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The heart of the 900 MHz magnetic resonance instrument is a superconducting magnet with a field strength of 21 Tesla,
Heat exchangers
Too hard, ok, easyer now?MSimon wrote:
Where do I put the at sign?
eerin at xylogas.
fi
I read some:
viewtopic.php?t=66&highlight=permanent+magnet
I see now it is posible to magnetize permanet magnet ring correctly. But correctly magnetized permanent magnet field lines keep inside magnet material and don't come out. Such device look like not magnetized.
In magnetazion process field lines that are inside permanent magnet freeze other field vanishes when magnetazion device off. Because correct field is circular, they are imposible to see outside.
only current is posible to make correct field, magnetic energy is stored in vacuum near magnet and magnetic field needs current to stay. it is like moving train. If try switch current off, field keeps current runnig until its energy is consumed -> volts go high until something break.
Ok, but if we have coil of normal copper and same coil is coupled with HTS bulk ring.
What happens when we put current to normal coil and turn it off?
First SC coil make repellion magnet field so reverse current induses it. But what happens when we switch off current?
Things come more complicated because induction depends field rising speed.
I try to ask how induze high teslas to bulk SC ring? Have anybody ideas dos it work or not?
Thousands of small energy pulses, and because all thigs are posible to reverse, how cancel SC field? Throtling posible?
</ Eerin>
eros,
The guys at Polywell are pretty smart. I guarantee you that if permanent magnets would work they would be using them esp. for experiments.
They won't work.
In fact Bussard did use them in one of his experimental versions. You can see the burn marks on the faces. The problem is that the field lines enter solid material. It is the nature of the beast. There is no shape that will keep the field lines from entering solid material. Draw a diagram.
Or look up the previous discussion.
The guys at Polywell are pretty smart. I guarantee you that if permanent magnets would work they would be using them esp. for experiments.
They won't work.
In fact Bussard did use them in one of his experimental versions. You can see the burn marks on the faces. The problem is that the field lines enter solid material. It is the nature of the beast. There is no shape that will keep the field lines from entering solid material. Draw a diagram.
Or look up the previous discussion.
Engineering is the art of making what you want from what you can get at a profit.
Helically wound?tombo wrote:I can't visualize your micro-channel heat exchanger. Gap-wound spiral insulator?
Take a long ribbon of conductor. Wrap two strings around and around it all the way along its length, kind of like the handle of a tennis racket. Remove one string, affix the other. Now, as you roll the ribbon onto the mandrel, the strings on the opposing faces create a cross-hatched labyrinth between the two layers of ribbon.
Coolant applied to one edge of the stack-up of ribbons will flow thru the cross-hatch of insulation (the string) which makes up the micro-channels on the plate.
I suppose just having cross-cut grooves in the insulation on one face of the ribbon might suffice, but the cross-hatch improves the turbulence and thus (usually) the heat transfer.