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Registered Member #2939
Joined: Fri Jun 25 2010, 04:25AM
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Posts: 615
Ready for the math?
I think you should also decide whether you are building a coal fired MHD generator or a coal fired still. Don't try to do both at once- that's probably going to result in poor performance on both counts.
Registered Member #2939
Joined: Fri Jun 25 2010, 04:25AM
Location:
Posts: 615
Hold on a second : where are you putting the 1-2 torr? Is it down stream of the coal furnace exit? If so you are going to need a f**king huge pump to maintain that pressure, given the likely mass flow. As an example my Edwards vacuum pump runs on a 1/2 Hp motor and takes roughly 30 seconds to evacuate a sealed bell jar with a volume of around 3 litres. Not fast.
Registered Member #2939
Joined: Fri Jun 25 2010, 04:25AM
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Posts: 615
It looks like you've drawn a venturi, and you are back to the same problem of needing an enormous high speed mass flow to achieve your desired pressure and pumping rate. Seriously: ditch the MHD and go with a turbine, maybe Tesla's bladeless design if you want to do something interesting. The MHD thing is a research project all by itself. I'm not trying to rain on your parade, but sometimes a little pragmatism is called for.
Registered Member #30
Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706
If you're reading 18V across the 1 ohm resistor, then 18A is flowing through it. The same 18A must be flowing in the 2.7k resistor, which would be dissipating 875kW and have 28 million volts across it.
Since you're plainly still alive and your house hasn't burnt to the ground, I conclude that you made some sort of mistake in your setup or measurements. Maybe it's really a 1k ohm resistor?
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Coal furnace, and pressure
