ( or close enough ), sadly they would be missed.


...Chambers.


I cant wait to see what you do with them!


Brant
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Vermin
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Post by Vermin » Fri May 16, 2008 1:34 am

It all sounds good guys but remember that a sphere will produce refractive waves directly back into the CC..this may not be a bad thing but we are looking to produce thrust....NO?. If i remember argus gave a valiant design effort (from Brunos ramble) with a 1/2 spherical CC that looks like it has a lot of potential ...Grim are you going to try something close to that with your aqusition?
V
Vern
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Ghrey
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Wow

Post by Ghrey » Fri May 16, 2008 8:22 am

Just looked ( yet again ) at "Bruno's ramble". Middle of page 17 there it is.

But not with a coaxial breathing setup, and designed to be encased in more metal, and fed compressed air.

Sure is similar tho... The text indicates some degree of success before "The Authorities" re directed the argus work.

The fueling at the top is worth considering as a viable alternative to many small jets aimed into the intake flow ( and in fact helping it ), I am concerned a little about aiming an injector straight down the tail pipe, seems like a flame thrower design like that... It would establish some flow through the unit tho.

So it is just not testable on paper is it. Some metal will have to get warm...

Still the acoustics do bother me, not entirely sure why...

Brant
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Post by Jutte » Fri May 16, 2008 10:42 am

Didn't the final Argus attempt use a trapped vortice arrangement to reduce the intake exhaust? I see that NASA and various others are now investigating trapped vortices to increase burn rate in turbines etc.
( 'Trapped Vortex Combustion')
Does anyone know if anything similiar has been tried on pulse jets?
( apart from the Argus people ).

GRIM
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Post by GRIM » Fri May 16, 2008 3:44 pm

Vern , i think I will likely make a small linear from one of these balls , just to see how it runs , 1/2 of one of the balls will likely become the dome on a russian look alike ,

the coaxial inlet concept is fascinating , but my experiments have been very disappointing, there are so many unknowns to deal with

Edit , McMaster carr sell stainless floats up to about 8" diameter , cheap they are not, but some interesting shapes.
Last edited by GRIM on Fri May 16, 2008 4:07 pm, edited 1 time in total.

Jim Berquist
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Sphere

Post by Jim Berquist » Fri May 16, 2008 3:58 pm

I seen them here in the hardware store. They sell them for float valves used on stock tanks!
WHAT TO FRAP, IT WORKED![url=callto://james.a.berquist]Image[/url]

Ghrey
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Deciedely complicated...

Post by Ghrey » Sat May 17, 2008 11:08 pm

No question about it, tuning that intake is the worst of it, Guess I will just have to clean up the old work shop and give it a try ( or 2 or 20 or 100 ... ) I have been thinking that a second internal deflector plate ( ok ring in this case ) may almost entirely stop reverse flow, thus upping the flow and lowering the probability of slagging the tail pipe, which is yet another unknown in this design. On that "trapped vortice" question, Yah I think so. Also I am working on a toroidal CC that, in one incarnation, does a trick like that, and spin amplification, and some other tricks, Mind Numbingly Complicated Design ( MNCD ) No .pdf yet sorry, and yes It REQUIRES a TIG welder to even attempt a build. I do not own a TIG yet.


Brant

Edited for clarity.
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Jutte
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Re: Spherical CC ?

Post by Jutte » Mon May 19, 2008 4:22 am

Hi Ghrey - have you tried an exhaust manufacture shop? Over here they have toridal donut thingys
that they use in exhaust pipes etc.I was thinking about a toridal CC a few months back incorparating the vortex trap...but the exhaust toridal donuts are too expensive for me.Some were even cut in half so you could build internal walls etc.
That's why I like oil filter bodies as they're free...or are my scottish genes showing through? :?

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Re: Spherical CC ?

Post by Bruno Ogorelec » Mon May 19, 2008 6:38 am

Jutte wrote:Hi Ghrey - have you tried an exhaust manufacture shop? Over here they have toridal donut thingys
that they use in exhaust pipes etc.I was thinking about a toridal CC a few months back incorparating the vortex trap...but the exhaust toridal donuts are too expensive for me.Some were even cut in half so you could build internal walls etc.
That's why I like oil filter bodies as they're free...or are my scottish genes showing through? :?
If you have 90-degree tube bends, you can split them in half lengthwise and use the halves as quarter-circles. Weld four of them together for a full circle.

Ghrey
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Re: Spherical CC ?

Post by Ghrey » Mon May 19, 2008 8:44 am

It is not strictly speaking, the torus that is the problem, It is the plumbing. The small scale of some of the parts is also an issue.

Lots of little TIG welds in Thin Stainless steal.

I edited for clarity and failed apparently. My bad.


Must sleep now, more L8R

Brant
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Re: Spherical CC ?

Post by Ghrey » Wed May 21, 2008 1:30 am

I have been thinking. the real issue here is not the CC shape, it is the coaxial design. For the time being I will see if I can build a working coaxial pulse jet, and worry about combustion chamber shape tuning later.

I am thinking this means pipe. It is easy and I have a considerable quantity on hand.

Jutte and Bruno I did not mean to sound disinterested, I am interested in any source of parts. I was just trying to stay on subject, silly considering I was the source of the diversion in the first place. The torus will have to wait in any event. The design is still not at the point where I would even consider an attempt at a build. I did manage to fix one problem last night, by borrowing from argus.

I have a conundrum now, New thread for coaxial, or post progress ( or congress ) here.

Hmmmmm...

Ghrey
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Re: Spherical CC ?

Post by Mike Everman » Wed May 21, 2008 2:21 pm

ha ha, keep the congress to yourself... ;-)
I'd start a new thread. just two cents from the guy behind the curtain.
Mike
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