Is There an Optimal Size for Magrid Casings?

Discuss the technical details of an "open source" community-driven design of a polywell reactor.

Moderators: tonybarry, MSimon

MSimon
Posts: 14331
Joined: Mon Jul 16, 2007 7:37 pm
Location: Rockford, Illinois
Contact:

Postby MSimon » Fri Mar 13, 2009 3:13 pm


Billy Catringer
Posts: 221
Joined: Mon Feb 02, 2009 2:32 pm
Location: Texas
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Postby Billy Catringer » Fri Mar 13, 2009 4:16 pm


tombo
Posts: 334
Joined: Fri May 09, 2008 1:10 am
Location: Washington USA
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Postby tombo » Sat Mar 14, 2009 5:59 am

-Tom Boydston-
"If we knew what we were doing, it wouldn’t be called research, would it?" ~Albert Einstein

93143
Posts: 1131
Joined: Fri Oct 19, 2007 7:51 pm
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Postby 93143 » Sat Mar 14, 2009 7:01 am


KitemanSA
Posts: 6114
Joined: Sun Sep 28, 2008 3:05 pm
Location: OlyPen WA
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Postby KitemanSA » Sat Mar 14, 2009 1:42 pm


KitemanSA
Posts: 6114
Joined: Sun Sep 28, 2008 3:05 pm
Location: OlyPen WA
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Postby KitemanSA » Sat Mar 14, 2009 2:00 pm

Last edited by KitemanSA on Sat Mar 14, 2009 7:59 pm, edited 1 time in total.

Billy Catringer
Posts: 221
Joined: Mon Feb 02, 2009 2:32 pm
Location: Texas
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Postby Billy Catringer » Sat Mar 14, 2009 5:19 pm

Last edited by Billy Catringer on Sat Mar 14, 2009 7:14 pm, edited 1 time in total.

MSimon
Posts: 14331
Joined: Mon Jul 16, 2007 7:37 pm
Location: Rockford, Illinois
Contact:

Postby MSimon » Sat Mar 14, 2009 5:40 pm


KitemanSA
Posts: 6114
Joined: Sun Sep 28, 2008 3:05 pm
Location: OlyPen WA
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Postby KitemanSA » Sat Mar 14, 2009 8:17 pm


Billy Catringer
Posts: 221
Joined: Mon Feb 02, 2009 2:32 pm
Location: Texas
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Postby Billy Catringer » Sat Mar 14, 2009 8:49 pm


MSimon
Posts: 14331
Joined: Mon Jul 16, 2007 7:37 pm
Location: Rockford, Illinois
Contact:

Postby MSimon » Sun Mar 15, 2009 4:12 am


MSimon
Posts: 14331
Joined: Mon Jul 16, 2007 7:37 pm
Location: Rockford, Illinois
Contact:

Postby MSimon » Sun Mar 15, 2009 4:17 am


tombo
Posts: 334
Joined: Fri May 09, 2008 1:10 am
Location: Washington USA
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Postby tombo » Sun Mar 15, 2009 7:00 am

Here is the square planform truncube with the legs moved out of the funny cusp area.
Image


Then I started to try to calculate the loads on the coil.
I started with Indrek’s equation at http://www.mare.ee/indrek/ephi/force/ but quickly discovered that he solved the hard part numerically for only 3 configurations and that his maximum radius was 1 meter and we are modeling 2 meter radius..
Then I slowly discovered that I could not extrapolate to 2 meters with any confidence. (I tried using excel’s multiple regression tool and found the resulting formula to be so sensitive to the coil spacing that it actually gave negative force predictions for some quite reasonable coil spacings.) This was not surprising given that the integrations he did must be quite non-linear.
So, I started trying to get my own handle on the force instead of using his black box.
I need an approximate model that is simple enough for me to solve.
To calculate (estimate) the forces on the bottom coil (Antarctica) I chose to substitute 2 concentric coils (tropic of cancer and tropic of capricorn) for the 4 coils on edge by reconnecting the corners at the equator (in my imagination) then including the top (arctic circle) as a third coil. The diameter is the one that will give the same area as the square coil. The spacing is some kind of average between the min and max of the actual coil.

BUT I stumbled over a problem: The load is not evenly distributed along the beam (of the coil supported by the legs).
The distance between the coil and the adjacent coil at the corner is 0.5 meter or less and in the middle it is 2 meters. Since the effect varies as 1/R the force varies by a factor of 8 or so.
This means that THE LEGS CANNOT BE ANYWHERE EXCEPT VERY CLOSE TO THE CORNERS for structural stress reasons. (I apologize for shouting but this is an important point.)
-Tom Boydston-

"If we knew what we were doing, it wouldn’t be called research, would it?" ~Albert Einstein

tombo
Posts: 334
Joined: Fri May 09, 2008 1:10 am
Location: Washington USA
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Postby tombo » Sun Mar 15, 2009 7:12 am

Ethylene glycol automotive antifreeze for both the water jackets can be used from 120C (higher at 15 psi) down to -40C = 233K which is only 156K above 77K which is not a huge temp difference. It is small enough in my mind to allow use of solid insulators. If sludge is a problem then just add filters to take out the sludge. That should work long enough for a proof of concept machine. It’s cheap, it’s safe (as long as you don’t drink it) and it has a high heat capacity.

I found a formula for B at the center of a square 1 turn coil B=(sqrt(2)*u0*I)/(pi*(sideofsquare/2))
From:
It is a higher field than for a circular one which reduces our max current and therefore forces.

Here is an interesting point about designing Bitter Coils:
“high magnetic fields” by Fritz Herlach, Noboru Miura says about Bitter coils: ”… properly subdividing a thick coil into a few concentric coils is of great advantage to the stress management.” It also refers to polyhelix & poly bitter magnets which I will look up sometime. But for now I want to stay focused on stresses.
-Tom Boydston-

"If we knew what we were doing, it wouldn’t be called research, would it?" ~Albert Einstein

KitemanSA
Posts: 6114
Joined: Sun Sep 28, 2008 3:05 pm
Location: OlyPen WA
[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Postby KitemanSA » Sun Mar 15, 2009 3:08 pm



[phpBB Debug] PHP Warning: in file [ROOT]/vendor/twig/twig/lib/Twig/Extension/Core.php on line 1236: count(): Parameter must be an array or an object that implements Countable

Return to “Design”

Who is online

Users browsing this forum: No registered users and 2 guests