Recovery.Gov Project Tracker

D Tibbets · Post by **D Tibbets** » Tue Nov 23, 2010 5:56 pm

That is a lot of liquid nitrogen. I wonder how many runs could be completed with that. I have no idea what the flow rate of the liquid nitrogen would need to be to keep the magnets near their cold starting temperatures. Lets see. assume there is ~ twice the volume available for windings. Assume there are are ~ 1600 windings (WB6s' 200 windings x twice the volume x 8 times the conductivity / 2 because the wires are twice as long per winding) in WB8. This would be ~ a 50% packing fraction. The rest is space for the liquid nitrogen plumbing. This would give the advertised magnetic field strength at the same current as WB6 (~2000 Amps?). Presumably with sufficient coolant flow the initial temperature could be maintained indefinitely.
How much liquid nitrogen per second would be needed to carry away this 2000A of heating while preventing more than eg: 10 degree C elevation of temperature?

Even without continuous cooling after the magnets have been initially cooled down, I speculate that the initial 5-8 fold improvement in conductivity would effectively increase the thermal mass to Ohmic heating ratio by a similar amount. So, if the WB6 magnets could be run for 1 second, WB8 might allow the magnets to run for 3-4 seconds. The average temperature would be in the middle of the range between liquid nitrogen temperatures and the cutoff temperature. This would relax the the timing constraints. If the power supply and other equipment are sufficient, the WB 8 may be capable of operating steady state for a few seconds. Also, the magnet on time may be even greater, as the liquid nitrogen plumbing could be smaller, and the packing fraction for the windings could be greater (more windings, thus less Amps and resultant heating for the same magnetic field strength).

Other issues would be that cool down time between tests would still be much less than WB6. The thermal shock (? the total delta T would be greater, but the rate of change would be less for most of the cycle) of each test would be greater and this might limit the lifetime of the machine.

Dan Tibbets

bennmann · Post by **bennmann** » Tue Dec 21, 2010 10:00 pm

Christmas update unlikely, guess I have to wait until April - UNLESS Nebel speaks to a member of the press like he did with 7.

Waiting is difficult.

Ivy Matt · Post by **Ivy Matt** » Tue Dec 21, 2010 11:28 pm

The next quarterly report is supposed to be posted on Recovery.gov on January 30, 2011.

davaguco · Post by **davaguco** » Fri Dec 24, 2010 8:33 am

Thanks for the reply. It will be hard to wait until january 30th.

ladajo · Post by **ladajo** » Fri Dec 24, 2010 3:53 pm

My New Year's prediction:
"Testing in progress".

rjaypeters · Post by **rjaypeters** » Fri Dec 24, 2010 8:33 pm

My New Year's Prediction:

"No report."

I'd rather see yours come true.

Giorgio · Post by **Giorgio** » Fri Dec 24, 2010 11:52 pm

Sadly, both replies will give us the same amount of informations. None.

June 2011 is the first hope date for any valuable news on my agenda.

Ivy Matt · Post by **Ivy Matt** » Sat Dec 25, 2010 3:21 am

My vote is for: WB8 is even more fully under construction, and even more progress made on theoretical modeling of the Polywell. Two more physicist jobs created or saved. However, primary focus has been relocation of personnel and chamber.

ladajo · Post by **ladajo** » Sat Dec 25, 2010 5:45 pm

And let's not forget that "construction and installation of the industrial capacity freeze-pop unit is well in progress and has created two new positions for sales associates and one marketing engineer."

rjaypeters · Post by **rjaypeters** » Sat Dec 25, 2010 10:01 pm

ladajo, those are two seemingly incompatible predictions.

Are we in a race to see who has the most pessimistic prediction? The worse we go the happier we will probably be when reality isn't so bad. See: Ben Franklin about expecting the worst and hoping for the best.

ladajo · Post by **ladajo** » Sun Dec 26, 2010 5:58 am

In truth, the proof in the pudding will be the funding for WB8.1. I do not expect much in details from WB8 until the 8.1 money paper flies which we will see.
They can not hide the release, only obscure it some, however, all gov. monies sourced to EMC are visible, it is just a matter of looking for it.

chrismb · Post by **chrismb** » Sun Dec 26, 2010 10:35 am

D Tibbets wrote:That is a lot of liquid nitrogen. I wonder how many runs could be completed with that. I have no idea what the flow rate of the liquid nitrogen would need to be to keep the magnets near their cold starting temperatures.

Are they running supercon magnets? I didn't think they were. More likely the LN2 is for cryogenic vac pumps, no?

chrismb · Post by **chrismb** » Sun Dec 26, 2010 10:36 am

ladajo wrote: "construction and installation of the industrial capacity freeze-pop unit is well in progress ...."

Is there a translation of 'freeze-pop'? Are they using the excess LN2 for making ice lollies?

chrismb · Post by **chrismb** » Sun Dec 26, 2010 10:43 am

rjaypeters wrote:Are we in a race to see who has the most pessimistic prediction?

I would be disappointed if I had not already lapped that finish line several times.

This project will prove, beyond any possible doubt, that if you spend 40 million bucks on feeding high voltage into evacuated boxes that you can get some glowing plasma in them.

If there are any better outcomes than this alone, then I promise to eat my 8oz steak.

rjaypeters · Post by **rjaypeters** » Sun Dec 26, 2010 1:25 pm

Yes, you win the contest!

I would be happy for you to eat your 8oz steak.