Comments on: Heat Shield

By: FAMULUS

FAMULUS — Thu, 03 Dec 2009 18:24:43 +0000

I saved up money from ruby on rails consulting. I have a few months of overhead runway left. But I will need some fresh money soon. I am building a fundraiser at http://www.kickstarter.com/

We are working on the video. Trying to launch this ASAP. Incidentally, a smaller fusor project won funding this way:

http://www.kickstarter.com/projects/jacob/fusion-in-a-bubblegum-machine

By: Wouter

Wouter — Thu, 03 Dec 2009 18:13:59 +0000

I’m not saying “don’t pursue a SC polywell”, I’m saying don’t focus on it NOW/YET. I fully agree with your last paragraph, but I see a pulsed device as a “checkpoint” for many of your other systems and operations.

But it is of course 100% your own call, so I wish you good luck on your chosen path. I’ll be reading to see if you’ll make it!

BTW, it’s probably none of my business, so feel free to not answer the following question, but how do you finance this project? Savings? As far as I can tell, you have no significant source of income. Without going into details about your finances, could you roughly indicate how long the current rate of development is sustainable for you? Are you going to look for outside investments/grants?

Cheers,
Wouter

By: M. Simon

M. Simon — Thu, 03 Dec 2009 15:41:15 +0000

I have worked out LN2 cooling for copper coils for a machine similar to WB-6. 10KW per coil IIRC. It was doable. I can send you the spread sheet if you like. e-mail me. The heat capacity of LN2 is built in.

Maximum pressure was in the 100 to 150 psi range. You wouldn’t need as much pressure if you kept the LN2 below 77K. Ten or twenty psi might be enough to prevent boiling at hot spots.

By: M. Simon

M. Simon — Thu, 03 Dec 2009 15:30:18 +0000

And Fluorinert minimum temperature is 120K – far too warm.

By: M. Simon

M. Simon — Thu, 03 Dec 2009 15:23:32 +0000

Fluorinert is ridiculously expensive. And you still have to cool it. And pump it. Pumping LN2 is not a bad way to get rid of modest amounts of heat. And its specific heat is not too bad.

If you pull a vacuum on LN2 it will cool. You can get it down to 63K. Which means a reasonable temp is 65K. That gives you a 10C delta T. From the specific heat vs power to absorb you can figure the flow rate. Also look at the equilibrium temperature vs pressure.

If you are going to a channel type system (vs pipes in pipes) pumping LN2 is your only option. LN2 will freeze the water. And parts of the shell will be too hot (far above 77K)

By: ike

ike — Wed, 02 Dec 2009 08:35:04 +0000

apparently they tend to get struck by lots of electrons when they’re that deep inside,seems like you have to move them out of the way

By: ike

ike — Wed, 02 Dec 2009 08:33:28 +0000

not to mention that the heat load most probably won’t be that big if you include that fancy heat shield.

By: ike

ike — Wed, 02 Dec 2009 08:32:42 +0000

but that means you’ll need two cooling circuits, complicating the whole a lot more than just pumping the nitrogen faster. any shortcomings like low heat capacity can be compensated by pumping stronger. plus, i could imagine that the hull of the grid should hug the coils as closely as possible to limit surface area electrons can impinge on.

By: FAMULUS

FAMULUS — Wed, 02 Dec 2009 03:55:35 +0000

what about them?

By: FAMULUS

FAMULUS — Wed, 02 Dec 2009 03:53:48 +0000

From what I understand… liquid nitrogen, although very cold, it not a good medium for gross heat removal. I’m imagining using something like Fluorinert:

http://en.wikipedia.org/wiki/Fluorinert